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- Опубликовано: 15 окт 2024
- We will test and create a ranking of the different charger modules of video #154 to help you to choose the right ones and save the money for the bad ones…
The focus of this series is to build a reliable power supply for small devices like an Arduino or a ESP8266 for the whole year round.
We will:
Test different solar charger technologies under different conditions and separate the good from the bad
Check out, if there are differences between linear and switching chargers
Find out, how much sun the chargers and the panels need to start charging.
And we will check the efficiency of the different concepts
Links:
CN3791 Solar Charger s.click.aliexpr...
BQ24650 s.click.aliexpr...
XL6009 Buck-Boost Converter bit.ly/2hTF7cb
LM2596 Buck Converter bit.ly/2vrq9Pl
CN3065 Solar Charger s.click.aliexpr...
MCP73871 Solar-Lipo-Charger s.click.aliexpr...
TP4056 Li-Po Charger unprotected bit.ly/2w63EzH
TP4056 Li-Po Charger protected bit.ly/2vXYMxP
DPS5005 Communication bit.ly/2vWyISN
Solar panels: s.click.aliexpr...
DPS Shop on Aliexpress s.click.aliexpr...
Power Meter: bit.ly/2x5rVEm
Electronic Load s.click.aliexpr...
UT383 Mini Lux Light Meter goo.gl/MBrsyt
Supporting Material and Blog Page: www.sensorsiot.org
Github: www.github.com...
If you want to support the channel and buy from Banggood use this link to start your shopping: bit.ly/2jAQEf4 (no additional charges for you)
Official Wemos Store: s.click.aliexpr...
/ sensorsiot
/ spiessa
www.instructab...
Please do not try to Email me or invite me on LinkedIn. These communication channels are reserved for my main job
Thank you for this follow up. After last weeks video I also tested a modified TP4056 charger by adding a 10K potmeter in series with the 1.2K resistor, allowing me to vary the charge current from about 100mA to 1A. Unfortunately the sun was too hazy here and my testing panel delivered insufficient current for a good test. Good to see your tests were succesful and thank you for your thoroughness to publish these extensive tests.
Please post your results.
Your channel keeps on giving! I've been following your years, and I am regularly finding myself here for different topics!
I'm glad you think so!
Outstanding systematic study and conclusions !
Thank you Andreas ! 👍👍
You are welcome!
Great video again! I have used the same bq24650 board with a 100w solar panel with the batteries in 3s configuration. This allows you to capture the shortest blinks of the sun with this tiny board, a 100w solar panel will still put out 3 to 8 watts for a few hours on the very worst of winter days which means you do not need that much storage.
Thanks for this comment. This is what I hoped for. I have a 30-watt panel and want to try a similar setup.
Congrats on the 40k subscribers! Seems only yesterday I was congratulating you on reaching 20k. 50k will be here in no time. Keep up the great work!
You were one of my first subscribers and still here. Thank you!
We will see how it goes in the future. 40k is quite a lot if I remember, that it was planned as a test of social media for me.
A lot of thanks for your systematic approach.
Please continue this investigation.
This series should be a "must see" for all those people rushing in with their optimistic "i will put my $XYZ on solar, look what i ordered from ebay".
My first question for them is always: Do you need to use it in the end or is it just about the learning experience and how to cope with failure and write off? (but off yourse i am a nasty person...)
I am an (optimistic) engineer. So, I test usually first...
Have been following your most informative videos for a few weeks now, especially with my interest to build a floating pool water temperature sensing project.
I attempted to use the ESP32 but failed dozen of attempts to upload IDE sketch then opted for 8266 with no issues.
I have procured a "6V" 4.5W panel with hopes to keep 1 or 2 18650 to power the 8266 and DS18B20 temp sensor, charged overnight. Plenty of sun in the sunshine state, so no issues with that.
My main concern is the charger selection, now that you have highlighted many choices, your recommendation for such project.
Thanks for all the great content.
Good luck that you will be able to upload an ESP32. I do this all the time and it should work.
Thank you for putting this video together, it's very helpful for me as I am trying to power my microcontroller with a small solar panel. Your videos are packed with info and insights. Keep making great content.
Glad you liked it!
Hi Andreas
Great video
I did some independent testing yesterday, as I didn't know you had already done a video about this a few months ago.
My tests were just using one small panel ("5V 1W" which is actually 5V 0.75W), into a real lipo cell, under a variety of conditions
I only tried 3 main combinations of charging configuration:
Direct connection with voltage clam using a Zener (or a string of diodes in series)
Using a TP4056 module (mine did not have protection)
Using the LM2596 DC to DC converter (the same one as you used)
I am pleased to say that I came to very similar conclusions as you did.
For me the TP4056 module was the best option because it gave the same charge current as the direct connection, but had the added benefit of providing better battery health management.
I did not see in the video what value for charge resistance you used on the TP4056, I found that for my panel (150mA output) that approx 8k seemed to deliver the best current under full or moderate sunlight.
If the resistor is too low ( which makes the charge current too high), I could hear the TP4056 start to squeal, which I presume if because its crashing the input voltage from the panel by applying too much load.
Strangely the same value 8K, seemed to be the optimum under all moderate light conditions e.g direct sunlight at different angles.
As in your test, ambient light does not seem to yield any useful charge current.
I have now ordered the CN3791 module, but using the CN3791 attached to a small panel, would not actually be cost effective. Because it better to pay $3 extra on and get 3 more "1W" panels, than to retrieve an extra 20% of the 0.75W panel (i.e 0.15W )
I've done a rather rambling writeup on by blog.
www.rogerclark.net/lipo-battery-charging-from-a-1w-5v-solar-panel/
Thanks for your feedback. You are right, we did similar investigations. I used two different TP4056, one with the original and one with a variable resistor like you. I do not remember their values.
And I think you are right using a bigger solar panel is cheaper. Then, we just have to pay attention to the real sunny days where the voltage easily crosses the 4.2 volts at the battery. The TP4056 does exactly that.
I think your strategy is to plan for a lot of over capacity through the whole year. First an esp32 or 8266 has a sleep mode which can keep the consumption low for instance doing a connected weather station can have a measurement each minute.
Second it is possible to have several batteries in parallel.
The thing I miss here is if there is overvoltage protection in those charger and if we need to do something if we harvest too much energy.
Will there be undervoltage protection in the boost ?
Are you planning to use protected batteries ?
1. You find videos on this channel about ESP8266 and ESP32 deep sleep.2. So far I did not cover the part between the battery and the MCU board. I think it has to have under voltage protection.
Thank you very interesting btw. Especially the fact that some have current draw with no sun. Maybe a bistable relay to stop the current draw might be better because I see the current as fairly low and the sun level might not change fast.
