That was about 7C since real cell capacity is just around 5Ah. Cell internal resistance decreases with temperature increase so that is the reason you see voltage increases as cell heats up. possible is just for a few seconds keeping the cell within the thermal limits.
You might not want to do the 'sniff test' at a battery cell that is heating up during high discharge. LiFePO4 might not explode/catch fire like a LiPo cell does, but if that cells vents it's electrolyte when you're that close you're going to have a very bad day.
Andy, I just returned to the TH-cam homepage after 4 days of binge watching your entire playlist and I feel like I live in your garage now. Amazing stuff. You’re also the first TH-camr i’ve “bought a beer” for :D Keep up the amazing content.
Wow, thank you for watching all my video and donating a beer. That's amazing. Great stuff. Whenever you may come over for a visit, you know where everything is now 😂
Correct me if I’m wrong but assuming these are more like 5500mah cells wouldn’t the continuous output current be 25Amps @5C rather than the stated 35Amps claimed by the manufacturer? That being said, it good to see these cells put under such harsh test and spreading the information regarding these cells . Great video 👍🏻
Well, in the previous video we went over the specs of the cells and they offered a 35A continues discharge. At 7.2Ah capacity (from the specs) that would be ~5C. But you're right, as the cells have only 5-5.5A a 5C discharge would be around 25A. I'll re-do the test with these figures soon.
Andy, when clamping terminals with the large alligator clips as you have done in this test, I advice you to place several cm of stripped welding cable in between the clip jaws and the terminals/tested piece. This is something I always use when welding as those clamps/clips have one to several contact points to the piece only, instead hundreds when using the multi strands from the welding cable as advised.
Despite the high voltage sag, and putting beside the fact that this is not an actual 7.2Ah cell (more like 5.2Ah) that is actually a much better result than I was expecting. You put any legit high rate lithium 18650 battery through a discharge test like that (35A) it will get basically that hot, though 18650 have less surface area for dissipation and a lower capacity (3Ah). I would say 20A is probably a more realistic rating and that's perfectly acceptable for a cheap cell.
Absolutely, this was a very extreme test and would not occur under normal circumstances. I'll do some more testing and see how they perform. I'm very pleased with the result and performance of these cells though.
Not just me then 👍 I thought that was a 7 C rate 🤔 still enjoyed it though 😎 Andy your my kind of nutcase 🤣 i wonder how much this test damaged the cell 🤔 I love this channel 😁👍👍👍
When the cell increases in temperature the chemistry inside gets more efficient hence the voltage goes up. When the temperature goes beyond where the chemistry is effective the voltage drops again. There are ev racing teams that heat their cells to increase the efficiency and draw more current from their cells
Tesla heats the battery to 55°C when supercharging. I tested this several times on my other channel. The same happens while charging with DC at any speed. Even a 'slow' 50kW charging heats it up this way. Hence I try to avoid any DC charging with mine.
LiFePO4 cells operate most efficiently at around 55degrees C, as the temperature increases the diffusion through the thick layers of LiFePO4 improves and allows the chemical reactions to proceed more efficiently. LiFePO4 cells are pretty robust, with significant damage only really occurring at temperatures higher than about 80degrees C. That said, there is likely a thermal gradient inside the cell, so reading 70+c on the case, the cell probably has internal hotspots to 80+. The rising voltage of the cells is pretty normal when they are at such a low temperature as they heat up, the chemistry becomes more active (more kinetic energy means chemicals are more likely to bump into each other for the reactions to take place/move forward, the faster the reactions can occurred the lower the chemistry portion of the internal resistance).
Thank you, great explanation. Tesla is heating up their batteries while DC fast charging deliberately to decrease charging time for the same reason. I have seen temperatures of 55°C while supercharging.
The voltage goes up during the discharge because the internal resistance decreases as they warm up. Heat is good for efficient discharge but bad for the "calendar life"/"cycle life" of the battery.
I know, that's what Tesla does during high power charging. They deliberately heat up the battery to over 50°C to increase charging speed. Hence I almost never do DC fast charging...
Hello Andy I live in the US and fish bass tournaments out of an electric boat. I was using 4 12v 150ah fork lift batteries in series for my 48v system. My electric motor pulls 175amps wide open and would pull the batteries down very quickly. I was getting about 65 ah on a victron 712 before the batteries hit 50%. I knew I had to change over to Lifepo4 batteries and I search high and low on the internet looking for tips on how to build a 48v pack. When I ran across your videos I hit the jackpot. I took your advise and purchased 16 eve 280ah batteries and copied your pack. I used a Daly smart bms because at the time I ordered you were having problem with the relay on your bms. I am not having any problems with my new battery pack I run the boat wide open every where I go. The most I have pulled out of the pack is 175 ah. I would like to let you know I appreciate all the work you put into your videos. Thank You Doug Hearn
Thanks so much for sharing and your kind words, Doug! What a great story and success! The Daly BMS is certainly the right choice for this battery and will work well. How do you charge the battery? Do you have a solar roof on the boat? Probably not when you do fishing...
@@OffGridGarageAustralia no I don't have any solar I use a NOCO 48 volt charger. The noco is the only charger on the market that I know of that will charge any type of battery including lithium iron phosphate.
