How much solar to stick on a 22-24 foot "C"?

If 400 amp-hours of battery bank, minimum to be able to equalize the bank is 240 watts with a GOOD temperature compensated charge controller.

For my detailed thoughts on solar surf here: https://freecampsites.net/adding-solar/

RoyB, you've been talking about this for years. Why don't you drop the cash and try it out so you can speak from experience. :) BTW, solar will supply power to equipment first and whatever is left goes to the batteries.

The standard minimum is 1 watt of solar for each amp of battery, so 200 to 400 watts. I'm at 300 watts for 240 amps. But I agree with others...fill the roof within reason.

Almot wrote:
Other than DC circuit of propane fridge and (possibly) some fans in summer, I can't think of other "12V stuff" with substantial current draw.

Fridge climate control heating element which on many fridge models these days can't be turned off. :M Doing so is a simple task by adding a switch to that circuit, saving considerable battery reserve. :B

In my case I want to charge my 255Ah battery bank as quick as i can charge it each morning when allowed to run my generator. My PD9260C 60AMP converter/charger can do it in as quick as about three hours.

My plan is to use my Honda 2KW Generator for the first hour to get past the very high initial current Battery Bank draw being hit with 14.4DC Volts and after the batteries start taking on charge the current draw is much less. When the Converte/charger drops back to the 13.6VDC Voltage mode then I want to use solar panels when the high sun is available after the initial first hour use of the generator.

I want to be able to produce around 20AMPS of solar power so this will need a couple of 120WATT panels on front of my POPUP trailer roof and maybe a 240WATT Panel across the back of the roof. A typical 120WATT panel will produce around 5-6AMPS DC current.. My POPUP roof size is right at 12 foot of space with a small Fantastic fan on one end and the 13,500 Air Conditioner on the other end.

This is going to be my game plan at any rate... If I have high sun then I can be in solar charge mode for a good 5-6 hours during the day light hours.

All of my DC Power amps consumption will be from my battery bank. The solar panels will only be used to re-charge the battery bank when in high sun...

Having been camping off grid since 2009 using my OFF-ROAD POPUP setup I seem to want to draw around 20AMPS of DC current from 6PM to around 11PM each night from my 600WATT PSW Power Inverter to run a few 120VAC things in my POPUP trailer and support my ham radio operations...

This is probably more then most causal campers will want to draw from their battery bank...

I run down my 255AH battery bank from its 90% state of charge to its 50% state of charge (Around 12.0VDC) over night and then run my 2KW generator the next morning for three hours to re-charge back up to the 90% state of charge. I can do around 12 days of doing this routine battery bank cycles without doing any harm to it...

My new battery bank of two groups of 6VDC Trojan T105 batteries in series that is currently in the planning stage is probably going to be around 440AHs so this may change my charging cycles abit for the better...

All still in the planning mode for the newer battery bank

Roy Ken

every rig is going to have vents, antennae, skylights, a/c etc in differing locations. Dont guess, climb up and see how much will fit without getting shading.

Daryll

Horizon170 wrote:
Cut a 2' X 4' (Or whatever size you are looking at) piece of cardboard and go up top and lay it out. More is best.

This.

Also, consider getting a catalytic propane heater like Olympian 3 or 5. Zero 12V draw and very easy on propane.

Other than DC circuit of propane fridge and (possibly) some fans in summer, I can't think of other "12V stuff" with substantial current draw. Without furnace it is possible to harvest enough for a day with a single 100W panel, but the more - the better.

Cut a 2' X 4' (Or whatever size you are looking at) piece of cardboard and go up top and lay it out. More is best.
I can get 4 on my short "C".

I would think you would have to climb up on the roof and see how much room you have.