cabin heater why not use excess inverter/motor heat ?

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kmp647

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So the leaf has a water cooled motor and inverter it would seem from looking at under hood photos. So why wouldnt nissan simply route some coolant to a heater core and use some of the excess heat for cabin heat, then maybe back it up with a good ole toaster coil?

Having a radiator means you are dumping heat/energy , then instead you use battery power to heat a toaster coil?

its not like its hard , every ICE car on the road has a heater core with coolant running thru it
add a backup electric element and some simple controls and voila. Free heat when available and toaster coil range robbing heat when its not


Anybody give me a good reason why Nissan wouldnt do this

I think we can rule out cost its just to simple and cheap to have a heater core

Kevin
 
I think it's because it wouldn't generate/capture enough heat to justify the weight, cost, complexity (more things to break). Think about it how many days a year do you use heat anyway?

EV's need to cut their teeth in moderate climates first, preferably without too many hills.
 
Here is the bottom line, it is so insignificant it would be pointless to have a secondary coil in the cabin. When the most cooling on the inverter, charger, and motor are needed is high temp summer days during normal temps it is low and when it is cold the fan would never be on.
 
I live in northern VA. it gets cold here. Very cold

My only guess is that during cold weather not much excess heat is generated by the inverter/motor . thats the only thing I can think of that would prevent them from using a coventional liquid filled heater core, with a coil backup.

i use the heat about 5-6 months of the year in my car

I am just east of the buleridge mountains and its cold.
 
Heating core for the interior of an ICE vehicle has a constant supply of 190 degree fluid controlled by a thermostat.
Leaf may well prefer to operate at a lower temperature and not have enough BTU in most conditions.
Just speculation.
 
Yup , I doubt the inverter/motor operate at 200 degrees

but....... at some point in a winter commute it would be possibble to turn off the toaster coil and extract heat from the coolant...... saving battery power for more range

It could go like this.

cold startup: call for cabin heat/windshield defrost=toaster coil
warming up : call for heat = toaster coil+ inverter coolant
full temp cruising: call for heat = 100% coolant heat
 
Although the pictures under the hood seem suggestive of a water cooling system, I have not seen a reviewer actually say that is the case. On the contrary, Mark Perry told me (in Feb when in Chattanooga as part of the Leaf tour) to a direct question that the Leaf will be air cooled and that the only liquid that needs to be changed for maintenance is brake fluid. When I have asked the Chat the same question recently I get the same response.

So what is the answer to the generalized question: "What liquids does the Leaf use?"
(BTW I don't include supercooled liquids like glass!)
 
Likely the inverter and motor do not operate at a high enough temperature to transfer heat effectively in this way. If they were allowed to, they would burn out before long.
 
I have worked on three EV cooling systems, on with a closed loop for the pack, inverter, motor and there is not enough heat to be useful and on demand to be useful to be used in the cabin. It is just not there and not practical

Secondly, if the Leaf motor, inverter and charger do not have VERY large cooling fins, which the motor and inverter clearly do not, then it's water cooled. This is factory EV 101 folks. It is pointless to stack a bunch of multiple loud fans on these parts when one water cooling system is far better and more efficient. You can even see the multiple fill locations and the cooling jacket connections on the components. This has already been discussed at length and modern EV motors and inverters are water cooled.
 
guess the answer is not enough heat from the system

makes you wonder why they need liquid cooling at all

guess its hotwhen you dont need heat in the summer
and runs cool in the winter and therfore would be useless
 
kmp647 said:
guess the answer is not enough heat from the system

makes you wonder why they need liquid cooling at all

guess its hotwhen you dont need heat in the summer
and runs cool in the winter and therfore would be useless
Click to expand...


Because the inverter and motor under load can get hot but a small bit of liquid cooling works better than fins and a fan.
 
I can understand that Nissan would not want a term like "water cooled" for its motor/inverter/charger be misapplied to its battery pack. And maybe the coolant is not water based (w/ added antifreeze) but some other liquid. In Feb I asked Mark Perry what the air intake in the front of the car was for and he said only for cooling the air conditioner compressor radiator. Perhaps the cooling design has changed since that time, but I have seen no official Nissan statement that the Leaf's motor/inverter/charger is water cooled, which I find a little odd at this late date. Understandably Nissan (and I for that matter) want the Leaf (and more broadly the electric car industry) to be successful, and perhaps they are concerned that revealing some details that aren't truly significant (like a small cooling system) might deter some early adopters from buying.