A MOSFET would maybe be a simpler solution. It can behave like a diode with a very low forward voltage
You are very methodical and thorough - excellent video series! Thank you.
You are welcome!
Hi Andreas I recently checked the MCP module you used and read through the datasheet.
What you observed is exactly what the datasheet says, 500mA is the default maximum current for the solar input.
This chip is build to get power from solar or usb or both at the same time and has multiple resistors to set the charge current, it seems to be possible to charge with up to 1.3A when you set the resistors correctly and supply the input power to both charge Inputs.
Thanks for the info!
Great series, with useful data. One small thing I wondered about - is there a difference in back-current if there is an unilluminated solar panel still connected to the charger module (eg: solar panel at night time), versus open circuit simulated by (ie: disconnecting your programmable voltage source).
Background: (1) solar panels connected directly to a battery without charger or diode will discharge the battery at night so apparently there is a resistive load, and (2) voltage regulators vary considerably in what they do when unpowered, depending on the impedances connected to their other terminals. So a solar panel connected to the inputs of a charger/regulator input MIGHT have higher back currents, than the charger/regulator alone. It would be nice to establish that detail (comparison) before wrapping up this testing and moving to other approaches.
I imagine it would be pretty easy to test with your setup.
Thanks for the hint. I have to do this test myself. I should have shortened the battery connections for my test...
Great pair of videos Andreas, thank you. I have just been trying the TP5100 which I bought last year. In full sun, it's efficiency is close to 100% using my 550mA 6V panel, but at much less than full sun, it really doesn't work and I am seeing pulses of current as though it is continuously restarting.
Based on your findings I think I will swap to a TP4056, but we should note that it would need a zener diode to keep the solar panel input Voltage below about 8v (which you might see if the battery was already fully charged).
I had no TP500/TP5100 here, but I ordered some of them. Maybe I will do a quick test in a Mailbag.
This was highly interesting and informative, Andreas. Thanks.
The basic takeaway is that solar power is not only fickle, it is all but a spurious resource for practical use and so unpredictable as to be essentially useless. That said, it is still a lure for people attempting to harness it because, in a direct sense, it has tremendous potential. Converting light energy may not be as good as converting heat energy is another assumption from your demonstration, although, I am not exactly sure how that might be accomplished efficiently. I have myself been keen on designing ways to harness the abundance of solar energy, and always, my ideas come up against the "Complexity Wall". One item that hardened me against solar is not that the sun only shines at best 40% in useful quantity, it is really only available for use when directly overhead (within a narrow range, of just a few hours around high noon) . Just because we can see it a few hours after dawn and before dusk is no use for energy harvesting at all. so, we have to "make our hay while the sun shines" usefully, which means huge collection areas and the control of large current into massive storage units to quickly gather in all we can while the useful energy is available over such short periods. This leads us into the area of impracticality. That is: Cost of solar v 'Something other than solar".
Now, I understand we are talking about small applications here. But, when I started watching this series on solar, I was delighted because I know with electrical use, size is not a difference. An amp or a volt is the same regardless of size. The only difference being cost. So, your experiments are completely viable and accurate for any size solar application. And, in the end, you came to the very same conclusions I did some years ago working with whole-house solar systems. It is something that can be accomplished, God knows, we use it here in Las Vegas where we have abundant sun. And still, it is sporadic in use and does not last very long term in a practical engineering sense or economic sense. There should be another strategy for use of it.
Thanks again for a most excellent video series. You truly are a treasure.
I tried to provide the basic formulas. You decide if it fits your needs. Of course, fuel is a better and more powerful energy source. But it also has its disadvantages...
Excellent series - now that I've finally tapped into IoT devices with the ESP8266/MQTT, it's very valuable info. My application is the typical thermometer/hygrometer running with an SHT21 compatible sensor, drawing only a few micro-amperes in Deep Sleep on two AA's. The sensor is accurate down to 2.1 volts Vcc; and an update interval of two minutes, plus a few Wifi tricks (static IP, intelligent reconnecting relying on auto-reconnect on power-up) help it to survive on around 0.6ma average, with an on-time of only around a second. A solar cell charging a lipo, or even a couple of AA NiMh cells should in theory make it work forever.
Interesting project. Thanks for sharing
So you finally sorted out your BQ24650 setup, nice! Happy with the result and the good thing about this module is you can push it up to 10A charging current with a little modification and proper cooling but that's a different story or i can say different application.
Each of the boards has its advantages and disadvantages and therefore its purpose...
Nice video series about solar chargers. Would be interesting to see options for LiFePo4 battery.
You are right, these batteries are more common now. Maybe I will do an update...
Again, many thanks Andreas. TP4056 has revealed that my panel is too small. Input voltage drops as sunlight increases. The TP4056 charges with more power but pulls the panel far below an efficient voltage. It charges my 500mA LiPo but very slowly. For topping up a low power, deep sleeping LoRa node with just a few a few daily wake-up and transmits some tuning and a bit more panel area may work. TP4056 does try to charge in ambient (not full sun) light but 10-20mA only.
+Garry Keogh Maybe you try the trick with the variable resistor? Or you change to another board
Andreas Spiess I agree. More work to do Andreas but low panel Watt output is constraining the TP4056, even with 4k7 resistor. I will try more tuning. Superb guidance via your videos, thank you again!
:-)
Nice series: thanks for doing this.
You should consider re-testing some of these though: I am not sure if they were all used on the same basis.
MCP73871: This was not set-up properly. It was run in default mode where output current is limited at 500mA. You need to vary the on-board resistance to allow what you need. The data sheet says this, as do the notes on the AliExpress link you supplied. This will completely revise the low efficiency your test data shows. You saw that input voltage was 6.5 Volts, so at a higher current it would probably be the most efficient of your samples.
And in fact it was ordered from China, and the chip might not actually be a real MCP73871: you might consider getting a system from a more reliable source (like SparkFun, Digikey etc).
In fact it looks like this was your case: if you read the MCP73871 data-sheet (Section 4.1), it says that when the battery voltage is >100 mV than supply voltage (from the panel) then the device is placed in shut-down mode, and battery reverse current shall be less than 2 uAmp. Since you measured 60 uAmp, something seems wrong. Either in your set-up, testing data or it wasn't a real MCP73871 chip.
BQ24650: The system you tested doesn't use this chip (Texas Instruments) but has a clone CN3722. They do admit that. Maybe you should change the labels to reflect that? And perhaps buy a real BQ24650 to test.
In fact there is another solar power chip made by Consonance: CN3795 see www.consonance-elec.com/product-E-Solar%20Charge%20Management.html
Maybe the CN3722 is not the best choice for your application.
