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HiTech's avatar
HiTech
Explorer
May 23, 2013

Checking hydrometer accuracy with charged battery voltage

Is it true that: Specific Gravity = Cell Open Circuit Voltage - 0.845? Could one average the specific gravity readings across cells in a battery, and use this formula to check the accuracy of th...
BFL13's avatar
BFL13
Explorer II
May 24, 2013
Baseline SG on my Interstate 6s is 1.300 When I get that they still have a surface charge from just having been "overcharged" so no idea of their "resting voltage" at that point. Then they go on Float so I never see their "resting voltage" anyway

1.300 + 0.845 = 2.145 x 6 = 12.87v so that is too high for their resting voltage I think.

This indicates your notion ASSumes a standard acidity for batteries, when we know they vary by brand and for what ambient temp intended service?

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