Marty
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Joined: Mon Aug 22, 2011 6:39 pm
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Leaf Number: 305053
Location: Connecticut

Re: Active cooling your leaf battery

Sat Apr 07, 2018 6:02 am

Nissan could put a hose connection on the car. Arriving home with a hot battery, attach the garden hose and turn on the water to cool the battery. We have 55 deg. well water that would cool the battery down. Sorry for the strange idea...

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TomT
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Re: Active cooling your leaf battery

Sat Apr 07, 2018 8:19 am

Maybe it would be best to simply buy a vehicle that already has a TMS...
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 2016 Volt Premier.

LeftieBiker
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Location: Upstate New York, US

Re: Active cooling your leaf battery

Sat Apr 07, 2018 1:58 pm

Marty wrote:Nissan could put a hose connection on the car. Arriving home with a hot battery, attach the garden hose and turn on the water to cool the battery. We have 55 deg. well water that would cool the battery down. Sorry for the strange idea...


It might be worth trying this: spray the rear underside of the car with cold water for 5 minutes or so when the pack temp is high, and see if it drops noticeably. I'm considering trying a portable air conditioner blowing through the cooling tunnel if the new car won't fit in my garage.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

jjeff
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Re: Active cooling your leaf battery

Sat Apr 07, 2018 2:43 pm

^^^ I''m guessing the bottom will be all plastic(or a plastic shroud like on my '13) so spraying water wouldn't really help as the plastic shroud would be a pretty good thermal insulator :(
Your portable A/C unit would be a better choice if you could get the cool air to blow through the battery, might be kind of a hassle and wouldn't really help on the road, but would be an option.
Too bad Nissan doesn't have a fan that blows air through the battery when charging(at least QC'ing) like on at least one other EV they sell.....as TomT is fond of saying, we don't need no stinkin' TMS on our Leafs :?
2012 SL purchased used 2/'16
2013 S w/QC purchased new
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LeftieBiker
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Re: Active cooling your leaf battery

Sat Apr 07, 2018 3:27 pm

jjeff wrote:^^^ I''m guessing the bottom will be all plastic(or a plastic shroud like on my '13) so spraying water wouldn't really help as the plastic shroud would be a pretty good thermal insulator :(
Your portable A/C unit would be a better choice if you could get the cool air to blow through the battery, might be kind of a hassle and wouldn't really help on the road, but would be an option.
Too bad Nissan doesn't have a fan that blows air through the battery when charging(at least QC'ing) like on at least one other EV they sell.....as TomT is fond of saying, we don't need no stinkin' TMS on our Leafs :?


I should have been more specific. There is (was?) an opening in the rear diffuser that one could use to spray water or air into the cooling channel. Can someone tell us if it is still there?
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

dilberine
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Joined: Tue Jul 24, 2018 10:56 pm
Delivery Date: 25 Jul 2018

Re: Active cooling your leaf battery

Tue Jul 31, 2018 9:35 pm

Rashi wrote:
according to my calculation when charging using 40 kW FC heat out put will be = 768 W (P = I^2 x R) (R from NREL document,2011 Nissan Leaf – VIN 0356 Adv anced Vehicle Testing – Beginning-of-Test Battery Testing Results)
https://www.dropbox.com/s/de4pveli1p783 ... e.JPG?dl=0

according to EERE (Thermal Management Requirements for EV) the thermal output is nearly 2 kW. So I'm not sure which is correct.
https://www.dropbox.com/s/vjszrcwj1kpzx ... 0.JPG?dl=0

Peltier has about 60% efficiency

With proper sealed ducting and filtering it would work. But I'm afraid to mess with battery casing.

We don't have battery warranty from our local Nissan agent that's why all this struggle!


That’s useful info thanks. The 2kw vs .768kw figure difference could be due to amps at full acceleration being much greater than amps at quick charge.

I’ve tried using Peltier cells to cool smaller lithium batteries. Using heat conductive pads for intimate contact, they were reasonably successful keeping at least the surface of the battery a few degrees cooler than ambient, but it wasn’t clear whether the temperature gradient between the battery surface and the battery internal was within acceptable limits that would help limit battery degradation. This could be why Tesla’s cooling system works so well — they run fluid around many small cells.

Last week I saw an online classified ad for a used 2013 Leaf in Malaysia; 83% SOC at 3 bar dash readout & 53km guess-o-meter range, asking price about USD15k. A new 24kwh battery here costs about USD17k including labour. Local Nissan dealer staff verbally said they need the old battery back, and will re-use the existing weatherproof casing. This sort of prevents further off-vehicle cooling experiments on the old battery pack, if we choose to get a new battery.

The 2013 Leaf battery warranty here is 3 years or 100k km; less generous than in the US.

hoppingbuffalo
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Joined: Fri Aug 31, 2018 12:00 am
Delivery Date: 31 Aug 2018

Re: Active cooling your leaf battery

Fri Aug 31, 2018 12:17 am

I have an MS in Physics and PhD in Materials Engineering. Parking over a puddle won't work because the water is cooling but not the air above it. However, you don't have to drill holes in the battery pack as long as you have a heat conducting path like metal, plastic or even an air pocket. Still air is a good insulator but above about a half inch gap air conducts heat by convection. That's how triple pane windows work. You can't just make a double pane window as thick as a triple pane and expect the same result.

Here's an idea - place water in a pan, put a jack in the water, and raise it until it touches your battery - it just needs to touch, you don't have to jack up the car. I'm looking to buy a leaf but when I do I'll have to get a leafspy and see how effective this is.

I live in Phoenix, AZ where 100+ temperatures are common so I'm investigating this issue.

Sincerely Yours,

Jim Sizemore

JackTheCommuter
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Joined: Fri Jul 06, 2018 6:11 am
Delivery Date: 13 Jul 2018

Re: Active cooling your leaf battery

Fri Aug 31, 2018 12:54 am

hoppingbuffalo wrote:Here's an idea - place water in a pan, put a jack in the water, and raise it until it touches your battery - it just needs to touch, you don't have to jack up the car. I'm looking to buy a leaf but when I do I'll have to get a leafspy and see how effective this is.


Interesting, setting up a heat sink / heat spreader. Unfortunately I don't think the battery area is directly exposed to the ground. Maybe a heat pipe solution?

LeftieBiker
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Re: Active cooling your leaf battery

Fri Aug 31, 2018 2:51 am

I think that most people are underestimating the amount of cooling needed by as little as "a lot" and as much as an order of magnitude. Pans of water, chests of ice, these might stand a chance only if every bit of cooling possible was achieved, leaving no water left over at all.
Scarlet Ember 2018 Leaf SL W/ Pro Pilot
2009 Vectrix VX-1 W/18 Leaf modules, & 3 EZIP E-bicycles.
PLEASE don't PM me with Leaf questions. Just post in the topic that seems most appropriate.

arnis
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Re: Active cooling your leaf battery

Sat Sep 01, 2018 11:29 pm

LeftieBiker wrote:I think that most people are underestimating the amount of cooling needed by as little as "a lot" and as much as an order of magnitude. Pans of water, chests of ice, these might stand a chance only if every bit of cooling possible was achieved, leaving no water left over at all.


Cold tap water with misting action happening (regular water pressure from hose is not enough, more like a third of pressure washer and a good nozzle(s) will do) ON the battery will have excellent result without LOTS of water wasted. I would say 0,5-1 liter per minute.
That water will cool down the air and will also make the battery case soaking wet. Pans don't work. nor does small fan outside the battery.
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