In fact there's a good head-to-head comparison of BQ24650 vs CN3722: ruclips.net/video/ROOU8c9TgM0/видео.html
He says CN3722 is better for < 2A, and BG24650 for > 2A
General issue with back-current: This can be controlled according to how you set-up the system. There are several ways, but you can add a Schottkey diode with a capacitor at the outlet to the battery to prevent this, although efficiency drops a little bit. And in some cases you wouldn't do it, because the solar panel itself might have a Schottky diode: no point in adding two.
Can you show us a schematic for each device you used, as well as the solar panel, to see what has been used?
My goal was to compare which boards are available on the (Chinese) market because most of my viewers source from there. Outside the US it is not cheap to buy from there and I have viewers in 250 countries. And I think, I got most of them or at least one of its kind.
I see: well maybe you should make that more clear in your title, or at least in the description. The title says "The Five Best", and that's perhaps not correct if you limit yourself to China, and Chinese cloners. I'm not trying to be nasty, but I for one am quite willing to pay a bit more if its justified.
In any case, are you sure that this makes sense? Is this a good item to penny pinch on?
You tested at full sunlight but these sorts of systems need to work under poor light, and for perhaps limited sunlight hours. With a fixed tilt. It seems to me that the best system would be one that can function there: you did one low light test and none of the ones you chose worked. Perhaps you didn't have the best ones, or they weren't configured optimally.
I think you should test something that you can really believe it is what is says it is, and then if it's good, you can see if the Chinese sourced item is as good. If the actual US-sourced systems don't perform then no need to search for a cheaper Chinese version.
Like you didn't actually test a BQ24650, it was a CN3722. And I also think the supposed MCP73871 was a clone: as I explained, it didn't give the correct back current behaviour. And also as explained it wasn't configured correctly: its current was being throttled back.
And in any case, you need to re-test a few because they weren't set up correctly, and unfortunately you have misleading results.
Good luck with your testing, I hope you can get some accurate results.
I for one have to say that the practical balance achieved by these product reviews gets me what I need and is great entertainment as well. I wouldn't have the time, or attention span for a academic deep dive. Sounds like you are not getting what you need here. Perhaps it is time to do your own vid. I reviewed the video you linked above. That video had no narration nor any supporting written material it was pretty useless for me. I wish you well in your quest.
Andreas, please use the TP4056 with a shunt regulator in parallel to the input. The maximum supply voltage of the TP4056 is 8V. The solar panel voltage will increase when the battery is full and fry the module.
+Bernd Godry The open voltage of my panel was below 8v. But you are right. I should have mentioned this fact!
Hello, could you be more specific please what regulator to use and how? Thank you.
I am building the beginnings of a solar powered outdoor weather station. I am using a 6v 120x60mm solar panel with a short circuit output of 180ma. A CN3065 to charge a 1000ma Li-Ion and using a ATMEGA328 and RFM69. Sensors are a DS18B20 to measure internal temperature of unit, BME280 for temperature, humidity and pressure. TLS2561 for ambiant light and VEML6070 for UV. Putting all things to sleep when not being used it the best way to reduce comsumption, which inturn reduces battery capacity and solar requirements. I believe that based on other devices I have built that I can run this completely of solar year round in the north of England.
Maybe I share my work with you one day.
Sounds very interesing! How do you switch the sensors and the RFM69 completely off?
Andreas Spiess I find putting them to sleep is more effective than any sort of circuit.
So, all sensors have a sleep mode?
Andreas Spiess Yes. Either a sleep mode or low power standby/idle mode when not actively reading. I select only components that state this in their datasheets before purchasing.
+ Russ You are right. And maybe we can replace the battery with a small solar panel and a super cap to get it completely maintenance free for areas where we do not have easy access or where we do not want to think about it or where we need a little more wake time (and the battery would last less than a year).
As always, very informative.
Maybe the goal, being completely independent and running on solar energy forever is a bit too ambitious, specially if you live in Switzerland. I would consider a small solar panel as a way to be independent during summer and maybe spring and autumn, but during winter I might still need to change the battery once or twice if it is a very bad winter.
I think that would be pretty good still. Yes, you will have to replace the battery during the year but without a solar panel you will for sure replace the battery multiple times.
Would that make sense?
I had now two different boxes running the whole winter and they survived. It depends a lot on power consumption, as I calculated in another video.
What about using an adafruit feather with built in charger. Run the solar panel direct to 5v on feather. Let the internal regulator work and charge a 18650 battery. The internal regulator of the feather should handle the 6v from the solar panel.
Hi Andreas, thanks again for the great video!
I was disappointed when you mentioned that small solar panels were not feasible for controllers like the ESP8266 :(
Are you sure that is correct, because according to your first video about solar panels (#142) I made the following calculations:
In Belgium we get 1020Wh/m2/day in December, so calculating 15% solar panel efficiency and 66% charger efficiency, I should be able to get about 100Wh/m2/day, or 10.10mWh/cm2.
My ESP8266 project (my heating fuel tank level gauge) only uses very little because it measures only once per hour.
During measurement it consumes about 70mA and this lasts only 15 seconds the rest of the hour is spent in DeepSleep at about 0.20mA, I calculated this to a total of 40mWh per day.
So for this 40mWh I would only need a solar panel of 4cm2, which I ordered, today looks to be a good day, hopefully I can do some tests outside :)
+Alex Goris I always had the goal to use the ESP the year round. In winter, the calculation is quite different. But I am interested in your results
The calculations were based on solar irradiation in December, so they should be good for the winter. If the calculations are done on winter figures they should be fine for the rest of the year, no?
+Alex Goris Yes.
So I am testing with these two solar panels:
www.aliexpress.com/item/Mini-6V-12V-Solar-Panel-China-Solar-Power-Panel-System-DIY-Battery-Cell-Charger-Module-Portable/32746689273.html
One of 80*55mm (0.16W) and one of 53*30mm (0.15W)
I have a CN3791 adjusted with a 62K resistor to keep the panel voltage at 4.9V
And also a TP4056 with protection and standard resistor of 1.3K for 900mA charging current
I'm getting some strange results:
Small 0.15W panel:
With the CN3791 the charging current is around 12mA, panel voltage around 4.9V
With the TP4056 the charging current is around 18mA, panel voltage around 4.4V
Bigger 0.6W panel:
With the CN3791 the charging current is around 50mA, panel voltage around 4.9V
With the TP4056 the charging current is around 65mA, panel voltage around 4.2V
So it seems both panels are capable of delivering more current at 4.2/4.4V compared to 4.9V
I should try changing the resistor on the CN3791 to a trimpot to find the ideal voltage, and see if this CN3791 can become as efficient as the TP4056.