@@douglashearn7175ok the waterproof part is a cool factor but there are many 48v capable chargers actually! I’ve been using such chargers it feels almost my whole life lol I’ve been doing professional radio controlled toys for many years and we probably are the first to begin utilizing lipo batteries on the consumer level as far back as 2007 I was flying a full cnc billet 3d helicopter pulling a constant 30 amps of power flying with a 11.1v 2200mah 1C lipo pack!!4-10min runtime depending on how you managed throttle input but needless to say it got the job done lol! I should point out batteries tech was at the worst then and man when we were introduced to 3c batteries let me just tell you GAME CHANGER 😂 why I tell you this is because the batteries in this video would have powered the international space station back in those time. But ya about the chargers for anyone who wants a badass all around top tier charger which will do up to a 12s battery and that just over 50volts then the next step up is the isdt 16s commercial charger which will require you to have high input voltage power supplies cheers 😊
I’ve had so many batteries puff on me an and heat up and out gas as well as catch on fire during use that nothing anymore with lithium should be taken for granted and don’t be sticking your face that close you can permanently loose your smell and vision
Nice video! What do you think of these little cells instead of the Big lifepo4 cells? And why did you move to Australia as a German (glaube ich) ? Keep on doing these nice videos! I love them! Greetings from Switzerland
I think those cells are toast. I have a 8 cell battery of what looks the same cells, but branded LiitoKala, but they are marked as 7000mAH. After some testing, 5000mAh seems a conservative but realistic number. Still, they WERE very cheap (cheaper than other 5000mAH cells), so I only expected them to give me 5000mAH, but I sort of hoped, beyond hope ... so, I have a cheap 12V 10A battery (and two spare cells, because I bought 10 just in case). But, at less than half the price of a ready made one of that capacity, and it was fun in making and testing.
Unrelated to this video, I am curious about your opinion on the following: In my 48v 310ah 16s Lifepo4 battery, I find the BMS to be superfluous. Once top balanced, when I set absorption to 54.4, there is zero chance any individual cell would ever be over 3.65v. Conversely, at a 46.4 battery cutoff, again, highly unlikely any cell would be under 2.5v, which is arguably less catastrophic than over voltage. With these conservative charging and discharging parameters of a properly top balanced battery, a BMS may be entirely unnecessary. Care to reply? Love your series, and thought I was the only one playing with Lifepo4!
I would always recommend a BMS. You can turn off balancing though, I agree. As you said it's unlikely, but still possible that on cells reaches higher/lower voltages. You always want the BMS to be the final system to disconnect in either a single cell or the battery as such reaches a dangerous voltage. Imaging your solar charge controller is faulty and lets 120V through to the battery... The battery costs you $3k and you should not spare on $200 for a BMS.
I have noticed my headway cells perform better when warm. That is an interesting curve though. Really neat to see it on a graph I want one of those testers more and more
All LiFeP04 performs best over 15C. Sweet spot is 25C to 35C...technically warmer than that but then you are balancing slightly. better performance with cell degradation C here means Celsius
Impressive performance from these cells. Cars have water cooled bats to cope with extreme charge/discharge rates. And to be fair to the bats they did deliver 35A to their real capacity, it's pretty impressive really
cell number 4 warmed up watching his brothers torture test. still thinking of buying some for a tiny lightweight bank to maintain my delta2 !!!but thinking of how many bad cells might find plus they come expensive in europe more than 15 euros each one
Grab you a cheap FLIR video unit for a cell phone and you can just watch temps live w/ out having to use the IR gun. They're pretty cheap these days. Your hot terminal from different mounting also shows how those who always say "make sure bus bars are flat and fully touching" don't really understand that something like a star washer that allows much firmer contact to a battery and related busbar is actually better than trying to make something "flat". That's why jumper cables have nice large teeth. Don't need lots of contact, just need really good contact.
@@OffGridGarageAustralia There is a company selling battery cells called LiitoKala on Alibaba - that means 'Flying Fish' in Finnish. I wonder sometimes who decides company names over there :)
You should have put a temp probe on the hottest part of the cell & recorded the temp & V on the same graph. The cell chemistry obviously performs less efficiently below 23 C & better until it reaches it's upper temp threshold--then it begins to lose V as the temp increases.. The truth is--the cell did perform at 35A discharge current--so far, it just doesn't have the rated Ah capacity. It's also questionable as to how many cycles the cell will last & how much capacity it loses with each cycle--which you'd need a programmable system to test & record the data--as well as let it cool down between cycles unless you can keep the temp 25C
I don't have a device which records temperature and create a graph so it would fit into the EB Software graph. This in itself would be a challenge already.
@@OffGridGarageAustralia You can use a NTC thermistor & an Arduino to record the thermistor resistance & convert the resistance into °C & also the date & time. My guess is that your charger software allows you to import a Temp vs time dataset...
Hey Andy! Need you help . You have mentioned in this video that the cells are charged at 3.6v and on the time of you experiment it is 3.341v. My question is: 1. Is it normal for every LifePO4 cell ?? 2. Or any other circumstances it will be changed? 3. Reason behind it. I think I will get correct answer from you. Waiting for your answer 😊😊
LiFeP04 settles when removed from the charger. Most cells settle between 3.35 and 3.45. There is really no capacity in the very upper voltage range which is why some people only charge up to 3.5 or 3.6
you should have discharged at a 25% lover rating as its capacity is 25% lower and then do a test i'am watching video and you have just said what i was telling you
"Why do they advertise such specifications?" Well, they sell lead acid batteries since decades, and they get destroied if you use the specified capacity. 😲 Very funny video, I like it! 🤣
Hi Andy, I really onjoy 😁your educational tests! If you have c tested for 5000 mah would it not have been fair to have tested it at 25 A as a 5c test, I suspect it might perform better, would like to see this test. Koos, from sunny hot N-Freestate South Africa. 🤪
Thanks, Koos. Yes, that would have been fair, but I wanted to test the battery as per the specs they hand out to customers. Not everyone is doing capacity tests before using such batteries and if the specs say 5C, it is 5C out of 7.2Ah.
