Sorry I am starting a new thread on this but I looked all the way back to December and couldnt find the old thread that I started then when I found this inverter.
Hosfelt Electronics in Ohio,
Has 9-24 volt input 2.3A 24 volt output inverter. Part #56-814 for $19.50 that can be modified to run the Iopener perfectly.
It is a brick 2.87" X 4.87" X 2" with a cord to a cigarette lighter plug on one end and a cord on the other end with a plug thatfits the I Opener AND is the right polarity.
First, in the interest of reducing heat, I suggest that you carve off the plastic cover so it can breathe. Be carefull and use a dremel tool right at the seam. There are two electrolytics at the corners that you dont want to hit but the rest of it is heat sink so wont be dammaged by the dremel tool. BUT....be careful anyway.
Inside there are three plastic pots. the one at the edge of the board near the LED is the one that controlls the output. It can be reduced to only 20.80 volts in this way. Then I added two 2 amp diodes in series with the positive output. This further droped the voltage to 20.24 The output from my wall wart is 19.3 so I figured this was within 5% and most devices can handle 10% errors so I left it at that.
I then hooked it up to the IO and the car with the engine running and with it off and it booted perfectly. I even tried starting the engine while running and there wasnt even a glitch. The output capacitors seem to have enough reserve to weather a short drop in input voltage.
If you have the Mark Turpin steel case, the whole thing fits inside the case with the HD and CD and the Wall Wart. I now will have two cords out the back, one with a two prong AC plug on it the other with a cigarette lighter plug on it.
I dont know if the IO could handle the full 24 volts or not, I suspect it could, but no sense stressing the circuits.