Built my own mesh infrastructure from Heltec lora v2's . 6v 90mw solar. I found the trick was to write in the code to check voltage and go into deep sleep for 8hrs and wake and test again if volts below 3.6v This prevents the devices crashing while in awake state, rather than low in low power state. If the battery drops below 3.6v then it is harder for the charge controller to keep the solar panel at it's maximum power point. And in dull days will struggle to recover from.
I've built a few solar-powered lora projects over the years, and I've come to the conclusion that the solar charge controller circuitry on the Heltec boards is a bit suspect. I've moved to the cheap SD05CRMA boards found on Amazon for ~$6 US. These boards are based on the CN3163 chipset and (as the video states) much more efficient than the Heltec circuitry. Since bypassing the Heltec charge circuitry, I've had no issues with charge performance or power brown-outs that plagued me before.
Excellent help on resolving the restart issue. I want to put a node on a tower. This should eliminate the need to climb and reset the device. We have extensive periods of little sun in the winter here and the likelihood of a battery going dead is a real issue.
Hysteresis is a good word... disconnect at 2.5, reconnect at 2.8, then you have enough juice at 2.8V to sag a little under load without disconnecting again... btw, I think the little mppt board you linked to on Amazon is different from the one you used.
when charging the battery and running the Heltec from solar, don’t forget around 15mA from the panel was also going into the Heltec, so the total solar panel output was say 15mA higher than the meter read
Their schematic shows it has a LGS4056H charge controller, the datasheet shows at 3.57V the current should have been >1A (but obviously limited by what the panel can provide). I'm sure the diode on the board going from the solar panel to the charging IC isn't doing it any favors, but I think based on the charging cycle it was still in 0.05A charging stage. There are 5 stages for that charge controller and it depends on the battery voltage where it ends up, but the first charging stage is 0.05A then 0.1A. On the power supply it looks like the internal charger was able to go to a high current, so I would say maybe the Heltec T114 internal charger isn't as bad as seen in the video?
I received my T114 (without screen) yesterday and have noticed that the default password does not work, so you may have to use Serial Console and there is no support for OTA firmware updates as yet. My RAK node that has a 1 watt solar panel and 3000mAh battery, struggled to maintain the battery voltage here during Australia's winter (Melbourne).
I use 3 of them solar panels in parallel on a Rak, it works 24/7 since spring time, but now winter is coming we will have long nights? great experiment especially for covert hill top nodes
I run a RAK off a 10W 12V standard solar panel, but I use a 5.5-20V to 5V buck converter before the solar input on the RAK, the kind used for solar USB chargers from China. The buck converter is rated for 2A, but runs in the 80%+ efficiency range with the low requirements from the RAK. The point of this, is to get some charging on cloudy winter days, as it gives some, the moment the 12V panel reaches a voltage of 5.5V. Will see if it works as well as I hope in winter.
I reckon if you interrupt it mid-boot, the contents of RAM will be b0rked. Then even with a flat-batt, it *may* have enough voltage to keep the RAM contents in place. This is why after 2nd boot it doesn't even show the splash ....... I think. I also think the batt protection fix is basically zeroing out the voltages and clearing RAM upon reconnect of "mains" ? What I'm thinking here is you can prove / disprove this by letting it "crash", restore power, observe no reboot, soft reset. If this works, you can monitor the voltage going into Green LED and if it's low for > certain time, you can spam the soft reset with 5v. Then again, what does a battery protection module cost ya?
Which Rak are you talking about, does it make a difference? Here in L.A. about half the people in the list are using the Rak 4631, they seem to be really popular and the most used here.
Have you had any issues with it not sending long messages? I have two of these without the screen, and messages over 63 characters rarely send successfully. Not sure if I've got a couple of duds, or if it's a firmware issue.
I seriously doubt that tiny panel will power a node through the deep winter. Also, Lithium batteries don't survive freezing temperatures. I have a much bigger solar panel in my setup and would like to add a heating system that keeps it warm through freezing temperatures.
They use the lgs4056h which has absolutely no battery protection. Not even one person thought about battery protection from design to finished product. 😂
No microprocessor likes supply voltage ramp-up from zero ... cannot guarantee a clean reset and if it does reset running, voltage may be below that required for reliable operation.👍
Built my own mesh infrastructure from Heltec lora v2's . 6v 90mw solar. I found the trick was to write in the code to check voltage and go into deep sleep for 8hrs and wake and test again if volts below 3.6v This prevents the devices crashing while in awake state, rather than low in low power state. If the battery drops below 3.6v then it is harder for the charge controller to keep the solar panel at it's maximum power point. And in dull days will struggle to recover from.
Do you have custom firmware i could take a look at? Been having this exact issue with a different board
Great video. It wasn't too long, and it was interesting to see you work things out as you went along.
I've built a few solar-powered lora projects over the years, and I've come to the conclusion that the solar charge controller circuitry on the Heltec boards is a bit suspect. I've moved to the cheap SD05CRMA boards found on Amazon for ~$6 US. These boards are based on the CN3163 chipset and (as the video states) much more efficient than the Heltec circuitry. Since bypassing the Heltec charge circuitry, I've had no issues with charge performance or power brown-outs that plagued me before.
Excellent help on resolving the restart issue. I want to put a node on a tower. This should eliminate the need to climb and reset the device. We have extensive periods of little sun in the winter here and the likelihood of a battery going dead is a real issue.
