Portable lithium project

[larrie]

One thing to check if you are buying a solar generator is the charging rate at 12 volts. Most of them have very low charging rates because they use a cigarette lighter type plug. Maybe only 5 amps. To charge a 100 AH battery up from 50% to 100% could take up to 10 hours of drive time.

This is why I built my own system; at 25 amps input the battery is fully charged in two hours of driving. My 200 watt solar panel puts out about 12 amps on a good day so it takes longer.

[rt66paul]

I agree there. Wiring it with another type setup would help, maybe it could be charges like the isolated second battery? I don't know, I don't boondock for a long time. I was speaking for the normal Joes that might charge up at a shore setup or from house current and then top off on the way. This could be a redundant system, while you are waiting for the isolated lead acid to die, you have extra. You are always much better off to engineer your system for your needs, or buy an pre-engineered system. If you want the cheapest, buying second hand(old tech) solar panels, battery packs from a scrapped E vehicle(also old tech) will give you more bang for your buck, but it can be very high maintenance.
I suspect that you could add a second alternator to do this job and charge the solar generator even faster. I am sure that shore power is the cheapest and the panels would just keep it topped off.