Right now, there's a lot of Hooplah (so to speak) over lithium Ion Batteries. You certainly pay a lot of pennies for it.
Other than Lithium Ion, most people use car batteries or deep cycle batteries and AGM (not as expensive as lithium Ion, but still a pretty penny)
The whole point of using big heavy batteries like lead acid was for the cold-cranking amps. And then I assume when you need other batteries for other uses in your vehicle, why not stick with batteries with a similar form factor.
If you don't need all the cold-cranking amps to run a teardrop, then it's possible to not need lead-acid at all.
Has anyone ever thought of revisiting NiMH batteries or even NiCad for building a 12V house battery for cheaper than a Lithium Ion battery? Apparently the technology has come a long way since the 80's and 90's.
I haven't done the math yet, but I think that price/amp-hour comes out comparable to lead acid, better-than considering, realistically, you can only use half the amp-hours of lead acid, anyways.
I think it also might have a better amp-hour:weight ratio.
http://www.mpoweruk.com/nimh.htm
http://www.mpoweruk.com/nicad.htm
I was just wondering if anybody's investigated this? Perhaps a whole home-built bank of them in series and parallel to get 12V and high current.
Sincerely, Sean