I think while I had it apart I would put an external connector so I could use an external battery for extended use. I love these little batteries and make all kinds of replacements.
I have been doing this for 5 years now. In fact, i now take the lead acid brick out when new and just put the LiFePO4 battery in from the start. The lead acid SLA batteries in most UPS's are not designed for multi C loads, and thus are usually good for 1 or possible 2 deep cycles before they are damaged to the point of not being able to hold a charge. This is done for purely profit motives as most people will either buy a new one or buy one of the terribly over priced replacement SLA batteries. My first Tripp-Lite true online UPS that i replaced those SLA batteries in, has been through many power outages (most lasting 30 minutes to over 3 hours) and those batteries have lasted almost 5 years! The secret is out now, and everyone should share this! By the way, you can just get the LiFePO4 batteries in the size of the SLA ones that come out of the UPS and skip having to make them yourself. Truly plug and play! Thanks for the video!
Yes. 4 cells in series matches the 12V, so if you have a bigger device, which lets say has a 10Ah lead acid battery inside, you can start adding cells in parallel. So you take lets say 2 LiFePo cells, put them in parallel, and connect with the next group of 2 cells in parallel. That is then called a 4s2p pack. You can use as many cells as you have space available. 4s3p, 4s4p, etc....
12:55 I know normally it may not be an issue with batteries, but when testing voltages, it's a good idea to not hold both terminals with bare hands. Remember, currently/voltage can flow through your body and can throw the readings off. It's better to push the probe down into the terminal to get a reading. You can hold the other terminal just fine. Or, if you wear rubber or nitrile gloves, you can get an accurate reading that way too. With what you are doing here, it may not make a difference, as you are getting a reference to verify proper voltage increase with each series connection. But something to be aware of when doing repairs on other types of electronics.
I got mine from here, but this might only be in Thailand and I didn't see a kit anymore: www.lazada.co.th/products/lifepo4-3270032650-1-set-4-32v-6000-6500mah-i3111984799-s11532539188.html?spm=a2o4m.searchlist.list.63.426c28c9sJmpPw&search=1 You can try this from AliExpress: www.aliexpress.com/item/1005001565728757.html?spm=a2g0o.productlist.0.0.126f2821fEs1dw&algo_pvid=c259103f-55fc-4903-830c-e5b7016dadad&algo_exp_id=c259103f-55fc-4903-830c-e5b7016dadad-18&pdp_ext_f=%7B%22sku_id%22%3A%2212000016612079308%22%7D&pdp_pi=-1%3B20.9%3B-1%3BUSD+17.43%40salePrice%3BUSD%3Bsearch-mainSearch And a BMS board: www.aliexpress.com/item/1005003079938137.html?spm=a2g0o.productlist.0.0.42a57837m56SPy&algo_pvid=232b117b-18fa-435a-bcc3-be409079c064&algo_exp_id=232b117b-18fa-435a-bcc3-be409079c064-0&pdp_ext_f=%7B%22sku_id%22%3A%2212000023953589268%22%7D&pdp_pi=-1%3B1.74%3B-1%3BUSD+1.79%40salePrice%3BUSD%3Bsearch-mainSearch
@@RolandW_DIYEnergyandMore I guess my point is that this battery will significantly reduce the load capacity of the UPS compared to using a lead-acid battery of the same size. It likely will not provide the maximum current that the inverter can draw.
That one has the bigger 7,2 Ah Battery inside, right? You would use the same 32700 LiFePo4 cells but might be able to fit at cells in a 4s2p configuration inside the case. If that wouldn't work, then you might consider to place the battery outside of the UPS as you need the stronger, higher capacity battery pack.
well, I am here in Thailand. They are selling this all over SE Asia. You would have to look up Amazon, Ebay or AliExpress, etc if you live in the west...
Nice idea and video! This work fine for small loads UPS, but one need to read up on battery discharge rates as well as BMS current rating when sizing the system. The batteries you use in this video, 32650 LiFePO4, usually has a max discharge around 5-8C. If someone were to use 18650 LiFePO4 batteries there’re usually around only 1C. Considering the cost of the kit in the video I’d more bet on 5C in this case. That means you have 5*5,5*4=110A available which is good for a bigger load (1400W). But that simple BMS probably only could (should) handle up to 20A from what I could find. That’s only 256W. Just something people need to be aware off!
how has it been holding up? do the trickle chargers in the UPS shut off early since Lifepo4 maintains voltage at a lower charge? or do they constantly trickle charge?
I only have 3 indicator LEDs. And I see the green one illuminated always. Can't really say what it going on inside. hehe. But what i have noticed after an extended grid down, if the pack is discharged a bit to much, it will not restart charging. Then I need to bypass the Mosfets of the BMS board to get it going again. But I just think the reason for it is the crappy, cheap BMS board which has a high drop of voltage over the switching circuit.
@@RolandW_DIYEnergyandMore i've been watching this Will Prowse guy on youtube. he has stated you can check battery level with voltage like you do with lead acid. in my experience the charger in the UPS turns on and shuts off based on battery voltage. HOWEVER he has also ranted on cheap/poor quality BMS as well
@@RolandW_DIYEnergyandMore Just use a balancer not a BMS, the UPS will manage low shutoff and the problem is gone. Upper voltage of the LIFEPO4 is higher too, so it should shut off well before the upper limit. Did you check the real capacity because the lead acid battery controll board will shut off before the LIFEPO4s are full.
