I have seen some solar panels hooked to car batteries.

If you have enough panels and batteries you can run your whole house all night, and let them charge during the day.

 

a single car battery would work for LED lighting or small recharging duties but heaters are a constant high draw and would quickly deplete the batteries charge. I started with the Harbor Freight 45 watt panels just to dip my toes into solar inexpensively, and then bought 2 more of these systems just for the redundancy of hardware. My next purchases were AGM (Absorbed Glass Mat) batteries from Sams Club (again for the price). I listen to The Survival Podcast and the resident guru there is Steven Harris. He has a site where he can show you things that will take you through every aspect of solar and I ended up getting his Emergency Home Battery Bank series, what a wealth of info!

 

A deep cycle battery is designed it does not hurt them if discharged 50%. If you do that repeatedly with a standard car battery it will eventually not recover. Generally car batteries can dump lots of amps in a short time like to power an electric starter. The deep cycle holds more energy but does not do well to give lots of amps in short burst.

 

Essentially folks have it coverd. If one plan a on electric heat, it is better to store the heat than the electricity, batteries are not 100 percent effecent and a large mass, either a water tank or say insulated hunk of concrete is cheaper than the batteries. This is a common strategy with wind chargers, called wind furnaces. Resistance heating elements draw directly from the generator, often as a braking mechanism for the wind turbine (maxing the feild on an alternator makes it harder to turn). The same concept has been used to make ice with surplus wind derived electricity. My suggestion for heat would be to cut out the middle man as to solar, and build a solor system for heat, be it a hot water heater, solar furnes or greenhouse. Then again wind and biomass are solar energy derived.

 

If your thinking bug out RV, upgrading to AGM or deap cycle batteries require a charge controller, as they don't charge right off of an automotive alternator. A set of solar panels also require a charge controller so kill two birds with one stone.
Automotive batteries will live aproximently 3 years in a system that dosnt draw them down more than 25%, marine deap cycle about the same on a 50% basis, electric forklift/golf cart batteries and deap cycle AGM batteries about 5 years at 50% cycle wile dedicated storage batteries, those designed for deep cycle storage such as server backup, solar or wind systems that don't deal with road vibrations may see 10 years or more of service with proper maintenance.

 

I am watching the development of lithium based batteries as they are soooooo much better than the regular lead-acid type!
Too damn expensive at present but the prices are dropping!

Storing electricity in batteries is just too expensive and weighty at present!

 

I am holding off on the solar/battery stuff as I am selling retreat and going mobile!

 

You got it, Donavon. Our batteries (44 of them, charging off 15 solar panels, which is more enough to run our entire household with no worries) are not "car batteries" at all, but deep-cycle batteries, which we do our best to keep above 50% (actually, 48% is the minimum we've set for ourselves). We have a back-up propane generator that kicks on to keep the batteries from discharging too much. In short, the deep-cell batteries can take a lot of beating, but a constant "rollercoaster" of high-charge to low-charge, day after day, will beat them into the ground.

Of course, a lot depends on how well they're maintained. (With care, and without defects, they should last upwards of five to seven years.)