One thing to consider is Amps are not Amps.
What I mean by this is most 6 volt batteries can be tested at a 75 amp rate and MOST (I say most because there may be one out there) 12 volt batteries are not tested at a 75 amp rate because their efficiency is severely lower than 6 volt batteries at a high amp discharge rate.
The posted amps on a battery is the 20 hour rate which is a very low 5 (or less) amps for a group 24 battery.
If a 12 volt battery bank of 210 amps was tested against a 6 volt battery bank of 210 amps at a rate of 20 amps per hour the 6 volt bank would CRUSH the 12 volt bank. At 8.1 amps per hour they would be a tie.
This is why I have the 6 volt. Sometimes my amp pull is as high as 30.
Another point I do not see often is how and when to check the voltage. Everyone agrees that 12.2 is at 50% discharge and that is when to recharge. The way to test this is to have the battery at rest for several hours and at 70 degrees or so. If you simply turn off everything and test the batteries and they show 12.2 they are likely much higher than 12.2 after several hours of rest.
Because of this, and I know many of you will not agree, I test my batteries while I am using them and am not concerned until they are at 11.8. I have even gone as low as 11.4. Again this is during use.
My batteries are several years old and still behave just fine. My boat batteries are 8 years old and still act just fine so I do have a proven record for my batteries lasting many years.
I do have one of the socket style volt plugs above and that is how I gauge by battery power. I also use that same chart above that shows the green, yellow and red. I use the yellow voltage numbers to determine when to charge.
Paul