The specks are based on 7.2ah,So 5C is 25,think about it.I'd like to see the test at 25 ah,could be interesting.andPS the price is too high. Can't wait for results Andy
Do the cells need a few cycles to get full capacity? I would also assume the cells were warm when capacity was tested and with a very low rate. So charge to 4V. Heat to 160F. Discharge at 1A down to 2V.
The product link on your webpage for these batteries leads nowhere. I'd like to see their actual price where you bought them from cause at one point you said $0.9/cell later you said $6/cell. At $0.9 it would still be great deal even for 5Ah.
They're $0.9 from Alibaba but he bought them on AliExpress for $6... You can find 32650 or 32700 cells on Alibaba even cheaper. I do wonder how good they are though..?
I think you need to fact check. Does it say you can do 5C continuously or is that the max peak short term surge without destroying the battery? Specs I have seen says Max pulse discharge is 5c but only for a few ms. It also says at max pulse current you can only expect to get 2V.
Keep those glasses on when doing the sniff test, mighty close if it decides to "erupt". Yes, I ordered an infrared camera and expect it this week from China.
Nah, that does not make a difference at all. If they would be 40°C there would be a difference. They like it hot to perform better which is bad for the longevity of the cells.
Good test except all the drama/BS :-p I'd call that a good result. Not sure about the longevity, but it produced 90% of the capacity under max load, which is pretty good. You could parallel up a bunch of them and the current density would be impressive. I dare you to do a 200A constant discharge of a Headway 38120HP or two. I've done that quite a few times, they'll do 325A from 8AH capacity, but much bigger than those. 200A also sits around 2.6V per cell, FYI.
Yes, I also think they have done well and could deliver the 35A. That was a very extreme test which will not occur under normal circumstances unless someone has designed the battery completely wrong.
@@OffGridGarageAustralia Yeah, you wouldn't do that to them continuously till flat, but you would do that to them intermittently. If you took 36 to 40 of them you'd have a hair less or more current density than the Headway setup for about twice the money, but you'd also have over 6x the capacity. Might place an order at some point and see how they go for automotive starting applications.
Hi Andy I don't think you should be handling this thing while its charging you don't want to loose your hand if it decides to go wrong be careful best wishes from South Africa
@@OffGridGarageAustralia I know that you're not supposed to have to run fans on a battery but clearly if you're going to run that battery it will have to have a fan lol
got lucky lithium did not go in thermal runaway at about 50°C Maybe LiFePO4 chemistery improved greatly and electrolyte did not evaporate at 71°C. Have a sand crate in the vicinity and a pair of big pryers to throw the battery in ( in case of thermal runaway or fire )
Why should a 5C discharge take one hour? Would be 12 Minutes, if you would get the full capacity at such a current... And with the real capacity beeing much lower, the 8 Minutes fit perfect. Also the discharge with real 5C instead of 35 Amps, i guess it stays under 60°C, which should be a acceptable maximun. You seem to have fun torturing... However, the curve is really cool. Thanks for sharing :-)
It’s really not that funny. You kind would kind of expect them to be close to or at limits when maxed out. They quote 5C and translate it to 35A but, as they are actually 5Ah perhaps they should have quoted 25A. I think they stood upto it quite well really and I imagine the missing capacity between tested and delivered is what produced the heat in the internal resistance, I suppose from this one could calculate a Peukert Number for them!
The specs say 35A. At the rated 7.2Ah, that's close to 5C. I'm going with the specs here. 25A would be the real 5C for the measured capacity which is still a lot of amps for these small cells.
Puts glasses on after doing sniff test with face up in that battery's business hahahahaha funny bugger. Yes no surprise on that epic fail of a cheap cell claiming 5c discharge. Thanks for a good watch and its good to see these things actually play out and to see the curve.
@@OffGridGarageAustralia yip the are 6 or 5.5 ah cells . We pay about 1.78 usd fir quality 32700 cells. As we don’t trust 50/100 ah cells as they tend to be old cells from busses. So we manf up to 750 volt packs using the 6 ah cells . Always guaranteed to be a new cell 😂
072621/0054h PST 🇺🇸 Brisbane 🇦🇺 072621/1754h Hello and good evening. That was insane, indeed. 171F! Thanks for exposing. Typographical labeling error, may be? Aw well… time for Oettinger und smooth Jazz.. ahhh.. Stay safe und 73s…
please if you do something like this again have the cells in a bucket of sand we dont wont you burning your garage down from a cell going into thermal runaway
@@OffGridGarageAustralia better connections and thicker / solid conductors = little to no stranded in high amp locations . I prefer non welded battery connections .
If I'm not mistaken the internal resistance decreases as the temp increased so battery voltage recovered a tiny bit until the chemistry was nearing drained and the final collapse. 35amp on a 5k battery is about 7C. The outside temp might have been in the 40s-50s but it's much higher inside. Have not seen later videos but there's a good chance the battery was damaged during this test. You use the words 'specifications' when you really mean aliexpress sales blah, blah, blah. It's lies used to sell product, and unless you know better you think....oh that's better than the other advertisement. We all get lied too when buying from shady sources. It's not specs, and even if they had a datasheet are they reputable as a company? if not, datasheets can lie as well. Beware.... You should name your test batteries, sh*tty and sh*ttier. As you said in your first video, if they would have labeled them as 5000ma you would have been happy. As for 5C testing, no battery does well at 5C but some do better than others.
I cringe every time you do the smell test! Full facial mask should be used; which kind of defeats the purpose of the whole exercise. Maybe a facial mask with two 1/8 inch holes to minimize the damage would be prudent.
