# 12V heater and voltage regulator **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [September 26, 2014, 2:35am UTC](https://community.cartalk.com/t/12v-heater-and-voltage-regulator/87362 "2014-09-26T02:35:52Z")\ **Posts on this page:** 11\ **Page:** 2
**Author:** ![MikeInNH](https://avatars.discourse-cdn.com/v4/letter/m/a587f6/32.png) [@MikeInNH](https://community.cartalk.com/u/MikeInNH)\ **Post date:** [September 26, 2014, 7:44am UTC](https://community.cartalk.com/t/12v-heater-and-voltage-regulator/87362/21 "2014-09-26T07:44:21Z")
My dad had one in his 69 Bug. And it lasted a month before we had to replace the battery (which was only a year old). From then on we just bundled up more…and had a window scraper hanging off the knob of the radio. ---
**Author:** ![bing](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/bing/32/4619_2.png) [@bing](https://community.cartalk.com/u/bing)\ **Post date:** [September 26, 2014, 8:10am UTC](https://community.cartalk.com/t/12v-heater-and-voltage-regulator/87362/22 "2014-09-26T08:10:01Z")
I think I agree you overloaded the alt. Just to veer a little, I seem to remember way back in about 1965, a high school kids folks bought a new Ford and I’m sure he said that it had electric heat in it. Don’t know if it was supplemental or not but said it was nice on those below zero days when they’d get instant heat. Never heard much about it and think it was another idea that Ford dropped. In desperation one winter when I was having head gasket problems with my diesel, I bought one of those little electric heater/blowers. Just to try and keep the windshield clear and get some heat in traffic. Really didn’t work very well. Think I always had pretty heavy duty alternators though and never had a power problem. Sounds like yours is a lot heavier duty. The best heater I ever had was that gas heater in my 59 bug. It would drive you out whether driving or sitting. Even if you could buy something like that, it would be pretty expensive. I like the idea of a trans cooler too. Maybe a look at (gulp) JC. They’ve got truck and jeep and whatever heaters. ---
**Author:** ![meanjoe75fan](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/meanjoe75fan/32/552_2.png) [@meanjoe75fan](https://community.cartalk.com/u/meanjoe75fan)\ **Post date:** [September 26, 2014, 8:24am UTC](https://community.cartalk.com/t/12v-heater-and-voltage-regulator/87362/23 "2014-09-26T08:24:42Z")
@wesw: What about VW-style heat? Rig a box over the exhaust manifold…you’d need a lot less amps just to _move_ air, than move it AND heat it, too! (Heck, you got a smog pump on that? You already have your air pump!) ---
**Author:** ![wesw](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/wesw/32/2713_2.png) [@wesw](https://community.cartalk.com/u/wesw)\ **Post date:** [September 26, 2014, 3:40pm UTC](https://community.cartalk.com/t/12v-heater-and-voltage-regulator/87362/24 "2014-09-26T15:40:02Z")
that is my question joe Mario, what do you think? it may have had one at one time mean joe. idk. not now tho ---
**Author:** ![wesw](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/wesw/32/2713_2.png) [@wesw](https://community.cartalk.com/u/wesw)\ **Post date:** [September 26, 2014, 3:41pm UTC](https://community.cartalk.com/t/12v-heater-and-voltage-regulator/87362/25 "2014-09-26T15:41:33Z")
I ll pass on the exhaust heat rig. too risky for me… ---
**Author:** ![Yosemite](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/yosemite/32/643_2.png) [@Yosemite](https://community.cartalk.com/u/Yosemite)\ **Post date:** [September 26, 2014, 4:20pm UTC](https://community.cartalk.com/t/12v-heater-and-voltage-regulator/87362/26 "2014-09-26T16:20:06Z")
@WESW; you could get one of these!!! [http://milwaukee.craigslist.org/grd/4670121910.html](http://milwaukee.craigslist.org/grd/4670121910.html) Put it right where the passenger seat is. You didn’t want any riders anyway. Yosemite ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [September 26, 2014, 7:18pm UTC](https://community.cartalk.com/t/12v-heater-and-voltage-regulator/87362/27 "2014-09-26T19:18:38Z")
I think overtaxing the alternator with a heater would cause the alternator (diodes) to fail, not the regulator. I think the regulator failure is unrelated. ---
**Author:** ![texases](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/texases/32/862_2.png) [@texases](https://community.cartalk.com/u/texases)\ **Post date:** [September 26, 2014, 7:30pm UTC](https://community.cartalk.com/t/12v-heater-and-voltage-regulator/87362/28 "2014-09-26T19:30:42Z")
Here’s what I’d do - buy a cheap heater core, some heater hose, a shut off valve, a blower and a switch. Fabricate a box to connect the blower to the heater core, re-plumb the heater hose with a shutoff (for the summer), wire up the switch, and there you go - high capacity heat that doesn’t blow out your charging system. ---
**Author:** ![Oliver70](https://avatars.discourse-cdn.com/v4/letter/o/7993a0/32.png) [@Oliver70](https://community.cartalk.com/u/Oliver70)\ **Post date:** [September 26, 2014, 9:23pm UTC](https://community.cartalk.com/t/12v-heater-and-voltage-regulator/87362/29 "2014-09-26T21:23:35Z")
A watt is a watt, so 100 amps @ 13.8 volts dc is 1380 watts. A toaster, 15 amps @ 117 volts ac is 1755 watts. 375 watts (1755-1380) will not make the difference between warm toasty feet and feet that will barely feel warm. A coolant heater, similar to a trans cooler for flatter connections, mounted to the floor under the seat might be more effective. ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [September 26, 2014, 10:29pm UTC](https://community.cartalk.com/t/12v-heater-and-voltage-regulator/87362/30 "2014-09-26T22:29:04Z")
So a 20A heater (what wesw’s heater is fused at) would put out 240 watts, not much compared to a household space heater. OTOH about one third of the gasoline’s heat energy goes into the coolant in a car engine, roughly the same amount as the mechanical energy put out. If the engine is delivering an average 10HP (stop-and-go or low speed cruising) it’s also putting ~10HP of heat into the coolant: 7460 watts. Even a quarter of that into a heater core is a lot more than a 12V electric heater could practically do. ---
**Author:** ![DustyB](https://avatars.discourse-cdn.com/v4/letter/d/7ab992/32.png) [@DustyB](https://community.cartalk.com/u/DustyB)\ **Post date:** [September 28, 2014, 1:25am UTC](https://community.cartalk.com/t/12v-heater-and-voltage-regulator/87362/31 "2014-09-28T01:25:14Z")
I’d say with a 20 amp fuse it can’t draw too much for most any charging system. That’s less than 250 watts. Your headlights probably draw more current than that. [Previous page](https://community.cartalk.com/t/12v-heater-and-voltage-regulator/87362.md?page=1)