2002
Well-Known Member
I guess I misunderstood their comment to mean cabin air temperature when they presumably meant ambient temperature.
So not using cabin air but using the same freon loop as cabin air.
20+ kWh to charge the battery
- Thread starter ken wells
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Pushmi-Pullyu
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KentuckyKen
Well-Known Member
@AnthonyW, my hero!
Superman ain’t got nothing on you!
I’m picturing you in in a Superman outfit but with a C instead of the S.
Up in the sky, it’s a bird, it’s a plane, no it’s @AnthonyW dispensing more info about the Clarity’s secret inner workings than all the dealerships combined!
PS: I can confirm that all 3 cooling loops are the identical Honda glycol based aqueous coolant. I accessed the coolant recovery tank under the front cover when I had it off to install an air horn. It’s the the same color and smell as the other two visible recovery tanks under the hood. So the battery coolant is not some high tech expensive non conducting fluid as some have speculated.
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My thanks to KKen and AnthonyW for getting this information! I am constantly amazed at the depth of collective technical knowledge on this forum. I read lots of technical specs on both the Volt and Clarity before buying, and obviously I confounded these two in my mind.
It seems like Honda was not engineering for maximum battery life if they didn't allow AC cooling of the battery. Operation at high battery temperatures is a big factor in battery life, and it would be easy to get into the high temperature regime on these 95F days.
It seems like Honda was not engineering for maximum battery life if they didn't allow AC cooling of the battery. Operation at high battery temperatures is a big factor in battery life, and it would be easy to get into the high temperature regime on these 95F days.
The battery teardown video that was posted a bit ago showed that the battery coolant runs through some metal plates that are in contact with the batteries, but no coolant actually touches a battery or electrical component.
Pushmi-Pullyu
Well-Known Member
I think that's the case with every EV liquid battery cooling system. They all run a water/glycol mix thru the battery pack, either in small tubes imbedded in flat metal plates (like the Volt) or in ribbon-like tubes that weave in and out of the battery cells (like Tesla).
While it's reasonable and plausible to argue that Honda's battery cooling system is inferior because it doesn't include a heat exchanger which allows the A/C to remove excessive heat from the system, that may be jumping to a conclusion. It's possible that Honda uses battery cell chemistry which is more resistant to heat, and it's possible that Honda has engineered the water/glycol cooling with sufficient capacity for heat exchange that it will keep the batteries within normal operating temperature even when it's hot outside. A two-speed, high capacity water pump to keep the coolant moving faster when needed, and a sizable radiator, may be all that's needed to eliminate the need for a heat exchanger connection to the A/C.
2002
Well-Known Member
An AC compressor essentially squeezes heat out of the system by compressing the refrigerant to raise its temperature so that the heat can be conducted away at a much higher rate. It is a really effective way to cool but the compressor uses a lot of power as evidenced by the power drain caused by our home and auto air conditioners. Especially if the compressor is running just to cool the battery, but even if it is used while cabin AC is running this will reduce the capacity for cooling the cabin so the occupants will likely run the cabin AC harder to compensate.
You could be right that Honda took a different route and made efforts in other ways to provide adequate cooling without using a compressor, thus saving power overall. It could be argued that maybe Volt was able to "shortchange" some aspects of battery cooling since they knew that they would be using a compressor to remove excessive heat when needed. Not saying they did but like you said we really don't know. In the end a cooling system comes down to cost, power, space required, and cooling efficiency. A car maker has to juggle all of those to come up with their particular strategy.
fotomoto
Active Member
I'll add one more: reliability.
To me, the two biggest cons of liquid cooling are complexity and reliability. The Volt is known for bricking and stranding drivers due to EV powertrain cooling issues; even something as minor a fluid level sensor can do it. A major issue that can happen, although rare, is an evaporator gets punctured by a rock and loses coolant. That's not covered by the warranty BTW. I haven't looked at the Clarity's front end design closely yet to see if it's "good enough" or if adding a mesh rock guard is prudent but since mine is going to become a highway commuter, I will definitely check.
Pushmi-Pullyu
Well-Known Member
I should have written more tolerant of heat, not resistant to heat.
I'm regretting recommending to the moderators here to cut off editing posts after ~2 hours. I'm enjoying the ability, on the InsideEVs News site, of editing out an error in my comments that I spot the next day.
And the big flaw in my argument, which I'm surprised nobody pointed out, is that no matter how big the battery pack liquid cooling system's radiator is, it's not gonna cool the battery down below the ambient temperature. If it's 114° in the shade outside, then the battery pack is gonna be too hot for li-ion batteries no matter how fast the coolant is flowing thru the pack.
The more I think about it, the more I think that yeah, Honda and every other EV maker ought to put in a heat exchanger that allows the A/C refrigerant fluid to suck heat out of the battery coolant when the latter gets too hot.
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