Route AC over battery

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DougWantsALeaf

Well-known member
Joined
May 10, 2013
Messages
3,797
Location
Chicago North Side
All,

I know battery temperature regulation is a big concern for those of us from all model years.

For winter use, with the ducted heat to the rear, I am eager to see in Jan/Feb if running the heat while charging can help bring up battery temps.

But as we are in July (for those in the northern hemisphere), I wonder if there is any easy way to route the AC through those same ducts, or via other ways (like into the rear hump) which would not be too obtrusive. I am guessing we see that happening on the 2020 Leaf given the precedent with the eNV 200, but not helpful for those of use with existing cars.

I have tried running the cooling cycle a few times while plugged in to see if does anything for the battery temp, but until i get Leaf Spy back up and running, the dash gauge isn't enough to if it even can take even a couple degrees off the battery.

All of that said, at least in Chicago, on 90+ F days here , my battery has been pretty consistently at midpoint on the temp gauge. Even when sitting in the sun. As we are close to peak summer here, the lack of thermal mgmt here hasn't been a concern yet.

We have a 2 day 850 mile trip in a couple weeks, so guess that will be the better test.
 
Assuming that the 2018+ Leaf still has the Emergency Disconnect on that hump in the rear passenger floor, then the accepted method is to route cold air from an A/C duct into that. However, the 40kwh Leaf virtually fills the under floor space with battery modules; it is my understanding that there is no longer an air space there to use for forced air cooling. Perhaps someone would like to check...?
 
Probably next week when it's supposed to get into the 100s during the day and not drop below mid 80s at night.
I may see 7 and 8 battery bar temperatures during the day.
I will open the battery door and run a ducted portable A/C into the window.
 
Oilpan4 said:
Probably next week when it's supposed to get into the 100s during the day and not drop below mid 80s at night.
I may see 7 and 8 battery temperatures during the day.
I will open the battery door and run a ducted portable A/C into the window.

Cool! (So to speak.) Thanks.
 
It seems that you are trying to make duplicate what the Kia did with th it’s battery packs. They have still replaced a few batteries from 2015-16 under warranty for degradation. It seems better than the Leaf, but not as good as liquid cooled.
 
Calaveras said:
It seems that you are trying to make duplicate what the Kia did with th it’s battery packs. They have still replaced a few batteries from 2015-16 under warranty for degradation. It seems better than the Leaf, but not as good as liquid cooled.


That's pretty much it. I wouldn't expect this improvised air cooling to be nearly as effective as the Hyundai/Kia design.
 
What is the hyundai and kia design?
When I looked all I could find was details on their sub 2kwh non plug in hybrid battery pack cooling that appears to use cabin air and a big blower.
Are the larger batteries the same way?
Only info I could find was "battery cooling : air" with no further description or detail.

I should be finishing my roll about 10k btu per hour open loop ducted cooling rig tomorrow or the next day.
It's going to be so hot the next few days I may not charge the leaf and leave it sitting and drive a gas burner if the battery rig does not get completed.
 
What is the hyundai and kia design?
When I looked all I could find was details on their sub 2kwh non plug in hybrid battery pack cooling that appears to use cabin air and a big blower.
Are the larger batteries the same way?
Only info I could find was "battery cooling : air" with no further description or detail.

The EVs use pretty much the same system. Cabin air is blown over the battery. It has not proven extremely effective overall, but I'm sure it cools the pack significantly when used.
 
I think for now I can get away with raising the hood, charging at night and avoiding full changes.
I was expecting to see 7 or 8 temperature bars this week but I have yet to see the 7th bar this year.
The portable wheeled A/C sucks down about 8 amps of 120v so I'm good with not using it for as long as possible.
I'm sure I can't dodge all the 7 and 8 bar days for the rest of the summer with a few boring tricks
 
Oilpan4 said:
I think for now I can get away with raising the hood, charging at night and avoiding full changes.
I was expecting to see 7 or 8 temperature bars this week but I have yet to see the 7th bar this year.
The portable wheeled A/C sucks down about 8 amps of 120v so I'm good with not using it for as long as possible.
I'm sure I can't dodge all the 7 and 8 bar days for the rest of the summer with a few boring tricks
You do realize that the temp bars are crap and have huge overlapping ranges, right?

You may want to look at the actual temps reported by the sensors in Leaf Spy. It can at least tell you what difference, if any raising the hood does. (Probably almost none.) It will also help inform you as to the effectiveness of other steps.
 
That is the low setting, normally don't run it on high. This A/C runs a single speed compressor and appears to have a fixed orifice.
This A/C runs open loop and I would need colder air rather than higher volume of slightly warmer air. Turning to the highest setting makes it act more like a fan that blows slightly air conditioned air.

I have leaf spy but don't leave it plugged in all the time. That 6th temperature bar does have a pretty huge range it can cover.
But I would say the upper range of the 6th temperature bar is acceptable not ideal, but 7 is putting you on notice, 8 is about the bottom of the danger zone, 9 and up you hate your battery.
First time I see the 7th temperature bar and as it flip flops between 6 and 7 bars my leaf spy blue tooth dongle will be going in.

Charged to 11 bars soc last night, but tomorrow it's going to be hot and I will have to do some day time charging.
 
I have 4 versions.
The control. Just plug it in. Did that last summer, saw 8 bars a few times, didn't have leaf spy.
Version 0, almost as simple as the control. Easy stuff any one can do, open the hood, charging at night, avoiding full charges.
Version 1 is simply remove the battery cover, but leave the fuse cover in place and stick a duct in the window through a scrap 2 inch thick construction foam window shaped cut out. This will definitely cool the car off some, maybe the battery too. A little of both would be ideal.

Version 1.1 now the ducting is longer and goes all the way up to the battery cover on the floor.
Almost all of the cool air ends up on the battery case.

Version 2, the secret weapon. insulated and climate controlled garage. All the insulation is bought, half of its installed, The coal furnace is in the garage and heats like summoning a portal to hell. It will help keep the garage warm in winter and I have a 2 ton split heat pump that I'm not using right now, was going to put it in my new rental but I think I would rather it be in my garage.
Only plan on getting the garage insulated by winter, the heatpump going for next summer.

Version 3. Crack open the battery repack the cells, add some heater pads, punch some holes in the battery for ducted forced air cooling, spray foam and asphalt coat the battery case. Probably summer 2021.
By 2021 I doubt I will be the first to do something like this.
 
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