Battery modules from eBay

I bought 5 modules from a seller on eBay and surprisingly they seem so bad it is hard to believe. They only charge to approx. 4500mAh before the charger (EV PEAK CQ3) stops and then discharge to approx. 3000mAh. They don’t improve by doing discharge/charge cycles on them.

My charger’s settings are: charge current: 4.0A, discharge current: charger’s max (1.2 to 1.6A), 10 minute rest between cycles, D. Peak: 8mV/cell.

All my other modules, including 7 that I bought from another seller, get between 5500 and 6300mAh on discharge.

The seller is telling me that the modules have been tested with “load 2.0 engine” whatever that means and have been specifically prepared to work in the car and not to be tested like I do. I don’t believe this and wanted to consult with the forum before I leave negative feedback. What do you guys think?

 

I am in Bulgaria and the seller is in the UK. I don't have time to deal with disputes and to send the modules back the UK as I will lose more doing that instead of doing my job. I already have 31 good modules between 5500 and 6300mAh and will select 28 and put the car back together at the weekend.

Those faulty modules were only £18 a piece and he has now reduced the price to £12. He said that he is sending me "very strong modules", but he lied. I wonder how a module can become that bad. The car they have been taken from must have been a very high mileage car or maybe he has damaged them somehow.

Later I plan to try and rehydrate them and see if they will improve.

 

The first thing I did when I received them was to check their voltage and it was in the 7.3-7.4V range - way lower than my other modules.

After cycling them at least 3 times, 4 modules now still show between 7.3 and 7.4V and one shows 8.01V, but I finished cycling that last one yesterday and it is a 3000mAh module. On charging they reach 9V too early and stop charging at about 4500mAh. My best modules reach 7500mAh or more when charged.