I have a problem with one of the four 6v batteries that I just installed earlier this month. I have tested the voltage on all four and 3 of them read 6.4v but the 4th one reads 5.4v. It stays like th...
It is possible that the battery is good. You need to "Equlize" perhaps 2 or 3 passes to bring that battery up. Just it and it's mate, drop the other two off (Disconnect them) for this job.
ALT put a 6 volt charger on JUST that battyery and bring it up.