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Old 12-29-2008, 11:09 AM   #4
dereckbc
Gone Wild
 
Join Date: Nov 2008
Posts: 240
Default Re: what's a full charge reading for a 48 volt 4 battery cart?

First off everything sounds OK.

What we are really talking about is the State Of Charge or SOC. The SOC using voltage only is a relative reading and several factors must be considered, plus it must be done correctly to be of any meaning.

Results vary widely depending on actual voltage level, temperature, discharge rate and the age of the cell and compensation for these factors must be provided to achieve a reasonable accuracy.

Basically at 100% SOC for a lead acid battery you are looking at a cell voltage between 2.125 and 2.208, or 12.75 to 13.25 for a 12 volt battery. So you are at the low end of acceptance.

To use SOC properly in your example, fully charge the battery, disconnect the charger, and pull one of the cables off the battery to fully an open circuit voltage. Then wait for a couple of hours and take the reading.

To be really accurate you would need to measure the specific gravity and temperature, then consult the manufacture specs for a compensated reading.
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