# Fluid heater (would this work)



## Woodsmith (Jun 5, 2008)

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.


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## dimitri (May 16, 2008)

david85 said:


> 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


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## Woodsmith (Jun 5, 2008)

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


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## BWH (Sep 26, 2008)

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.


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## david85 (Nov 12, 2007)

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).


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## Woodsmith (Jun 5, 2008)

david85 said:


> 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.


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## david85 (Nov 12, 2007)

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.


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## david85 (Nov 12, 2007)

This is the blog link I mentioned earlier:

http://www.upstate-ev.com/?p=46


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## Woodsmith (Jun 5, 2008)

It is much easier to circulate water through an engine block, most of it is wide open channels around the cylinders and the rest are large bore passages in the head to make heat removal effective. 

The heater core is the opposite, lots of restrictive pipes to slow down the flow so it gives up heat to the airflow.

Thermo syphon would be very ineffective with a heater core.

What you would want is to keep the warm water moving, but not moving too fast. The idea is that there should be a temperatire difference between the inlet and outlet equating to the heat lost by the core to the airflow. If it is too slow then there will not be sufficient heat in the core to be extracted by the airflow. Basically the core will never heat up enough and the heater will spend more time off then on.


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## david85 (Nov 12, 2007)

Guess I should start looking for a pump then.


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## Woodsmith (Jun 5, 2008)

Something like this might do.


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## david85 (Nov 12, 2007)

I'm holding out for something brushless like this:

http://cgi.ebay.ca/12V-WATER-CIRCUL...dZViewItemQQptZUK_Gadgets?hash=item4ceb7ad6c4

Not sure yet what flow rates are needed.

You figure 6.5LPM would be enough?

http://cgi.ebay.ca/NEW-Mini-DC-12V-...cmdZViewItemQQptZBI_Pumps?hash=item4149b9e410


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## dimitri (May 16, 2008)

David,

there were several threads over past year covering all this stuff. I know that JRP3 and I were participating a lot. I can't find specific posts now, don't have much time to look.

Bottom line, thermostats fail closed on DC current unless they are rated for that DC current and this one is not rated for high DC current. It will fail for sure, I tried 

You can still use these heaters, just wire thermostat thru relay, its easy to do.

Any pump with 1-2 GPM will work fine, but make sure pump is rated for hot water, so it won't melt the impeller.

I would recommend electric auto pumps from diesel cars like VW, you can find them on Ebay, they have same size ports and very quiet.


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## david85 (Nov 12, 2007)

Sounds like this could work then. 2 LPM is really low and should be easy to find.

I take it this is the pump you recommend?

http://cgi.ebay.ca/VW-Eurovan-EOS-V...r_Truck_Parts_Accessories?hash=item1c0c78c603

Bosch # 0392020073 / VW #'s 3D0965561D (in case the listing expires, you can google those part #s later on)

Tried doing a search before I started this thread, but didn't find much. I know Brian was able to build a nice fluid heater using a hot water tank element and some steel pipe fittings, but this cold be simpler to slap together.


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## dimitri (May 16, 2008)

david85 said:


> Sounds like this could work then. 2 LPM is really low and should be easy to find.
> 
> I take it this is the pump you recommend?
> 
> ...


That's exact pump I use to cool my controller, although I wouldn't pay that much for it  , I found mine for $50 on Ebay, maybe I just got lucky.

It would work perfectly with those heaters...


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## david85 (Nov 12, 2007)

I have no intention of paying that much either. But putting the part # might help some one else when this thread gets searched later on. Good score at $50 though.

Chances are local wreckers won't be able to help much either. Leaning more to the asian imported pumps. They claim them to be good up to 110C. Cutting it a little close, but it could be done.


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## david85 (Nov 12, 2007)

Found a video for the cheap Ebay (light brown) pump I posted earlier.










http://www.youtube.com/watch?v=46U6Owh9pok

Homepage:

http://images.google.ca/imgres?imgu...2V+brushless&ndsp=20&hl=en&sa=N&start=20&um=1

Seems to move water well enough for what I need.


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## JRP3 (Mar 7, 2008)

Here is the pump I will be using:
http://www.adventurerv.net/shurflo-...p-1713.html?osCsid=l2i413g3hl9i92iec6b73l3um1
Plumbed after the heater core just before the heater the water should be pretty well cooled off before it enters the pump.
I'm using the Katz heater 
http://www.amazon.com/gp/product/B000BQUUR6
Sitting in a cold garage plugged into AC power it puts out a lot of heat with the blower running, even without the pump.


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## JRP3 (Mar 7, 2008)

That SSR on the upstateEV site doesn't look as if it's rated high enough. 5-10 amps continuous won't be enough for 1500 watts, at least with my 115 volt pack: http://sure-audio.net/goods.php?id=191


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## kittydog42 (Sep 18, 2007)

You should consider pumping into the heater core (as opposed to sucking out of it), or else you probably will have a rough time getting the air out of the system.


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## david85 (Nov 12, 2007)

JRP3 said:


> Here is the pump I will be using:
> http://www.adventurerv.net/shurflo-...p-1713.html?osCsid=l2i413g3hl9i92iec6b73l3um1
> Plumbed after the heater core just before the heater the water should be pretty well cooled off before it enters the pump.
> I'm using the Katz heater
> ...