That for sure. I just didn'thave anythingby hand and as all the casing and other stuff inside was insulated, I thought it's going to do without it. haha. Thanks for the good comment!
Coming along pretty good there, Roland. You're getting better with the video 😉👍 If you can, though, i would recommend a lapel mic to help pick more of your voice up and lower the sounds of the buggy/froggy orgy going on in the background 😜 Your voice is clearly heard, though. I had no problem hearing/understanding you.
Can you comment on runtime vs the lead acid. While cheaper to replace with LifePo4 and build yourself, does this significantly increase your runtime ? I have a APC 1300 with dual 12v la 7ah in series that provides approx 45min of run for a 110watt load. Would love to increase that runtime within the same UPS
The Lifepo4 32600 cells will give you about the same capacity in the same volume as the original lead acid battery, but typically you can discharge LFP deeper without damaging the cells then the LA. So runtime might not be increased, but lifetime will. If you need more runtime, you could go for a LiPo 7s pack built out of high capacity 18650 cells giving you the 24V. Or you might add a few cells in an external battery extension for the LFP.
Lead acid batteries have a voltage drop-off as their state of charge decreases, but that's why the UPS has a large transformer. It takes the declining voltage for the lead acid battery and converts to whatever voltage your electronics need that is plugged into the UPS. LiFePO4 is better because it holds voltage much longer, but anyway the transformer is doing the work to increase the voltage. I think Roland is right...you won't get a lot more capacity unless you build a bigger battery that is not inside the case. This is also a pretty easy project.
The issue with larger battery reserve. You need to charge them back up again.. And being the built in charger in these things have small output. You would spend the next two+ days charging it back up to 100%....Why You would need an external charger with at least 5amps output. That can charge the type of batteries you are using... I would add. If you so chose to use an external battery charger. You have to decouple the batteries from the internal one..As you will burn out the MB on the UPS...
If your running 24 volt that's even better you could have the option of using cobalt cells also. Most power disruptions are intermittent so.etimes just enough to cause a reboot of your equipment ups fix that I use them on all my TVs exc
hello my friend, can you share with me how did you get results in long use, because normally lifepo4 batteries and other used batteries do not have the same charging logic, so did you encounter any problems during long usage or charging process, thank you very much.
Hi, the UPS is still working. It held up fine during many of our short power interruptions. I do not think that charging characteristics are playing much role for a UPS as the battery is anyways just sitting there fully charged all the time and just used for seconds or minutes at the max
I have bought it online here in Thailand. This stuff is quite easy to get in SE Asia/China. You might have to improvise if you live somewhere in the West or buy a finished LFP 12V replacement battery...
I have done the same project LiFePo4 4S1P 30A BMS. I have an issue in this, once my UPS gets full charge BMS shuts off charging and my UPS turn off automatically. Do you have any suggestions for me.
That means either, that your charging regulator is set a bit to high, or one of the cells is running away and out off balance. Regulator cannot be changed, but if it is a weak cell, it could be fixed by getting a new cell. Did you measure the total voltage and individual cell voltages before it happens and the BMS is shutting off? Or try to top balance cells first
I really enjoyed your explanations but your video could have been better if you had used a lapel microphone or a wireless microphone to record your speech without the background noises (birds and vehicle traffic-?). As a hobbyist just getting back into electronic projects, I appreciate good explanations at every step. Hope to see more of these videos in future projects!
Hi. Yes, sorry. I think that was one of the last videos of the pre-lapelmic aera. My later videos got an audio upgrade :) Thanks for watching and commenting!
Can I also replace 2x 12v7ah lead acid batteries in serie, just straight forward with 2x 12v7ah LifeP04 batteries? the voltages of charging etc will be correct?
@@RolandW_DIYEnergyandMore Do I need the BMS if it is a complete battery, that looks like the original lead acid battery? (not cells linked) But two complete similar looking batteries (just lifeP04 types).
@@dermeister314p no, in that case the protection circuit will alread be built into the finished battery pack. but you might get a problem to restart your UPS in case the battery is depleted and the packs are shut down. in that case you will have to jumpstart the ups from outside.
Are you sure you can't use 3Li-ion in series? A PB 12v lead acid batt can full charge at 12.7v while a 3series Li-ion battery will full charge at (4.2x3) 12.6v so how is that not possible?
12,7V LA might be the nominal Voltage. A fully charged LA battery will be close to 14V, while at around 12V it will be close to depleted. LiOn cells only hold a fraction of capacity between 4,0 and 4,2V (maybe 5-10%). Your UPS will shut down before you pack even gets started. It just doesn't work in 3s, while 4s is similarly bad as the cells don't get enough voltage....
Hello Roland, I was looking at your circuit and had a question: I see that you bypassed P+ port on BMS board and directly connected Battery Positive to UPS Positive wire. Is there a reason for doing this? and is it ok to first connect my battery positive to B+ port on BMS and then connect P+ port of BMS to UPS Positive wire?