What I don't understand about the TP4056, is why is it not trying to charge the 900mA it is set to, and pulling down solar cell voltage too low in the process? It seems to keep one cell at 4.4V, the other at 4.2V, but I have no idea why...
So I added a trimpot to my CN3791, and tried finding the optimal voltage.
The optimal point seems to be @4.65V, but only added a couple of mA at the charging side.
So it seems even though the TP4056 pulls the solar panel voltage lower than 4.65V, it manages to get a better charging current out of them.
Also the 18mA charging current I measured, matches my calculations more or less, so it should be feasible for keeping an ESP8266 project with battery charged, if you only measure once every hour
Thanks a lot, Andreas, very useful!! Maybe it would be interesting to know the consumption when there are no solar radiation, as it would happen most of the time
You are right.
A great video. I hope you will give us a final circuit design when your series completes. Nice work!
The circuit is quite simple for the moment and as shown in the video...
Excellent video! I'm a little confused... it sounds like you are giving up on the smaller solar panel. I don't see why it can't work as long as you have a good battery, and you aren't running the ESP-8266 all the time. Your videos have already shown that the ESP can run on next to nothing as long as it is put to sleep for some period of time. Surly, you can make something useful with a small solar panel, and a good battery, and an ESP that only wakes once every 5 or 10 minutes. If the battery charge is low, it can wake less often. Having temperature, or moisture, or other data once every few minutes is still very valuable and often more than what is needed. For example, the rumen loggers I've coded run for years on a 9-volt battery, waking once every few minutes. The limiting factor is the shelf life of the battery.
+James Newton l do not give up on small panels. What I wanted to say was, that in winter, the small panels will probably not be able to power an ESP with some additional sensors. But of course, your energy calculation decides on the panel size, not me ;-)
Ah, yes, I understand now. Thank you. I'm really looking forward to seeing more in this series.
Really nice series that interests me and a lot of other people it seems. Not sure if you have a long term plan to power something at the end of the series. I suspect that you want to use a pi or so. Would be interesting to see the real world differences between the pi's and maybe undervolting and underclocking the core to get the minimum consumption.
Sunday mornings are awesome. Was that your son in the video??
+Luc Peeters 1. I only want to power small devices using deep sleep.
2. It is my young lab helper
HI - I have been able to use one 6 volt / 2 watt solar panel to charge 3x18650 in parallel (4.2v), which powers a temperature/humidity/light intensity/relay/door sensor for over a year now. TP4056, 328P-PU, NRLF2401+, DHT22.
Also, since January 2017, I have a ESP8266 (ESP-12E) running on 6x18650s in parallel using Deep Sleep with an external interrupt from DS3231 (RTC) to wake up to take a sensor reading then go back into Deep Sleep..... Battery voltage is still at 4.08 volts :)
+Michigan 18650 Powerwall Thanks for your feedback. Indeed, other communications like the NRF or LoRa are probably more suited to work with low power or solar.
Good video as always Andreas. I think the TP5000 should be a try. The key factor is the winter radiation levels. In summer I used to charge 3000mAh LiPo Battery with 2 piece of 6V solar panel and a TP5000 charger quite fast. The clouds has large effect on the time which is requires for the full charge. I would like to try in the winter what can I reach.
TP5000 are on order ;-) The winter stuff was part of the first video of the series. But, of course, you are right.
Really great experiments. Thanks for all of this Andreas, you really put a lot of work in your job. I will use protected one for future projects.
You are welcome!
Your tests and results are greatly appreciated
Thanks!
Mr.Andres i think you are wrongly mentioning the buck ic its LM2596 thats what you shown in the video . but you are mentioning it as LM9526 . excuse me if am wrong .
I do not think so.
Yet another great post on your series. Thank you Andreas😀
You are welcome! And have a nice Sunday.
Great work Andreas. I appreciate all the time you have invested in this project.
I am puzzled by the results for the BQ24650. It is supposed to be an efficient energy harvesting IC that can produce useful power even in low light conditions. I was about to purchase a module based on the LTC3588 which is another well regarded energy harvesting IC. After seeing your results it looks like I should instead just rely upon a cheap TP4056.
As regards the choice of device, the ATmega328 and ESP8266 / ESP32's all run at 3.3 volts (and lower) and that seems to be the sweet spot for reduced current.
I am looking forward to your tests with supercapacitors. I suspect that running them at 2.5 v (with protection) and feeding the voltage directly into low voltage CPU's will be the most efficient technique as it will avoid the need to convert voltages. Perhaps using solar cells producing 3 v or so will be the best option for them?
+Paul Robertson Interesting idea to play with the voltage. The ESP is only rated to 3.0 volts. So, I probably have to go to around 4-5 volts and use a LDO. Like that, I would be able to use more of the super caps capacity. It is a pity that the super caps are not rated up to 3.3 volts.
According to this research esp8266 is reliable at 2.5 volts -
forum.makehackvoid.com/t/esp8266-operating-voltage-range-and-sleep-current/286
Thanks for your link. I had similar experience, but only at room temperature. Somebody should maybe also do some tests in low and high temperature environments as this is very important for solar/outdoor projects
Hey Andreas, i know this video has been posted a long time ago. But i would like to add an advice. I use the MCP73871 that in in your test it's current output was fixed on 0.51A. That's because that board contain a resistor to do that current control with the objetive of do a slow charging on batteries. If you change that resistor you can reach higher output levels.
Thank you for the addition!
I used the 4056 and the system was very sensitive to the sun condition. The main problem is in the sunrise and sunset were the power path is open but the ESP8266 does not get enough power although the battery is fully charged, so it gets into instabilities in the early mornings and late afternoons. I Switched to MCP73871 and seems nice so far. Stable power all day. I might be paying for this stability with lower efficiency, but I have not checked yet.
It might be that the board that Andreas checked did not had good resistor configuration.... I will check the power in full sun and compare to the 4056...
Changing the output current with the resistor configuration and lowering the VCPP to be closer to 4v got me a very nice performance...
Hi Andreas, please keep up a good work! Being a subscriber for a year, I've watched and enjoyed almost all of your videos. I am little bit confused with a link you've provided for CN3791 module. I wanted to buy it, but description there says that the module is suitable for 12-18V. Is it a wrong link?
I think I made the remark in the former video that I had to change a resistor to adapt the MPP voltage to 5.4 volt
I believe the MC73871 did not perform well in your tests because the chip is programmed via an external resistor to charge at max 500 mA. This can be changed by varying the resistor, so possibly the efficiency of the charger could be improved in your results if the resistor had been changed. Anyways, great videos as always, thanks for what you do!
You are right. Back then I did not want to change the modules.
Andreas very nice work!, I have tried the CN3791 on my project, but I could not power my microcontroller in parallel with the battery because the MPPT would not have an output
Strange.