On a slightly different topic, that of the Leaf's charger which has drawn a certain amount of criticism for only being 3.3 kW (which I think is wholly adequate for overnight home charging of its current 24kWh battery pack), note that ORNL has reportedly designed an EV charging system that does not require a separate charger, but mainly uses the EV's inverter to take external AC and charge its battery pack (rather like what happens with regenerative braking, but not using the motor/generator to provide the AC power). If this is ultimately practical, it may eliminate the "my on-board charger is only x kW" complaint of subsequent EVs.
 
Well it seems clear from the hi res underhood photos there is a cooling system that uses liquid

that means you have excess heat, and still makes me wonder why when you are trying so hard to conserve battery power, an engineer would: dump heat(energy) into the atmosphere
instead of utilizing it when needed to heat the cabin.


I am hoping that the "cold weather package" is avilable soon (by december orders)

I need the seat heaters and wheel heater, and have hopes that the thermal management system will let me warm the pack when connected to grid power
 
garygid said:
The coolant might be antifreeze rather than water, but clearly some liquid.
Click to expand...


There is always antifreeze in the mixture, the parts would corrode otherwise.
 
MikeD said:
I can understand that Nissan would not want a term like "water cooled" for its motor/inverter/charger be misapplied to its battery pack. And maybe the coolant is not water based (w/ added antifreeze) but some other liquid. In Feb I asked Mark Perry what the air intake in the front of the car was for and he said only for cooling the air conditioner compressor radiator. Perhaps the cooling design has changed since that time, but I have seen no official Nissan statement that the Leaf's motor/inverter/charger is water cooled, which I find a little odd at this late date. Understandably Nissan (and I for that matter) want the Leaf (and more broadly the electric car industry) to be successful, and perhaps they are concerned that revealing some details that aren't truly significant (like a small cooling system) might deter some early adopters from buying.

MIke, any early adopter or anyone with decent Ev knowledge knows water cooling is the best method and Nissan likely does not mention it because most consumers don't care or even understand what that means. Auto makers don't say the ICE is water cooled, at the least they are trying to keep things simple. What other liquid would they use to cool the car, oil? Good luck pushing that through a pump efficiently. Do you really think Nissan has retooled and made new castings for the motor and inverter to include heat sinks and loud high-output fan for the motor? They decided at the last minute to use an inferior cooling system and spent all that money to make those changes? And why would Nissan mention any cooling system specs? Did they mention the radiator cooler for the AC on the specs? Common sense says it's water cooled like 99% of all OEM AC induction traction motors today and if Nissan keep it a secret it was air cooled then it was only to keep people who know EVs from canceling, it's not a DC conversion. By the way, water cooled motors are quieter and weigh less.
Click to expand...
 
EVDRIVER: I agree that it makes total sense that there is some water cooling of motor, inverter, and even possibly charger. Not having previous EV experience plus allowing for possible advances in technology caused me not to assume too many such details about the Leaf. I am trying to learn as much about the Leaf as possible so ask a lot of questions from Mark Perry when available, read and listen to available media sources, including the Leaf Chat facility and of course this forum. In fact I want to be well informed about a lot of things that may affect my life (especially politics, ever since my narrow escape from a firsthand Vietnam war experience), and so I am more likely to want more details than most about certain issues. I'm especially drawn to issues that at least to me seem unaccountably concealed such as when I ask a pretty direct question and I get a pretty non-equivocal answer which seems less than accurate.

In your experience with EV AC motor cooling, what are some of the major maintenance/component failure issues, if any? Should I be aware of the possibility of anti-freeze leakage that can kill my cats and dogs via kidney failure should they lap it off the driveway (a variation of which has happened to a pet of mine)?

I would hope that a draft version of the Leaf User Manual will be made available before too long... Thanks, EVDRIVER, for all your well considered input to this forum!
 

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