Hi, B+ and P+ are basically the same port on a BMS. On this board they are just connected on the PCB anyways. BMS's typically switch on the negative pole of the battery. You can of course connect your UPS and battery separately via each port if you wish.
@@chriss4365 So if you top-balance 2x 12v lifepo4 batteries then put them in your ups, and your ups simply keeps them at 13.8v each / 27.6v in series, 1 amp maximum, what are you missing out on?
(ตัวเมียลบ) Promotion 4 ก้อน แบตเตอรี่ลิเธียม LiFePO4 32650 3.2 v 6000-6500mAh แถมฟรี!!!ตัวยึด 2 ช่อง 4 ชิ้น | s.lazada.co.th/s.3iv2H ฿85.00 -57% | วงจรป้องกันแบตเตอรี่ BMS LiFePo4 3.2V 30A 4S (Peak 56A) บาลานซ์: 58mA ชนิด Common port | s.lazada.co.th/s.3iBBO But I think this is only available for Thai domestic. If you live in another country, please check your preferred online shop for 32650 LiFePo4 cells and a small 4s LiFePo BMS
Yes correct. I would say it's a 80% match. On the high end the UPS will stop charging before LFP is full so there is nothing wrong with that, and on the low end the BMS will typically kick in for protection. It all depends if the solution can fit to your application. If you are only protecting against relatively short grid outages where you don't want your PC die before you have the chance to shut it down safely, then this will still work well. These small UPS's don't have massive run times with the original batteries either. But the LiFePo cells will at least hold up much longer then the Lead Acid ones.
@@RolandW_DIYEnergyandMore Yep, (I don't know the specs of your UPS) a LiFePO4 maximum voltage = 3.65x4 = 14.6Vmax with Vnom = 12.8V and minimum cut-off = 10.0Vmin .... so if the UPS cuts off maximum voltage between 12.8V and 14.6V then that is acceptable for Vmax. If the UPS cuts off Vmin at higher than 10Vmin, then that is also OK.
HI Roland. My UPS lead acid battery went dead a couple of days back and I had to urgently replace it. And so I replaced it with a Lifepo4 battery pack. The many RUclips videos made on this mod made me decide in doing so. I bought it readymade online. Its rated at 12.8v 6000mAh, and has a BMS. I am running my UPS for the last 8/9 days on this LifePo4 battery. I have not been running my system when the power cuts off. I get nervous and switch it OFF asap because I am still unsure of this mod. Is there something that I need to be careful about? Also what about the charging voltage? Will there be a problem with the BMS? Have connected a volt meter to the battery and it shows 13.2v max charge of the battery. But if the power fails, it drops very quickly (almost immediately) to 12.5v. Then it slows down on its discharge rate. Why is this? Thks for your time.
Hi. Replacing the Lead Acid battery with the readymade LFP pack was a good decision and the UPS will work similarly as before. LFP a very close match in voltage to LA. But still, it is not a 100% match. The initial drop in voltage comes from the LFP charge and discharge curve, which is steep at the ends, but very flat in the middle. Thats very normal. Nevertheless, the onboard charging unit of the UPS will handle it just fine. In my UPS I have noticed that the system will shut down a bit sooner than you might expect from the capacity. So, it's probably only about 85% of energy which you can get out of the battery now. I have also noticed that after a full discharge, the UPS control board will not start charging anymore and I have to bypass the Mosfets on the BMS to reset the unit. This is because the BMS is causing a bit of an extra voltage drop, which at the end seems to be a bit out of specs and the UPS needs a bit of a push to do its job again. But anyways, an UPS should just keep your PC alive at a power outage, so that you can safely shut down your computer. Never let the UPS run until it dies itself. A small battery like that will only give you 10-15 minutes of time.
@@RolandW_DIYEnergyandMore Thks Roland. BTW, I have also connected a voltage meter to the battery to know how the voltage is dropping. And Also so that I make sure that I keep the battery within a certain range, so that it does not drop below a certain level. It would also help me to know how fast the Battery is discharging and when is the right time to shut down the computer.
@@mediatrix1111 OK, good idea to use a voltage meter. As said, the voltage will keep steady for most parts of the discharge and then suddenly start to drop quickly at the end of the cycle.
@@RolandW_DIYEnergyandMore Noted. So then I guess I might not have enough time to shut down the computer when the voltage meter starts to show the drop. Cause it will be very fast towards the end. Will have to learn how to work around it by experience. Thks a bunch Roland. It was good to learn this.
@@RolandW_DIYEnergyandMore thanks for a very interesting video. I replaced a lead acid battery with a lifepo4 battery. I ran the ups until it switched off. But after connecting the mains to the ups nothing happened. With the lead acid battery in the ups it would start charging immediately. Is there no way to overcome this please? I cannot afford to let a backup battery run down and not getting charged again. If this is connected to an alarm system then the alarm will trigger every time the power gets restored from the mains. We get a lot of power failures in my country. Usually for 2 hours at a time but lately up to 4 hours
Are you sure you did the right thing ?! I think the bms input voltage is exactly 12.6 volts. And in the old battery it is charged between 13.8 and 14 volts. Can't your bms burn or more ?! By the way I thought to put some diodes directly to the ups, and put an external charger of 12.6 volts. I would be happy if you answer me in full detail.
