[DIYguy]

OK, so I spent some time searching this and came up with next to nothing. My search "meter" was running close to "frustrated"...so I bailed out and decided to post a new thread. Excuse me if I missed something of significance.... as I'm sure this has been bashed about a time or two..

So, the cabin heater is something I have not finished up yet on my truck. I, like many I'm sure, like to ponder the details as I move fwd. (not too fast! lol ) While I am trying to learn more about the "identity" of my new toy... (like checking a multitude of things after every run) I always let the motor blower run after parking and put my hand on the motor to feel the temp and add to my almost empty, but slowly growing, mental database of "symptoms" an EV...or rather, my EV... has. Now, I haven't calculated efficiency of the motor and how much power I am pushing through and what should be available as heat.... but I must say, there is always a steady flow of nice warm air exiting out those DE air ports. (its a 9 inch GE DC motor in a Mazda B4000... 192 volt nominal, Soliton1 with AGM's) At first I figured that the higher amp jaunts were the only times when much heat would pour out these ports. . . but u know, even after some pretty "normal" driving... I think there is enough heat available for what I would call "low level" or supplemental heat. My cabin is not huge and on a cool day, I think it would be enough. On a cold day, it would definitely need to be "boosted" by other means.

In a world of power conservation such as ours, seems a shame to let it "blow away". Perhaps a removable, winter shroud connected to the heater blower?

This is an early pic...when I was still rigging things up...... That's a 3" SS blower and pipe.

Thoughts?

[JRP3]

I suppose you could calculate the average amount of watts your motor is using, multiply it by 15% or so and that's how much heat energy you have to play with. I'd guess it won't be much. Concentrated in a small area blowing out of the motor it may feel warm but once dissipated through the cabin I'm not sure you'd notice, but as you say it is free heat, as long as ducting isn't restrictive causing overheating.

[Kelmark]

Originally Posted by DIYguy

OK, so I spent some time searching this and came up with next to nothing. My search "meter" was running close to "frustrated"...so I bailed out and decided to post a new thread. Excuse me if I missed something of significance.... as I'm sure this has been bashed about a time or two..

So, the cabin heater is something I have not finished up yet on my truck. I, like many I'm sure, like to ponder the details as I move fwd. (not too fast! lol ) While I am trying to learn more about the "identity" of my new toy... (like checking a multitude of things after every run) I always let the motor blower run after parking and put my hand on the motor to feel the temp and add to my almost empty, but slowly growing, mental database of "symptoms" an EV...or rather, my EV... has. Now, I haven't calculated efficiency of the motor and how much power I am pushing through and what should be available as heat.... but I must say, there is always a steady flow of nice warm air exiting out those DE air ports. (its a 9 inch GE DC motor in a Mazda B4000... 192 volt nominal, Soliton1 with AGM's) At first I figured that the higher amp jaunts were the only times when much heat would pour out these ports. . . but u know, even after some pretty "normal" driving... I think there is enough heat available for what I would call "low level" or supplemental heat. My cabin is not huge and on a cool day, I think it would be enough. On a cold day, it would definitely need to be "boosted" by other means.

In a world of power conservation such as ours, seems a shame to let it "blow away". Perhaps a removable, winter shroud connected to the heater blower?

This is an early pic...when I was still rigging things up...... That's a 3" SS blower and pipe.

Thoughts?

I am just starting my first conversion, but I had thought of doing the same with the controller somehow. My kit car is on a VW chassis which had ductwork that ran from the rear engine compartment anyhow. I was thinking of channeling the waste heat to a custom built heater box then into the cars dash. Then use fans that can be reversed during the summer to draw air out of the cabin and cool the controller.


Some might say that the energy saved wouldn't be worth the effort but if efficiency is your goal then I think it’s worth it.

[EVfun]

The motor air may stink from Ozone when the motor is under a good load (when it's making the most heat.)

