Modifying PARKSIDE PABS 16 Charger for Samsung Li-ion 2600mAh Cells Compatibility

Hello

After replacing the cells (4 pcs. x 3.7V 2000mAh) in the battery of the Parkside PABS 16 screwdriver with Samsung Li-ion 3.7V 2600mAh cells, the charger does not charge the battery. The cells are properly heated, the battery worked as it should, but I can't charge it. Despite the fact that it is discharged - the charger shows that it is charged (I attach a video). Can this charger be modified in some way to make it work?

IMAG08..jpg Download (2.26 MB) IMAG08..jpg Download (2.08 MB) IMAG08..jpg Download (2.39 MB)
IMAG08..jpg Download (1.77 MB)

Why are these links so heavily unloaded? Maybe there is a reason.
Try to recharge them one at a time and see if it will move.

If the battery is not accepting current, the charger will also say that it is charged.
What is the voltage of the battery and individual cells?

The problem may not be the charger but the balancer in the battery.

What do you suggest? What to do now? How to recharge these cells? Will it work with a workshop power supply?
Individual cell voltages:
3.342V
3.346V
3.384V
3.384V
Balancer photo:
IMAG08..jpg Download (2.25 MB) IMAG08..jpg Download (2.29 MB)

And the workshop power supply, acting as a charger, the current consumption is?
Charge the cells manually, one at a time, with a workshop power supply.
I don't know what the system in the balancer means, I can't find the catalog card. It's a bit higher technology than most cheap Li-Ion screwdrivers, because I see I2C there. It is possible that the system does not communicate with the charger and therefore does not charge or is blocked.

My battery did not charge after replacing the cells with larger ones. The charger claimed to be charged OK. Under the bench power supply, the consumption was always only 70mA. Only a short circuit unlocked it. Giving plus charge to CH+ and minus to B+. Now the battery normally accepts current and charges, connected to CH+ and B-. However, it's simpler electronics without fancy controllers like in your case.

Making preliminary measurements, the meter shows that the diodes D3, D5, D6 are damaged. I will measure them tomorrow and write what I came up with, because I have to desolder them.

Edward7979 wrote:

Individual cell voltages:
3.342V
3.346V
3.384V
3.384V

And the meter showed 10 V the whole package, which is about 2.5 V per cell.

The meter showed 10 between the charging contacts, between the screwdriver contacts it shows 13.44 V.

Hello
Yesterday, taking advantage of the moment, I unsoldered diodes D3, D5, D6 and transistors Q4, Q5 to check if they are operational. The diodes are ok, but both transistors are damaged. Q5, after being gently heated and caught with tweezers, fell apart, i.e. its housing. These are N-mosfet LR8726 transistors. I ordered new transistors. I'm waiting for the package. We'll see if replacing them changes anything.

Unfortunately, replacing the transistors did not help. I have already ordered another balancer. The topic can be considered closed.