Track I run at has no AC power. Im planning to run ebuugy and sc. Is a car battery enough to charge a 4s lipo and a 2s lipo for 4 rounds of racing?

It should be fine.

will there be enough charge left to start my car and drive home?

I would buy a dedicated battery for that.

If you have a harbor freight near you. They sell a small generator that is like $90. Works great just to charge a few packs on race day. It will run Charger,fan and a light that I know of.

Turn on the engine and let the alternator charge the battery.

any recommendations on which battery to get? or can I just go to sears and get the cheapest one

+1 just start ur car a time or 2 throughout the day, you will be near it any ways. Much cheaper than buying a seperate battery.

If you’re going the separate battery route, get a deep cycle like used for marine trolling motors. Modern regular auto batteries don’t like being discharged very far, the plates are thin to provide very high starting current, but that makes them fragile for significant discharges. Then they typically die very quickly, leaving you stranded.

Don’t go too small, it depends on how fast you are charging, especially the 4S. Lead acids can deliver a lot of current, but the voltage drops significantly under even moderate loads. Can easily drop below the minimum needed for a typical RC charger. Here is a recent similar thread for reference:

http://www.rctech.net/forum/radio-el...uch-power.html

If you stick with your car battery, start it frequently, expect shorter life depending on how often. Did it for years, definitely makes a difference. If you can spring for it a generator is great to have.