# water heaters



## rwaudio (May 22, 2008)

Rob_of_Waterloo said:


> Has anyone used a Kat's Circulating tank heater as a cabin heater. They are about 1/10 the cost. If so, did you just electrically connect it across the battery pack (with fuse and control).
> 
> Rob


I'm using a pair of them, I've only tested so far but they work well. I'm using a Tyco EV200 on the main pack to switch the heaters on/off. (I tested in parallel, off of ~100V but will be using them in series off of ~300V)

http://www.northerntool.com/shop/tools/product_200339137_200339137


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## DIYguy (Sep 18, 2008)

Rob_of_Waterloo said:


> Has anyone used a Kat's Circulating tank heater as a cabin heater. They are about 1/10 the cost. If so, did you just electrically connect it across the battery pack (with fuse and control).
> 
> Rob


Hi Rob from Waterloo. This is Gary from Kitchener. (Actually New Dundee).  (for those of you who don't know, these are sister cities)
Yes, I used this approach. . . it was a different brand, but same idea. I also used a Kilovac contactor with it. It pumps out about 4.5 kw of heat (211 volt nom pack). I just need to implement a way to throttle it back. I have a few ideas but working on other things. I just turn it on and off in the cold. Of course I have fan speeds but, once the cabin is warm . . I would like to cut back the power. Open loop control would be fine. I've looked at PWM control but will likely try a temp probe and switching relay (a lot cheaper).
Edit; oh yes, one other thing.. . you need to split the snap switch out of the high voltage DC circuit. It will weld shut. I used mine in series with the 12 volt control of the relay. This works well. If the water gets too hot, it switches off nicely. This switch is designed for AC . . it will die on pack voltage DC.


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## PTCruisin (Nov 19, 2009)

I am very interested in this heater solution but have a couple of questions. 

Do you connect this directly to the heater core?

Does it require a pump or is it self-circulating?

Thanks!


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## DIYguy (Sep 18, 2008)

PTCruisin said:


> I am very interested in this heater solution but have a couple of questions.
> 
> Do you connect this directly to the heater core?
> 
> ...


Yes, it circulates to the original heater core. I did not want to rip my dash apart and cut up the heater core to add elements. This keeps the high voltage out as well. 
Yes it needs a pump. I wore out a cheap noisy one, now I have a very good, and quiet pump.

Additionally, I visited a local motorcycle shop and bought a used overflow tank and pressure cap from a liquid cooled bike. These are perfect size for this system and have worked flawlessly. I think you can do the whole thing for less than $!50 or there abouts......


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## Yukon_Shane (Jul 15, 2010)

wow, this thread should be relabed "the canadian approach to heating an EV"


DIY and RW: Can you offer a bit of your thinking around going this fluid based heater route vs. the traditional ceramic heater installation?

I'm going back and forth between these two options right now and am having a bit of trouble deciding. I've started to try and mount two ceramic heaters in my cab but I'm not convinced of the safety of this approach (or rather my ability to design it safely) and I'm starting to lean back towards the fluid based heating system that you both have choosen.

What are you using to circulate the water? Are you using an overflow reservoir?

thanks,
Shane


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## DIYguy (Sep 18, 2008)

Yukon_Shane said:


> wow, this thread should be relabed "the canadian approach to heating an EV"
> 
> 
> DIY and RW: Can you offer a bit of your thinking around going this fluid based heater route vs. the traditional ceramic heater installation?
> ...



See my last post. . answers some questions. I ended up buying a 12 volt Shurflo RV water pump. There are a number of models but you can find one on EBay for $50 or so depending. It's quiet, has good flow/pressure ability and seems like it can handle the heat. . . which i was a bit worried about and I think did in my first pump.


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## rwaudio (May 22, 2008)

Yukon_Shane said:


> wow, this thread should be relabed "the canadian approach to heating an EV"
> 
> 
> DIY and RW: Can you offer a bit of your thinking around going this fluid based heater route vs. the traditional ceramic heater installation?
> ...