Thats something else I was wondering about!!!! I'm glad you mentioned that.

If the heater is right next to the heater core, I would expect a decent amount of thermal conductivity through the fluid without even havint to circulate anything.

I'm even toying with the idea of installing the complete heating system inside the passenger compartment to eliminate any possibility of waste heat outside the car.

How far from the heater core is your fluid heater?

Have you measured what temperature you are getting at the vents?

That pump is something I might be able to get locally, I see them in fliers on occasion. Typically marketed for pesticide sprayers so corrosion resistance is not an issue. I just feel its a bit of an overkill that will add to battery drain.

Oh, and the electric BMW I linked to earlier is using 144V nominal, so on a full charge, you get more than 150V, so 10 amps @ 150VDC = 1500 watts.

*kittydog42*

I'm planning to have the pump installed below the top of the heater core. That eliminates any issues related to priming, since the impeller chamber will always be full of water. Ideally, the heater, pump and heater core will all sit about at the same level.


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## JRP3 (Mar 7, 2008)

david85 said:


> I'm even toying with the idea of installing the complete heating system inside the passenger compartment to eliminate any possibility of waste heat outside the car.


I wrapped my heater and hoses with pipe insulation.


> How far from the heater core is your fluid heater?


I have about 12 inches of hose between the heater and heater core. Have not measured temperature.


> That pump is something I might be able to get locally, I see them in fliers on occasion. Typically marketed for pesticide sprayers so corrosion resistance is not an issue. I just feel its a bit of an overkill that will add to battery drain.


The pump is a low pressure low flow pump, I wouldn't think it would work in a sprayer application. It draws less than 2 amps at low pressure. More details:
http://store.solar-electric.com/100-00-21.html



> *kittydog42*
> 
> I'm planning to have the pump installed below the top of the heater core. That eliminates any issues related to priming, since the impeller chamber will always be full of water. Ideally, the heater, pump and heater core will all sit about at the same level.


You will need to bleed air out of the system somehow. I did it crudely by overfilling it a few times while holding the connections above the rest of the system. I may put in a pressure relief valve or a remote radiator cap setup. http://www.siliconeintakes.com/product_info.php?products_id=1064


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## Woodsmith (Jun 5, 2008)

david85 said:


> If the heater is right next to the heater core, I would expect a decent amount of thermal conductivity through the fluid without even havint to circulate anything.
> 
> I'm even toying with the idea of installing the complete heating system inside the passenger compartment to eliminate any possibility of waste heat outside the car.


If you are really keen to run without a fluid pump then it would be best to site the heater as low as possible with a section of pipe going straight up, That would help get the thermosyphon working. The system needs to be a vertical layout rather then a horizontal one. Also large bore pipe helps.

Fitting it into the passenger footwell would be a good way to do this. Maybe even running large bore pipe along the tunnel and around the inner sills and across the top of the dash would work with a thermosyphon system. The heater would be under the dash and the water would rise to the dash and then slowly work its way around the sills and back along the tunnel for each side of the car.

It would be like a Victorian hot house system.


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## mill (Aug 22, 2008)

david85 said:


> I'm holding out for something brushless like this:
> 
> http://cgi.ebay.ca/12V-WATER-CIRCUL...dZViewItemQQptZUK_Gadgets?hash=item4ceb7ad6c4
> 
> ...



good luck getting the air out of a heater core with no pump, especially since its the highest thing in a thermosyphon. I would use the pump from the top link, that's a new style vw/audi coolant pump and they are indestructible so far, we haven't seen one fail at the shop. the other vw pump shown on this thread somewhere is known for leaking. in real life they only pull about .6 amps and you cant really even hear them when they run. I'll check the shop tomorrow and see if I can scrounge one up if your interested.


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## JRP3 (Mar 7, 2008)

Don't know about David's setup but it was pretty easy for me to lift the rubber hoses up higher than the heater core in mine to get the air out.


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## mill (Aug 22, 2008)

JRP3 said:


> Don't know about David's setup but it was pretty easy for me to lift the rubber hoses up higher than the heater core in mine to get the air out.


not saying it would not work, I am not familiar with the saturn setup either, I just think a having a pump would be a good sure fire way to go, especially in his climate.


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## kittydog42 (Sep 18, 2007)

I don't have a problem when I pump into the heater core. Every time I have tried to suck out of it, however, I have had to punt and reverse the lines. That is just my experience, though, it sounds as if others have made it work both ways.


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## JRP3 (Mar 7, 2008)

kittydog42 said:


> I don't have a problem when I pump into the heater core. Every time I have tried to suck out of it, however, I have had to punt and reverse the lines. That is just my experience, though, it sounds as if others have made it work both ways.


I'm not sure of the difference in a closed system. It's essentially a circle so the pump is always both pushing and pulling.


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## Woodsmith (Jun 5, 2008)

The impellor in the pump may cavitate and produce bubbles so it would be better to put the pump where the bubbles can quickly escape to a high point for bleeding off.


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