multipule batteries useage/charging

[strgrazr]

I just bought 2 6v golf cart batts and have one large 12v true deep cycle batt. Installed a batt switch, off/1/2/both. I have 300watt solar and the manuf converter. Should/can I charge on both without hurt batt inorder to bulk charge longer??? Will using both while discharging drain the batts equally??? Individually is simple, I'm referring to that recharge after 3 or days of cloudy weather while boondocking using solar/ gen. maybe both?? Batts down at 50-60%.

[timfromma]

It's never a good idea to run different battery types / brands / ages at the same time. Your set up should work fine provided you only use or charge your golf car batteries and your deep cycle battery separately.

[TitanMike]

Originally Posted by strgrazr

I just bought 2 6v golf cart batts and have one large 12v true deep cycle batt. Installed a batt switch, off/1/2/both. I have 300watt solar and the manuf converter. Should/can I charge on both without hurt batt inorder to bulk charge longer??? Will using both while discharging drain the batts equally??? Individually is simple, I'm referring to that recharge after 3 or days of cloudy weather while boondocking using solar/ gen. maybe both?? Batts down at 50-60%.

Charging both at the same time shouldn't be an issue as whichever battery (2 6v's in series would be considered one 12 v battery) reaches full charge first will draw less current with the rest going to the low battery until it's charged. Boaters will do this all the time, switching separate battery banks on at the same time while engine(s) are running.

Discharging could be more problematic as you have two different batteries with different characteristics. You could well run into one battery discharging to far less than 50% while the other is still above that level. It will depend on the specific batteries.

Ideally all batteries in a parallel configuration should be of the same type, even manufacturer so you don't have the kind of mis-match you will with a setup you describe.

One solution would be to charge both banks at the same time using whatever charge source you have. Then select one or the other for use at different times. When loads are light and you might want to use the single 12 v battery and then switch to the larger bank for overnight when you could be using the furnace.. The following day switch both together and charge via solar or generator.

Not an ideal setup but it can be made to work. When the 12 volt battery fails (logically it would be the first to go) consider upgrading by adding another series 6 v's in parallel with the other 6v batteries.

If you don't have room for four 6v's or the ability to carry the weight, then a pair of Lithiums would be a good upgrade, reducing weight and still have the same usable power as four larger/heavier batteries.

Just some thoughts.

[strgrazr]

Thanks,I sized my batt box with future upgrade in mind, going to cycle the older 12 v batt the most, when boondocking we turn the furnace down to 55 at night and use an electric mattress pad. Uses less energy but still can pull a 110 ah batt to 60% on a cold night.