Testing high-capacity Li batteries

Two factors

A. Your willingness to spend $300+ on something very OTS ready, get up to maybe 20-30A?

Or B. for cheaper, and/or maybe higher amps, willingness to DIY maybe solder components

I have tons of unorganized notes scattered around, links to lots of threads across different forums some very very long.

There may very well be a cheaper OTS unit in there.

Just need to know which direction to start from.

Example: https://www.ebay.co.uk/itm/EBD-A20H...ity-Tester-Resistance-Multimeter/163109074258

Another approach

https://hackaday.com/2020/01/07/liquid-cooling-keeps-this-electronic-loads-mosfets-from-burning

https://hackaday.com/2017/02/28/beefy-100-amp-electronic-load-uses-two-mosfets

From this thread https://www.rcgroups.com/forums/showthread.php?3490399-High-Power-LiPo-Discharger-Project

LotusElite said:

A few years ago I mistakenly left the DC/DC charger on before going on a long trip. When I returned, over a third of my pack of 45 CALB CA180s were toast. After a long period of mourning and denial, I'm ready to get my EV up and running again, but need to test the remaining 28 batteries that didn't go to 0V to determine if any can be salvaged. Are there some affordable test instruments that can do this reliably? Any advice would be appreciated.

Scott

Click to expand...

you may need to kick start the cells with a charger, or parallel to a 'good' battery to get the voltage up to the point a cell charger will see the cell and start charging.

I've had really good luck with the Revolectrix powerlab unit for charging, top balancing, and capacity testing large capacity single cells. They are programmable for different chemistries, charge/discharge rates, etc.

Thanks, All. Here are more details.

I have three banks of 8 (2P4S) and one of four. They all charged up fine and have maintained ~3.35/cell when paralleled and after the bus bars were removed. That's a good sign, but since a number of the cells were discharged to <2V I suspect they would be weak links in a 150V string. Right now I'm using a resistance coil to discharge them individually but that is tedious.

That ZKE unit looks promising; has anyone used it? I'm also considering one of the hacks.