BMS for LiFePo4 cells will disconnect the battery at a high voltage of 3.65V per cell, and low voltage of 2.5V per cell. So for this 4 cell pack, the voltage range is 10-14,6V. This is well inside Lead Acid voltage range of the UPS charger, which as you saw stopped charging at around 13,6V. Where do you get the voltage of 12.6 or 3.15V per cell? I think you misunderstand the term of 'nominal voltage', which is 3.2V for LiFePo4. Nominal voltage is just the average voltage of a cell chemistry's voltage range. It is only used to define cells. For LiPo and NMC it is 3,7V, but the voltage range there is 3.0-4.2V...
@@RolandW_DIYEnergyandMore Thanks for your kind reply .I really appreciate it. Can you answer me some questions ?! I have lead acid battery UPS. I want to connect 18650 cells My BMS charging is written 12.6V Possible output of BMS for example to a 12V fan. Now I want to connect the BMS port to the UPS charging port Is it possible ? After all, about 14 volts will go into the BMS volt input What can you teach me about this? I would be very happy for your detailed answers, it will greatly help. Yes I may not know or do not understand much, for that there are good people (teachers) like you. I thank you on behalf of everyone.
@@user-zg3nb1mk5b26 OK, now I understand. You want to replace Lead Acid by 18650 laptop cells with Lithium Ion chemistry. Sorry to say, but will not work! LiIon cells are unsuitable to replace Lead Avid in 12V systems due to the incompatible voltage range. You would need 3,5 cells in series. 7s 24V and 14s 48V can be done with LiIon. Please don't do it, its not worth the trouble even with using a buck converter to reduce voltage from the onboard charger, as 3s is to little voltage to keep the UPS running for long enough when discharging. 12V must use LiFePo4 cells!
@@frzen technically you can go with a 14s Lion battery as well. I would prefer LFP cell from the safety standpoint especially when you have the UPS somewhere indoors. It will end up to be a decision on which cells you can get easier, right? LFP packs are bulkier as well.
how about ups charging lifepo4 voltage is 12v? I believe lifepo4 need 14.5v to charge until full charge so if ups charge only 12v it will keep charge lifepo4 n never be full?
12V is only nominal rating for Lead Acid batteries, a full charged LA battery will be close to 14.2V, so the charging circuit in the UPS has to be able provide a bit above this to fully charge a LA battery. In older cars it was not uncommon to see over 15V at battery terminals when the battery was being charged by the alternator. Deep Cycle Lead Acid batteries as used in UPSs, I think, are very slightly different in terminal Voltage. Have another look through the comments, it is mentioned that the LiFePO battery will be only very slightly under charged, but this is good for any Lithium based cells as they tend to last longer if not charged to 100% all the time. Hope this clarifies the situation regarding Your concerns.
for this project ,I need to buy 4 pcs of life04 battery with all positive (male) and all negative (female)? is that right? sorry I am a noob at this thing.
Hi, you can use whatever cells you get. They should all have same terminals so that you do not mistake a pole when connecting them ito series. where you have male or femal is not relevant.
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Great video. I have a couple of UPSs with dead batteries and this is a brilliant idea. Thanks!
Thank you for the video with the demo of the UPS working. Wonderful job, I will attempt the same.
I think while I had it apart I would put an external connector so I could use an external battery for extended use. I love these little batteries and make all kinds of replacements.
I have been doing this for 5 years now. In fact, i now take the lead acid brick out when new and just put the LiFePO4 battery in from the start. The lead acid SLA batteries in most UPS's are not designed for multi C loads, and thus are usually good for 1 or possible 2 deep cycles before they are damaged to the point of not being able to hold a charge. This is done for purely profit motives as most people will either buy a new one or buy one of the terribly over priced replacement SLA batteries. My first Tripp-Lite true online UPS that i replaced those SLA batteries in, has been through many power outages (most lasting 30 minutes to over 3 hours) and those batteries have lasted almost 5 years! The secret is out now, and everyone should share this! By the way, you can just get the LiFePO4 batteries in the size of the SLA ones that come out of the UPS and skip having to make them yourself. Truly plug and play! Thanks for the video!
Your exactly right the only issue is due to the larger battery capacity and longer runtime there may be issues with cooling.
Good job Roland.
Great project. The more cells added , you’ll get a much longer time and handles the surge with better efficiency.
You could overstress the sine generator, it is specified for a fixed amount of max time.
@@NavySeal2k Just put a fan on it, it'll be fine.
@@NotoriousPyro Tell me you have no clue about electronics without saying you have no clue about electronics
very good e
and clean work
This is so informative. What to do to connect more cell I this? do I have to add cells in multiples of 4 to match 12 v charging???
Yes. 4 cells in series matches the 12V, so if you have a bigger device, which lets say has a 10Ah lead acid battery inside, you can start adding cells in parallel. So you take lets say 2 LiFePo cells, put them in parallel, and connect with the next group of 2 cells in parallel. That is then called a 4s2p pack. You can use as many cells as you have space available. 4s3p, 4s4p, etc....
