cabin heater why not use excess inverter/motor heat ?

[AndyH]

The short answer is that there's really not much 'excess' heat.

The motor and controller and absolutely water cooled - we have enough under hood pictures showing cooling hoses, and cut-away pictures of the motor at Nissan, to verify that without a verbal comment or video from a review.

When it comes down to heat transfer, the difference in temperature is critical. Even if we add a heater core and fan, how much heat will we get in a 50° cabin when the coolant in the heater core is only 60°? And how far and how fast will we have to drive to get the motor and controller up to 60°?

The only time the Leaf's cooling system will be capable of providing enough heat to make a dent in a cold cabin is on a hot summer day. Anyone expecting a hot motor/controller and a cold cabin is still thinking ICE.

Earlier EVs - like the EV1-era S10 - use a diesel fired cabin heater to supplement the heat pump because the motor doesn't provide enough heat, neither does the heat pump when it's really cold.

 

[EVDRIVER]

The short answer is that there's really not much 'excess' heat.

The motor and controller and absolutely water cooled - we have enough under hood pictures showing cooling hoses, and cut-away pictures of the motor at Nissan, to verify that without a verbal comment or video from a review.

When it comes down to heat transfer, the difference in temperature is critical. Even if we add a heater core and fan, how much heat will we get in a 50° cabin when the coolant in the heater core is only 60°? And how far and how fast will we have to drive to get the motor and controller up to 60°?

The only time the Leaf's cooling system will be capable of providing enough heat to make a dent in a cold cabin is on a hot summer day. Anyone expecting a hot motor/controller and a cold cabin is still thinking ICE.

Earlier EVs - like the EV1-era S10 - use a diesel fired cabin heater to supplement the heat pump because the motor doesn't provide enough heat, neither does the heat pump when it's really cold.

This is a given- now watch a post will pop up as to why it wont be. I really hope the car has EPS but I think that due to the weight creep it may use an energy burning pump system. EPS uses so little energy and americans don't need to turn the wheel with one finger in a parking spot.

 

[garygid]

The LEAF uses an electric-assist Power Steering system. No fluids.

 

[DaveinOlyWA]

I would also surmise that the the penalty for the extra components outweighs the possible benefit.

On my Prius I block 90 percent of the grill Every winter to help maintain heat. Without the bloc's My prius struggles to maintain a proper operating temperature When driving around town Because the engine onlyruns about 2 thirds of the time.

It also has an inverter that generates heat Which is also connected to the radiator 4 cooling. Granted the prius would not be Generating the same level of heat from the inverter process, but the 1 thing that is obvious is that only a wasteful system degenerate that much waste heat begin with.

Nissan not providing the options Only implies that This if they are using is efficient

 

[kmp647]

I thought of one more good reason to use motor/inverter coolant to heat the cabin

there are times when you need to defrost/defog the windshield when you have both the a/c on (to dehumidify ) and the heater on.

example its rainy and 55 degrees and you are up in the am to go to work

its a bit damp and foggy and your windshield is fogging on the inside, its also 55 in the cabin

a/c on , and the toaster coil running , double drain from climate control on your range.

in this case once you are moving and the motor warms up the coolant you could use that heat, along with the a/c to keep the screen clear, and save juice on the toaster coil

happens alot esp in winter and fall

 

[EVDRIVER]

I thought of one more good reason to use motor/inverter coolant to heat the cabin

there are times when you need to defrost/defog the windshield when you have both the a/c on (to dehumidify ) and the heater on.

example its rainy and 55 degrees and you are up in the am to go to work

its a bit damp and foggy and your windshield is fogging on the inside, its also 55 in the cabin

a/c on , and the toaster coil running , double drain from climate control on your range.

in this case once you are moving and the motor warms up the coolant you could use that heat, along with the a/c to keep the screen clear, and save juice on the toaster coil

happens alot esp in winter and fall

Let's be clear on this- there is not enough heat on demand from this system to be of benefit, even if it were slight the extra cost, complexity and weight would render it pointless. There is no reason to use the closed loop cooling system of these components in the cabin.

 

[indyflick]

Let's be clear on this- there is not enough heat on demand from this system to be of benefit, even if it were slight the extra cost, complexity and weight would render it pointless. There is no reason to use the closed loop cooling system of these components in the cabin.

