Hey all I was wondering what the most common way is to charge batteries at an outdoor track with no power. If anyone could point me in the direction of a diy car battery charger or does anyone use the premade car battery booster things. Any help or advice would be appreciated.

I just hook up to my battery with vehicle running

Where i race a few of our members have purchased small generators, cheaper than a leisure battery and lasts a lot longer.

I use an old car battery but you don't get many charges out of it.

I use this inverter here:
https://www.harborfreight.com/750-wa...ter-66817.html

Nice and compact plus far more quiet than gasonline generators... I'll run a 25' extension cord from the inverter to the bed of my truck to power my supply/charger setup.

Only catch is that I need to start my automobile once every couple of hours for about 15-20 minutes to keep the main battery fully charged... first time I used it, I needed a jump start after 8 hours of sustained use.

Local track has power but local flying field does not, I use one of these batteries to power a quad charger at the flying field and can charge many packs with it. In my personal experience a car battery will drop voltage fast and cause a lot of chargers to error out, batteries made for constant, heavy draw are better for a charger. Wheelchair packs are great and come in even larger sizes.

UPG UB12350 Sealed Lead Acid Battery For Trident Front Wheel Drive

Some places have banned charging lipos in or on a car in case of fire etc. I use a 700watt AC generator. I also have a relatively small 12v PB battery I use if I'm only going to the track for a few runs or I can't be bothered to goto the gas station on the way to the track

I made a power pack. I used 2 x 4s 5000mah lipos in parallel(10k mah total). and a radio shack project box. I only run nitro on-road so my demand is not very high. I made 2 of these one for my tire truer and one to charge batteries with.