[DavidDymaxion]

Electric motors can make ozone. In an extreme case, it can make smoke. You wouldn't want to be blowing those things into your car. You could make a heat exchanger to safely harvest the little bit of heat. A heat exchanger can be as simple as a fresh air hose inside of a hose that is exhausting the motor heat (or vice versa), kind of the like the heater on an old VW bug or Porsche.

[peggus]

Ozone and carbon dust! Getting black lung from driving an EV would be rather sad.

[bipole]

Can you measure the temperature of the intake and (so called) 'exhaust' air from the motor?

[Tesseract]

Originally Posted by Kelmark

I am just starting my first conversion, but I had thought of doing the same with the controller somehow. ...

Most dc motor controllers are going to be 96-98% efficient without even trying hard so they really aren't a worthwhile source of cabin heat. I suppose in this case DIYGuy could run a coolant loop through the Soliton1 first and then through a heat-exchanger sitting in the blower exhaust from the motor because...

Originally Posted by DavidDymaxion

Electric motors can make ozone. In an extreme case, it can make smoke. You wouldn't want to be blowing those things into your car. You could make a heat exchanger to safely harvest the little bit of heat. A heat exchanger can be as simple as a fresh air hose inside of a hose that is exhausting the motor heat (or vice versa), kind of the like the heater on an old VW bug or Porsche.

...David makes a good point here! From seeing what goes on in the motor during dyno tests I definitely wouldn't want to be breathing the exhaust from one! Big clouds of black dust when I unload the motor and crank up the RPM (the point being to do just that - clear out all the carbon dust that had built-up from running at high-amps).

That said, the motor will dump about 1.5-7.5kW of waste heat on average, which is right in the middle of what the average vehicle's heater core can handle. The air -> liquid heat exchanger is the way to go, IMO, because the heater core - that uses liquid, duh - is already in place so no tearing apart the dash.

Another advantage of this setup is that it is easy to insert an inline engine heater after the motor's heat exchanger but before the cabin's. This will help out on extra cold days and/or when the motor is delivering a low average power (because the roads are icy or the like). Something like that 1500W job they sell at Northern Tool (KAT is the brand, IIRC?).

[DIYguy]

Thanks for the feedback everyone. I hadn't considered ozone or other contaminants.... Tesseract is right, heat exchanger would be way to go. As for available energy, I wouldn't consider capturing anything from the controller...it just doesn't generate anything appreciable. The drive motor though, definitely does. I would say it is blowing the equivalent of at least that of a 1000 watt heater. Using some numbers off the top of my head...even at 125 amps and with the chopper an average of say 90 volts (??) and a motor efficiency of 90 % (likely conservative numbers) thats the equivalent of 1125 watt heater. Drop a little for the exchange process and shouldn't I be able to get about 1000 watts out of it? Not bad I'd say.

I already have a 1500 watt in-line engine heater installed (not finished wiring yet).

As for measuring the air in vs out.... ya, I probably could. I like to do what I call the "sanity test". (stems from homework with the kids lol) Just a practical way to determine if you are in the "ball park". Like feeling the motor heat with my hand on it, and the temp of the air coming out of it. Compare it to a heater blowing in your car. It's not all that different. Now contrast that with the controller. I ran my truck up to 85 mph the other day (still had more ) and the controller was barely warm. After normal driving, it is not much different than ambient. I know it's cool out now in Canadian spring weather...but when it's hot out, I won't need this heat anyways.

The way the weather is right now, it would make a lot more sense to figure this out than run that 1500 watt heater and pump.

kewl...

[bipole]

I did some comfort experiments this winter with my girlfriend's 2001 diesel jetta in 30-45 degree weather. I tried driving her car for few days with no heater, only the heated seat. I was very surprised at how comfy I was.

I ordered a heated seat kit from Jegs for about $75 and it only took about two hours to install and wire it up in the GTM. It draws 3 amps on the high setting at 12 volts. In my opinion this is the best 36 watts spent on comfort by far. You just can't beat direct contact heat.