Gday all,
Looking for some assistance to fault find a 18v RIDGID / AEG chinese knockoff battery.
New 4.0Ah battery pack, charges fine, drops out under low load, and capacity seems diminished.
After full charge battery voltage at Positive and negative terminal at BMS output terminals is 20.58v dropping to 18.21v after a couple of hours.
battery voltage at pack still reads 20.58v however.
there looks to be a voltage drop from the pack through the BMS.
Wiring connections look substandard and wiring underated for the task.
Looking for some advice as to possible faults in the circuitry before I dissassemble.
photos attached.

Thanks in advance

 

Measure between the battery terminals B+, B1, to B4, and B-, to see where the voltage drop is, the batteries are in series with fets to connect them together.

B->B1>B2>B3>B4>B+

 

Measure between the battery terminals B+, B1, to B4, and B-, to see where the voltage drop is, the batteries are in series with fets to connect them together.

B->B1>B2>B3>B4>B+

Cheers dave, ill give it a go

 

Measure between the battery terminals B+, B1, to B4, and B-, to see where the voltage drop is, the batteries are in series with fets to connect them together.

B->B1>B2>B3>B4>B+

4.11v at each cell group, ill keep looking.