Brenthasty
Posts: 49
Joined: Tue Dec 23, 2014 6:24 pm
Delivery Date: 13 Nov 2014
Leaf Number: 023724
Location: Near portland oregon
Contact: Website

how is cooling air ducted around the leafs battery; ideas for augmented cooling

Mon Jul 06, 2015 10:51 am

how is cooling air ducted around the leafs battery?
Images?

Any ideas for augmented cooling?

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gbarry42
Posts: 887
Joined: Mon Jan 10, 2011 5:48 pm
Delivery Date: 06 May 2011
Location: Moonlight Beach

Re: how is cooling air ducted around the leafs battery; ideas for augmented cooling

Mon Jul 06, 2015 11:02 am

It's not. The battery is in a sealed container that's (slightly) pressurized.
And there goes the first capacity bar! At 24,000 mi on 9/9/2013.
Second bar at 30,500 mi on 2/7/2015.

GerryAZ
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Delivery Date: 12 Jun 2011
Location: Phoenix, AZ

Re: how is cooling air ducted around the leafs battery; ideas for augmented cooling

Tue Jul 21, 2015 10:02 pm

There are openings in the splash shield to allow air flow to the underside of the sealed battery case. There is also air flow over the top of the sealed battery case from under the hood through the "tunnel" under the console. This air flow above and below the sealed battery case is somewhat effective because I have noted battery temperatures drop a few degrees while driving on the highway after charging or being parked. I have also noted battery temperatures increase a few degrees when the car is parked after being driven on the highway.

Gerry
Gerry
Silver LEAF 2011 SL rear ended (totaled) by in-attentive driver 1/4/2015 at 50,422 miles
Silver LEAF 2015 SL purchased 2/7/2015

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TomT
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Joined: Sun Aug 08, 2010 12:09 pm
Delivery Date: 01 Mar 2011
Leaf Number: 000360
Location: Foothills of Granada Hills, CA
Contact: Website

Re: how is cooling air ducted around the leafs battery; ideas for augmented cooling

Wed Jul 22, 2015 3:41 pm

The battery has significant thermal mass so I don't think any practical external cooling would be effective...

Brenthasty wrote:Any ideas for augmented cooling?
59,991 miles/12 bars/289 Gids/68.54 AHr/101% SOH/101.64% Hx 7May15 w/ new Lizard (barely made the warranty).
71,770 miles/12 bars/256 Gids/59.04 AHr/88% SOH/87.92% Hx 3Mar16 at lease return.

Now driving a 2017 Volt Premier. Model 3 reserved.

Graffi
Posts: 362
Joined: Wed Nov 27, 2013 12:01 pm
Delivery Date: 06 Sep 2013
Leaf Number: 414757
Location: San Diego, CA

Re: how is cooling air ducted around the leafs battery; ideas for augmented cooling

Wed Jul 22, 2015 4:59 pm

Here is an interesting thread that can be read. It was a while ago, but still applies.

viewtopic.php?f=9&t=13106&start=10
2013 SL Metalic Slate
MFG 08/13 Dlv 09/06/13 @ 10 mi
12/27/13 LeafDD at 100% measured at noon (4,817 Miles):
259 gids, 96.93% SOC, 92.20 g%, 58.01 Ah, 19.7*c (67.4*f)
S 96.9375
C 59.8475 V 395.5
H 91.52
# 77 100 mile club
# 10 200 km club

Vincam
Posts: 7
Joined: Thu Dec 03, 2015 2:53 pm
Delivery Date: 08 Dec 2015
Leaf Number: 009055

Re: how is cooling air ducted around the leafs battery; ideas for augmented cooling

Mon Jun 20, 2016 12:57 pm

TomT wrote:The battery has significant thermal mass so I don't think any practical external cooling would be effective...

Brenthasty wrote:Any ideas for augmented cooling?



I live in Las Vegas and this is my first summer with the LEAF. I have read extensively on here about the heat problems with the battery on the leaf and I have come up with something that is pretty effective so far.

I have modified a small A/C unit to do what I needed and can cool the battery down approximately 2 degrees Fahrenheit per hour using about 500 watts of electricity from my house. So basically as it's parked I cool it down and when I'm ready to drive it the battery has cooled from approximately 95 degrees to 75 degrees in 10 hours. So 5 kw of electricity and I only pay about $.05 KWH so about $0.25 a day to cool it.

Worth it to me so far for the three hottest months here to extend the life. It was a new battery when I bought the car and I'd like to help it survive. Something interesting to note that I have found is about the thermal mass time to heat/cool. The cooling air flow around the battery at freeway speeds is actually very effective with enough temperature differential. With a 30 degree cooler air differential and the air flow I can use to maintain this the battery will cool, like I said, about 2 degrees per hour. However the same 30 degree hotter differential when I drive to work will heat the battery 20 degrees an hour. Significantly faster with the increased volume of air. Of course there is some pack heating from discharging the battery but is seems to be minor in comparison to the heating that takes place on my commute.

I am looking to find a way to actually stop the "cooling" air flow that goes across the battery when driving as this is actually heating the battery under my conditions when leaving with a cool battery. Anyways just wanted to comment, I will be posting more info about what I am doing as I develop it. I just wanted to test the concept so far and what I have built is quite ugly but was less that $200. I want to refine it, do some more experimentation with air flow etc. and see if I can improve the efficiency.