@@RolandW_DIYEnergyandMore how long does it power the computer after power outage?
@@Kogi-freedom 20 min max. It of course also depends on your power draw. This UPS only has a small battery really...
12:55 I know normally it may not be an issue with batteries, but when testing voltages, it's a good idea to not hold both terminals with bare hands. Remember, currently/voltage can flow through your body and can throw the readings off. It's better to push the probe down into the terminal to get a reading. You can hold the other terminal just fine. Or, if you wear rubber or nitrile gloves, you can get an accurate reading that way too.
With what you are doing here, it may not make a difference, as you are getting a reference to verify proper voltage increase with each series connection. But something to be aware of when doing repairs on other types of electronics.
Do you have a link where you purchased this kit
Thank you
I got mine from here, but this might only be in Thailand and I didn't see a kit anymore: www.lazada.co.th/products/lifepo4-3270032650-1-set-4-32v-6000-6500mah-i3111984799-s11532539188.html?spm=a2o4m.searchlist.list.63.426c28c9sJmpPw&search=1
You can try this from AliExpress: www.aliexpress.com/item/1005001565728757.html?spm=a2g0o.productlist.0.0.126f2821fEs1dw&algo_pvid=c259103f-55fc-4903-830c-e5b7016dadad&algo_exp_id=c259103f-55fc-4903-830c-e5b7016dadad-18&pdp_ext_f=%7B%22sku_id%22%3A%2212000016612079308%22%7D&pdp_pi=-1%3B20.9%3B-1%3BUSD+17.43%40salePrice%3BUSD%3Bsearch-mainSearch
And a BMS board: www.aliexpress.com/item/1005003079938137.html?spm=a2g0o.productlist.0.0.42a57837m56SPy&algo_pvid=232b117b-18fa-435a-bcc3-be409079c064&algo_exp_id=232b117b-18fa-435a-bcc3-be409079c064-0&pdp_ext_f=%7B%22sku_id%22%3A%2212000023953589268%22%7D&pdp_pi=-1%3B1.74%3B-1%3BUSD+1.79%40salePrice%3BUSD%3Bsearch-mainSearch
Do you have any links to any of the stuff you show in the video?
How do you cope with the lower peak current capacity?
@@pleappleappleap you will obviously only use such a DIY UPS for applications which it can handle.
@@RolandW_DIYEnergyandMore I guess my point is that this battery will significantly reduce the load capacity of the UPS compared to using a lead-acid battery of the same size. It likely will not provide the maximum current that the inverter can draw.
How is the ups now? Hopefully it has not smoked yet
No no, working perfectly :)
Great informative video.
Which LiFePo4 battery can I place inside an APC Smart UPS Smart SC 420?
That one has the bigger 7,2 Ah Battery inside, right? You would use the same 32700 LiFePo4 cells but might be able to fit at cells in a 4s2p configuration inside the case. If that wouldn't work, then you might consider to place the battery outside of the UPS as you need the stronger, higher capacity battery pack.
@@RolandW_DIYEnergyandMore Thanks for these configuration suggestions. Yes, it's a 7.0 Ah battery inside. I'll just have to give it a try.
where did you get the battery kits?
From an online shopping platform here in Thailand called Lazada. You would have to look what you can find in your country/region...
Where did you get the kit to build this? Interesting process & option.
well, I am here in Thailand. They are selling this all over SE Asia. You would have to look up Amazon, Ebay or AliExpress, etc if you live in the west...
Nice idea and video!
This work fine for small loads UPS, but one need to read up on battery discharge rates as well as BMS current rating when sizing the system.
The batteries you use in this video, 32650 LiFePO4, usually has a max discharge around 5-8C. If someone were to use 18650 LiFePO4 batteries there’re usually around only 1C. Considering the cost of the kit in the video I’d more bet on 5C in this case. That means you have 5*5,5*4=110A available which is good for a bigger load (1400W). But that simple BMS probably only could (should) handle up to 20A from what I could find. That’s only 256W.
Just something people need to be aware off!
how has it been holding up? do the trickle chargers in the UPS shut off early since Lifepo4 maintains voltage at a lower charge? or do they constantly trickle charge?
I only have 3 indicator LEDs. And I see the green one illuminated always. Can't really say what it going on inside. hehe. But what i have noticed after an extended grid down, if the pack is discharged a bit to much, it will not restart charging. Then I need to bypass the Mosfets of the BMS board to get it going again. But I just think the reason for it is the crappy, cheap BMS board which has a high drop of voltage over the switching circuit.
@@RolandW_DIYEnergyandMore i've been watching this Will Prowse guy on youtube. he has stated you can check battery level with voltage like you do with lead acid. in my experience the charger in the UPS turns on and shuts off based on battery voltage. HOWEVER he has also ranted on cheap/poor quality BMS as well
@@RolandW_DIYEnergyandMore Just use a balancer not a BMS, the UPS will manage low shutoff and the problem is gone. Upper voltage of the LIFEPO4 is higher too, so it should shut off well before the upper limit. Did you check the real capacity because the lead acid battery controll board will shut off before the LIFEPO4s are full.
