AntronX
Posts: 83
Joined: Sun May 22, 2016 12:17 pm
Delivery Date: 14 May 2016

Cooling battery with home central air conditioner

Sun Jun 25, 2017 12:37 pm

Hi everyone. Summer is here in full swing in south FL and my Leaf's battery temps are holding around 90 - 100F around the clock. Seeing how I lost about 3% of my battery capacity last summer, and winter loss was basically flat, I could not let my battery rot in the heat again this year. So I decided to explore ways to help keep it cool.

First, I cleaned out my garage to make space for parking my Leaf there overnight at around 78F indoor ambient temp and keep it out of the afternoon sun (I depart to work at 4pm). Doing that made little to no improvement in battery temps, but made much more comfortable experience of starting the drive in pre-cooled car. I was still arriving at work with highest temp sensor reporting ~100F.

I decided to use flex air duct to channel my house central AC air directly under the Leaf. That did not make a difference, due to Leaf's plastic battery under belly cover blocking cold air stream from reaching the battery. So then I tried channeling that air into open battery disconnect plug hatch inside the cabin. It worked, and i could feel cold air escaping underneath the car. Next day the highest battery temp was 85F and was 90F after driving to work.

Next I tried adding a booster fan to my air duct with fan speed adjusted using a variac. This about doubled the air flow and allowed for cool air to keep flowing around the battery when AC was off. Next day the battery temps were 80F, 75F and 73F. After the drive to work they were 87F, 85F and 84F. So it appears that I managed to lower average temp from around 95F down to 85F by doing this. I think average temp will get down by another 5 degrees once I let the battery sit one more day unused while being cooled.

I should mention that the weather was the same these 3 days, with ambient temp in 89 - 92F range and sunny. My drive is 60 miles round trip, I charge from 20% SOC to 70% from 2am - 5am, then finish to 90% SOC in last hour and a half before departure. I arrive at work at ~50% SOC and the car sits there for about ~7 hours.

I plant to add further improvements to this cooling method and make this setup a bit more user friendly. Here are pictures of my contraption: https://imgur.com/a/pD8FP

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DNAinaGoodWay
Posts: 2690
Joined: Mon Dec 17, 2012 1:43 am
Delivery Date: 03 Dec 2012
Leaf Number: 23156
Location: Central Massachusetts

Re: Cooling battery with home central air conditioner

Sun Jun 25, 2017 5:02 pm

Wow! That's pretty cool! (Couldn't resist)

And you work at night? So it's dark and maybe a little cooler when you leave work? What's it read then?
'12 SL last reading @ 2 yr, 22k, 260 GIDs, 62.35 Ahr

'15 SV w/QC, Mfd 5/14, Leased 8/14, 292 GIDs, 64.38 Ahr when new

@ 25 months, 25k, 267 GID, 56.88 AHr
@ 36 months, 34k, 270 GID, 57.49 AHr


6.72 kW Array

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Stanton
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Posts: 1922
Joined: Thu Feb 03, 2011 10:56 am
Delivery Date: 01 Sep 2011
Leaf Number: 7458
Location: Plano, TX
Contact: Website Twitter

Re: Cooling battery with home central air conditioner

Sun Jun 25, 2017 5:28 pm

Just when you think you've seen it all! I have no idea what affect this has on your home A/C unit, but you're definitely having a positive affect on your Leaf. Of course, you won't know the results until we get through summer and you take some AHr readings to compare with last year.
2011 Blue Ocean SV w/floor mats & window tint
12v LiFePO4 battery & FIAMM 74100 horns
Wet Okole seat covers (front)
Tor's low-power heater mod
2013 sun visor
3G modem upgrade
L2 EVSE Upgrade
Battery Pack replaced (Rev E) @51 months and 41k miles

AntronX
Posts: 83
Joined: Sun May 22, 2016 12:17 pm
Delivery Date: 14 May 2016

Re: Cooling battery with home central air conditioner

Sun Jun 25, 2017 10:57 pm

DNAinaGoodWay wrote:...And you work at night? So it's dark and maybe a little cooler when you leave work? What's it read then?


Not much difference, maybe 2F cooler, depending how hot it was when I got there. Usually still around 93 - 95F.

Stanton wrote:Just when you think you've seen it all! I have no idea what affect this has on your home A/C unit, but you're definitely having a positive affect on your Leaf. Of course, you won't know the results until we get through summer and you take some AHr readings to compare with last year.


Can't think of any negative effects to my AC, the same air that would usually just flow into the garage is now flowing through the Leaf first, then returning back to the house. By backdrafting house air back into the air outlets by leaving booster fan on when AC is off, I could be introducing house dust into the air ducts. Will see how dusty they get after a while. I plan to make this setup look nicer for longer term use. My Leaf is at 86 - 85% SOH, so I could be losing 12th bar any time now. I log every trip with LeafSpy, so there should be enough data to plot on a chart after few months.

GetOffYourGas
Posts: 1506
Joined: Tue Dec 20, 2011 6:56 pm
Delivery Date: 09 Mar 2012
Location: Syracuse, NY

Re: Cooling battery with home central air conditioner

Mon Jun 26, 2017 5:11 am

I'm glad to see you're taking steps to care for your Leaf. It's a shame you have to do this, but I'm thrilled you took the initiative (rather than, for example, trying to abuse the battery just to get a new one).