Basically I didn't want to open up my dash for the ceramic route so it was pretty much the only option, but I also wanted the heater to work like it does from the factory, so by circulating coolant (50% water/antifreeze) everything works the same. In my car the temperature dial controls the flow of coolant through the system, so I will be able to "turn it down" however there will probably be some wasted energy as I'm probably heating the coolant necessary at certain times. 

I'm using the PC water cooling pump that's recommended quite often, I got the variable speed one and it works well and is very quiet.


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## Yukon_Shane (Jul 15, 2010)

Well I think you've both convinced me to change gears (again) and go back to the fluid heater idea. This approach makes alot of sense: keep the stock system in place and; keep the high voltage out of the cab

RW: did the Kat's heater have an easily identifiable temperature snap switch that you were able to tie into the DC contactor (like DIY described for his fluid heater)? 

I purchased a snap switches that I was thinking I'd use for this purpose when I first started planning the heating system but I'd prefer to use the Kat's stock temperature control if possible.

Shane


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## PhantomPholly (Aug 20, 2008)

As for controlling temperature, here are a couple of ideas:

1. An ordinary home thermostat, placed in a strategic location and activating the heater contactor (I think many of these simply energize a 12v control signal which in turn activates the furnace / AC unit). This could be used in conjunction with #2 for more even heating.
2. Hi/Low setting, achieved by having two heaters which are run either in parallel (Hi) or series (Low), or with mu. To avoid using extra costly contactors, you might have a manual crossover switch between the two heaters that controls whether they are wired in parallel or series, and simply turn the contactor off when switching modes (kind of like shifting to neutral before changing back and forth from 4 wheel drive).
3. A variable timing device that activates the contactor for variable periods of time. More complicated than the thermostat, but might be a fun project.


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## rwaudio (May 22, 2008)

Yukon_Shane said:


> Well I think you've both convinced me to change gears (again) and go back to the fluid heater idea. This approach makes alot of sense: keep the stock system in place and; keep the high voltage out of the cab
> 
> RW: did the Kat's heater have an easily identifiable temperature snap switch that you were able to tie into the DC contactor (like DIY described for his fluid heater)?
> 
> ...


I did pull the covers and don't recall a temp switch. I haven't wired them up permanently to the dc system yet, I'll double check. The temp switch (if it works on DC) is not really a "temperature control" with some of these heaters it's simply a safety system to prevent the element from self destructing if you had a coolant leak or something and the heater ran dry.



PhantomPholly said:


> As for controlling temperature, here are a couple of ideas:
> 
> 1. An ordinary home thermostat, placed in a strategic location and activating the heater contactor (I think many of these simply energize a 12v control signal which in turn activates the furnace / AC unit). This could be used in conjunction with #2 for more even heating.
> 2. Hi/Low setting, achieved by having two heaters which are run either in parallel (Hi) or series (Low), or with mu. To avoid using extra costly contactors, you might have a manual crossover switch between the two heaters that controls whether they are wired in parallel or series, and simply turn the contactor off when switching modes (kind of like shifting to neutral before changing back and forth from 4 wheel drive).
> 3. A variable timing device that activates the contactor for variable periods of time. More complicated than the thermostat, but might be a fun project.


I would add a #4, PWM could be used for a variable system with feedback that could actually maintain a pre-set temperature.


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## bluefxstc (Dec 29, 2007)

I used one of these to control the temp. It is an Airpax temperature regulator.. They come in various temperatures. You can find them at Digi-Key for around $10.00. Here is a link to them. http://search.digikey.com/us/en/cat/circuit-protection/temperature-regulators/655643?k=airpax You can find a data sheet on them here. http://airpax.sensata.com/site/utilities/eliterature/pdfs/6700.pdf It is a normally closed solid state switch that opens the contactor when the heater is up to temp. Pretty simple and cheap. I made my heater out of some pipe fittings and home water heater element so I just welded a tab on pipe to sense the temp.


