Hello
I have Ryobi cordless drill 18v battery Pack.
How do i find the bad sub -c battery in the battery pack ,there is 15 sub-c battery at 1.2 volt to make 18 volts.
I charge the battery using the charger that come with the drill.
After charge the battery a week later ,the voltage drop way below 18 volts.
I don't know how many of the sub-c battery is bad.
So any idea on how to find the bad sub -c batter in a battery pack?
Thank for the help
mrel

 

You can open the battery and can check the voltage output of each sub C battery units using a multimeter.

 

short each cell with an amp meter, and a .05 ohm resistor, combined with the resistance of the meter leads, (another typically .05-.1 ohms) you should see at least 10 amps, and this should be fairly consistent with each cell. (+/- 15%)

there is no need to worry about the cells exploding, this is only 2-4 x what the motor draws anyway.