The Stovebolt Site Forums The Shop Area The Electrical Bay 12 volts & a heater

Would it be better to:

a) replace the heater motor with a 12 volt replacement,
b) have the current one altered to accept 12 volt, or
c) install a voltage reducer and leave it original.

Thanks for your suggestions.

I don't think it is feasible to convert a heater motor to 12V, but I could be wrong. Using a resistor is unpractical for a heater motor. You can get DC-DC convertors for probably equal to or more than buying the 12V motor. I'd buy the 12V motor.

I have a 12v-6v reducer on my heater and it works great. Just get one that has a built in heat sink to dissipate extra heat build-up. I think it cost ~$7.50.

How long ago did you do it and how often do you use it? I don't expect to use mine much, as the truck wil be parked in the winter. We get some cold mornings and evenings, so it would be nice to have. Price sounds good too.

Thanks!

I got mine at Amican Classic Truck Parts, Although I notice it is $15 not $7.50.
THe truck was converted to 12V about 2 years ago and it is driven nearly daily year round. I have run the heater for over an hour with no troubles at all.

This guy has pictures of replacing the old six volt motor with a new 12 volt replacement that fits in the old case. Take a look.

http://www.speedprint.com/Deves50/HeaterRestore.html

Does your 6v heater have a 'speed' control? Most Chevy heaters had a 3 speed, or a variable control.

If you do, then you actually already have a voltage reducer. I'd guess that a 12v supply to a 6v heater motor running at 1/2 speed has the same rpm as 6v supply to a 6v heater motor running at full speed.

I'm not sure this is exact, but DC motors in general have a really wide latitude in supply voltage. Of course, running a 6v motor at 12v high speed will run hotter than with a 6v supply.

Personally, I'd run the 6v motor on high speed for 5 minutes or so (with the motor cold and not running) - then see how hot the motor is actually getting. Any potential damage to the motor in this situation will likely be from heat - melting solder, etc.

If you do this, make sure the heater motor has an appropriate fuse for safety in case of motor failure.

I rebuilt my heater and replaced the original 6 volt motor with a 12 volt motor that I ordered from Grainger online http://www.grainger.com/Grainger/wwg/start.shtml . You may not be able to buy directly from them like I did, but you can determine what motor to get there and pick it up at any electrical supply store locally. I think I paid about $20 bucks for mine, and it fits and runs just fine.

If you decide to rebuild it, make sure to have the heater core pressure tested and repaired if it leaks.

I used a reducer and a 12 volt three-speed switch with the 6 volt motor at first. Between the resistance in the switch and the reducer the motor ran fine and cool. However, top end speed was fine, but middle and slow were very poor. I'm going to remove the reducer when I get a chance and see what happens with just the switch. From past experience, I'll make certain to keep my fire extinguisher handy.

I've been running a reducer between source and my variable heater switch for a couple years it it works great. Have noticed since the beginning that the top speed is too fast and I'm concerned that I'll burn the 6 v motor so I use the lowest speed which is about the same as the original's top speed. Lots of heat.