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## rwaudio (May 22, 2008)

bluefxstc said:


> I used one of these to control the temp. It is an Airpax temperature regulator.. They come in various temperatures. You can find them at Digi-Key for around $10.00. Here is a link to them. http://search.digikey.com/us/en/cat/circuit-protection/temperature-regulators/655643?k=airpax You can find a data sheet on them here. http://airpax.sensata.com/site/utilities/eliterature/pdfs/6700.pdf It is a normally closed solid state switch that opens the contactor when the heater is up to temp. Pretty simple and cheap. I made my heater out of some pipe fittings and home water heater element so I just welded a tab on pipe to sense the temp.


What temperature did you pick?


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## bluefxstc (Dec 29, 2007)

90C or 194F. I figured that was pretty close to what the heater system in the car was normally designed to run at.


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## PhantomPholly (Aug 20, 2008)

I would add a #4, PWM could be used for a variable system with feedback that could actually maintain a pre-set temperature.[/QUOTE]

That's what I meant by #3, although there may be some arbitrary semantic limit at which it is PWM instead of simply cycling on and off. My intent was a device that would only turn on the element for some percentage of each second, with some kind of control that lets you vary the ratio of "on" to "off" time.


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## PhantomPholly (Aug 20, 2008)

bluefxstc said:


> 90C or 194F. I figured that was pretty close to what the heater system in the car was normally designed to run at.


That's pretty close to 212, the boiling point of water at sea level. Climb a mountain and you may be above the boiling point. With the cars radiator removed from the loop, you should have some kind of pressure relief mechanism (normally performed by the radiator cap) to prevent catastrophic failure if the temperature rises too high.


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## Yukon_Shane (Jul 15, 2010)

bluefxstc said:


> I used one of these to control the temp. It is an Airpax temperature regulator.. They come in various temperatures. You can find them at Digi-Key for around $10.00. Here is a link to them. http://search.digikey.com/us/en/cat/circuit-protection/temperature-regulators/655643?k=airpax You can find a data sheet on them here. http://airpax.sensata.com/site/utilities/eliterature/pdfs/6700.pdf It is a normally closed solid state switch that opens the contactor when the heater is up to temp. Pretty simple and cheap. I made my heater out of some pipe fittings and home water heater element so I just welded a tab on pipe to sense the temp.


This is what I picked up: http://www.ebay.ca/itm/4x-KSD-301-T...672?pt=LH_DefaultDomain_0&hash=item27b5e07ce0 

It seem's pretty simliar to the airpax temperature regulator you used.

I was admiring your design in a previous post and was looking to copy it but I think I need atleast 3kW of heating in my climate which would mean I'd probably have to find a way to incorporate two heating elements (I don't think anyone makes a 120V, 3kW element).

It might not be too tricky but at $50 a peice it may be easier to just put two of these Kat's block heaters together.


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## bluefxstc (Dec 29, 2007)

The car only has a range of about 50 mi. It is my commuter car (22 mi round trip), I will not be taking it on any trips or to an altitude that may cause a problem. I built it for what I need, your need may be different. Total elevation change in my typical drive is less than 100 - 200 ft (2800 -3000ft). I am not running a pressurized system but I did keep the stock expansion tank so the fluid has plenty of room to expand if necessary. With 50/50 antifreeze the boiling point (265F @ 15psi) is probably at least 10% above 90C so I am ok with it. If I have a problem with boiling I will turn it off and put a different switch in. It is only $10 and boiling will not damage my engine or leave me stranded. So far I haven’t found the temp to get above about 100F (1600w output from 4000W element at 144 VDC) so the switch doesn’t do anything, just a safety issue. If I had to do it again I wouldn’t put it in. Plenty of heat at 20f outside but not enough to worry about. In an electric car there is no need for a radiator, if you size the heating element correctly. I am only producing about 1600W of heat, not the massive amounts produced by an ICE. A radiator is for waste heat and unnecessary in my experience. They also make the switch in a large variety of temps, so pick a lower temp if you are worried.


