Why dont I hear of people using this?!
I have thought of something that I am wondering why I have not heard of anyone using this?
Why not use a sepperate battery to mount in your vehicle to power your hho cell? Then you would not be using your engine to power your hho cell and therefore you can use more hho without using more fuel to produce it. Then you just charge the battery up when you get home.
I have researched this before...
Here is a pretty darn good reference table:
http://www.lifelinebatteries.com/marinedeepcycle.php
For 20A@12V => 5 hours you would need the GPL-30HT which weighs a whopping 96 lbs!
http://www.lifelinebatteries.com/marineflyer.php?id=4
If you don't mind recharging every night, a less expensive alternative could be the GP-24T
http://www.lifelinebatteries.com/marineflyer.php?id=1
Granted you are using your car only for traveling to work and back (where a round trip is 2 hrs max) and max draw is 20A X 12V = 240 W
It would be smarter to go with ~15A max draw using a very efficient reactor.