@@AndreasSpiessI have fixed that.That was a bad resistor on the board. Nevertheless my esp 32 takes about 150mA with the sensors that I am using, then my battery is draining quicker than the cn3791 can charge it.
Andreas, for the MCP based charge controller, try adding a 2K thru hole resistor to PROG in parallel with the 2K SMD if the holes are electrically in parallel or replace the PROG SMD 2K resistor with a 1K. This should get you 1A of charge current.
Thanks for this tip!
Correct, I was just going to say this. There is a good description of using it in the Adafruit sitelearn.adafruit.com/usb-dc-and-solar-lipoly-charger/using-the-charger?view=all#downloads
By varying the resistor, you can get from 50mA to 1.8Amps. (Current = 1000/resistor).
The default is 1 kOhm.
You can buy an Adafruit MCP73871 on Aliexpress: I'm not sure if it really uses the MCP chip though).
I'm guessing it does use the MCP given the design similarity and cost. I think the Adafruit one is a bit too expensive compared to other options. I have one, but it could be better for the price. I am now trying the Elecrow model which has an onboard boost converter with a USB A connector, which is more convenient for my application.
so are you using 18650 batteries with this config? I was tempted to use a USB power bank (as it would seem you get more mAh for your buck). But I don't know how to charge it from solar or power my ESP32 simultaneously. I want to build several esp32 water monitors using u/sonic and solar powered but i am a bit stuck on the solar side of the project.
By the way, my Voltage and current measurements were all made using the INA219 devices - they seem really well suited to this application and my whole board (Arduino pro mini, Nokia 5110 LCD, INA219 and BME280) only draws about 8mA.
The Arduino could easily go on a diet and lose its power LED and regulator, but in UK summer it is happily maintaining its power supply vertically behind a window facing South. The Arduino could also easily go to sleep, but my aim is to build a solar powered weather station using the Pro Mini and use an ESP8266 to push the data to a server and remote displays.
Obviously angling the panel has quite a lot of impact on the current output. I wonder if (for small panels) a simple pair of model control servos could steer the panel about and make good use of evening sun which would normally not be seen by the panel.
For this, the Arduino would need to know the time and use the library that calculates the bearing to the sun every half hour or so. My panel was producing about 250mA in the evening against 550mA at noon when angled towards the sun, but nothing usable otherwise.
gte24v, have u considered to have a solar tracker functioning independently? U might have it working every 30mins so energy is preserved and the overall efficiency is better off
misc luke - yes, this is what I am suggesting. The tracker itself can go to sleep except when needed and because the panel is small (200x200cm) it would not need much energy to move it around.
+gte24v A solar tracker is on my list...
Andreas Spiess - Excellent, I will look forward to that. I forget which library does all the calculations easily, but using that and a pair of model control servos would probably do the job. Plus there is an excuse to use the 3D printer! ;-)
I hope that I do not need any calculation. I am not sure how much current the servos need if they do not move. We will see...
Great video! Sheds some light on the issue.. by the way: what's the most efficient DC-DC converter to power a microprocessor (e.g. ESP32) from a LiPo?
This topic is still in my plans...
Hi Andreas,
Thanks a lot for this interesting review! I am planning to build a solar powered beehive scale controlled by an Arduino Uno and ordered a 12V/5W solar panel and a CN3791 regulator with 12V input voltage. Question: what kind of regulator, if any, would you use between battery and Arduino? I want to prevent the batteries from damage by excessive deload (2-3 Li hydride 3.7V, 5k mAh batteries). Would TP4056 be an option? What is the highest voltage that can be applied to the Arduino barrel power connector (would 3x3.7V in series be ok?)?
I am a total newby to the world of electronics and would highly appreciate your feedback.
Best wishes from Basel,
Christian
First I probably would use a pro mini. If you run it on 8MHz it should run from around 3 to 5 volts without a regulator. This would fit one or more Lipo cells. This fits also the CN3791 (it has a max output of 4.2 volts for one LiPo). So no additional voltage regulator is needed. The only thing you can consider is a low voltage protection. But this maybe could be done by the Arduino itself (measure the voltage and adjust sleep pattern if the voltage is too low)
If you want, you can visit me for a discussion. You should find out where I live and call me or write me an SMS
Hi Andreas,
Thank you so much for your helpful answers to my questions and for even offering to contact you for further discussion. I'll order the Arduino you suggested. Once all the parts have arrived, I'll start testing them. It would be great if I could ask you for further input once I start playing around. I saw your address in one of the videos and should be able to find out your phone number ;-)
In the meantime, I wish you all the best.
Kind regards,
Christian
P.s. should you have any questions regarding bees, please don't hesitate to contact me.
Du findest mich im Telefonbuch...
Spannend wirds dann auch noch beim Anlaufverhalten nach einer Kompletten entladung der Batterrie. Alle Regler die ich bis jetzt angeschaut habe schützen zwar die Batterie vor Tiefentladung, laufen aber viel zu früh wieder an, und bleiben dan in einem power on - power off loop hängen, da das Solarmodul nicht genügend Strom liefert um den Akku und den Bootvorgang zu versorgen.
+Andreas Fuchs Das geschieht wenn die Regler zuviel Strom ziehen. Ich habe dieses Verhalten bei keinem der Regler beobachten können. Ich war überrascht. Welche Regler hast du verwendet?
Based on the specification MCP73871 can deliver up to 1A Fast Charging current that is programmable by the resistor. I think that this might put this module on the top and not the bottom of your list. The maximum available charge current is also limited by the value set at PROG1 input that by default might be set to 500mA. Please check that module that was used for your test has 1K resistor for PROG1 and also that SEL value is set to High. I assume that you are using DC input and not USB mode.
+Bartek Sońta I just used the module as it was delivered and made a remark in the video. The resistor is 2k which stands for the 500mA and the sel pin is high
I has exactly the same thought. I guess you could fit a 1K resistor and charge at 1000mA if there is sufficient sun? The MCP73871 data sheet also describes pre-conditioning, fast charge and constant voltage modes. This makes sense to me if the chip is used to start with an empty battery and fully charge it over a few hours, but how would it apply in this case where the battery is used as a buffer? In your tests can you tell which mode the chip is operating in to know if you are actually measuring the fast charging mode?
Sorry - I forgot to say - These are great video's. Very useful - Thankyou!
Hi Andreas, thanks for the great job! Have you investigated the effect of temperature on the charging process of lithium-ion batteries? (if the batteries will be in the winter on the street at -20 C) And have you investigated the charge controllers for solar panels for LiFePO4 and lithium-titanate batteries? (they work better in the cold)
And about MCP73871 - at 5.55 you said that maximum charge current is 0,51A. May be it is posible change with PROG1, PROG2 and SEL input pins?