As u can see your Battery's are way too cold! As the temperature rises the internal resistance gets lower and the voltage drop is smaller so the voltage on the clamps rise. And this battery has a thermal mass. If this cold cell with a high internal resistance gets stressed, more heat produces an this is not direct on the outside and has to move first to the outside. As I would say: Alter, f*ck nicht deine Akkus, sonst f*icken sie zurück. Also lass deine Akkus vorher mal auf Betriebstemperatur kommen, bevor du die so dermaßen stresst! Meine Fresse ey, da kann ja wohl echt nicht wahr sein... Tut das echt not leuten im Internet zu zeigen, wie man Zellen misshandelt? Nachher schaut's einer, der nicht den großen plan hat und macht das mit nem LiPo... Denk mal bitte 2 Cent weiter. Ehrlich, ich mag deine Videos und habe mir auch an einigen Dingen ein positives Beispiel genommen, aber das heute hat mir nur gezeigt: 1. Du bist irre! 2. Ich werde zusehen, dass mein LiFePo4 nicht zu kalt wird um Stress von der Zelle zu nehmen.
@@OffGridGarageAustralia for testing under cold conditions? If they where warmer (say 30°C) an you discharge them with 1C, I think you will get more than 5Ah of Capacity. I think they lie with 7200mAh, but have more than u testet in the 2 Videos. All around the world specs are given under ideal conditions. Mostly... So u could test one under better conditions on temperature and get some better results for the capacity. Certainly not 7200 but I expact around 6000mAh.
@@launacorp Yeah, the cells were cold'ish with only 17°C but I doubt we will see a better result even at 30°C. I may increase a few mAh but won't give us the full capacity either.
That was about 7C since real cell capacity is just around 5Ah. Cell internal resistance decreases with temperature increase so that is the reason you see voltage increases as cell heats up.
possible is just for a few seconds keeping the cell within the thermal limits.
You might not want to do the 'sniff test' at a battery cell that is heating up during high discharge. LiFePO4 might not explode/catch fire like a LiPo cell does, but if that cells vents it's electrolyte when you're that close you're going to have a very bad day.
Loved the tests Andy! Content like this keeps me coming for more videos. Not only it's informative, it is also super fun to watch!
Thank you Rodrigo! 😉
the voltage going up must be the temp the cell is at its most efficient to transfer electrons
Yeah, He measured 5500 Mah yesterday in his frozen garage. .0083 ohms he measured yesterday at 35 amps is over 10 watts. Kind of a heater in my book.
Crazy test results! You never disappoint Andy!
Andy, I just returned to the TH-cam homepage after 4 days of binge watching your entire playlist and I feel like I live in your garage now. Amazing stuff. You’re also the first TH-camr i’ve “bought a beer” for :D Keep up the amazing content.
Wow, thank you for watching all my video and donating a beer. That's amazing. Great stuff. Whenever you may come over for a visit, you know where everything is now 😂
Correct me if I’m wrong but assuming these are more like 5500mah cells wouldn’t the continuous output current be 25Amps @5C rather than the stated 35Amps claimed by the manufacturer? That being said, it good to see these cells put under such harsh test and spreading the information regarding these cells . Great video 👍🏻
Well, in the previous video we went over the specs of the cells and they offered a 35A continues discharge. At 7.2Ah capacity (from the specs) that would be ~5C.
But you're right, as the cells have only 5-5.5A a 5C discharge would be around 25A. I'll re-do the test with these figures soon.
Andy, when clamping terminals with the large alligator clips as you have done in this test, I advice you to place several cm of stripped welding cable in between the clip jaws and the terminals/tested piece. This is something I always use when welding as those clamps/clips have one to several contact points to the piece only, instead hundreds when using the multi strands from the welding cable as advised.
Despite the high voltage sag, and putting beside the fact that this is not an actual 7.2Ah cell (more like 5.2Ah) that is actually a much better result than I was expecting. You put any legit high rate lithium 18650 battery through a discharge test like that (35A) it will get basically that hot, though 18650 have less surface area for dissipation and a lower capacity (3Ah). I would say 20A is probably a more realistic rating and that's perfectly acceptable for a cheap cell.
Absolutely, this was a very extreme test and would not occur under normal circumstances.
I'll do some more testing and see how they perform. I'm very pleased with the result and performance of these cells though.
I watch your videos in the morning, Andy. Your enthusiasm makes my day. Thanks, mate. Bloody ripper.
Hahaha, thanks a lot! 😁
Given that they tested with an ACTUAL capacity of 5200 mah, should you test them at 25 or 26 amps continuous draw?
i agree
I'd be interested in seeing a normal capacity re-test after this 5C test.
It says 35A continues discharge current in the specs.
Not just me then 👍
I thought that was a 7 C rate 🤔 still enjoyed it though 😎 Andy your my kind of nutcase 🤣 i wonder how much this test damaged the cell 🤔
I love this channel 😁👍👍👍
@@OffGridGarageAustralia - That's true, but it also "says" 7,200 mah, which we know was a lie! :D
Nice test! You crack me up mad scientist!
Sniffle test, ha! They are BS!
When the cell increases in temperature the chemistry inside gets more efficient hence the voltage goes up. When the temperature goes beyond where the chemistry is effective the voltage drops again. There are ev racing teams that heat their cells to increase the efficiency and draw more current from their cells
Very interesting. Specs are most often at room temperature. It wouldn't surprise me that they are more efficient at say....40 deg C.
I bereave Tesla for instance conditions its batteries on the way to a supercharger and deliberately lets them get a bit warmer than usual.
40degC is roughly the temperature that Teslas auotomatically preheat their batteries to when driving to a Supercharger so this all makes sense.
Tesla heats the battery to 55°C when supercharging. I tested this several times on my other channel. The same happens while charging with DC at any speed. Even a 'slow' 50kW charging heats it up this way. Hence I try to avoid any DC charging with mine.
