Newbie battery capacity testing 280ah EVE cells

Just John

Photon Sorcerer
than

Thanks. If will likes it or one like it thats good enough for me. Just to clarify my battery is a sealed 24v 170ah battery so I wont have access to the individual cells unless I want to break the warrantee seal. So I will be using this to test the capacity of the entire battery. Will it work? I do need it sooner so will probably just pay the extra bucks.
It will work, but it wouldn't exactly be a "high C rate test". They are limited to 20 amps max draw and 180 watts (whichever is lower). More voltage, less amps and the 180w heat dissipation limit is the factor. If you plan on building a 24v system, it might be best to get an inverter and test at .2C using a different measuring device.

Will's video on battery testing, intermediate level.

That being said, I'm going to try using the "beginner friendly" cheap testers in parallel. Should work, just add all the results on the units together. I haven't tried this yet, but I did get 4 of them to make individual cells tested faster. Of course "should work" is based on my last formal training in electronics was in 1978. I'll also add I designed and built power supply test jigs for manufacturing in the mid 1980s. Ask me why you won't want to use a wire wound resister to test a switching power supply. :)
 

Just John

Photon Sorcerer
I have two of the $11 one, they do not have load disconnect function when it reaches your Voltage alarm set point, it just gives alarm tone. The one with the fan and heatsink ($30) does have load disconnected when the set point is reached.
Yes, and it even works! :)

Having it stop the test when you reach the low voltage set point is very useful.
I'm looking at the 4 wire with color display and Bluetooth, not sure it is worth it, but the 4 wires should make the voltage readings much more accurate. Currently I've been setting it at 2.4 volts, so it stops at 2.6 volts.
 

Bud Martin

Solar Addict
Yes, and it even works! :)

Having it stop the test when you reach the low voltage set point is very useful.
I'm looking at the 4 wire with color display and Bluetooth, not sure it is worth it, but the 4 wires should make the voltage readings much more accurate. Currently I've been setting it at 2.4 volts, so it stops at 2.6 volts.
That is the same setting I had to use too, 2.4V. My tester with the fan did blow up when I crank it up to 20A, luckili I have the MOSFET for the replacement so now I run my test at 15A instead.
 

Just John

Photon Sorcerer
That is the same setting I had to use too, 2.4V. My tester with the fan did blow up when I crank it up to 20A, luckili I have the MOSFET for the replacement so now I run my test at 15A instead.
I have 4 of these testers and all have the same offset even with 10 Guage wire. None of mine have blown yet, but I am just testing cells, so can't get close to the heat dissipation rating. I am sure they all could use better thermal compound. No problem running them maxed for cells so far (20 amps or above).
 

cinergi

1.21 Jigawatts
I have 4 of these testers and all have the same offset even with 10 Guage wire. None of mine have blown yet, but I am just testing cells, so can't get close to the heat dissipation rating. I am sure they all could use better thermal compound. No problem running them maxed for cells so far (20 amps or above).

20 amps at 3.2 volts is quite different than 20 amps at 12 volts. That's why you're not going to get a lot of heat when testing individual cells - it's only ~60 watts of heat.
 

Bud Martin

Solar Addict
I have 4 of these testers and all have the same offset even with 10 Guage wire. None of mine have blown yet, but I am just testing cells, so can't get close to the heat dissipation rating. I am sure they all could use better thermal compound. No problem running them maxed for cells so far (20 amps or above).
I only test one cell at 20A, the 20A is the max rating of current handling even though the power rating is not reached, so bascially which ever max rating is reached first.
 

Bud Martin

Solar Addict
BTW, I also having problem clicking the button to set the up/down over/lower limit value the manual say to click fast 2-times, or 3-times but I sure have a hard time setting it.
 

Just John

Photon Sorcerer
BTW, I also having problem clicking the button to set the up/down over/lower limit value the manual say to click fast 2-times, or 3-times but I sure have a hard time setting it.
Yes, I just set it at 2.4 and leave it. Fortunately it apparently has nonvolatile memory and keeps that.
 

Capt Bill

Sailing Options
So I ordered this for capacity testing. More than I wanted to spend but should save a ton of time.

looks like good idea, while sketchy w no reviews or question and answer section. Do you know if it works with a automatic cut off when discharging a LiFePO4 battery or battery cell ? Have you downloaded and studied the manual? While I would love to obtain a better faster LiFePO4 Battery Amp Ah Tester with that automatic cut-off @ < 2.5v feature; as compared to that kind of low cost 150 -200 watt draw (depending on which model you find) fan heater unit from China with that cut off feature; ... I sure would want to see some positive reviews before spending $300. Have you seen any reviews mention a LiFePO4 test? ... my two cents / my curious creator take today.
 

hammick

Solar Enthusiast
looks like good idea, while sketchy w no reviews or question and answer section. Do you know if it works with a automatic cut off when discharging a LiFePO4 battery or battery cell ? Have you downloaded and studied the manual? While I would love to obtain a better faster LiFePO4 Battery Amp Ah Tester with that automatic cut-off @ < 2.5v feature; as compared to that kind of low cost 150 -200 watt draw (depending on which model you find) fan heater unit from China with that cut off feature; ... I sure would want to see some positive reviews before spending $300. Have you seen any reviews mention a LiFePO4 test? ... my two cents / my curious creator take today.
I sent it back. Discharging my 16s pack it can't do anything close to max amps. It couldn't do max amps discharging a single 3.2v cell. Way overpriced.

The automatic cutoff does work. But I would not assume 2.5 volts is accurate on the unit. It doesn't come with any leads so you need to source your own.

When I capacity tested a Lischen 272ah cell I set the LVD to 2.8 volts I believe. I then ran an additional discharge and used a separate meter to read the voltage because I didn't trust it to stop at an accurate 2.5v
 
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