Understanding Charging Systems

[AKCamper]

Originally Posted by Rossue

Was under impression that you needed to remove any charging source before testing specific gravity, and we have solar. Is that not the case?

Specific gravity should be the same while charging as after sitting. I guess under a heavy charge the sulfuric acid which sometimes can get stratified could read higher when stirred up by the bubbles (part of what equalization does), but I really don”t think we are talking about that high of a charge rate. I don’t think it would hurt to let the batteries rest, but I just don’t think it’s necessary.

[gbaglo]

This is what Trojan battery FAQ says on the topic:

2. How can a flooded battery’s state of charge be accurately measured?
The state of charge of a lead acid battery is most accurately determined by measuring the specific gravity of the electrolyte. This is done with a hydrometer. Battery voltage also indicates the level of charge when measured in an open circuit condition. This should be done with a voltmeter. For an accurate voltage reading, the battery should also be allowed to rest for a period of one hour minimum in order to let the voltage stabilize.

Sounds like no need to rest to read specific gravity.
Trojan site has tons of useful information on batteries.