Thanks for another informative and funny video.
Thanks for this very informative and fun test!
Thank you.
LiFePO4 cells operate most efficiently at around 55degrees C, as the temperature increases the diffusion through the thick layers of LiFePO4 improves and allows the chemical reactions to proceed more efficiently.
LiFePO4 cells are pretty robust, with significant damage only really occurring at temperatures higher than about 80degrees C. That said, there is likely a thermal gradient inside the cell, so reading 70+c on the case, the cell probably has internal hotspots to 80+.
The rising voltage of the cells is pretty normal when they are at such a low temperature as they heat up, the chemistry becomes more active (more kinetic energy means chemicals are more likely to bump into each other for the reactions to take place/move forward, the faster the reactions can occurred the lower the chemistry portion of the internal resistance).
LiPo chemistries are much less stable than LiFePO4 chemistries though so are much more prone to degradation and runaway at higher temperatures
Thank you, great explanation.
Tesla is heating up their batteries while DC fast charging deliberately to decrease charging time for the same reason. I have seen temperatures of 55°C while supercharging.
The voltage goes up during the discharge because the internal resistance decreases as they warm up. Heat is good for efficient discharge but bad for the "calendar life"/"cycle life" of the battery.
Agree, since discharging a battery is a chemical process, this reaction (like most others chemical reactions) gets faster with higher temperatures.
I know, that's what Tesla does during high power charging. They deliberately heat up the battery to over 50°C to increase charging speed. Hence I almost never do DC fast charging...
Hello Andy
I live in the US and fish bass tournaments out of an electric boat. I was using 4 12v 150ah fork lift batteries in series for my 48v system. My electric motor pulls 175amps wide open and would pull the batteries down very quickly. I was getting about 65 ah on a victron 712 before the batteries hit 50%. I knew I had to change over to Lifepo4 batteries and I search high and low on the internet looking for tips on how to build a 48v pack. When I ran across your videos I hit the jackpot. I took your advise and purchased 16 eve 280ah batteries and copied your pack. I used a Daly smart bms because at the time I ordered you were having problem with the relay on your bms. I am not having any problems with my new battery pack I run the boat wide open every where I go. The most I have pulled out of the pack is 175 ah. I would like to let you know I appreciate all the work you put into your videos.
Thank You
Doug Hearn
Thanks so much for sharing and your kind words, Doug! What a great story and success! The Daly BMS is certainly the right choice for this battery and will work well.
How do you charge the battery? Do you have a solar roof on the boat? Probably not when you do fishing...
@@OffGridGarageAustralia no I don't have any solar I use a NOCO 48 volt charger. The noco is the only charger on the market that I know of that will charge any type of battery including lithium iron phosphate.
I should have mentioned the noco is an on board waterproof charger it travels with the boat
@@douglashearn7175ok the waterproof part is a cool factor but there are many 48v capable chargers actually! I’ve been using such chargers it feels almost my whole life lol
I’ve been doing professional radio controlled toys for many years and we probably are the first to begin utilizing lipo batteries on the consumer level as far back as 2007 I was flying a full cnc billet 3d helicopter pulling a constant 30 amps of power flying with a 11.1v 2200mah 1C lipo pack!!4-10min runtime depending on how you managed throttle input but needless to say it got the job done lol! I should point out batteries tech was at the worst then and man when we were introduced to 3c batteries let me just tell you GAME CHANGER 😂 why I tell you this is because the batteries in this video would have powered the international space station back in those time. But ya about the chargers for anyone who wants a badass all around top tier charger which will do up to a 12s battery and that just over 50volts then the next step up is the isdt 16s commercial charger which will require you to have high input voltage power supplies cheers 😊
I’ve had so many batteries puff on me an and heat up and out gas as well as catch on fire during use that nothing anymore with lithium should be taken for granted and don’t be sticking your face that close you can permanently loose your smell and vision
Thanks for testing these. Great information.
Nice video! What do you think of these little cells instead of the Big lifepo4 cells? And why did you move to Australia as a German (glaube ich) ? Keep on doing these nice videos! I love them! Greetings from Switzerland
I suspect that the internal heating up is also pressing the layers as a result the voltage coming up a little because of better conductivity.
Higher temperature lowers the internal resistance, hence the voltage at the terminal rises. I hope there was no internal compressing as you said 🤔
@@OffGridGarageAustralia , as you know heating up material is expanding.
I think those cells are toast. I have a 8 cell battery of what looks the same cells, but branded LiitoKala, but they are marked as 7000mAH. After some testing, 5000mAh seems a conservative but realistic number. Still, they WERE very cheap (cheaper than other 5000mAH cells), so I only expected them to give me 5000mAH, but I sort of hoped, beyond hope ... so, I have a cheap 12V 10A battery (and two spare cells, because I bought 10 just in case). But, at less than half the price of a ready made one of that capacity, and it was fun in making and testing.
Yeah, even at 5Ah, they still seem to be a good deal.
hi andy, if we assume it is 5ah cell, can you do a test in 25a ? i'm keen to see the result.
Yes, will do it tonight.
Unrelated to this video, I am curious about your opinion on the following:
In my 48v 310ah 16s Lifepo4 battery, I find the BMS to be superfluous. Once top balanced, when I set absorption to 54.4, there is zero chance any individual cell would ever be over 3.65v. Conversely, at a 46.4 battery cutoff, again, highly unlikely any cell would be under 2.5v, which is arguably less catastrophic than over voltage. With these conservative charging and discharging parameters of a properly top balanced battery, a BMS may be entirely unnecessary.
Care to reply? Love your series, and thought I was the only one playing with Lifepo4!