Nice Project. I think you should have wrapped the cells in shrink wrap material before attaching the BMS to the outside provide better insulation.
That for sure. I just didn'thave anythingby hand and as all the casing and other stuff inside was insulated, I thought it's going to do without it. haha. Thanks for the good comment!
Coming along pretty good there, Roland. You're getting better with the video 😉👍
If you can, though, i would recommend a lapel mic to help pick more of your voice up and lower the sounds of the buggy/froggy orgy going on in the background 😜
Your voice is clearly heard, though. I had no problem hearing/understanding you.
Thanks mate! Yeat, the tropics are a permanent concert of noises :)
Can you comment on runtime vs the lead acid. While cheaper to replace with LifePo4 and build yourself, does this significantly increase your runtime ? I have a APC 1300 with dual 12v la 7ah in series that provides approx 45min of run for a 110watt load. Would love to increase that runtime within the same UPS
The Lifepo4 32600 cells will give you about the same capacity in the same volume as the original lead acid battery, but typically you can discharge LFP deeper without damaging the cells then the LA. So runtime might not be increased, but lifetime will. If you need more runtime, you could go for a LiPo 7s pack built out of high capacity 18650 cells giving you the 24V. Or you might add a few cells in an external battery extension for the LFP.
Lead acid batteries have a voltage drop-off as their state of charge decreases, but that's why the UPS has a large transformer. It takes the declining voltage for the lead acid battery and converts to whatever voltage your electronics need that is plugged into the UPS. LiFePO4 is better because it holds voltage much longer, but anyway the transformer is doing the work to increase the voltage. I think Roland is right...you won't get a lot more capacity unless you build a bigger battery that is not inside the case. This is also a pretty easy project.
The issue with larger battery reserve. You need to charge them back up again.. And being the built in charger in these things have small output. You would spend the next two+ days charging it back up to 100%....Why You would need an external charger with at least 5amps output. That can charge the type of batteries you are using...
I would add. If you so chose to use an external battery charger. You have to decouple the batteries from the internal one..As you will burn out the MB on the UPS...
If your running 24 volt that's even better you could have the option of using cobalt cells also. Most power disruptions are intermittent so.etimes just enough to cause a reboot of your equipment ups fix that I use them on all my TVs exc
Get a "power station" as UPS'es are only designed to run for a short time.
Hallo! Würde das auch mit 24v Systemen funktionieren? wie sieht es mit dem Ladestrom aus? Raucht der Laderegler bei LiFePo4 nicht ab?
Hallo. Ich denke schon, dass es genauso bei 24V geht. Also der Laderegler macht keine Probleme. Läuft bei mir jetzt schon fast 2 Jahre so...
@@RolandW_DIYEnergyandMore Super Danke für die Antwort!..Werds einfach probieren mehr als schrotten geht eh nicht .
oh you made a little pack to go in there. i'm going to make custom cables and put in a big 12v 100ah lifepo4 IF i decide to put lifepo4s in one
Hehe, good luck. Hope that such a big pack won't blow up the small board :)
@@RolandW_DIYEnergyandMore hopefully my other reply didn't get blocked for linking a forum post with my last big upgrade
@@cdoublejj yes, posts with links are blocked, but i didn't receive it for review as well
hello my friend, can you share with me how did you get results in long use, because normally lifepo4 batteries and other used batteries do not have the same charging logic, so did you encounter any problems during long usage or charging process, thank you very much.
Hi, the UPS is still working. It held up fine during many of our short power interruptions. I do not think that charging characteristics are playing much role for a UPS as the battery is anyways just sitting there fully charged all the time and just used for seconds or minutes at the max
WOW! $12?? Where did you get that kit? I cannot find anything like it.
I have bought it online here in Thailand. This stuff is quite easy to get in SE Asia/China. You might have to improvise if you live somewhere in the West or buy a finished LFP 12V replacement battery...
I have done the same project LiFePo4 4S1P 30A BMS. I have an issue in this, once my UPS gets full charge BMS shuts off charging and my UPS turn off automatically. Do you have any suggestions for me.
That means either, that your charging regulator is set a bit to high, or one of the cells is running away and out off balance. Regulator cannot be changed, but if it is a weak cell, it could be fixed by getting a new cell. Did you measure the total voltage and individual cell voltages before it happens and the BMS is shutting off? Or try to top balance cells first
I really enjoyed your explanations but your video could have been better if you had used a lapel microphone or a wireless microphone to record your speech without the background noises (birds and vehicle traffic-?). As a hobbyist just getting back into electronic projects, I appreciate good explanations at every step. Hope to see more of these videos in future projects!
Hi. Yes, sorry. I think that was one of the last videos of the pre-lapelmic aera. My later videos got an audio upgrade :) Thanks for watching and commenting!
Can I also replace 2x 12v7ah lead acid batteries in serie, just straight forward with 2x 12v7ah LifeP04 batteries? the voltages of charging etc will be correct?
Yes, just use 8 cells in series and a 8s BMS
@@RolandW_DIYEnergyandMore Do I need the BMS if it is a complete battery, that looks like the original lead acid battery? (not cells linked) But two complete similar looking batteries (just lifeP04 types).
