Thor Forums

[Chance]

Originally Posted by Yosemitebob

I use two 6v batteries wired parallel, Each battery is rated at 232AH in parallel it stays the same only voltage adds up, hence I have 12v at 232AH. Plenty as long as i start out full. We run the refer, and two TV's during the night, handles it right nicely. But then I have 400w of solar power on the roof too, to bring them up to charge again during the day. The more batteries you have, means longer charge times as well. Figure out your needs, you may not need four batteries.

That's a nice system you have there, particularly if you camp off grid during the day. I was intrigued to figure out how the solar "may" affect relative capacity (very rough estimate without much details).

Like you say, it's not about the number of batteries, but their size/capacity and how much energy and/or power the user needs. In your case it appears that your two batteries are considerably larger or of greater capacity than those of the OP. By the way, I think you probably meant to say your two 6-Volt batteries are wired in series, not parallel.

Most entry-level motorhomes I've looked at have house batteries rated around 80 Amp-hours each (must be common size), which gives the equivalent of 160 A-hour if it were 6-Volt. Since your two batteries are rated 232 Amp-hours, it makes them close to 3 of the ones often installed by manufacturers (obviously they can vary based on MH cost or other factors).

In your case solar could make all the difference. In rough numbers, a typical house battery like installed in many Class Cs can supply 1 kW-hr of energy. But since batteries should be limited to around 50% discharge, that means most owners will get about 0.5 kW-hr (500 watt-hours). So the common two-battery system can only supply 1 kW-hr of energy before it needs recharging.

By comparison, your 400-watt solar system may produce 2 kW-hrs or more on a sunny day. That's the equivalent of 4 Harris 80 Amp-hour X 12-Volts batteries if discharged to 50%. And if you add that your batteries are also larger (close to 3 Harris 80 Amp-hour X12-Volts), then your system can supply far more energy on a 24-hour daily cycle. I'd guess at least 3 times more.

I'm not defending Harris batteries in any way, but it's easy to see that if an owner only has two 80 Amp-hour X12-Volt batteries (total of 1 kW-hour of useable energy), then they have to limit power consumption to less than 50 Watts average in order for it to last a full 24-hour day. And that's not likely to work if owner runs a large residential refrigerator on a warm day.


I'm curious if your solar controller tracks how much energy the system provides daily. Do you ever get around 2,000 watt-hours in a 24-hour period? Whatever it is I'm sure it's extending your capacity significantly.

P.S. -- Sorry for length of reply, but how battery capacity will affect the future of RVing is an exciting subject to me.