GetOffYourGas
Posts: 1340
Joined: Tue Dec 20, 2011 6:56 pm
Delivery Date: 09 Mar 2012
Location: Syracuse, NY

Re: how is cooling air ducted around the leafs battery; ideas for augmented cooling

Mon Jun 20, 2016 10:39 pm

Vincam wrote:
TomT wrote:The battery has significant thermal mass so I don't think any practical external cooling would be effective...

Brenthasty wrote:Any ideas for augmented cooling?



I live in Las Vegas and this is my first summer with the LEAF. I have read extensively on here about the heat problems with the battery on the leaf and I have come up with something that is pretty effective so far. I have modified a small A/C unit to do what I needed and can cool the battery down approximately 2 degrees Fahrenheit per hour using about 500 watts of electricity from my house. So basically as it's parked I cool it down and when I'm ready to drive it the battery has cooled from approximately 95 degrees to 75 degrees in 10 hours. So 5 kw of electricity and I only pay about $.05 KWH so about $0.25 a day to cool it. Worth it to me so far for the three hottest months here to extend the life. It was a new battery when I bought the car and I'd like to help it survive. Something interesting to note that I have found is about the thermal mass time to heat/cool. The cooling air flow around the battery at freeway speeds is actually very effective with enough temperature differential. With a 30 degree cooler air differential and the air flow I can use to maintain this the battery will cool, like I said, about 2 degrees per hour. However the same 30 degree hotter differential when I drive to work will heat the battery 20 degrees an hour. Significantly faster with the increased volume of air. Of course there is some pack heating from discharging the battery but is seems to be minor in comparison to the heating that takes place on my commute. I am looking to find a way to actually stop the "cooling" air flow that goes across the battery when driving as this is actually heating the battery under my conditions when leaving with a cool battery. Anyways just wanted to comment, I will be posting more info about what I am doing as I develop it. I just wanted to test the concept so far and what I have built is quite ugly but was less that $200. I want to refine it, do some more experimentation with air flow etc. and see if I can improve the efficiency.


Please share what you have done! Even the proof-of-concept would be neat to see.

I don't envy you guys in hot climates. But I applaud your ingenuity in solving a problem that Nissan chose to ignore.
~Brian

EV Fleet:
2011 Torqeedo Travel 1003 electric outboard on a 22' sailboat
2012 Leaf SV
2015 C-Max Energi (302A package)

Brenthasty
Posts: 49
Joined: Tue Dec 23, 2014 6:24 pm
Delivery Date: 13 Nov 2014
Leaf Number: 023724
Location: Near portland oregon
Contact: Website

Re: how is cooling air ducted around the leafs battery; ideas for augmented cooling

Sat Dec 03, 2016 9:23 am

to reduce the hot airflow warming your battery on hot days, make some simple foam plugs that can partially block the grille. leave yourself about a 1' gap in the middle for the airflow to the cabin AC

Brenthasty
Posts: 49
Joined: Tue Dec 23, 2014 6:24 pm
Delivery Date: 13 Nov 2014
Leaf Number: 023724
Location: Near portland oregon
Contact: Website

Re: how is cooling air ducted around the leafs battery; ideas for augmented cooling

Sat Dec 03, 2016 9:33 am

GerryAZ wrote:There are openings in the splash shield to allow air flow to the underside of the sealed battery case. There is also air flow over the top of the sealed battery case from under the hood through the "tunnel" under the console. This air flow above and below the sealed battery case is somewhat effective because I have noted battery temperatures drop a few degrees while driving on the highway after charging or being parked. I have also noted battery temperatures increase a few degrees when the car is parked after being driven on the highway.

Gerry

it does seem the battery is in a wind tunnel formed by the bottom of the car, and the bellypan, that is aspirated through the grille.

I have now done a complete down to the last bolt teardown of a leaf, and have observed this duct in detail, the battery has an inch or two of space around it for the air to flow. Incidentally after this teardown i discovered the very first piece it appears they attach to the car is the firewall sound dampening insulation...

they took the trouble to seal the engine compartment and wheel wells so the grille could scoop up air to flow through the radiators, over the motor, around the battery and out the tail.

what the leaf and other ev's appear to need most is active shutters.

I have a simple foam plug I take in and out of the grille as needed to cool OR conserve heat depending on the season.

Incidentally this foam plug when installed gives me about an extra .5 miles per kwh and aerodynamically helps significantly at 70+ mph freeway speeds. At 80 mph im still about 3.5 m/kwh (with my other aeromods)!

User avatar
TomT
Posts: 10507
Joined: Sun Aug 08, 2010 12:09 pm
Delivery Date: 01 Mar 2011
Leaf Number: 000360
Location: Foothills of Granada Hills, CA
Contact: Website

Re: how is cooling air ducted around the leafs battery; ideas for augmented cooling

Sat Dec 03, 2016 11:10 am

Yep, no need for a TMS in the Leaf.... ;)
59,991 miles/12 bars/289 Gids/68.54 AHr/101% SOH/101.64% Hx 7May15 w/ new Lizard (barely made the warranty).
71,770 miles/12 bars/256 Gids/59.04 AHr/88% SOH/87.92% Hx 3Mar16 at lease return.

Now driving a 2017 Volt Premier. Model 3 reserved.

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