I am planning on adding a hydrogen conversion to a few cars but was wondering if there are any issues with the hydrogen conversion on cold weather? I'm talking about Minnesota weather, so it gets really cold. What do I have to do to keep the conversion working in the winter?

If your thinking of running an HHO system which is basically H2O with a potassium elecrolyte it should be good to -15*F but a type of antifreeze may also be warranted....however placing propolyne glycol or ethylene glycol thru an electrolysis process and then inducting it into the engine to be burned is NOT a good idea. DON'T use regular antifreeze. However you can use isopropyl alcohol (rubbing alcohol). I'd check with the manufacturer of the unit for advice and concentration.