I would always recommend a BMS. You can turn off balancing though, I agree. As you said it's unlikely, but still possible that on cells reaches higher/lower voltages. You always want the BMS to be the final system to disconnect in either a single cell or the battery as such reaches a dangerous voltage. Imaging your solar charge controller is faulty and lets 120V through to the battery...
The battery costs you $3k and you should not spare on $200 for a BMS.
Great fun, LOL, just be careful it doesn't explode.
I am. they don't do that unlike Li-ion. They will swell a lot before anything happens.
I have noticed my headway cells perform better when warm. That is an interesting curve though. Really neat to see it on a graph I want one of those testers more and more
All LiFeP04 performs best over 15C. Sweet spot is 25C to 35C...technically warmer than that but then you are balancing slightly. better performance with cell degradation
C here means Celsius
the more the cell heated up the more Andy was LOL.I couldnt help but laugh along
You never know where such experiments end up so, I cannot help myself... 😁
Impressive performance from these cells. Cars have water cooled bats to cope with extreme charge/discharge rates. And to be fair to the bats they did deliver 35A to their real capacity, it's pretty impressive really
but failed the temperature safety cutoff limit. Should cut off at 60 Celsius
Thanks Andy
cell number 4 warmed up watching his brothers torture test. still thinking of buying some for a tiny lightweight bank to maintain my delta2 !!!but thinking of how many bad cells might find plus they come expensive in europe more than 15 euros each one
Grab you a cheap FLIR video unit for a cell phone and you can just watch temps live w/ out having to use the IR gun. They're pretty cheap these days. Your hot terminal from different mounting also shows how those who always say "make sure bus bars are flat and fully touching" don't really understand that something like a star washer that allows much firmer contact to a battery and related busbar is actually better than trying to make something "flat". That's why jumper cables have nice large teeth. Don't need lots of contact, just need really good contact.
Finnish word "palo" means "fire" in general. "Tulipalo" happens to house etc. "Tuli" means almost "flame". Maybe name is sort of prediction 😎
AHHHH, good one! That's were the name comes from 😊
@@OffGridGarageAustralia There is a company selling battery cells called LiitoKala on Alibaba - that means 'Flying Fish' in Finnish. I wonder sometimes who decides company names over there :)
Lmao! Andy is testing hard... "Burning Down The House " pop music tune plays in background lol Cheers buddy great show!
Nothing burns down, all tests have been done under safe SGTC (Standard Garage Test Conditions)
it takes a man to sniff a chinese battery at 5C with no saftey goggles
Indeed!
:-)
You should have put a temp probe on the hottest part of the cell & recorded the temp & V on the same graph.
The cell chemistry obviously performs less efficiently below 23 C & better until it reaches it's upper temp threshold--then it begins to lose V as the temp increases..
The truth is--the cell did perform at 35A discharge current--so far, it just doesn't have the rated Ah capacity. It's also questionable as to how many cycles the cell will last & how much capacity it loses with each cycle--which you'd need a programmable system to test & record the data--as well as let it cool down between cycles unless you can keep the temp 25C
I don't have a device which records temperature and create a graph so it would fit into the EB Software graph. This in itself would be a challenge already.
@@OffGridGarageAustralia You can use a NTC thermistor & an Arduino to record the thermistor resistance & convert the resistance into °C & also the date & time. My guess is that your charger software allows you to import a Temp vs time dataset...
Hey Andy! Need you help .
You have mentioned in this video that the cells are charged at 3.6v and on the time of you experiment it is 3.341v.
My question is:
1. Is it normal for every LifePO4 cell ??
2. Or any other circumstances it will be changed?
3. Reason behind it.
I think I will get correct answer from you.
Waiting for your answer 😊😊
LiFeP04 settles when removed from the charger. Most cells settle between 3.35 and 3.45. There is really no capacity in the very upper voltage range which is why some people only charge up to 3.5 or 3.6
you should have discharged at a 25% lover rating as its capacity is 25% lower and then do a test i'am watching video and you have just said what i was telling you
"Why do they advertise such specifications?" Well, they sell lead acid batteries since decades, and they get destroied if you use the specified capacity. 😲
Very funny video, I like it! 🤣
Hi Andy, I really onjoy 😁your educational tests! If you have c tested for 5000 mah would it not have been fair to have tested it at 25 A as a 5c test, I suspect it might perform better, would like to see this test. Koos, from sunny hot N-Freestate South Africa. 🤪
Thanks, Koos. Yes, that would have been fair, but I wanted to test the battery as per the specs they hand out to customers. Not everyone is doing capacity tests before using such batteries and if the specs say 5C, it is 5C out of 7.2Ah.
The specks are based on 7.2ah,So 5C is 25,think about it.I'd like to see the test at 25 ah,could be interesting.andPS the price is too high. Can't wait for results Andy
OK, I do a new test... 😉
danke
Do the cells need a few cycles to get full capacity? I would also assume the cells were warm when capacity was tested and with a very low rate. So charge to 4V. Heat to 160F. Discharge at 1A down to 2V.
They should have full capacity without cycling. Both cells were at 14°C when I started the test.
@@OffGridGarageAustralia I guess I am wondering if they cheated by using really crazy testing conditions, or if they outright lied. LOL.
The product link on your webpage for these batteries leads nowhere. I'd like to see their actual price where you bought them from cause at one point you said $0.9/cell later you said $6/cell. At $0.9 it would still be great deal even for 5Ah.
The shipping is a buck a cell.
They're $0.9 from Alibaba but he bought them on AliExpress for $6... You can find 32650 or 32700 cells on Alibaba even cheaper. I do wonder how good they are though..?