Exactly. To get a grasp on this we need to get our minds out of what we are accustomed to in the mechanical/combustion domain and into the electrical domain. There are electrical components which produce a lot of heat, but over a very small area. So they need liquid cooling, which offers the thermal mass to absorb and transport the waste heat. This keeps the components at a stable temperature and well within their operating window. However, the electrical components don't produce enough BTUs in total from the waste heat to effectively heat the cabin.

 

[indyflick]

What about an optional propane heater for cold weather climates? They could use a propane heater to heat water and then circulate the water through a traditional heater core.

 

[evnow]

What about an optional propane heater for cold weather climates? They could use a propane heater to heat water and then circulate the water through a traditional heater core.

That will never happen. Remember Zero Emissions.

 

[gasmiser1]

But have you seen a Nissan represenative say the Leaf is water cooled?

Yes. Confirmed by a Nissan rep @ Boardwalk Nissan "Touch Tour" yesterday, that the electric engine is liquid cooled.

 

[indyflick]

What about an optional propane heater for cold weather climates? They could use a propane heater to heat water and then circulate the water through a traditional heater core.

That will never happen. Remember Zero Emissions.

Good point. Okay what about a microwavable seat cushion?I know, I know... microwaves use electricity and electricity is made from coal so you are heating your fanny with coal. Actually I had one of these types of cushions for years, not this brand. I used it at football games and it would stay warm last through the first half. I actually think this type of thing would be useful for LEAF owners in cold climates.

 

[evnow]

Good point. Okay what about a microwavable seat cushion?

Those are nice if you want to heal some tissues faster ...

I wouldn't worry - since we can preheat the car. Afterall I've not had heated seats ... ever.

 

[indyflick]

Good point. Okay what about a microwavable seat cushion?

Those are nice if you want to heal some tissues faster ...

I wouldn't worry - since we can preheat the car. Afterall I've not had heated seats ... ever.

I'm thinking of the LEAF owners in Chicago, Minneapolis, and Fargo. Perhaps not a target market...

 

[evnow]

I'm thinking of the LEAF owners in Chicago, Minneapolis, and Fargo. Perhaps not a target market...

They can get the cold weather spec Leaf ...

ps : As Mark Twain never said "The coldest winter I ever spent was a summer in San Francisco".

http://www.snopes.com/quotes/twain.asp

 

[garygid]

Nissan seems to carefully say "zero TAILPIPE emissions"?
Perhaps due to possible coolant or brake fluid leaks?

 

[evnow]

Nissan seems to carefully say "zero TAILPIPE emissions"?
Perhaps due to possible coolant or brake fluid leaks?

No - that is because of power plant emissions.

 

[Edelman]

If this is covered somewhere I apologize but I didn't see it.

My first post, Leaf on order.

I'm assuming the Leaf uses a heat pump for heating rather than resistance coils, right? It would seem reasonable given one can expect 2-4x the efficiency but I can't find it specifically mentioned anywhere.

I know you can preheat/precool the car, but even then I'd rather do it more rather than less efficiently. I've still got to pay for those kilowatts.

 

[planet4ever]

This was answered at least once, six months ago, but I don't know how authoritative the answer was:

http://www.mynissanleaf.com/viewtopic.php?f=6&t=173&start=12

It's a resistive heater. Heat pumps don't work when it gets really cold out. You can preheat the car using utility power if it's connected to the EVSE. Also, the seats are heated.

In particular, we now know that the heated seats are only going to be in the cold weather package, which will apparently not be available for a year or so.

 

[Edelman]

This was answered at least once, six months ago, but I don't know how authoritative the answer was:

http://www.mynissanleaf.com/viewtopic.php?f=6&t=173&start=12

It's a resistive heater. Heat pumps don't work when it gets really cold out. You can preheat the car using utility power if it's connected to the EVSE. Also, the seats are heated.

In particular, we now know that the heated seats are only going to be in the cold weather package, which will apparently not be available for a year or so.

Uh. He's right but the crossover is down below 32 degrees. Above that heat pumps are always more efficient and generally much more efficient. In the regions where they are rolling out the Leaf you would expect a COP of 2-4 so the heater would use about a third of the energy per btu than a resistance heater.

Funny thing is that heat pumps are basically air conditioners with a reversing valve so they are only marginally more complex and expensive. I can only guess that while residential heat pumps are common nobody makes an automotive one since there is plenty of waste heat and Nissan didn't want to hold up the project engineering one or take the risk there would be problems. Seems a shame though. All that technology working to squeeze most range out of the battery's limited capacity and then to squander energy using a wire to make heat.