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## bluefxstc (Dec 29, 2007)

Yukon
Two elements are easy. Just put a Tee at both ends and an element at both ends. The pipe between the tees just needs to be long enough for both elements to fit in without touching. Cost an extra $25-25 more. I have been thinking of adding another element myself. Maybe to get another 800-1000W. Heat faster and a little warmer. I will probably do it when I hook up my Soliton 1 liquid cooling since I am using the same system for both. If I do that I will lower the temp switch and make sure the controller is after the heat exchanger. Pick up the heat from the controller and heating elements for my cabin. So not having liquid cooling for the Soliton hasn’t been a problem but it probably will be this summer.


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## DIYguy (Sep 18, 2008)

Let me try and address a few of these points . . at least based on my experiences.

The switch inside most of these heaters is really meant for protection as RW said. They probably all have one. You need to split it off of the DC pack voltage. The other options for a switch are still just that.... a set temperature switch. It does not really "control" the temp so much as it protects the system. If you want to pick a lower temp switch, ok, but then u loose the ability to heat the way you want. Use the switch that comes with the heater, it works.

As for using two. . well, you need to measure the resistance of the coil or test it with your battery voltage. Mine is a 115Volt 1500 watt heater. On 215 VDC, it puts out 4.5 kw. 

There isn't too much out there for PWM above 24 volts, but I did find this unit a while ago.http://www.ebay.ca/itm/Constant-Current-PWM-HHO-PCU-250-Volt-/250875201338#ht_2645wt_1413 
I just don't know if I want to spend the money to test it. 

One of the easiest ways may be to use a cheap fan temp control switch (Capillary tube) from Summitt Racing or other like this one.http://www.summitracing.com/parts/FLX-31147/ 
Connect it to a SSR.

A few guys have tried a PID controller to a SSR but they don't like to work well in low temps. Besides, I really don't think u must have closed loop. Just my opinion but. . . set it and if u don't like it... turn it down a bit.

What I found is that I want the high output I have because it gets friggin cold and I want it warmed up. But then I must turn it off and on all the time. I would just like to throttle it back to half or whatever and draw 8 amps instead of 22 or whatever it is.

My OEM temp control in the truck (like many) has a fresh air blend damper which basically controls temp by mixing a variable amount of cold outside air. Fine when u have abundance of heat to dump from an ICE. Not what I wanna do tho. 

Hope that helps someone....


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## rwaudio (May 22, 2008)

PhantomPholly said:


> That's pretty close to 212, the boiling point of water at sea level. Climb a mountain and you may be above the boiling point. With the cars radiator removed from the loop, you should have some kind of pressure relief mechanism (normally performed by the radiator cap) to prevent catastrophic failure if the temperature rises too high.


I think most people are going to use a water/antifreeze mix just like the stock cooling system which has a boiling point higher than just water. (plus pure water would freeze when you need heat the most)


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## Yukon_Shane (Jul 15, 2010)

DIYguy said:


> Let me try and address a few of these points . . at least based on my experiences.
> 
> The switch inside most of these heaters is really meant for protection as RW said. They probably all have one. You need to split it off of the DC pack voltage. The other options for a switch are still just that.... a set temperature switch. It does not really "control" the temp so much as it protects the system. If you want to pick a lower temp switch, ok, but then u loose the ability to heat the way you want. Use the switch that comes with the heater, it works.
> 
> ...


That's very helpful; particularly the reminder of the change in power associated with grid voltage vs. pack voltage.

Just a quick check on my math:

Most of these elements seem to be (like yours) 1500 Watts at 115V AC so using Ohms law I get a resistance of about 8.82 Ohms (V*V/P)

Taking my nominal pack voltage of 160 V that gives me a total power of 2900 Watts. Which is probably all I need so I guess I can get by with just one element.

