Whatever you do, stay away from those cheesy, plastic “emergency compressors” you see everywhere. They usually display their supposed max pressure proudly but don’t mention flow rate. If you’re lucky they’ll get 5psi in a real world car tire before they break.
The best source for info on 12V air compressors that actually
work are your local 4x4 enthusiasts and suppliers. They’re the guys who really use them.
Name brand companies like QuickAir, ARB or ExtremeAire make great products but be prepared to pay for quality.
For occasional, non-extreme use a decent knock-off should be fine.
Here’s a review of an offshore compressor that the guys on one random offroader forum I found were pretty happy with.
PC.