Like our friend
@bykfixer I had a couple of those 12V units that plug into the cigar lighter socket. They had a VERY slow flow rate, but could go to relatively high pressures.
They are not ideal for blowing up rafts for the beach, or inflating a very low on air, car tire. They do however work. ALso one is limited in the distance it can travel from the car.
I have a 3 gallon reserve tank compressor (I think it is a Craftsman) it works well but it is loud (as loud as most of those pancake compressors are). I keep attached to it a ? 10 foot long coiled flexible hose. I also have a couple of 25' extension hoses. It can run a 1/2 drive impact hammer for a very short time, but often long enough to break a nut free.
As mentioned above various tool manufacturers make battery operated tools that share their same battery. I bought into the Ryobi brand, so I have a number of their tools that run on the 18V platform.
I have both the Ryobi inflator, and the High Volume inflator.
The inflator is more for inflating tires, or basketballs, although it could be used to inflate a raft, if you are a patient person.
The high volume has been used to inflate a king sized 12 inch high bed mattress a number of times, although a really quick method is to use a leaf blower. It is certainly convenient for beach balls, and rafts etc.
The tools are particularly inexpensive if you already have the batteries.
Here are pics of the inflator
And of the high volume inflator