[david85]

http://www.tractorpartsinc.com/tank_...rs_270_ctg.htm

They say it will run on 110-120 AC OR DC.

This is basically a glorified engine block heater and has a built in pump (presumably a universal AC/DC motor) and thermostat. Heater elements range from 800watt to 1500.

Some one tell me whats wrong with this because it seems too good to be true.

In theory this could run direct off most battery packs to heat the stock heater core.

Hard to beat the price.......

[Woodsmith]

Looks good to me.

If it is designed to preheat engine coolant then that is all you are wanting to do, just without the engine.

Control on DC would be the only real issue. The pump could be switched by a solid state DC relay and the heater element could be controlled by a suitable PWM motor controller as a temperature controller.

You would need to keep antifreeze and a header tank with a pressure cap on it though.

[dimitri]

Originally Posted by david85

This is basically a glorified engine block heater and has a built in pump (presumably a universal AC/DC motor) and thermostat. Heater elements range from 800watt to 1500.

I don't see pump mentioned anywhere? Wishful thinking perhaps?

Picture shows the same heater I tried before, sure it runs on DC, but thermostat fails quickly, I guess they forgot to mention this part

[Woodsmith]

You could use something like this, a dishwasher heater. I suggested it to jackbauer.

[BWH]

Hey David,

That appears to be the same type of tank heater I picked up. http://www.amazon.com/Kats-13200-Alumininum-Circulating-Heater/dp/B000I8XCYA/ref=pd_sbs_auto_6 (Just a quick link, you can find them much cheaper elsewhere.) There is no pump in there, just a heating coil and a simple thermostat.

When they say you can run it off of DC they mean 12v DC. Any higher and it burns out the thermostat. I’ve found a way to get around this but I haven’t tested it yet. Disconnect the thermostat wires from the heater coil power cables and rewire it to the 12v relay/contactor wire instead. It will keep the thermostat happy and still let it turn the heater on and off, just not directly.

[david85]

Did some more reading after I posted and it seems they do not have a pump. Somehow the heat alone causes a low volume circulation. Whats nice is they already have a heater, and thermostat so thats most of the work done. I found a blog called bimmerEV where he used a similar heater and he said he could get 100F air at the vents with it. I'm wondering if you put it close enough to the heater core that a pump isn't needed.

Don't understand why the thermostat would fail though. Thats not an electrical part (I don't think).

[Woodsmith]

Originally Posted by david85

Did some more reading after I posted and it seems they do not have a pump. Somehow the heat alone causes a low volume circulation. Whats nice is they already have a heater, and thermostat so thats most of the work done. I found a blog called bimmerEV where he used a similar heater and he said he could get 100F air at the vents with it. I'm wondering if you put it close enough to the heater core that a pump isn't needed.

Don't understand why the thermostat would fail though. Thats not an electrical part (I don't think).

The 'stat would fail as it is an electrical switch to turn the heating element on and off. It will be rated to run at ac voltages adn high dc voltages would cause the contacts to fuse.
You could use the 'stat at 12v and then use the 12v circuit to trigger a high dc voltage solid state relay that will control the element.

Relying on thermal syphon circulation may not work due to the small size of the plumbing and the restriction of the heater core. You would just get locallised heating and then it will cut out while the water slowly circulated. It would be very inefficient.

[david85]

What I've read about them is they are intended to circulate the coolant through an engine at a rate of 3-4x per hour depending on the exact model. My reasoning is that circulating through just the heater core would be much smaller that might be enough. If needed, a heater pump can be added later. Some european diesel cars now have an auxiliary electric water pump for the heater core.

The other thing I like about this, is running direct off the traction pack would be more efficient than taking power through a DC/DC converter. Lower amps, and you bypass the ~10% loss in the converter. 12V power to the thermostat would complicate things slightly but it sounds doable.

BWH, I'd be very interested in how that turns out for you.