Ya, thats the question. Batteries are really the only practical DC storage system but there are others although cost is prohibitive. In my business (battery backup systems, what else) we have Flywheel storage devices available but not really cost effective for a homeowner. Molten Sodium? ha.
Ultra capacitors are my hope for the future but theyre not quite there yet. Batteries it is for now. I would prefer wet cells (VLA) in parallel at 24vdc would probably be the most practical. Of course for now, buying diesel for my Chevy is easiest. A lot of technology needs to evolve before the convenience of fossil fuel is surpassed. Still, I'm looking for a wind turbine right now to get started.
