Peter A Forbes
Free Member
Just out of interest, I'm running a discharge test on a 6V 225AH AGM battery for a customer. The test is a resistive load to give 21A load at the start of the test, reducing slightly as the battery volts drop down.
Off load the battery was 6.59V after a full recharge.
Test started at 10:26am with 6.26V terminal voltage at 21.20A load.
As I type it was 6.05V at 20.05A at 15:31pm.
The shunt is a 60mV to 30A type, the actual amps is a formulae conversion.
Volts Shunt mV Actual Amps Time
6.59 0.00 Off Load 10:25:00
6.36 42.40 21.20 10:26:00
6.32 41.80 20.90 11:03:00
6.28 41.70 20.85 11:30:00
6.24 41.00 20.50 11:57:00
6.22 40.70 20.35 12:34:00
6.20 41.10 20.55 12:55:00
6.15 40.70 20.35 13:52:00
6.12 40.50 20.25 14:30:00
6.09 40.40 20.20 15:00:00
6.05 40.10 20.05 15:31:00
So 5 hours and just over 100AH taken out. It should produce 194AH at that discharge rate.
The test takes the block down to 5.70V (6V block)
I'll post the final figures later, this is a used but nearly new battery.
Peter
Off load the battery was 6.59V after a full recharge.
Test started at 10:26am with 6.26V terminal voltage at 21.20A load.
As I type it was 6.05V at 20.05A at 15:31pm.
The shunt is a 60mV to 30A type, the actual amps is a formulae conversion.
Volts Shunt mV Actual Amps Time
6.59 0.00 Off Load 10:25:00
6.36 42.40 21.20 10:26:00
6.32 41.80 20.90 11:03:00
6.28 41.70 20.85 11:30:00
6.24 41.00 20.50 11:57:00
6.22 40.70 20.35 12:34:00
6.20 41.10 20.55 12:55:00
6.15 40.70 20.35 13:52:00
6.12 40.50 20.25 14:30:00
6.09 40.40 20.20 15:00:00
6.05 40.10 20.05 15:31:00
So 5 hours and just over 100AH taken out. It should produce 194AH at that discharge rate.
The test takes the block down to 5.70V (6V block)
I'll post the final figures later, this is a used but nearly new battery.
Peter
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