Hum. What could you do with all that time being alone with the wife in the darkened interior RV?

Solar Panels can be setup with legs. You set it up daily.

1 X 280 Watt solar panel $207. If you are OK with a CE Marked charge controller, 30A, $135. 12V - 250 Ah battery (3 kWh) $560. 1000 Watt pure sine wave inverter $350.

The solar panel can produce up to 2200 Watt-hours per day.

What size battery do you have now?

Where are you getting 280W panels, nothing that high around here...

Here's a fun solar reference as well
http://www.samlexsolar.com/customer-support/pdf/Guides/RV_Solar_Power_Guide.pdf

Battery is so small it isn't to be considered at all. Like 225 cranking amps which is not even to be considered. I need new golf cart sized batteries.

Here is a document with some info and diagrams on batteries in series or parallel, skip to chapters 8-9-10

http://samlexamerica.com/documents_solar/manuals/11020-SRV-100-150-30A-1013%20Lrez.pdf

Sunelec

I have access to up to 385W panels. They are big! Usually, I use 180-250W panel.

Hugh, what size battery compartment do you have?

The design we're doing for the Gourmet food trucks is:

4-6 Solar Panels - 235W each (6 to 8 kWh per day)
4 x 3kWh batteries
3000W Pure Sine-wave inverter
MPPT Charge controller

The system does require the batteries to be plugged in at night. The solar panels extend the power during the day. This replaces a 2-3 kW gasoline generator, using about $100 of gasoline per week.

I'd have to measure the battery box, but about 18"x24" by 14 deep.

The "big boy"

L: 20.47in (519.9 mm)
W: 10.55in (268 mm)
TH: 9.65in (245.1 mm) - Includes terminals
Weight: 154 lbs

http://upgi.com/Themes/leanandgreen/images/UPG/ProductDownloads/45964.pdf

3 kWh (12V x 250 Ah)

or with your dimensions, three of these would fit, 135 Ah, giving you 405Ah, or just under 5kW.

L: 13.39in (340.1 mm)
W: 6.81in (173.0 mm)
TH: 11.22in (285.0 mm)
Weight: 87 lbs

http://upgi.com/Themes/leanandgreen/images/UPG/ProductDownloads/40994.pdf

If the box is actually 28 inches long, 4 of them will fit giving you almost 6.5 kWh.

Interesting:

Thanks, how is their discharge and recharge life compared to a couple of six volt golf cart batteries in series?

The "big Boy" seems to go for $450 or more.

I think I can get two Trojan Golf Cart batteries for 1/2 that.

Hugh I bought two 12 V deep cycle Optima blue tops for our coach. They aren't as good as the twin 6V's.... Don't last as long, don't seem to put out the amps...

Two six-volts in series amount to one 12 volt, as in two 12 volts in series amount to 24 volts.

Anytime you can place the batteries in parallel, you are in a win-lose situation, such as the two 12 volts in parallel.

Win is you have more cranking amps at start-up, and reserve when the alternator is not running. The additional battery also provides more stability(like a capacitor) across positive/negative to avoid power spikes and drops(which may not be too good for some of the sensitive circuits).

Lose is the alternator now has additional work required to maintain that level of charge when running, as well at start-up if the batteries are used when not running. At start-up as well, if not enough resistance is provided, you may cook the starter(or wiring to/from the starter) since an over-amperage could occur. This may be mitigated by a higher fuse rating for that circuit, but this really is only a band-aid approach.

My recommendation is simply buy the a single 12-Volt quality battery with the highest amperage rating that can be safely installed in that vehicle. The manufacturer or manual may give some insight to this.

I don't know why, but the spec battery for my 911 is giant...like a marine battery, but it fits, and works fine, and when it gives up the ghost, I'll buy something more modern.

Good luck.

I believe you'll find that 2 of the six volt batteries have 1/2 the capacity of the "big boy". The big boy is also AGM, so even if it cracks, it won't leak acid everywhere. Like a giant Optima.

The standard T-105 batteries are "wet-cells" which will need distilled water every once in a while. And they will need a place to vent hydrogen.

I put two 12 volt deep cycle in parallel in my Sprinter based class C with one slide. It was almost double the cost to buy 2 decent 6 volts. When I last camped with no hookup we just needed to turn on the power to run the water pump. Fridge, water heater and stove all run off propane. Keep the lights off and use a wind up powered LED lantern and just load up the ipad or laptop with entertainment before you leave the house and I showed full reserve on my house batteries in the morning.

Revival,

While I wait for my solar panels to come in where the hell can I find a dual 12v battery box? I have a single now, but I want to move to a dual, but can't find one.

Yes I searched on goggle

Thanks