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Lishen 272AH thread?

Higher temps mean higher capacity.

This is a rough example.

1614654735769.png

A long while back I was building tiny electric endurance racers (like with bicycle parts). We would heat our batteries up before each race to get max energy extraction. With lead that meant 120F, with lithium variants it was a bit lower.
 
Luthj said:
Indeed, I would say ~10% reduction between 25 and 0C
Click to expand...
I haven't done enough testing to see if it is charging, discharging, or both that are affected. But I was quite surprised when my BMS wouldn't let me charge because I had the temperature set to 10 degrees Celsius. Surprised.
 
Charge acceptance speed does drop quite a bit as you approach 0C. Efficiency drops a bit, but its not crazy. Once you hit 0C the charge rate needs to be quite low, and below it should be zero.

The blue line is the nominal resistance for a random cell vs temperature.

1614654946972.png
 
Luthj said:
Charge acceptance speed does drop quite a bit as you approach 0C. Efficiency drops a bit, but its not crazy. Once you hit 0C the charge rate needs to be quite low, and below it should be zero.

The blue line is the nominal resistance for a random cell vs temperature.

View attachment 39127
Click to expand...
I can say that when my wife asked me to move my testing to the garage, I definitely noticed the difference vs my office.
 
Just John said:
I'm in Mesa, you should not have these in a box in the summer sun. 55 degrees Celsius is a common high, and I am pretty sure that 60 degrees is where you should not charge or discharge.
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Should I be worried the trailer burning up? Do other people have these inside RVs?
 
Booboo said:
Should I be worried the trailer burning up? Do other people have these inside RVs?
Click to expand...
Mine will be inside in an air-conditioned environment. LiFePO4 cells like the same temperature that you do. I would not worry much about them catching fire, but if the temperature would kill you, it will kill your expensive battery.
 
Just John said:
Mine will be inside in an air-conditioned environment. LiFePO4 cells like the same temperature that you do. I would not worry much about them catching fire, but if the temperature would kill you, it will kill your expensive battery.
Click to expand...
I could see them getting to 110 degrees but probably not much more.
 
Booboo said:
I could see them getting to 110 degrees but probably not much more.
Click to expand...
Do we live in the same Arizona? I am not talking Flagstaff, in the Phoenix area a high temperature above 110 degrees is quite common, putting anything in a metal box in the sun means temperatures well above that. If you can burn your fingers on the car door or steering wheel, it is too hot for LiFePO4.

Now if you are talking about a shaded storage compartment, they might survive. I would expect a reduction in capacity and longevity with the extreme temperatures.
 
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Just John said:
Do we live in the same Arizona? I am not talking Flagstaff, in the Phoenix area a high temperature above 110 degrees is quite common, putting anything in a metal box in the sun means temperatures well above that. If you can burn your fingers on the car door or steering wheel, it is too hot for LiFePO4.
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I'm putting mine in a storage compartment not a metal box. They will not see direct sunlight and the trailer is in the shade. We do see temps above 110 but I wouldn't say its common.
 
It's important to note that you are not as concerned with the peak temperature as you are with the average temperature over a five or four hour span. Because the batteries have mass they will flatten the peaks and troughs of the temperature curve.
 
testbench.jpg

Hello everybody, this is my "testbench" for the Lishen 272 cells. For charging I use a Riden 6018. For discharging the single cell I use a ZKE tech EBC-A20 that is verry accurate. I discharge with 20 Amps, that takes around 14 hours and 40 minutes. All cells are charged to 3,65 volts with cuttoff at 0,1 Amp, than I let them rest for one hour and discharge them down to 2,5 volts. After that I charge them up with exact 100 Ah and stop charging. So after the test they are at the same SOC and measure all around 3,300 Volt +/- 0,020 volts.

After every discharging I save the graph and data for my files:
 

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Tuscumbia said:
Update to my 16 Lishens 272 that I received in february. At the moment I test every single cell, the capacity is between 290,8 and 294,0 Ah. I already testet 8 of 16.
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Are you testing at 0.2c or 0.5c?.
 
Berseker said:
Are you testing at 0.2c or 0.5c?.
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I test with 20 Amps, my tester can not handle more. I bought a bigger one that can charge and discharge with 40 Amps but it is still on its way to me. For later on, I will discharge the batterypack (16 s) not with a much higher current at most times anyway but I also think I can get more Ah out of the cell if I discharge with a low C rate. --> (I don't have the equipment to discharge a single cell with 0,5 C = 136 Amps).
 
Luthj said:
It's important to note that you are not as concerned with the peak temperature as you are with the average temperature over a five or four hour span. Because the batteries have mass they will flatten the peaks and troughs of the temperature curve.
Click to expand...
This is true, they have a substantial thermal mass. I have also watched my thermometer on the back patio register over 100 degrees Fahrenheit at midnight. Just be careful and be aware that the cells like pretty much the same temperature you do.
 
Tuscumbia said:
View attachment 39222

Hello everybody, this is my "testbench" for the Lishen 272 cells. For charging I use a Riden 6018. For discharging the single cell I use a ZKE tech EBC-A20 that is verry accurate. I discharge with 20 Amps, that takes around 14 hours and 40 minutes. All cells are charged to 3,65 volts with cuttoff at 0,1 Amp, than I let them rest for one hour and discharge them down to 2,5 volts. After that I charge them up with exact 100 Ah and stop charging. So after the test they are at the same SOC and measure all around 3,300 Volt +/- 0,020 volts.

After every discharging I save the graph and data for my files:
Click to expand...

Looks familiar!
IMG_20210302_134707559.jpg

Let me guess, you ordered one of these:
www.aliexpress.com

134.0US $ |EBC A40L Electronic Load Battery Capacity Tester Lithium Lead Acid Battery Capacity Tester Charge / Discharge 40A 110V/220V 200W|Battery Testers| - AliExpress

Smarter Shopping, Better Living! Aliexpress.com
www.aliexpress.com www.aliexpress.com

I've been waiting more than a month for that. Seems now they've gone down in price by $3, but shipping is up by $25.
The cheap shipping has taken approximately 45 days so far.
 
Last edited:
I ordered February, 19th, paid 72 Euros for DHL Express but that still will take a couple weeks. They have sent it on the 28th, I let you know when it arrives.
 
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