@@dermeister314p no, in that case the protection circuit will alread be built into the finished battery pack. but you might get a problem to restart your UPS in case the battery is depleted and the packs are shut down. in that case you will have to jumpstart the ups from outside.
@@RolandW_DIYEnergyandMore thank you, I appreciate the help.
Are you sure you can't use 3Li-ion in series?
A PB 12v lead acid batt can full charge at 12.7v while a 3series Li-ion battery will full charge at (4.2x3) 12.6v so how is that not possible?
12,7V LA might be the nominal Voltage. A fully charged LA battery will be close to 14V, while at around 12V it will be close to depleted. LiOn cells only hold a fraction of capacity between 4,0 and 4,2V (maybe 5-10%). Your UPS will shut down before you pack even gets started. It just doesn't work in 3s, while 4s is similarly bad as the cells don't get enough voltage....
Hello Roland, I was looking at your circuit and had a question: I see that you bypassed P+ port on BMS board and directly connected Battery Positive to UPS Positive wire. Is there a reason for doing this? and is it ok to first connect my battery positive to B+ port on BMS and then connect P+ port of BMS to UPS Positive wire?
Hi, B+ and P+ are basically the same port on a BMS. On this board they are just connected on the PCB anyways. BMS's typically switch on the negative pole of the battery. You can of course connect your UPS and battery separately via each port if you wish.
Issue is ups has wrong charging system for lifepo4 cells.
Assuming the lifepo4 battery is already top-balanced, and the battery is never flattened, what issues does this bring up? Thanks
@jimmybrad156 charging system is for lead acid, not lifepo4
@@chriss4365 Why wouldn't this work? Would it work but with trade off/s?
@@jimmybrad156 wrong charging system.
@@chriss4365 So if you top-balance 2x 12v lifepo4 batteries then put them in your ups, and your ups simply keeps them at 13.8v each / 27.6v in series, 1 amp maximum, what are you missing out on?
please post link to seller for parts!
(ตัวเมียลบ) Promotion 4 ก้อน แบตเตอรี่ลิเธียม LiFePO4 32650 3.2 v 6000-6500mAh แถมฟรี!!!ตัวยึด 2 ช่อง 4 ชิ้น | s.lazada.co.th/s.3iv2H
฿85.00 -57% | วงจรป้องกันแบตเตอรี่ BMS LiFePo4 3.2V 30A 4S (Peak 56A) บาลานซ์: 58mA ชนิด Common port | s.lazada.co.th/s.3iBBO
But I think this is only available for Thai domestic. If you live in another country, please check your preferred online shop for 32650 LiFePo4 cells and a small 4s LiFePo BMS
The UPS cutoff voltage(s) [max/min] does NOT correspond with LiFePO4 cutoff voltage(s) [max/min].
Yes correct. I would say it's a 80% match. On the high end the UPS will stop charging before LFP is full so there is nothing wrong with that, and on the low end the BMS will typically kick in for protection. It all depends if the solution can fit to your application. If you are only protecting against relatively short grid outages where you don't want your PC die before you have the chance to shut it down safely, then this will still work well. These small UPS's don't have massive run times with the original batteries either. But the LiFePo cells will at least hold up much longer then the Lead Acid ones.
@@RolandW_DIYEnergyandMore Yep, (I don't know the specs of your UPS) a LiFePO4 maximum voltage = 3.65x4 = 14.6Vmax with Vnom = 12.8V and minimum cut-off = 10.0Vmin .... so if the UPS cuts off maximum voltage between 12.8V and 14.6V then that is acceptable for Vmax. If the UPS cuts off Vmin at higher than 10Vmin, then that is also OK.
HI Roland. My UPS lead acid battery went dead a couple of days back and I had to urgently replace it. And so I replaced it with a Lifepo4 battery pack. The many RUclips videos made on this mod made me decide in doing so. I bought it readymade online. Its rated at 12.8v 6000mAh, and has a BMS. I am running my UPS for the last 8/9 days on this LifePo4 battery.
I have not been running my system when the power cuts off. I get nervous and switch it OFF asap because I am still unsure of this mod.
Is there something that I need to be careful about? Also what about the charging voltage? Will there be a problem with the BMS? Have connected a volt meter to the battery and it shows 13.2v max charge of the battery. But if the power fails, it drops very quickly (almost immediately) to 12.5v. Then it slows down on its discharge rate. Why is this?
Thks for your time.
Hi. Replacing the Lead Acid battery with the readymade LFP pack was a good decision and the UPS will work similarly as before. LFP a very close match in voltage to LA. But still, it is not a 100% match. The initial drop in voltage comes from the LFP charge and discharge curve, which is steep at the ends, but very flat in the middle. Thats very normal. Nevertheless, the onboard charging unit of the UPS will handle it just fine. In my UPS I have noticed that the system will shut down a bit sooner than you might expect from the capacity. So, it's probably only about 85% of energy which you can get out of the battery now. I have also noticed that after a full discharge, the UPS control board will not start charging anymore and I have to bypass the Mosfets on the BMS to reset the unit. This is because the BMS is causing a bit of an extra voltage drop, which at the end seems to be a bit out of specs and the UPS needs a bit of a push to do its job again.
