Hi!
I have several AA rechargeable Li-pol batteries 1.5v with a controller inside.
Like that
or
It is easy to measure their charge during charging with any USB tester.
Is there a device to test/measure their charge during discharging?
An analyzing charger with a discharge function will do it OK.
Note - some analyzing chargers will discharge then go into a charge function automatically. That may or may not work in this case, see below.
It probably will NOT charge them properly. Some may appear to, but the internal circuitry interferes with the charging.
Better/more accurate would be a ‘pure’ discharge device. There are numerous types of these available. The link is the one I have.
with a cell holder: https://www.ebay.com/itm/4-Wire-Battery-Resistance-Capacity-Test-Holder-Stand-For-18650-26650-21700-AAA/392723698763?hash=item5b7028144b:g:~EEAAOSwiEVeaa9w
Yeah, I’ve already found two parts to assemble as an analyzer:
this is a testing board:
https://www.aliexpress.com/item/32614219909.html
and this is a holder:
https://www.aliexpress.com/item/4000606429744.html
But I really want to have a single device such an Opus or Liitokala.
Opus BT-C3100 looks very promising for me, but I’m still unsure.
I have the Opus BT-C3100, along with a couple others. I consider it to be my ‘best’ charger. It does have a dedicated [discharge] function. It will be fine for most charge/discharge needs. The test board will be more accurate I think.
Not familiar with the testing board you linked.
I have 2 of the holders and think those are great.
Does the Opus have a reverse polarity protection?
Yes.
[Auto Circuit Detection: YES
Built-in Protected Circuit: YES
Over Voltage Protection: YES
Short-Circuit Protection: YES
Over-Charging Protection: YES
Over-Discharging Protection: YES ]
https://lygte-info.dk/review/Review%20Charger%20Opus%20BT-C3100%20V2.1%20UK.html