Sorry if it was a bit vague, but my idea goes like so:
The tanks are charged, by the on-board system, and/or by a home (or possible future gas-station) based H2 generator, giving you a range of about 350 miles, or 560km, on 5 tanks. While driving, the on-board system generates hydrogen, recharging the tanks (or recharging one or two, while the others supply to the engine) as you drive, using the H2 chem cell plan. When the car is stopped (anywhere, a rest stop, gas station, hotel, restaurant, home, etc.), the on-board system continues to refill the metal hydride tanks until they are full. The system, to what should be a high degree, generates its own electricity, and continiuing the reaction. The battery is recharged by one cell (active) as it charges the other (inactive cell). My recharging system also aids in recharging the battery, using the heat generated by the cell's reaction while producing hydroxy, although my system is slightly more efficient while the car is moving. When the tanks are completely full, the cells' connection to the battery are disconnected, and, being incapable of recharging with no battery connection, the cells stop producing H2. Any H2 produced after it is shut off (probably will be a small amount some times) can be stored in a small overflow tank, or other spot, since it shouldn't be able to hang in limbo in the tubes and in the tank (fire and explosion (not really, just a very fast burning) hazard).
When you start the car again (after tanks are fully charged), you'll have a range of 350 miles again, plus the constant refilling from the cells. We won't even have to supply half the car's hydrogen need (if we do, that's 1.5x range on tanks alone, or 525 miles (840km), but the higher production we can get, the better.
True, water injection would give us a boost in mileage. The water could be cooled in a pipe in front of the radiator before being misted into the intake, to make it as dense as possible, and able to absorb more heat from the incoming air, and allowing us to turn down the amount of water injection a bit, since a denser unit of water can expand to more steam than a warm, equal unit of water. The ideal temperature for water is 4oC, and we should be able to reach close to that, at highway speed.
An obvious bit is that the cells continuing to run after the car is turned off would deplete the water in the tanks, and the water level in the car. It's only converted into more useful hydrogen, not gone, but you could top it off before you leave, if you like.
Having gas (really gas, not liquid

This system has the possibility of adding some weight and taking up space in the car, so we'll need to keep the size of the cells and tanks under control. Having 2-4 cells (which need not be very big) stacked, and tucked away, with the tanks similarly either positioned in odd spots (in place of part of the old gas tank wouldn't be too bad, maybe we can even use the old tank to store the hydride, as long as that much hydride doesn't weight too much, or break something). Possibly, the tanks could be made in a rectangular or box shape, making them easier to stack and store, but that would bring up a few small problems of ditributing the hydrogen in the tank to bond to the hydride (easily solved), getting the H2 out efficiently and completely (not stagnant parts), and heating the tanks evenly to release the H2 (also semi-easily solved).
But to the easier parts right now...
I think having both chems remain in solutuion (not precipitated) would be ideal, since it would keep all of the chems exposed, in easy contact with the electrodes for a faster, more efficent and simpler recharging. Having a properly polarized plate (or set of plates) on the bottom to take care of the precipitated chemicals.
Or we can substitute the chemical that precipitates with another that won't and still has a similar volatge created, but that shouldn't be neccesary if we can design it properly. If the precipitated compound can't be reached, then we can't (or can barely) recharge the cell. We'll need corrugated plates (thrival's drawing, more surface area) fairly close together, and touching the bottom of the tank, to reach as much of the preciptate as possible. Any ideas about this?