1. AFAIK Lithium batteries should not be charged below 0 degrees. Concerning LiFePo: I think there are specialized modules/chips available, but I did not work with them so far.
2. I only tested the modules I had on hand. You are right with the PROG pins.
The MCP73871 is meant to charge at 0.5A as stock configuration. If you want to charge with 1 amp, use a 1k resistor for rprog or a second 2k in parallel. This is well documented.
You are right!
@@AndreasSpiess thank you for this, it helps my meshtastic project in a big way.
The SD05CRMA is pretty interesting too
Nice video as usual.
I plan to run an ESP8266 (using DeepSleep) with solar panel and LiFePO4 battery using a MCP73123 chip (Linear Charge Management Controller chip).
Which kind of solar panel is most suitable for it ? 5V or 5.5V (around 1W panel) since I want to limit overheat. I live in center of France so sun is not very shiny.
I did a video about calculating the right size of the solar panel. If the battery is charged, the charger will not take any current from the solar panel, so I do not see a big danger of overheating.
Even when charging ? since LiFe batteries have a lower voltage then LiIon, anyway it's low current. I bought 5 V and 5.5V solar panels from Banggood, to run some tests. You convinced me to use LiFePo4 batteries from your #64 video.
As I wrote: If the battery is charged, the charger should stop charging automatically. This is usually done by measuring the battery voltage.
Hi Andreas, thank you for the video. Maybe you can you repeat the tests from the previous video with the protected TP4056. I have made the experience, that the protection circuit has a lot of backdraw.
I included the protected version in this video. However, I only connected it at the battery pins. What kind of backdraws did you experience?
What is the specification of the solar panel and the battery and what max charge current? I have successfully ran esp8266 for a month off a 1000 mah battery with 10 min interval, using the valuable information from your previous videos.
The link to the solar panel is in the description and the (different) charge currents are in the video
for us that live where the sun always shines, i would love to see the concept tested with the TP4056 and show it can run through your sunny months putting your maths into practice before you move on to super caps; which also of high interest - since lithiums arent fond of sun and heat (eg, cars and roofs where insurance might get involved). also like to see NiMH and SLA on that note
+lotsarats I think, somebody in your area has to do this tests as we quicly are moving towards autumn. As I said, I will try to build a simple monitor. Maybe we will find a few viewers which will build and install one and report the results...
your speaking pace (words/minute) really increased for new videos. If that's your brain changing and not some video post processing - that's impressive
These days you never know if it is the brain or if it is post processing ;-)
Do you think there's merit in using a low power micro-controller, directly powered by solar, varying the R(prog) of the TP4056 to constantly try to find the MPP?
I built such a setup, and can report that it appears to work. I used the panel voltage as the basis to find MPP. The logic just said: if the panel voltage collapses, we're drawing too much current, so reduce the charging current of the TP4056.
However, I don't have the test gear to fine-tune the setup and check if my results are better than a plain unmodified TP4056. I suspect that in full sun there won't be much difference, but in low-light conditions we might see a slight improvement. But, I'm not sure if these modifications are worth the effort.
+Rakesh Pai As you say, this works. But it might be an overkill as you can buy chips which already stabilize the input voltage to a defined level.
In theory there's no point. If the TP4056's current limit is set above the level the panel can supply, then it's designed to drag the panel voltage down to the minimum that can support the output voltage. Because the TP4056 is linear this should be ideal; it maximises current and minimises power dissipation in the chip. (This is in the data sheet, though it's intended to allow you to put a current-limited switch mode supply in front of it not a solar panel.)
If you look at the solar panel diagrams, there seems to be a MPP voltage point for each panel, not a current point (I showed it in my video). If you limit the current (the voltage therefore will fluctuate) with the TP4056, you only can maximize it for low or high Lux levels. The controllers wich stabilize the voltage adjust this current automatically and should get over all illumination situations the higher current. For my purpose, I think, it is ok to maximize a TP4056 for lower Lux levels because you get anyway enough in high Lux level situations...
+makomk I couldn't find mention of such a current limiting feature in the TP4056 datasheet. I found the LTC4056, a similar chip, which mentions current limiting - maybe you're getting them mixed up? Or is that implicit in the nature of linear chargers? It would be awesome if the TP4056 did what you said though. That's effectively MPPT built in!
+Rakesh Pai Here you find the info: electronics.stackexchange.com/questions/152931/how-to-autoregulate-a-tp4056-for-maximum-solar-power-extraction
But MPP is a voltage point, not a current point, as described in the video. You only can approximate it if you set a maximum current. But for small currents it is ok...
Great video, thank you! I am having trouble finding a battery that is suitable for a device that will be out in the sun, because they are generally not rated for such high temperatures that can accumulate in the enclosure in the sun. Do you have any advice?
In my opinion, there are two ways:
1. Separate the solar panel from the device and put the device in the shadow
2. Use old lead-acid batteries
Exactly my conclusion, thanks. I'm using gel cells.
I think the lm2596 could perform better with higher input voltage by stepping up output current. I think now it's just working more like linear regulator with just opened internal bjt switch. Atm I think the output current is the maximum current of solar panel in short circuit. Am I right? Best! I appreciate Your work and videos!
I did test all boards only in the actual situation. But, as I said, i general, Switching regulators are better for high voltage differences. This does not mean, that the LM2596 board will be a good solar charger anytime, because it has no means to stabilize the MPP
Andreas I'm little bit confused because in the last video the clear winner was TP4056 in the contrary to CN3791 which is the best in this video. So which controller should I order for my solar project?
+pawel753 In the first time Idid no systematic tests, just initial playing around. So, I would use theresults of the second video. Bear in mind, the differences are not so big.
If you don't need Wifi/Bluetooth,and just need a simple uC to perform whatever task,you might consider the MSP430 chips. They can run on very little power.
Ohh,and they can be programmed/coded much like an Arduino/ESP using the "Energia" IDE.
Thanks. I think I have one of these in my shelf (from a MOOC course).
Great video can't wait for the super capacitors version - do you think this work could be adapted to run the esp32 instead of the esp8266? Did you ever work out how to wake up using the ulp co processor ?
i would think yes but esp8266 are going to be easy to work with for most, as the ESP32 module kinda needs a breakout that gets in the way or you need elite maker skills. otherwise i bet the variance on your solar output for your location may have more impact on it working then the idle/sleep/transmit current differences between the esp32 and esp8266. but on this note i'd like to see how the LOLIN32 charge/regulator compares with the TP4056.
This video does not depend on which microprocessor you use. It only depends on how much current they need.
Thanks a lot for your very informative videos! I really enjoy them a lot!