Does that make sense or am I missing something?


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## rwaudio (May 22, 2008)

Yukon_Shane said:


> That's very helpful; particularly the reminder of the change in power associated with grid voltage vs. pack voltage.
> 
> Just a quick check on my math:
> 
> ...


Just be careful not to go too much over rated power. It should be able to handle more than 1500W but you may shorten it's life or risk having it fail when you could really use heat. These aren't like ceramic heaters that are somewhat self regulating and you can over voltage them to a certain extent without harm. Is 160V your nominal pack voltage? Will the heater be exposed to a higher voltage when it's fresh off the charger?


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## Yukon_Shane (Jul 15, 2010)

rwaudio said:


> Just be careful not to go too much over rated power. It should be able to handle more than 1500W but you may shorten it's life or risk having it fail when you could really use heat. These aren't like ceramic heaters that are somewhat self regulating and you can over voltage them to a certain extent without harm. Is 160V your nominal pack voltage? Will the heater be exposed to a higher voltage when it's fresh off the charger?


That's a good point. 160 is nominal so it could see a voltage as high as 185 at the end of charge which would be close to 3,900 watts. Probably a bit to far over rated.


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## DJBecker (Nov 3, 2010)

bluefxstc said:


> I used one of these to control the temp. It is an Airpax temperature regulator..


The Airpax part is in TO-220 package, which is good for automated assembly onto a circuit board but not the best choice for this application.

Why not use a Therm-o-disc? They are easier to mount, easier to wire, and the larger ones can even carry enough current to directly control many heaters.


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## PhantomPholly (Aug 20, 2008)

rwaudio said:


> I think most people are going to use a water/antifreeze mix just like the stock cooling system which has a boiling point higher than just water. (plus pure water would freeze when you need heat the most)


Ah, I wasn't sure about that - I knew glycol lowered the freezing point, but thought that the boiling point was raised through pressurization, not from the glycol.

In any event, my original point: Make sure you add a popoff valve if you removed the car radiator from the loop.


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## rwaudio (May 22, 2008)

PhantomPholly said:


> Ah, I wasn't sure about that - I knew glycol lowered the freezing point, but thought that the boiling point was raised through pressurization, not from the glycol.
> 
> In any event, my original point: Make sure you add a popoff valve if you removed the car radiator from the loop.


Yep, I agree 100% with this, OR leave the system "open" so that pressure can't build up.


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## Yabert (Feb 7, 2010)

Yukon_Shane said:


> Most of these elements seem to be (like yours) 1500 Watts at 115V AC so using Ohms law I get a resistance of about 8.82 Ohms (V*V/P)
> 
> Taking my nominal pack voltage of 160 V that gives me a total power of 2900 Watts. Which is probably all I need so I guess I can get by with just one element.


 
For your information, I use a 1500w water heater (120v AC) in my Smart.

It generate 2600w of heat at 158v after a fresh charge when the cells had a resting voltage of around 3.3v and probably around 2200-2300w when I drive the car.

2600w can seem a lot for a small car cabin, but at -15°C isn't that much! But dropping my range by 15-20% isn't my goal, it's why I don't use two heater.
So I take glove...


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## PhantomPholly (Aug 20, 2008)

rwaudio said:


> Yep, I agree 100% with this, OR leave the system "open" so that pressure can't build up.


Yep. If you leave it open, we're back to requiring a really good heat control mechanism (I like the little thermostatic sensor someone posted) and "remember to check your fluid level frequently" since some will evaporate.


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## Yukon_Shane (Jul 15, 2010)

Yabert said:


> For your information, I use a 1500w water heater (120v AC) in my Smart.
> 
> It generate 2600w of heat at 158v after a fresh charge when the cells had a resting voltage of around 3.3v and probably around 2200-2300w when I drive the car.
> 
> ...


Answering the question "How much heat is enough" is really kind of tricky isn't it?