Rokas, just checked the link and it works fine in several browsers and on several devices.
off-grid-garage.com/batteries/
@@OffGridGarageAustralia Yep, works for me! Thanks Andy 👍
"ONE POINT TWENTY-ONE GIGAWATTS?!?!"
We were so close! 🤣
That is really badass Andy! :) "So you got shot? Well, I sniffed on batteries while discharge them at 5C without protection" :)
I disconnected them before sniffing. Just for safety reasons.
I think you need to fact check. Does it say you can do 5C continuously or is that the max peak short term surge without destroying the battery? Specs I have seen says Max pulse discharge is 5c but only for a few ms. It also says at max pulse current you can only expect to get 2V.
Do we need to stage an intervention?
What happens if you charge the cells in reverse polarity?
Keep those glasses on when doing the sniff test, mighty close if it decides to "erupt". Yes, I ordered an infrared camera and expect it this week from China.
Yep, correct.
It’s your starting temp . If it was 25 deg I think it maybe higher
Nah, that does not make a difference at all. If they would be 40°C there would be a difference. They like it hot to perform better which is bad for the longevity of the cells.
Didn't you know they get hot!! That's how they shrunk wrap them Ha Ha Ha
Hahaha, maybe, yeah!
Are you sure that cell is not a heating element instead of a battery?
It looks like it at these rates...
Good test except all the drama/BS :-p I'd call that a good result. Not sure about the longevity, but it produced 90% of the capacity under max load, which is pretty good. You could parallel up a bunch of them and the current density would be impressive. I dare you to do a 200A constant discharge of a Headway 38120HP or two. I've done that quite a few times, they'll do 325A from 8AH capacity, but much bigger than those. 200A also sits around 2.6V per cell, FYI.
Yes, I also think they have done well and could deliver the 35A. That was a very extreme test which will not occur under normal circumstances unless someone has designed the battery completely wrong.
@@OffGridGarageAustralia Yeah, you wouldn't do that to them continuously till flat, but you would do that to them intermittently. If you took 36 to 40 of them you'd have a hair less or more current density than the Headway setup for about twice the money, but you'd also have over 6x the capacity. Might place an order at some point and see how they go for automotive starting applications.
but they failed in regards to temp. Should cut off at 60 Celsius
Do you have any Alibaba link for these batteries? I want to build a 31S11P battery pack for an electric motorcycle (96v 10Kw (peak 20Kw))
Hi Andy I don't think you should be handling this thing while its charging you don't want to loose your hand if it decides to go wrong be careful best wishes from South Africa
That is LiFePO4, they don't suddenly explode or start a fire.
Put a fan on the battery, there is a reason power stations have fans and them, they get hot.
Hahaha, nah, that's not the problem....
@@OffGridGarageAustralia I know that you're not supposed to have to run fans on a battery but clearly if you're going to run that battery it will have to have a fan lol
Do the test over at the spec. temp.
How do I keep it that cold though? A fan would not be enough.
@@OffGridGarageAustralia What are they spec.ed at? Less than 14C?
You kept saying that a 5C test would fully deplete the cell in one hour but 5C would be 60 min / 5 = 12 minutes to empty.
Ha, you had several days now to find that out, I was recording on the fly 😉
You should have placed the cell on a ice pack during the test to keep the temp down
Some cold beer might have helped 🍺
Well 35A squared times 8mOhms = About 10W of heat to dissipate in a smallish package so no wonder the heat!
got lucky lithium did not go in thermal runaway at about 50°C
Maybe LiFePO4 chemistery improved greatly and electrolyte did not evaporate at 71°C.
Have a sand crate in the vicinity and a pair of big pryers to throw the battery in ( in case of thermal runaway or fire )
That happens at 80+°C. There was still a bit of room when I hit the 71°C. But not much...
Why should a 5C discharge take one hour? Would be 12 Minutes, if you would get the full capacity at such a current...
And with the real capacity beeing much lower, the 8 Minutes fit perfect.
Also the discharge with real 5C instead of 35 Amps, i guess it stays under 60°C, which should be a acceptable maximun.
You seem to have fun torturing...
However, the curve is really cool. Thanks for sharing :-)
It says in the specs 'continues discharge current: 35A'. So I went with this.
Kannste dir ja prima Taschenwärmer fürn Winter bauen 😬😅
Winter?
@@OffGridGarageAustralia unter 25°c ist doch Winter in Down Under oder?🤔
It’s really not that funny. You kind would kind of expect them to be close to or at limits when maxed out. They quote 5C and translate it to 35A but, as they are actually 5Ah perhaps they should have quoted 25A. I think they stood upto it quite well really and I imagine the missing capacity between tested and delivered is what produced the heat in the internal resistance, I suppose from this one could calculate a Peukert Number for them!
I think they sell used cells because 7000mha is the new capacity and 70% of that is 5000mha
Junk , always have Ben , No mater the chemistry . I call them Fire starters !
I hope the "Tables Battery" that Tesla's Working on keeps it's COOL !
5c would be 25A because it tested to be 5Ah. and why not test it by raising the current gradually?
The specs say 35A. At the rated 7.2Ah, that's close to 5C. I'm going with the specs here.
25A would be the real 5C for the measured capacity which is still a lot of amps for these small cells.
Puts glasses on after doing sniff test with face up in that battery's business hahahahaha funny bugger. Yes no surprise on that epic fail of a cheap cell claiming 5c discharge. Thanks for a good watch and its good to see these things actually play out and to see the curve.
hast du keine bedenken gehabt das die Zelle in Brand gerät? Please dont't burn down the Off-Grid Garage!
That's LiFePO4. It will take a lot before they start a fire. Unlike Li-ion. Alles gut, alles unter Kontrolle 😉
Wow
Test them as 6 ah at 1 c and 3 c they should be fine
Yes, they will be fine. I think they are good cells, even with 5.5Ah.