You are welcome!
Hello Andreas, thanks for sharing these videos on solar charging. I am now studying the design of solar chargers. As your videos show the topic is indeed very much complicated with lots of hypothesis along the way…
I think your opinion and figures on linear vs switching solar charger are wrong. You postulate that chargers charge at maximum voltage (4.2V). This is not the case. Li batteries charge at constant current for 85% of the charging cycle with a voltage that is increasing. This means linear chargers will be far less efficient during 85% of the charge. Plus one could prefer to charge only to 85% since it would preserve the battery and it is difficult to optimise the charging of the remaining 15%. Also in real condition you will have to oversize the battery and most of the time will not charge at 4.2V. So the all concept of comparing the charge at 4.2V is not correct.
The chargers charge up to 4.2 volts, you are right. If you use a constant current, not the charger, but the battery decides on the voltage. The charger only decides when to stop.
Yes, this is why I challenge the idea of testing the efficiency with an electronic load at constant voltage of 4.2v. Anyway thanks for the test. I am surprised how good the TP4056 does. Did you test BQ24070?
Wie viel Energie vebrauchen diese Schaltungen im Dunkeln aus dem Akku ?
Ich habe eine Schaltung mt einem TLV431 gebaut, der die Solarzelle über einen BD136 kurzschliesst, wenn die maximale Ladespannung des Akkus erreicht ist.
Bis dahin fliesst die gesamte von der Solarzelle abgegebene Energie über eine Diode in den Akku, der die Spannung der Solarzelle während des Ladens auf seine aktuelle Spannung herunterzieht.
Bei sehr ungünstigen Bedingungen (bewölkter Himmel, leichter Regen) habe ich mit zwei seriell geschalteteten kleinen 1W/6V Solarmodulen noch einen Ladestrom von 5,4 mA gemessen, bei intensivem Sonnenschein waren es 108 mA (genau Richtung Sonne ausgerichtet, aber in einem vertikalen Winkel von ca. 30 Grad zur senkrechten Achse).
Die Schaltung mit dem TLV431 verbraucht im Dunkeln nur 0,02 mA (20 Mikroampere) an einem Blei-Akku mit 6,7 V Maximalspannung
Ich glaube, der "Back Current" entädt die batterie bei Dunkelheit 8ruclips.net/video/ttyKZnVzic4/видео.html )
Andreas did you made that video you where talking about, bigger solar panel and super capacitor?
So far I did not create this video :-(
An arduino pro mini 3.3v with voltage regulator removed when put to sleep draws just a few uA also when connected to nrf24l01 chip since it has a very low quiescent current too.
I think, this is an interesting way. I also think about LoRaWan
Andreas Spiess the usual setup are for small sensor nodes for home automation, but Mysensors also supports rfm95 radios so in theory you could make a very low power remote node with a small solar panel. The problem with supercaps is the low voltage so you either need a booster or a balancing circuit if you use them in series.
Hi, quick question if I may. Would a 6v panel connected to a TP4056 be able to charge a mobile phone? Thanks in advance.
Phones usualy need 5V and The TP4056 is made for max 4.2 volts of Li-Ion batteries.
@@AndreasSpiess Many thanks.
Hi Andreas, with the TP4056 do you recommend using a diode between the +sig from the solar panel and the module? or it is not necessary? Thanks!
So far, I did not use a diode.
In my opinion the main issue with the ESP32 or ESP8266 is the WiFi. This is a great solution if you have mains power available. But if not, you should better use a different transmission method. Maybe BT would be better?
As long as the sensor is accessible from time to time but has no access to mains I am using my "Homematic" components with a battery - alkaline or lithium primary cells. The Homematic components are transmitting @868 MHz using an optimized protocol to keep power consumption down. So a battery is good for severals years of service.
This is much cheaper and much more reliable than a solar cell, LiIon battery, charger etc. And most probably also more ecofriendly.
But of course not so interesting.
I think, you have a very good point. I would also take the sensors/actuators into account. Usually, you do not want to have only a microprocessor, but it should do something. And this part can also need some current. This is mainly why I said around 100 mA with sleep phases in-between. I think, LoRa is also a good alternative, BT less, because (for the moment) the reach seems to be rather short.
A typical I2C sensor as BME280 or SHT31 does not need too much current. But using a deep sleep concept without any extras on the receiver side limits the application range to sensors making most actor applications nearly impossible.
There are solution like RF burst wake mode to solve this.
The disappointing point is: if you are succesfully in bringing down the quiescent current far enough you'd better use a battery instead a solar cell.
klassich D - You're right. Wifi requires plenty power. My everlasting project involves sensors/actors in and around the house. I'm still testing what works vs. what I want and I think the eventual constellation will consist of an mqtt server and mains powered ESP wifi gateways/bases coupled to battery/solar powered RF nodes. I'm still working on the power issue, so these videos by Adreas are very useful.
+klassisch D My sun curtain is controlled by a device with a small solar cell and a super cap. It extends the curtain if sun is shining and retracts it if it has too much of wind. I like the solar cell there, because I can forget it and do not have to change batteries from time to time...
Yes, thats a cool application. The power is needed when the sun is there or at least close.
The ams1117 also come in 1.5v boards too.
Good to know
Do you know of a good 6S or higher voltage solar charger that can be used as a power backup? So it charges or supports pass through power or draw from batteries?
I do not know because I only focused on the low voltage side
I've been playing with some of the small panels you show and came to the same conclusion, in the UK they are too small to generate useful power. Now if we could somehow generate power from clouds and rain... :)
Just look at the comment of another viewer from the UK. He has a board running...
The north of england guy who is using sleep mode? Not useful for my project, but I guess that shows the limitations of small solar panels. My display is the issue really, I look forward to doing some truly low power projects and then I will use them.
Great!
Where did you find that BQ24650 board? It's not on Amazon or Banggood. And I can only find the unmounted chip from Digikey.
All links are in the description of the video.
What about a simple 4.2v zener diode circuit? For small panels
I do not like Zeners because they need a resisor which burns most of hte energy.
@@AndreasSpiess for most applications, i agree, but i think for a simple 5v / 40mw panel to keep a LIR2450 charged (which would last for weeks/months without charging anyway), the energy waste is neglectable if it makes the circuit smaller and cheaper. Anyway I will test it soon.
Thank you for another great video!
+Ernest G. Wilson II :-)
How about the new TP5000 ?.It can be used for 2A.
Also a possibility.
Thanks you Andrea for your videos. Best regards
You are welcome!
Very informative . Thank you!
You are welcome!
