Thermoelectric coolers vs compressor coolers vs passive coolers: Compressor coolers are the only real no-ice solution for hot days

Thermoelectric coolers plug into your car and only cool 40°F below ambient—useless on a hot day. Compressor coolers (Dometic, Engel) are mini fridges that freeze and run on battery, but cost $500+. Passive coolers with phase change packs still need frozen packs. For most people, a regular cooler with ice is simpler and cheaper.