Battery Upgrade

DrewE wrote:
I'm not sure why you'd need the ground to go to the other side; just find a good ground on the ground side of the RV. Maybe I'm missing something (perhaps needing a lower impedance ground than the chassis provides for the inverter).

What you post at the top is not quite balanced, as it turns out, but only pretty close. See http://www.smartgauge.co.uk/batt_con.html for a more thorough explanation, and (at the end) this nifty approach:

If you draw a horizontal line separating the four batteries shown you will see the positive needs to be connected on one set and the ground on the other set. If he uses existing conditions both + & - will be on same side.

I'm not sure why you'd need the ground to go to the other side; just find a good ground on the ground side of the RV. Maybe I'm missing something (perhaps needing a lower impedance ground than the chassis provides for the inverter).

What you post at the top is not quite balanced, as it turns out, but only pretty close. See http://www.smartgauge.co.uk/batt_con.html for a more thorough explanation, and (at the end) this nifty approach:

Yes you can do that all sorts of ways.

-If you run parallel links to join each "pair" you only need to ground one to the frame.

-You can have one side only do the inverter and give it its own solar set for recharging plus a portable charger when no solar. the other side can do the usual rig stuff, and have its own solar set and charger. Now you don't need the long parallel links

-You can put the inverter in the middle and have two wire sets for it.
Two wires from pos terminal and two from its neg terminal. One pos and one neg to each "pair". Now the inverter-battery wires are also the parallel links and they don't have to be so fat since each is carrying about half the amps.

-If you have a Trimetric with its shunt, it means if you split the bank you can only monitor the pair the shunt is on, but you don't really need a momnitor anyway :)

I have played with these set-ups a different times and they all work.

You need to recharge those T-1275s seriously to 14.8v temp adjusted or they won't last, so don't expect to keep them going with a 14.4 volt converter. A solar controller with adjustable voltage will help with that, plus an adjustable voltage charger for when not using solar. This type would be a good choice for that--he can do one up as a 100 amper for you.

http://www.bestconverter.com/Boondocker-BPCM-75-75-Amp-Adjustable-Power-ConverterCharger_p_587.html#.VkJ-FHmFNjo

Here is one of my past set-ups with the two T-1275s on inverter only with the Solar30 controller and the four 6s (two are out of sight to the right) doing the rest of the work with an Eco-Worthy controller for them. The Trimetric would only do the four 6s in that set-up.

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It is possible to have TOO MUCH battery capacity and exceed your ability to keep them charged.....or overload the charging equipment in the rig or the tow vehicle.

I think you need a somewhat sophisticated controller to handle 4 batteries but there are some "experts" on here who can be more specific.