But anyways, an UPS should just keep your PC alive at a power outage, so that you can safely shut down your computer. Never let the UPS run until it dies itself. A small battery like that will only give you 10-15 minutes of time.
@@RolandW_DIYEnergyandMore Thks Roland. BTW, I have also connected a voltage meter to the battery to know how the voltage is dropping. And Also so that I make sure that I keep the battery within a certain range, so that it does not drop below a certain level. It would also help me to know how fast the Battery is discharging and when is the right time to shut down the computer.
@@mediatrix1111 OK, good idea to use a voltage meter. As said, the voltage will keep steady for most parts of the discharge and then suddenly start to drop quickly at the end of the cycle.
@@RolandW_DIYEnergyandMore Noted. So then I guess I might not have enough time to shut down the computer when the voltage meter starts to show the drop. Cause it will be very fast towards the end.
Will have to learn how to work around it by experience.
Thks a bunch Roland. It was good to learn this.
@@RolandW_DIYEnergyandMore thanks for a very interesting video. I replaced a lead acid battery with a lifepo4 battery. I ran the ups until it switched off. But after connecting the mains to the ups nothing happened. With the lead acid battery in the ups it would start charging immediately. Is there no way to overcome this please? I cannot afford to let a backup battery run down and not getting charged again. If this is connected to an alarm system then the alarm will trigger every time the power gets restored from the mains. We get a lot of power failures in my country. Usually for 2 hours at a time but lately up to 4 hours
Are you sure you did the right thing ?! I think the bms input voltage is exactly 12.6 volts. And in the old battery it is charged between 13.8 and 14 volts. Can't your bms burn or more ?! By the way I thought to put some diodes directly to the ups, and put an external charger of 12.6 volts. I would be happy if you answer me in full detail.
BMS for LiFePo4 cells will disconnect the battery at a high voltage of 3.65V per cell, and low voltage of 2.5V per cell. So for this 4 cell pack, the voltage range is 10-14,6V. This is well inside Lead Acid voltage range of the UPS charger, which as you saw stopped charging at around 13,6V. Where do you get the voltage of 12.6 or 3.15V per cell? I think you misunderstand the term of 'nominal voltage', which is 3.2V for LiFePo4. Nominal voltage is just the average voltage of a cell chemistry's voltage range. It is only used to define cells. For LiPo and NMC it is 3,7V, but the voltage range there is 3.0-4.2V...
@@RolandW_DIYEnergyandMore Thanks for your kind reply .I really appreciate it.
Can you answer me some questions ?!
I have lead acid battery UPS.
I want to connect 18650 cells
My BMS charging is written 12.6V
Possible output of BMS for example to a 12V fan.
Now I want to connect the BMS port to the UPS charging port
Is it possible ? After all, about 14 volts will go into the BMS volt input
What can you teach me about this?
I would be very happy for your detailed answers, it will greatly help.
Yes I may not know or do not understand much, for that there are good people (teachers) like you. I thank you on behalf of everyone.
@@user-zg3nb1mk5b26 OK, now I understand. You want to replace Lead Acid by 18650 laptop cells with Lithium Ion chemistry. Sorry to say, but will not work! LiIon cells are unsuitable to replace Lead Avid in 12V systems due to the incompatible voltage range. You would need 3,5 cells in series. 7s 24V and 14s 48V can be done with LiIon. Please don't do it, its not worth the trouble even with using a buck converter to reduce voltage from the onboard charger, as 3s is to little voltage to keep the UPS running for long enough when discharging. 12V must use LiFePo4 cells!
@@RolandW_DIYEnergyandMore if I have a 48v UPS would you recommend I go with liion or lifepo4? thanks
@@frzen technically you can go with a 14s Lion battery as well. I would prefer LFP cell from the safety standpoint especially when you have the UPS somewhere indoors. It will end up to be a decision on which cells you can get easier, right? LFP packs are bulkier as well.
The backgrounds noise is very bad. We cannot hear you.
how about ups charging lifepo4 voltage is 12v?
I believe lifepo4 need 14.5v to charge until full charge
so if ups charge only 12v it will keep charge lifepo4 n never be full?
12V is only nominal rating for Lead Acid batteries, a full charged LA battery will be close to 14.2V, so the charging circuit in the UPS has to be able provide a bit above this to fully charge a LA battery. In older cars it was not uncommon to see over 15V at battery terminals when the battery was being charged by the alternator. Deep Cycle Lead Acid batteries as used in UPSs, I think, are very slightly different in terminal Voltage. Have another look through the comments, it is mentioned that the LiFePO battery will be only very slightly under charged, but this is good for any Lithium based cells as they tend to last longer if not charged to 100% all the time.
Hope this clarifies the situation regarding Your concerns.
Please close your windows before recording. Or use a unidirectional lavaliere microphone.
for this project ,I need to buy 4 pcs of life04 battery with all positive (male) and all negative (female)? is that right? sorry I am a noob at this thing.
Hi, you can use whatever cells you get. They should all have same terminals so that you do not mistake a pole when connecting them ito series. where you have male or femal is not relevant.
@@RolandW_DIYEnergyandMore thank you