Here's a very short discussion on one that appeared on e-bay in 2005:
1957 Oberhausen Supercharger - THE H.A.M.B.
There is an electric supercharger made today, but they claim an average of 5% increase, up to 15 hp. Not much for $300-350. Says it produces 1 psi only at WOT (and from other sources that's tops, 0.5 psi is average). 1.2 hp, draws 62 amps. Looking at the test results it appears that it's only been used on 3.0L engines and smaller, which makes sense. Even 0.5 psi will make a slight difference at WOT on a small engine, but not much. 5 hp on a 100 hp engine, and maybe more like 2.5-3 hp. Put two on a V-8 and get maybe a 10 hp gain for only $600-700!
eRacing :: Products :: e-RAM Electric Supercharger :: 1psi
This is a good article -- gives positives but also explains the negatives of an electric supercharger.
Electric supercharger - Wikipedia, the free encyclopedia
The main problem with an electric driven supercharger is the amount of electric power needed. This on (http://www.turbomagazine.com/tech/04...r/viewall.html
) has been around a while. Claims up to 10 psi, but only for a short time. It uses 24V -- you have to add a second battery and wire in a switching system that comes with the kit to keep the batteries charged. You can only run the thing for 20 seconds or less before the batteries are depleted enough it won't boost any more. Then you have to drive around until the batteries charge back up. Hope it has a circuit that cuts it out once the batteries are down so far, not so far it won't start back up! I read a bit about it on a discussion board and come to the same conclusion on my own -- for a few seconds just get a cheater 50-100 hp nitrous kit. Cheaper in the short term for sure. If you use it much you might run some costs up in nitrous, but only a little at a time.