My ultracap bank is seven 2600 Farad Maxwells, put together with a balancer by EBay seller cusdn, had it 3 years now. Here's a current listing for an identical version.
Maxwell BCAP0010 7 Ultracapacitor Surge Booster Assembly | eBay
I put it inside a plastic box with an Anderson connector, so can easily swap it from vehicle-to-vehicle. It can crank the 6.9L International IDI diesel all by itself, but sure puts a load on the alternator right away, since ultracaps want those electrons back just as fast as they'll give 'em up!
I've yet to try it for a long drive in the EV conversion, but intend to.
Hadn't put two-and-two together yet for using it as part of an alternator shutoff/delete. Running off the ultracap only provides such a small buffer that it would pert' near immediately transfer all load to the alternator, but switching in a lithium house battery that can maintain 15V under load sounds like a great way to unload the alternator. Thanks!