Great video Andy! Thanks from the Dutch Meshtastic community!
RAKS vs Heltec T114 would make an interesting video, solar wise
Bender T114 Edition should be here early next week with some more exciting stuff in the pipeline. Thanks Andy 😘
Can't wait!
Hysteresis is a good word... disconnect at 2.5, reconnect at 2.8, then you have enough juice at 2.8V to sag a little under load without disconnecting again...
btw, I think the little mppt board you linked to on Amazon is different from the one you used.
Hi mate, yes indeed👍🏻 the board should be correct, just checked it.
@@andykirby You can connect your solar panel and batteries but you can't connect to your Heltec or Rak
when charging the battery and running the Heltec from solar, don’t forget around 15mA from the panel was also going into the Heltec, so the total solar panel output was say 15mA higher than the meter read
Yes that is true 😁👍🏻
Their schematic shows it has a LGS4056H charge controller, the datasheet shows at 3.57V the current should have been >1A (but obviously limited by what the panel can provide). I'm sure the diode on the board going from the solar panel to the charging IC isn't doing it any favors, but I think based on the charging cycle it was still in 0.05A charging stage. There are 5 stages for that charge controller and it depends on the battery voltage where it ends up, but the first charging stage is 0.05A then 0.1A. On the power supply it looks like the internal charger was able to go to a high current, so I would say maybe the Heltec T114 internal charger isn't as bad as seen in the video?
I received my T114 (without screen) yesterday and have noticed that the default password does not work, so you may have to use Serial Console and there is no support for OTA firmware updates as yet.
My RAK node that has a 1 watt solar panel and 3000mAh battery, struggled to maintain the battery voltage here during Australia's winter (Melbourne).
I use 3 of them solar panels in parallel on a Rak, it works 24/7 since spring time, but now winter is coming we will have long nights? great experiment especially for covert hill top nodes
I run a RAK off a 10W 12V standard solar panel, but I use a 5.5-20V to 5V buck converter before the solar input on the RAK, the kind used for solar USB chargers from China. The buck converter is rated for 2A, but runs in the 80%+ efficiency range with the low requirements from the RAK. The point of this, is to get some charging on cloudy winter days, as it gives some, the moment the 12V panel reaches a voltage of 5.5V. Will see if it works as well as I hope in winter.
I prefer to learn as you learn rather than a polished "everything pre sorted" video. Thanks Andy, I appreciate your hard work on RUclips.
That seems like the exact same thing that happens with Rak. You gotta a test running the solar right into the USB port.
Thank you @andy!
Wish a sorted Solar set up was available for sale for Meshtastic.
Does the Heltec have a diode for the solar panel to prevent reverse bias?
yes
I reckon if you interrupt it mid-boot, the contents of RAM will be b0rked. Then even with a flat-batt, it *may* have enough voltage to keep the RAM contents in place. This is why after 2nd boot it doesn't even show the splash ....... I think. I also think the batt protection fix is basically zeroing out the voltages and clearing RAM upon reconnect of "mains" ?
What I'm thinking here is you can prove / disprove this by letting it "crash", restore power, observe no reboot, soft reset. If this works, you can monitor the voltage going into Green LED and if it's low for > certain time, you can spam the soft reset with 5v.
Then again, what does a battery protection module cost ya?
It possible add lto battery? it should charge quickly and more power efficiency, most that mcu runs fine on 2.3v.
Which Rak are you talking about, does it make a difference? Here in L.A. about half the people in the list are using the Rak 4631, they seem to be really popular and the most used here.
Have you had any issues with it not sending long messages? I have two of these without the screen, and messages over 63 characters rarely send successfully. Not sure if I've got a couple of duds, or if it's a firmware issue.
I seriously doubt that tiny panel will power a node through the deep winter. Also, Lithium batteries don't survive freezing temperatures. I have a much bigger solar panel in my setup and would like to add a heating system that keeps it warm through freezing temperatures.
Move to the south lol, US,
Check out the LTO solar battery kit from Voltaic Enclosures.
@@RabbitHoleAdventures I've located them. Really neat kit. Similar, but more efficient version of my setup.
@ChristieNel I have one being delivered any minute now. I'm curious to see how well it'll work throughout the hot summers and frigid winters.
@@RabbitHoleAdventures Yes, me too. I'm just wondering about their battery capacity. With my setup it's easy to attach really huge batteries.
J'ai commandé le miens. Peut être que un BMS S1 sauverait la batterie ?
Nyet polski vladna
😎😎
They use the lgs4056h which has absolutely no battery protection. Not even one person thought about battery protection from design to finished product. 😂
No microprocessor likes supply voltage ramp-up from zero ... cannot guarantee a clean reset and if it does reset running, voltage may be below that required for reliable operation.👍
I got a batch of batteries now with connectors that are too big for my heltec haha
i think tge solar charge controller is just using tp4056 like the rak is
Sadly this didn’t age well as the T114 has proven so problematic that it’s been removed from the Meshtastic flasher today.
everyone says the heltec v3s are power hogs
This was a messy video. But I Do clicked, as a solar charged meshtastic node is something I find really interesting.
Messy, poor grammar in your response. Make your own video and contribute something to the world.
Da grazie andy polski vladna non verificatas!