Originally Posted by PeterFTH
Check your figures - 6 volt batteries rated amp hours stays the same when put in series with another 6 volt battery to form a 12 volt bank. I would guess that the 4 golf cart batteries I removed wouldn't exceed 200 amp hours at 12 volts. I also have the ability to both shut off all electrical supply OR isolate one battery from the other with the 1/2/both switch.
His figures are correct.
Most 6 volt batteries are rated at 215 AH or more. 2 in series raise the voltage to 12 volts.
The other set, in parallel, would the double the AH to 430 per more.
You replaced 430 to 490 AH bank with a 500 AH bank but sacrificed a backup, start battery.
You also claim that you don't understand putting batteries in parallel yet you did just that with your new batteries.
One benefit of starting batteries is that they work as a buffer for your engine charging system.
When you first start up, the alternator output is directed to the lightly discharged start bank.
Once it reaches 13.6 or so the interconnect relay connects between the start and house bank.
The start battery will then discharge to the house bank, combined with the alternator output.
If the voltage drops too low, on the start battery, the interconnect opens, giving the alternator a chance to cool down before connecting again after a programmed time delay.
With the high acceptance rate of your large AGM battery bank and your alternator directly connected to the bank, it could overheat.
As a stationary MH your solar will be fine but for that early morning departure you may have a problem.
I am a full-time boater who manages a large battery bank. During my morning departures, I keep my RPMs low for the first hour of cruising to prevent my alternator from overheating.
I only cruise at 7 MPH so 6 MPH for an hour is no big deal.
That may not be as easy in a MH.
Good luck with your system.