GroundLoop
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Re: Does the Leaf have a radiator?

Wed Nov 10, 2010 7:14 pm

kmp647 wrote:
GroundLoop wrote:Excellent info! Thanks!

I am curious about the design of the cabin heater, and why it benefits from having an indirect (coolant) stage. Why not just resistive heat in the cabin airflow directly? Seems like it would take longer to heat fluid than just glow into a fan.

The A/C compressor.. runs directly of HV battery pack power?
Heater is safer as water coolant instead of coil , also provides more consistent temp and holds some heat when the heating elemnt is de activated
This is good news
I see. A thermal buffer, of sorts. Makes sense if you're trying to keep hot wires out of the passenger area.

Do you know if the heater is also HV powered?

Also, do you know if a service tool (Nissan Consult-II?) is able to adjust the convenience options, like unlocking all the doors together?

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EVDRIVER
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Re: Does the Leaf have a radiator?

Wed Nov 10, 2010 8:03 pm

GroundLoop wrote:
kmp647 wrote:
GroundLoop wrote:Excellent info! Thanks!

I am curious about the design of the cabin heater, and why it benefits from having an indirect (coolant) stage. Why not just resistive heat in the cabin airflow directly? Seems like it would take longer to heat fluid than just glow into a fan.

The A/C compressor.. runs directly of HV battery pack power?
Heater is safer as water coolant instead of coil , also provides more consistent temp and holds some heat when the heating elemnt is de activated
This is good news
I see. A thermal buffer, of sorts. Makes sense if you're trying to keep hot wires out of the passenger area.

Do you know if the heater is also HV powered?

Also, do you know if a service tool (Nissan Consult-II?) is able to adjust the convenience options, like unlocking all the doors together?

Heating water is far less efficient and a traditional heater is perfectly safe when sealed in an enclosure. It will run off pack voltage as it would be ridiculous to use 12V, that would mean something like 300 amps. Heaters that use water based systems also have a lag time. AC also off pack.

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garygid
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Re: Does the Leaf have a radiator?

Wed Nov 10, 2010 10:26 pm

I agree, a hot water heater seems inefficient, unless one is heating a "thermal mass" of water while plugged in.

Perhaps there is also a hot water tap for that early-morning refill of hot chocolate?
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edatoakrun
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Re: Does the Leaf have a radiator?

Mon Dec 20, 2010 8:39 am

Going over the owners manual, I'm a bit mystified at the coolant system(s) design.

I find reference to the 7 quart capacity cooling system and water pump. Seems like a lot of mass and hardware.

Is the only purpose of this system to cool the charger and inverter?

Is this system in any way connected to the cabin heater?

Is there a separate coolant ("heat-ant") fluid reservoir for climate control, entirely separate from the coolant system?

Sure seems like the heat stored in the thermal mass of 7 quarts of coolant could come in handy on a cold day.
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JasonT
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Re: Does the Leaf have a radiator?

Mon Dec 20, 2010 9:07 am

edatoakrun wrote:Is the only purpose of this system to cool the charger and inverter?
Is this system in any way connected to the cabin heater?
Is there a separate coolant ("heat-ant") fluid reservoir for climate control, entirely separate from the coolant system?
Yes (and maybe the motor, but probably just the charger and inverter)
No
Yes (heat is electrictric, but apparently goes through some water)

Last answer edited - I do not know what I'm talking about and should only answer things I am sure about
Last edited by JasonT on Mon Dec 20, 2010 9:49 am, edited 1 time in total.

kmp647
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Re: Does the Leaf have a radiator?

Mon Dec 20, 2010 9:22 am

THE heater uses water to conduct heat to the cabin thru a typical heater core

the heater element is resistive coil in a tank under hood

it uses a pump, resivoir and heater core and is a seperate system from the inverter-charger-motor coolant circuit.
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edatoakrun
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Re: Does the Leaf have a radiator?

Mon Dec 20, 2010 9:34 am

"it uses a pump, resivoir and heater core and is a seperate system from the inverter-charger-motor coolant circuit."

And there is no heat exchange between the two systems?
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Smidge204
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Re: Does the Leaf have a radiator?

Mon Dec 20, 2010 9:37 am

edatoakrun wrote:And there is no heat exchange between the two systems?
Would be a shame if there wasn't, IMHO. That's a very simple thing to do and it's potentially "free" heating. Although exactly how much heat the motor/inverter throws off is questionable, if it's enough that they went with liquid cooling in the first place then it's enough to provide some degree cabin heating/defrost air.
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garygid
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Re: Does the Leaf have a radiator?

Mon Dec 20, 2010 9:39 am

We believe the primary coolant cools the Inverter and Electrical Motor.

Some conjecture about it cooling the hump-located Charger, but I doubt it ... but it could. If it does, the coolant pump (and perhaps radiator fan) would need to come on, at least when the charger was getting "too" hot.

The heater fluid system appears to be entirely separate from the motor/inverter coolant system.

In cold weather, when you need heat in the cabin, the main coolant system might be quite cold, so of no use in heating the cabin.
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turbo2ltr
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Re: Does the Leaf have a radiator?

Mon Dec 20, 2010 10:01 am

garygid wrote:Some conjecture about it cooling the hump-located Charger, but I doubt it ... but it could. If it does, the coolant pump (and perhaps radiator fan) would need to come on, at least when the charger was getting "too" hot.
I believe I read in the manual that while charging a fan could start and/or you could hear some sort of pump. I remember thinking "oh the charger must be water cooled" and being a bit surprised at it.
In cold weather, when you need heat in the cabin, the main coolant system might be quite cold, so of no use in heating the cabin.
Good point, no need to artificially heat up the rest of the system just to heat the cabin..not to mention how much more thermal mass the motor/inverter cooling circuit has which would require a lot more energy to make warm... At first I couldn't understand why they wouldn't take advantage of the heat produced by the system for cabin cooling, but when you get into it, it does create more problems than you would initially think.
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