I built the circuit by using TP4056 as battery i chose 1500mAh 3.7v phone battery. And the circuit charged my battery. Only problem is that, to charge up the battery, the load ( esp8266) must be disconnected. The problem is, i cannot disconnect the load and wait battery to charge up. Is there any chargerboards which feeds the load and also charges the battery at the same time?
Maybe you have a look at this site: tech.scargill.net/the-kitchen-sink/
İ have read the article and checked that as plan b. 'Cause i am looking for single board solution. TP4056 is suitable for charging but cannot feed the load at the same time. Is there any single chip solution exists?
I do not think so.
I see, thanks for your answer and guidance, sir
I see D2 and D3 appears missing, could you explain what you did to optimize the CN3791 pertaining to resistors, thanks
I think, I showed this in my last video.
Andreas
During peak times our controllers are discarding energy because we can't overload the battery and then 10 minutes later clouds reduce the panel output. Would it be possible to regain some of this excess energy if we placed some super caps in between the panel and controller.
I think, you always can add more capacity, either as batteries or as super caps. Super caps have the advantage that they support many cycles and can provide very high currents. But they are more expensive for the same capacity.
Andreas, I think you missed the point of my question. I'm suggesting the addition of a super cap between the solar panel and the regulator to capture the higher energy the panel delivers during full sunlight and then making that energy available to the regulator during times when the sun is covered by clouds.
Maybe it's better just to use super caps instead of a Lipo battery at all? I'm new at this, so maybe there are reasons against that.
hope the microAmp microcontroller will soon be available on aliexpress, banggood, ..
I am not sure. Seems to be "Swiss Precision" and therefore maybe not cheap. But I thought to reduce the speed of an ESP8266. Maybe we can run it at 2.6 volts (super caps)
would be worth to be tested :)
RUclips does not make it easy to go from this video, to the promised successors.
Do you have somewhere a list of all your videos? Even better would be some kind of mind map showing linkages...
You find playlists of the typical topics
where?
On my RUclips channel. Look for "playlists" and you should find several topics.
I wonder where i could possibly send you some modules ???
I am on Facebook messenger and on Twitter
Good video as always, danke!
:-)
Cool!! Andreas, you save my time a lots. /Thanks.
:-)
This video helps me a lot ! Thnxs !
Glad to read that!
But can I supply the 6Volts to an esp8266?
Yes, if you want to kill it ;-) Its specification is up to 3.6 volts only. Then you need a voltage regulator. Or you use a development board that has such a voltage regulator built-in. These regulators are for 5 volts and usually specified up to 6 volts. But you have to check
Sehr gut gemacht!
Danke!
I see that the BQ24650 boards are $21.00 no including shipping + tax AND they don't do 1s for Lithium only 2s, 3s, and 4s YET we only need a 1s high quality solution because 1 Li-Ion 18650, etc... would do the job perfectly.
If you only have one cell you might want to watch my new video about the topic. There I use a TP4056 for a few cents...
@@AndreasSpiess Oh, thank you as I have 20 of those TP4056 Micro on order (the one with R3).
I have that semilunar one with the many wires coming out of it, still in a box somewhere. Anybody any experience with that one?
I never used it in a project.
@@AndreasSpiess Danke, I think i will stick with the 4056 from your test. Have a couple of those too
Awesome Video!!
:-)
Thank you. Now i am waiting the next video :)
:-)
Which of these chargers has load sharing capability?
What is "load sharing"? They just provide a voltage at the output.
@@AndreasSpiess Load sharing is when the board directs current from solar to a load and uses excess, if any, to charge the battery. When solar panel does not produce enough current for a load the board switches to using battery.
Its purpose is to avoid charging and discharging the battery at the same time. I know that MCP73871 board (Adafruit design, not sure about AE clones) does it.
I do not remember all boards. You can check which boards have a second output for a load. I do not think many.
@@AndreasSpiess Ok. Although, does a second output necessarily mean the board has load sharing? Hm
No. But the contrary is true: If it does not have a second output, for sure it has none ;-)
Awesome tutorial as always! :)
I never expected the TP4056 to be this efficient (or be used as a solar charger)! This is something I can experiment on with some of my future projects.. :D
So enjoy your experiments!
Keep it comming, self sustaning micro controller projects like this is something not alot of people have dedicated time to and it is really interesting :)
Thanks for sharing, you are the best👍😀
+Asger Vestbjerg (-:
Bitte, die Best Solar Charger Boards von raspberry. super video, besten dank
Maybe later...
Maybe, you can use the "ESP-NOW" protocol for the remote node... This should be the "low-power" communication for ESPs.
There is already a library for this...
I found a comment here: blog.hekkers.net/2015/04/06/esp8266-good-enough-for-a-battery-powered-sensor/#comment-68028
"Just for information.
My sensor application uses ESPNOW (that is a low-power communication protocol of ESP8266, not WiFi), and I got 30 days for 1 sample/30 sec with eleloop 2500mAh.
So It is expected to work 1 years for 1 sample/6minites."
Did you ever measured the power consumption with the ESP-Now?
Thanks for the link. I will look into it in the next time.
We're informative!
Thanks
Awesomeness
:-)
Has anyone ever tried using supercapacitors to "stage" a rapid intermittent energy source (solar, hydro, wind, wave) into a slow energy storage system e.g., hydrogen separation? Is the energy lost in conversion offset by the additional energy captured? How can anyone ever say "I'm bored!" with so many things to investigate, and why is it illegal to club such people like a baby seal?
I think, there are many projects to store solar energy. On a large scale here in Europe it is not the short-term storage which has to be solved, it is the longterm storage from summer into winter...
Yes, I apologize. This question was more general than your video's intended application. I was just curious, and was speaking to larger applications such as off-grid home power. In such installations, it is not unusual to install 40,000 watts of solar panel to power a 12,000 watt home on Winter solstice. But what about April, the peak for solar in the North? Most of that energy is wasted w/o grid-tie. In April, batteries will be charged by mid-morning. Almost all of the power such a system generates is wasted. So I was wondering if anyone reading comments has experimented with staging energy sources from short term (supercap and battery) to longer term energy storage (e.g., hydrolysis) and measured the efficiency as you did so well in your video. Maybe with a link to a white paper. :o)
In large scale hydro-power pumped storage is frequently used. The electrical, mechanical, and hydraulic losses are about 15% each way. These losses don't much matter when the market prices vary by a much, much larger margin and the flexibility is fantastic. In the tiny scale of my Vantage Pro II weather station, I think (but am not sure) the Davis company uses a capacitor to harvest what I call "solar opportunities" of brief cloud breaks in the dark days of winter. Nobody told me that it is illegal to club bored people which I do routinely (more of a dope-slap actually). However, at sleepless times I envy them. Giblet, you are funny.
very good thank plz keep it experiment
Thank you!