Hi there, I have a battery bank consisting of 6 golf cart batteries, two wired in series to make a 12 volt system, and then parallel. Each set of batteries were not purchased at the same time. I would say each set were purchased one month apart from another. Anyways, the problem that I notice is when the charge controller is charging the batteries during the day time, when I measure voltage from each battery on a string of two, I notice there's a big difference in voltage between the two batteries. For instance, the charge controller is set to charge at 14.6Volts, but when I measure each battery in one string, it'll read something like 7.00 volts and 7.60 volts. And another string would read 7.15 volts and 7.45 volts. But only one string had voltages that were very close within range, something like 7.29 volts and 7.31 volts. So I'm a little concern. So is this perfectly normal or should I take the batteries back to Costco and exchange them? I tried equalizing the batteries and it didn't seem to help. I have a morningstar TS-45 charge controller if anyone know what range I should set it to in order to fix this dilema. Oh yeah, just want to point out one more thing. On two of the uneven strings, 2 batteries were manufactured 08/06, one 09/06, and the other 11/06. One pair of string consisted of 08/06 and 09/06 and the other string consisted of 08/06 and 11/06 battery. And the perfectly even strings had the same manufactured date of 08/06. I had to buy them this way because Costco didn't have more than two in stock during the time. Could it be because one battery sat a month or two longer than the other, so it had a bigger discharge? Please if anyone can help me I would greatly appreciate it. Thanks in advance.
Steven