Quality battery

Welcome @Humgat!

I'm not sure what your setup is (# of panels, type of panel, type of inverter/charger, load, and load run duration). But in general, 12V DC systems (consisting of a single battery) do not hold up well. Particularly if your DOD (depth of discharge is >10% or so).

I'm certainly not an expert in PV Storage solutions. But the first thing to know is that lead acid batteries (regardless of quality) do not tolerate being run flat and then recharged. Based on on your electrical loads and run duration, you'll want to design a larger, higher voltage, multi battery bank solution such that your daily (or two day) DOD is no more than 30-50% of the capacity of your bank. The shallower your DOD the longer you bank will last (properly maintained -- water, acid, specific gravity, temperature).

Step 1 will be to add up the wattage of each of your loads (are they 12V DC or do you use an inverter to make 120V AC?). And then determine how many hours you wish to run them.
Step 2 is to evaluate the number and type (Wattage, Voltage, # of cells, etc.) of solar panels you have. The latitude, inclination, and orientation of the panels, and the number of sun hours you generally receive per day.

That said, many/most folks with RV solar solution's generally do not have a large enough surface area to be useful unless they are stationary/permanent and build a ground mounted array.

The larger your battery bank (and the higher the voltage) the larger of a PV array you will need to charge it.

Is this a hobby or are you planning to live off grid?

-Jonathan

Trojan is one of the best. There are one or two other companies as well whose name eludes me. Often you're looking at running 2, 4, or more high capacity lower voltage batteries (e.g. 6V or 2V) in series (not parallel) to get the string voltage up to 24V (sometimes 48V) to keep the DC load draw current low -- assuming you're inverting to AC. But then you need several large residential sized solar panels and a high voltage / current MPPT/charger and inverter to handler the loads.



Non lead-acid is also possible, becoming somewhat more common, but the initial capital cost is high.

Hi @Humgat,

There are several nice threads on this topic on the board. Here's a recent one that's just getting started

Rolls was the other main company I was thinking of.

Here's a link from Trojan's page where they are casting some shade


Here's a nice link that shows the effect of DOD on cycle number (for high quality, well maintained batteries)


Trojan has a nice design tool as well (for the bank part)

In terms of value it's pretty hard to beat a GC2. They're 6v so you'd need 2 of them but they're generally ~$100 or so and you can find them at Interstate Battery, Costco and sometimes Wal-Mart or Sams.

If you're willing to spend a bit more IMO L16s are a great longer term value. They're ~$300ea. I just added 8 more L16s to my bank.

Thanks for the useful links!
I didn't think about Trojan batteries, so I'll read more about them.