What are your plans for a more permanent solution? I hope you'll share more pictures!
~Brian

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

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TomT
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Leaf Number: 000360
Location: Foothills of Granada Hills, CA
Contact: Website

Re: Cooling battery with home central air conditioner

Mon Jun 26, 2017 8:03 am

To me it is just idiotic that we should have to do things like this to maintain the battery! Yep, Nissan was right, we sure as hell do not need a TMS! NOT!
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.

BrockWI
Posts: 512
Joined: Fri Mar 28, 2014 6:28 am
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Leaf Number: 423875
Location: Green Bay, WI.
Contact: Website

Re: Cooling battery with home central air conditioner

Mon Jun 26, 2017 8:28 am

I understand you will get more cooling to the pack itself this way, but if you just ducted you home A/C to the garage (cooling your garage to whatever temp the house is set to) and then using that same inline duct booster and forcing more past the batteries wouldn't it be almost the same with less duct runs? Or becasue the A/C is hitting the batteries first does it cool them that much more?

I would think overtime the pack would get to the "room" or garage temp with just a duct booster right on the batteries?

I am thinking what could most folks to to cool their batteries without the A/C part.

In other words does forcing 50 cfm of air over the batteries for 12 hours get them to room temp?
3 kw solar pv - XW6048 - 8 L16's
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Stanton
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Posts: 1922
Joined: Thu Feb 03, 2011 10:56 am
Delivery Date: 01 Sep 2011
Leaf Number: 7458
Location: Plano, TX
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Re: Cooling battery with home central air conditioner

Mon Jun 26, 2017 8:31 am

AntronX wrote:My Leaf is at 86 - 85% SOH, so I could be losing 12th bar any time now. I log every trip with LeafSpy, so there should be enough data to plot on a chart after few months.


That all depends on your AHr reading: what is it?
I'm also around 85% SOH on my second battery pack as well, but compared to my first pack I'm not close on AHr (57).
The biggest difference I've seen with the "lizard" pack is that my health metrics have actually stabilized when the weather turned hot...instead of continuing to drop. However, I still have another 4-5 months to go for the equivalent time I lost the 12th bar on my original battery pack.
2011 Blue Ocean SV w/floor mats & window tint
12v LiFePO4 battery & FIAMM 74100 horns
Wet Okole seat covers (front)
Tor's low-power heater mod
2013 sun visor
3G modem upgrade
L2 EVSE Upgrade
Battery Pack replaced (Rev E) @51 months and 41k miles

User avatar
Stanton
Forum Supporter
Posts: 1922
Joined: Thu Feb 03, 2011 10:56 am
Delivery Date: 01 Sep 2011
Leaf Number: 7458
Location: Plano, TX
Contact: Website Twitter

Re: Cooling battery with home central air conditioner

Mon Jun 26, 2017 8:33 am

BrockWI wrote:In other words does forcing 50 cfm of air over the batteries for 12 hours get them to room temp?


I did something similar (with a large shop fan) on my first battery pack and I don't believe it had any (positive) affect; you can see from my sig that I ended up with a warranty replacement pack with almost a year to spare on the warranty.
2011 Blue Ocean SV w/floor mats & window tint
12v LiFePO4 battery & FIAMM 74100 horns
Wet Okole seat covers (front)
Tor's low-power heater mod
2013 sun visor
3G modem upgrade
L2 EVSE Upgrade
Battery Pack replaced (Rev E) @51 months and 41k miles

AntronX
Posts: 83
Joined: Sun May 22, 2016 12:17 pm
Delivery Date: 14 May 2016

Re: Cooling battery with home central air conditioner

Mon Jun 26, 2017 12:14 pm

GetOffYourGas wrote:I'm glad to see you're taking steps to care for your Leaf. It's a shame you have to do this, but I'm thrilled you took the initiative (rather than, for example, trying to abuse the battery just to get a new one).
What are your plans for a more permanent solution? I hope you'll share more pictures!

Thanks! I bought my 2011 SL at 75k miles and 91 SOH battery (58.7Ah, 87.2Hx) with original battery already replaced at 59k miles. I am not aware of any warrany it still may have, so I assume this second battery will be the last free one. I hope to extend the life of this battery to allow enogh range to cover my 60 mile commute for another 1 - 1.5 years. By that time I expect to get a Tesla.

TomT wrote:To me it is just idiotic that we should have to do things like this to maintain the battery! Yep, Nissan was right, we sure as hell do not need a TMS! NOT!

Eh, I'll let them slide on this one. First truly mass market EV, was expensive to make back then, so they had to cost shave at every turn. The degradation problem is most evident in hot southern climates. Also the capacity is relatively small, so they could have calculated that it would be cheap enough to just replace affected packs in the future once battery prices have come down. Now after everything Nissan has learned with our Leafs, if their second gen Leaf, with it's presumed 40 - 60 kWh battery does not have active TMS, then that would be a huge FAIL on Nissan's part. I fully agree that we should not have to resort to this kind of measures that I am doing to extend the life of our cars. Sorry Nissan, but no TMS = no next buy from me!

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