# heater core



## lou-ace (Jul 21, 2009)

Now some of this stuff is absurd.I live in the northwest and must have at least a defroster and a heater in my rig. when I was shopping for a electric heater core these $200-500 dollar units pushed me over the edge. I took a cheep ( I mean really a $9.99 unit) space heater and salvaged the parts. tungstun steel heater elements have been around since Mr. Tesla. I gutted the unit, measured out the wire used the existing frame work and now have a unit that i plan on puttng in my blower. I used 6" of the existing 36" 20g tungstun for the element. My math= 750wts devided by 36" ( the total length of wire) X 6" ( my length) devided by 12 ( my voltage) and I should have a 10 amp heater core. I ran this unit on a 12 volt batt. and it put out good heat. The other accessory that I need is a brake vac booster assembaly. I'll be damned if I'm going to pay $300 dollars for a simple vacume pump. WE are the heroes here, and I'm pretty fed up with the industry screwing us with this retail markup screw job! All of our needed parts are readily available and cheeeeep if we can find the right supplier, It's the application that is the bitch. see my blog for my own adapter plate and connector for the E-motor/tranny arrangement if it works well, cloudelectic can shove that $1100 dollor adapter kit right up their ars.


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## EVfun (Mar 14, 2010)

This is what I'm using in my Datsun. I have used hardware store space heaters before, in my Pickup. I bought 2 of them at closeout for about $20 each. I looked for units where you could see what looks like a radiator inside because those are ceramic cores (the ceramic heating elements are between the fins and the fins are both the way to get the heat out and the electrical connections.) They cost a little more than old style nichrome wire heaters but are safer too. In the case of blocked airflow the ceramic heaters limit their input power to limit the maximum temperature. With zero airflow they can char paper after about 15 to 20 minutes. 

To use these heaters on the DC pack voltage in an EV you need to get a high voltage DC relay (P&B KUEP series is commonly used) and install the heater(s) in place of the original water core. The advantage is *a lot* of heat. Each core put out between 1200 and 1500 watts of heat with good airflow. By turning the fan down you can reduce the heat, you can also switch off half the elements to limit heat (that requires 2 relays.) 3000 watts is driving in western Washington warmth


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## PatricioIN (Jun 13, 2008)

I think most EVers do what I did. They take out the original heater core and replace it with a cheap (Target, Meijer, etc) ceramic heater core wired to their traction pack. I think I spent $10-15 on my heater core, built a frame the exact dimensions of my ICE OEM heater core, and about $15 for a relay. Add some wire and an off/on switch and I spent maybe $35 total for an electric heater that works just fine. The off/on switch is wired into the power lines coming from the cars fan switch so the heater can only be on if the fan is running. Also, since it's electric, you'll get heat in about ten seconds compared to five minutes for a modern engine to heat up!

Bottom line is I agree with you.. many of the high priced options from EV suppliers are there for convenience - for those who want plug and play. Much of that can be fabricated on your own. I spent about $90 for the plate aluminum for my adapter plates and cut them out myself with a standard handheld jigsaw, $5 worth of metal blades (a lot of them!), and a lot of patience. Rock on you DIYer, Rock on!


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## Woodsmith (Jun 5, 2008)

I have been toying with some heater ideas to save money.

Heater core









Tumble dryer heater









Two fan heater elements









Three cooker rings interlaced









I did all that to figure how to fit something in the space available and the found that it wouldn't work as the heater is horizontal in a plastic box with a plastic flap above and below it. Any of these options would melt the plastic if the flaps closed.

So, having cut a hole in the firewall to get the heater out...









...to save pulling the dash...









I could have just removed the AC box from behind the glove box and put a heater in there.









It is a big, easily accessible box and puts the heat flow in a better space leaving the original heater core untouched.

I will probably get a ceramic heater in the AC box next but I have read on this forum about difficulties switching and fusing the high start up current of ceramics on DC.


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## lou-ace (Jul 21, 2009)

hey! here in the great NW like me. So Have you found a local supplier for such items as high voltage relays, contactors, switches, variable potentiometers,.. ect.... thats really what is missing in this project is a supplier like is what radio-shack used to be 20 years ago. ??? and really do we need to pay $80 dollars for a 0-5k potentiometer with a lever that we can use for a throttle? thanks again.


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## EVfun (Mar 14, 2010)

I have a few resources for some things, but surplus stuff comes and goes.

I bought a 5 KUEP relays a long time ago and will be putting #4 into my Datsun. I paid about $10 each surplus but here is an even better deal (from a western WA EVer too.)

As far as the throttle pots, there is a Chinese made knock off but I'm not sure who in the USA is selling it. I have never had to replace the pot inside the throttle box so I have just ponied up the money once for each EV. If someone is selling the PB-5 (instead of PB-6) you can save some money, provided you don't need the microswitch.

For high voltage, relatively low amperage switches, old DC rated home switches pop up in home improvement stores from time to time. I still have a couple, one I got from an online store and the other I found at a local Lowes. They generally have a 5 or 10 amp rating at 130 volts DC. They are generally round surface mount switches with a heavy click to the switch. The DC rating is listed on the bottom.


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## Tesseract (Sep 27, 2008)

lou-ace said:


> ...I used 6" of the existing 36" 20g tungstun for the element. My math= 750wts devided by 36" ( the total length of wire) X 6" ( my length) devided by 12 ( my voltage) and I should have a 10 amp heater core. I ran this unit on a 12 volt batt. and it put out good heat. ...


Hey lou... incandescent light bulbs use tungsten for the filament; heating elements use Nichrome. I mention this mainly because you can buy Nichrome wire and ribbon for "cheep" and skip the hassle of extracting it from some crummy space heater.

Secondly, your math ain't quite right. Assuming your 750W space heater ran on 120V then the current that you have to push through it is: 750W/120V = 6.25A.

You correctly surmised that the wattage is proportional to the length of wire, so if you only used 6" of the 36" long wire then you now have a 125W heater, but it still requires 6.25A to reach operating temperature, and 125W/6.25A = 20V, not 12V.

Unfortunately, a 125W heater is between 10x and 20x too small to be effective at heating up a car. In other words, you need more than 1000W to do this job with any sort of effectiveness.


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## lou-ace (Jul 21, 2009)

tesseract, yea this element is wimpy, and thanks for the corrections, thats why I come here you guys can teach me alot!! I'm probably going to wait till My EV is more complete till i accessorize but than I plan on using the other half of this coil ( still 750 wtts) and my pack voltage through a relay should work, I only hope it doesn't drag down my pack too much. thanks again-Lou-Ace


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## lou-ace (Jul 21, 2009)

EVfun said:


> I have a few resources for some things, but surplus stuff comes and goes.
> 
> I bought a 5 KUEP relays a long time ago and will be putting #4 into my Datsun. I paid about $10 each surplus but here is an even better deal (from a western WA EVer too.)
> 
> ...


 Great price I ordered two now.... you rock thanks


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