HF Battery testers
I have a bunch of car/truck batteries sitting around in my shop and I want to test them so I can recycle the bad ones and use the good ones for a rare non-electric-hookup 3 day campout with our TT. ...
Forum Discussion
Impedance tester = Handy analysis by algebra
Carbon Pile = Absolute proof analysis by work
Charge old battery until it is both bubbling in the cell and 25 degrees warmer than when you started.
Clean battery posts bright.
Connect cables to battery
Twist load knob to get 250 amps draw.
Voltage needle must stay above nine point six volts for a full 15 seconds.
Amperes must stay at 250 the whole time.
Shut off load
Volt needle must not jump back to 10 volts then slowly rise to 12.
This is a gentle load less than what is applied to a new battery
If the battery fails this test it is a goner.
There is no question a carbon pile load test is more reliable than an impedance measurement. It you want to futz further, a hydrometer can tell you which batteries may benefit from a full equalization.
Carbon Pile = Absolute proof analysis by work
Charge old battery until it is both bubbling in the cell and 25 degrees warmer than when you started.
Clean battery posts bright.
Connect cables to battery
Twist load knob to get 250 amps draw.
Voltage needle must stay above nine point six volts for a full 15 seconds.
Amperes must stay at 250 the whole time.
Shut off load
Volt needle must not jump back to 10 volts then slowly rise to 12.
This is a gentle load less than what is applied to a new battery
If the battery fails this test it is a goner.
There is no question a carbon pile load test is more reliable than an impedance measurement. It you want to futz further, a hydrometer can tell you which batteries may benefit from a full equalization.