We get pretty cold temperatures here sometimes but I probably won't drive the car much below -20C and even then I'll dress appropriately (if I can walk the dogs for 1 hour at -40C I'm sure I can manage the 10 minute drive to work) so really all the heating system is for is to keep the ice off the windshield. 

But how much heat is that?


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## skooler (Mar 26, 2011)

Hi all, great thread!

I'm looking for a solution for my RX8 solution, I dont fancy pulling the dash out and I want to keep it as stock as possible.

A water heater is obviously the answer. I was thinking about the possibility of using a power shower (pump and heater built in) and stumbled across this:

http://www.ecrater.co.uk/p/12169026/eccotemp-l5-portable-tankless-water

My concern is that it may not be powerful enough. Although its specified as having a 37,500 BTU output.

Isn't that about 10KW? doesnt seem right!

Thoughts?

Cheers,

Mike


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## rwaudio (May 22, 2008)

skooler said:


> Hi all, great thread!
> 
> I'm looking for a solution for my RX8 solution, I dont fancy pulling the dash out and I want to keep it as stock as possible.
> 
> ...


Only if you want to carry around a propane tank..... There might be an electric version though.


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## PhantomPholly (Aug 20, 2008)

"How much is enough" is certainly a question - I can't answer it, but here's another way to think about it.

Modern cars intentionally have a lot of air leakage from outside to prevent CO poisoning. There might be a good bit of opportunity for insulating and sealing to reduce heater requirements. 

The nice thing about insulation is that once you install it it works forever for free...


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## skooler (Mar 26, 2011)

rwaudio said:


> Only if you want to carry around a propane tank..... There might be an electric version though.


 
That'll be the catch! I should have read it properly first! 

I also found the one below but I dont think it will produce anywhere near enough heat.

http://www.outdoorgb.com/p/ring_automotive_12_volt_portable_shower/

Cheers,

Mike


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## Yabert (Feb 7, 2010)

skooler said:


> I also found the one below but I dont think it will produce anywhere near enough heat.


18W only.....brrrrr, cold shower!




> Originally Posted by *Yukon_Shane*
> _But how much heat is that_?


Over 2200w seem enough to warm the cold air and defrosted the windshield.
Interesting point, my water circuit only contain one liter of water/antifreeze (fast heating).


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## JRP3 (Mar 7, 2008)

This is an interesting pump that Miz found, should be quiet and designed for heat:
http://www.techloops.com/thermaltake-clw0132-p500-water-pump.html


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## electricmini (Oct 21, 2008)

skooler said:


> That'll be the catch! I should have read it properly first!
> 
> I also found the one below but I dont think it will produce anywhere near enough heat.
> 
> ...


Hi Mike,

I got a pair of 115Vac 1500W water heaters from Canadian Tire last time I was in Canada, for the Supra project. These work fine on 132Vdc, produces lots of heat.
But, you need to rig up a pump (I found two Audi coolant circulating pumps on Ebay, perfect for this job), a header tank and a pressure cap of some sort. My rig leaked, had far too many joints in it! I have separated out the thermostat that is mounted into the top of the heaters, so they can operate the heater contactors (they were wired in series with the element by the lead that came with the heater)

However, I've since installed a pair of 1500W ceramic heaters into the Supe, so the water heaters are sitting in the garage, unused!
If you've got the room to mount them and have a header tank at the highest point in the system, should work well for the Mazda.

Email / PM me if you're interested
( I also have some 240V 1500W ceramic elements, if you want to go that route)


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## MN Driver (Sep 29, 2009)

PhantomPholly said:


> "How much is enough" is certainly a question - I can't answer it, but here's another way to think about it.
> 
> Modern cars intentionally have a lot of air leakage from outside to prevent CO poisoning. There might be a good bit of opportunity for insulating and sealing to reduce heater requirements.
> 
> The nice thing about insulation is that once you install it it works forever for free...


