Don't know if it's any good but Sierra usually has one that's got battery, clips, air compressor, inverter etc...all in one unit. With a 35% off coupon it's priced pretty well.
There was a thread here or on another site, I forget? But you can hook up a air cond compressor in your truck to have a on board one all the time.
I will have to see if I can find it, unless someone else knows about them??
Bruce, it's been about 10 years since I ran the beaches but we use to carry an air tank with 100 pounds of air. I could air down to 8 to 10 PSI and air back up when I can off the beach to about 18 to 20 PSI. More than enough to get me to a gas station. We never found a DC compressor that was worth the bother.
Once the rangers on the Cape put in the air up station it was a no brainer. I only ran RI once or twice as you can walk just as easy to the good places to fish.