Direct wire 12V Heater

[silentdub]

Has anyone installed a 12V powered heater for the cab? This is a custom vehicle and the factory equipment has been removed along with extensive modifications done to the tub and suspension. The factory heater is no longer an option.

Looking for a 12V heater than I can direct wire in that works and provides enough heat to warm the cab. Not sure how well it is going to work considering the rag top but looking at options that work.

 

[Living in the Past]

Unless you have an electric vehicle or air cooled engine I see no reason not.to take advantage of the heat produced by an internal combustion engine. Why go to extra the wiring and huge alternator to generate enough electricity for an electric heater.

 

[SteveH]

IMO - no electric heater will be able to provide enough BTUs to heat the inside of a soft top FJ40. You'd be better off with electrically heated seats than cab heat, unless (as Living in the Past suggested) you run a hot water fueled heater.

 

[charliemeyer007]

Go to a junk yard. Score a subaru radiator with the electric fan and bracket. Build a wood box for behind the front seats that holds the radiator/fan assembly. Plump into the coolant system and wire in a switch for the fan. Add a flow valve to shut it off when heat isn't needed. Boom heat. You could do some ducts to move some warm air up front by your feet.

Couple hundred bucks for everything ought to do it. Several hours. I ring shanked my wood box assembly except to the top which is screwed on so I could easily service the unit easily. I have storage bins on both side of the heater. It was like one 2"x6"x8' and some scrap pieces of 1x4 or 6. Mine is wall to wall between the wheel wells and fits in the floor recess.

 

[zerotreedelta]

Indeed, I'd use the cooling system similar to OEM. There's pre-fab fan boxes like this, and I'm sure you could find some that either fit under the front seat or in the front-rear like the OEM rear heat.

https://www.amazon.com/JEGS-70601-Auxiliary-Heater-Assembly/dp/B07HB9M6TC

You could also build your own - Chevette heater cores are popular due to ready availability and cheap:

REACH COOLING GROUP 18-12097 Reach Cooling Heater Cores | Summit Racing

Free Shipping - Reach Cooling Heater Cores with qualifying orders of $109. Shop Heater Cores at Summit Racing.

www.summitracing.com

 

[45Dougal]

Google tells me that most cars need between 4 and 8kw of heat. For the rag top you'll be at the top end of that at least.
8kW / 12V = 660A. That's one hell of an alternator you'll need, and it'll cost you about 10bhp.
Piping water from the engine is really the only way, but tbh, the biggest problem i found is fitting a blower which can move enough air within a small volume.

How much space do you have to play with?