You can't stop the air leakage though, you'll need to pull fresh air from the outside otherwise the humidity of the occupants will very quickly fog up the interior and if its colder than freezing outside the car the glass will frost in less than a minute of driving.

After playing with a 1500 watt space heater sitting in the back of my 1st Gen Honda Insight (tiny two seater, not a very big interior) when the thermostat was a little leaky and wouldn't get enough heat inside the car to warm it last winter, I ran the space heater for 15 minutes and then drove to work. After 10 minutes of driving it was still fairly warm. 1500 watts at the windshield is probably not enough to melt ice and keep it off and if you want to wait 10 minutes for the car to be lukewarm and 15 minutes to be warm enough to shut it off when its -10f then you might be okay with 1500 watts. From my experience playing with it, once I get mine converted I'll be looking for around 10,000 BTU, or about 3000 watts of electric resistance heat. I'd really rather not use the electricity for heating the car though but it seems not many people here are interested in using a liquid or compressed fuel to do the job even though it would be a great way to keep up your range, performance, and if you get stuck in the snow you can be warm without emptying the pack. I'm just not sure how that could be done using a small tank or cylinder for fuel.

So the plan so far is probably a 1500 watt heater for my pack voltage of 204.8v, or 217.6v fresh off a charge which that higher initial voltage will run a higher wattage right when I get going which would be convenient and apparently the wattage I'd pull with the higher voltage will be great. I might use 240v rated heaters though to hang on the reliable side.


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## DIYguy (Sep 18, 2008)

JRP3 said:


> This is an interesting pump that Miz found, should be quiet and designed for heat:
> http://www.techloops.com/thermaltake-clw0132-p500-water-pump.html


Where are the specs?

My Surflo will move 3.5 gpm with 45psi built in bypass IIRC. It is self priming and can lift water 12'. It can run dry without damage to motor or pump. I've been running it for a while now so, I don't think the heat will hurt it. I don't recall any specs on hot water though. I'll probably use a similar pump for the Shiva.


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## JRP3 (Mar 7, 2008)

http://www.thermaltakeusa.com/Product.aspx?C=1162&ID=1639


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## DIYguy (Sep 18, 2008)

JRP3 said:


> http://www.thermaltakeusa.com/Product.aspx?C=1162&ID=1639


OK, thanks. hmm. 500 l/h . . I think that works out to 1.8gpm. It's got 3/8" fittings which isn't a good match for heater hose, most are 5/8" I think. 0.6 amps. May be a bit on the light side.


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## bluefxstc (Dec 29, 2007)

DJBecker, good info on the temp switch. Much better form factor than the one I had. I will use it when I add another element to my heater. 

I used a pump like this http://www.amazon.com/Bosch-0392020073-Electric-Water-Pump/dp/B0049PLFGK. I got it from these guys http://www.ips-parts.com/ I just stopped in a talked to them since they are on my way home from work and do have a small physical location. It was an aux water pump out of a Mercedes. I think I paid $70 and then had to go to a wrecking yard to find the correct connector. I know a lot of the VW, Audi and Mercedes had an aux water pump which seems to work well for our application.


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## redcelt007 (Oct 2, 2008)

I decided to try and keep the existing heater core in my Mazda truck. I installed a small cooler in the engine compartment where the radiator used to be. Inside the cooler is a 12v bilge pump that I got from Harbor Freight. Mounted through the cooler wall in an aluminum plate is an electric water heater element sealed with high temp silicone. The pump circulates water from the cooler to the heater core and back again by way of hoses. The heater element is wired to the battery pack (60 volts) which gives me about 500 watts of heat for the water. In the summer I drain the cooler of water/ antifreeze and use ice water to circulate through the heater core for air conditioning. Here in Little Rock, the winters are usually milder compared to the summer, so my AC gets used more in the truck. It also cools faster. I use an immersion heater to speed up the heating of the water in the winter before I drive away. So far so good.


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