@@OffGridGarageAustralia yip the are 6 or 5.5 ah cells . We pay about 1.78 usd fir quality 32700 cells. As we don’t trust 50/100 ah cells as they tend to be old cells from busses. So we manf up to 750 volt packs using the 6 ah cells . Always guaranteed to be a new cell 😂
Get them while their HOT !!!! ;-). That smell is probably the electrolytes , Wash your hands !
I wonder how many recharges ?
I know it’s cold where you are but using lithium batteries as a space heater is probably not advised - ahahah…
It was like 15°C in the garage so not too cold. Extreme test with very good result, I guess.
Palo: Pay low price and get low Ah.
I'm off to sniff test my new battery in my camper 😁
LiFeP04 smells like wee to me 🤔
FLA smells like fart 🤔
I wonder what NiCad smells like 🤣🤣
072621/0054h PST 🇺🇸 Brisbane 🇦🇺 072621/1754h Hello and good evening. That was insane, indeed. 171F!
Thanks for exposing. Typographical labeling error, may be? Aw well… time for Oettinger und smooth Jazz.. ahhh..
Stay safe und 73s…
All of these batteries are labelled the same 7.2Ah. If this is an error, someone should have noticed that by now 😁
please if you do something like this again have the cells in a bucket of sand we dont wont you burning your garage down from a cell going into thermal runaway
Good point. Though, these are LiFePO4 not LiPo, they will not be as violent in a self-destruct. I'd actually like to see one pop :P
@@rokask yeah i know they are safer but would you really wont to take the chance
@@1981dasimpson Lemme rephrase that - do really not won't to see it happen? :P
Andy is a professional extreme tester. He was ready to put out any fires with his face, Respect.
@@rokask if it was outside yes if it was going to risk his garage then no
Remember Heat is wasted ENERGY !!
And nothing we can do about it...
@@OffGridGarageAustralia better connections and thicker / solid conductors = little to no stranded in high amp locations .
I prefer non welded battery connections .
If I'm not mistaken the internal resistance decreases as the temp increased so battery voltage recovered a tiny bit until the chemistry was nearing drained and the final collapse. 35amp on a 5k battery is about 7C. The outside temp might have been in the 40s-50s but it's much higher inside. Have not seen later videos but there's a good chance the battery was damaged during this test.
You use the words 'specifications' when you really mean aliexpress sales blah, blah, blah. It's lies used to sell product, and unless you know better you think....oh that's better than the other advertisement. We all get lied too when buying from shady sources. It's not specs, and even if they had a datasheet are they reputable as a company? if not, datasheets can lie as well. Beware.... You should name your test batteries, sh*tty and sh*ttier.
As you said in your first video, if they would have labeled them as 5000ma you would have been happy. As for 5C testing, no battery does well at 5C but some do better than others.
that is a way to high c rating discharge they are claiming the cell getting hot is acting like a short
DON'T GET HIGH OFF YOUR LITHIUM SUPPLY . LIKE YOU SAID , THEY ARE NO GOOD UNDERRATED .
I think they are very good and have proven to deliver 35A discharging as per the specs.
do the test at 2c
I will.
@@OffGridGarageAustralia will be an interesting curve to compare and the temp curve too
You can almost soder whit the terminals of that battery 😇🤪🤪
That lifepo is only 1 electrode its a fake data sheet saying 5C
Quit sniffing battery fumes , we need you .
If they are really only 5500mAh then 5c should have been closer to 25A.......
But the specs say 35A, so...
5c would discharge it in 12 minutes, not an hour.
You had 2 days to figure this out. I recorded on the fly without thinking about it. So, I won with my estimate 😉
I cringe every time you do the smell test! Full facial mask should be used; which kind of defeats the purpose of the whole exercise. Maybe a facial mask with two 1/8 inch holes to minimize the damage would be prudent.
The sniffle-test is a very important part of battery testing! 😁
As u can see your Battery's are way too cold! As the temperature rises the internal resistance gets lower and the voltage drop is smaller so the voltage on the clamps rise.
And this battery has a thermal mass. If this cold cell with a high internal resistance gets stressed, more heat produces an this is not direct on the outside and has to move first to the outside.
As I would say:
Alter, f*ck nicht deine Akkus, sonst f*icken sie zurück.
Also lass deine Akkus vorher mal auf Betriebstemperatur kommen, bevor du die so dermaßen stresst! Meine Fresse ey, da kann ja wohl echt nicht wahr sein... Tut das echt not leuten im Internet zu zeigen, wie man Zellen misshandelt? Nachher schaut's einer, der nicht den großen plan hat und macht das mit nem LiPo... Denk mal bitte 2 Cent weiter. Ehrlich, ich mag deine Videos und habe mir auch an einigen Dingen ein positives Beispiel genommen, aber das heute hat mir nur gezeigt:
1. Du bist irre!
2. Ich werde zusehen, dass mein LiFePo4 nicht zu kalt wird um Stress von der Zelle zu nehmen.
Don't know what you exactly want but this was the purpose of this test. These are test batteries bought exactly for this purpose.
@@OffGridGarageAustralia for testing under cold conditions? If they where warmer (say 30°C) an you discharge them with 1C, I think you will get more than 5Ah of Capacity.
I think they lie with 7200mAh, but have more than u testet in the 2 Videos. All around the world specs are given under ideal conditions. Mostly... So u could test one under better conditions on temperature and get some better results for the capacity. Certainly not 7200 but I expact around 6000mAh.
@@launacorp Yeah, the cells were cold'ish with only 17°C but I doubt we will see a better result even at 30°C. I may increase a few mAh but won't give us the full capacity either.