arnis
Posts: 904
Joined: Sat Jan 23, 2016 3:21 pm
Delivery Date: 23 Jul 2014
Leaf Number: 015896
Location: Estonia, Europe

DIY - Improving battery cooling - active cooling

Sun Jan 31, 2016 3:00 pm

First of all I should mention that I just came up with the idea.
Second: this is dangerous if children are in the car.
Third: this will not void the warranty.

Straight to the idea. I came up with that in another topic:
Which factors have the biggest impact on battery life?

I believe that removing carpet and metal cover of service plug will allow MASSIVE airflow improvement.
I ask somebody to do some measurements with hot battery (no need for hot weather) :idea:
If temperature outside is lower than temperature near the fuse (without airflow) it means heat is trapped there.
If air will start flowing then it will drastically speed up battery heat dissipation.
It is even possible to push cold AC air from cabin onto the battery upper part if vehicle is stationary and
air recirculation is disabled. Tight space between car and battery is ideal for uniform distribution of airflow (stationary).
It is safe only if there are no children inside the vehicle. But for adults it is absolutely safe. Just don't remove the fuse.
Depending on airflow this might have to be closed when driving on highway (15 second operation with thumb-screws).


If this is the case I guarantee a massive change in battery cooldown period while stationary (or heatup for nordic users):

stationary in garage, windows ajar, heat rises:
Image

stationary, climate switched on (remote precool or rapid charging and waiting), windows closed:
Image
Technically that last one is active air cooling :o :D

It is possible to install cheap 120mm computer fan and power it using random 12V DC wallbrick, route low voltage DC cable thru window or door.
Or have heavy mod and suck power from onboard 12V battery. 0.2-0.3Amps each hour so 3Ah per shift from 40-50Ah battery - no problem.
It is better to suck air from outside into the cabin. If exhaust one-way flap Leaf has (somewhere in the bottom of the trunk) is light enough
those fans will push air thru it, no need to open any windows.
This will only work if ambient is not as hot as chemistry inside.
If this is an old idea then paste a link here. I would like to know more why is it not practiced.
Short range EVs <30kWh -- Medium range: 30-60kWh -- Long range: >60kWh
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Brenthasty
Posts: 59
Joined: Tue Dec 23, 2014 6:24 pm
Delivery Date: 13 Nov 2014
Leaf Number: 023724
Location: Near portland oregon
Contact: Website

Re: DIY - Improving battery cooling - active cooling

Fri Feb 19, 2016 12:51 pm

Good thoughts.
Any clue what the airflow path ago under the battery is on the freeway?

Ever check that airflow out the service hole plug?

arnis
Posts: 904
Joined: Sat Jan 23, 2016 3:21 pm
Delivery Date: 23 Jul 2014
Leaf Number: 015896
Location: Estonia, Europe

Re: DIY - Improving battery cooling - active cooling

Fri Feb 19, 2016 3:35 pm

I'm waiting for hot weather. It will take a while here where I live :lol:

I think that renting an anemometer would be overkill. Just a hand while driving on freeway should do the trick.
Short range EVs <30kWh -- Medium range: 30-60kWh -- Long range: >60kWh
Charging: Trickle <3kW -- Normal 3-22kW -- Fast 50-100kW -- Supercharging >100kW

DesertSprings
Posts: 158
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Delivery Date: 21 Dec 2014
Leaf Number: 319100
Location: Southern California

Re: DIY - Improving battery cooling - active cooling

Fri Feb 19, 2016 3:48 pm

What would one use to measure battery temp? Is that something reported in LeafSpy?

arnis
Posts: 904
Joined: Sat Jan 23, 2016 3:21 pm
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Leaf Number: 015896
Location: Estonia, Europe

Re: DIY - Improving battery cooling - active cooling

Fri Feb 19, 2016 4:41 pm

Yes. At least 3 sensors inside the pack.

But the temperature that must be "manually" measured it above the battery.
Just normal Chinese digital thermometer works fine.
Short range EVs <30kWh -- Medium range: 30-60kWh -- Long range: >60kWh
Charging: Trickle <3kW -- Normal 3-22kW -- Fast 50-100kW -- Supercharging >100kW

LeftieBiker
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Re: DIY - Improving battery cooling - active cooling

Fri Feb 19, 2016 9:32 pm

If you are looking for active air cooling at rest, I suggest a couple of high-volume fans in the existing cooling intakes, powered by either a much larger accessory battery or externally. The fans would, of course, reduce cooling while driving at speed.
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
Posts: 904
Joined: Sat Jan 23, 2016 3:21 pm
Delivery Date: 23 Jul 2014
Leaf Number: 015896
Location: Estonia, Europe

Re: DIY - Improving battery cooling - active cooling

Sat Feb 20, 2016 2:30 am

That's the idea. High volume is not needed. Also those fans must be IP46.
That center part is pretty much water free. Also the main idea is that volume is not as
important as we might think. There is no noticeable airflow inside the battery so convection
there would lag behind. The thing is that there is absolutely no airflow at all while parked
outside main battery.


And where is that existing cooling intake?
Short range EVs <30kWh -- Medium range: 30-60kWh -- Long range: >60kWh
Charging: Trickle <3kW -- Normal 3-22kW -- Fast 50-100kW -- Supercharging >100kW

Arlington
Posts: 94
Joined: Tue Jun 23, 2015 11:47 am
Delivery Date: 29 Oct 2015
Leaf Number: 414434

Re: DIY - Improving battery cooling - active cooling

Fri Mar 11, 2016 8:36 pm

How about:
1)a tray (plastic toboggan?) of cold tap water slid under the car or that the car parks over. Goal is for the water to trap heat radiating from the battery

2) a swamp cooler or garden hose mist spray (assumes it is in a driveway). I have an asphalt pad that I park my Leaf on. My goal is to keep the pad cool by day, radiate its heat away at night (if the car is not there), and to be cooler than the battery so as to be a sink for the battery's heat when the car is parked atop.

3) a radiant barrier on a driveway to reflect away the sun (when car is not there) which you remove to allow the driveway to absorb (radiant) heat when the battery is parked above.

arnis
Posts: 904
Joined: Sat Jan 23, 2016 3:21 pm
Delivery Date: 23 Jul 2014
Leaf Number: 015896
Location: Estonia, Europe

Re: DIY - Improving battery cooling - active cooling

Sun Mar 13, 2016 7:12 pm

A tray of water does not work. Yes water has the capacity for the heat but battery does not radiate heat. Radiation
heat is noticeable on objects that are very hot (usually they glow). Battery heat is extracted mostly by convection.
If we drip some water on the battery and that water just flows off or evaporates, that will work.
As it is not as safe as it could be playing with water is not recommended. Some corrosion might happen.

But the third option is reasonable idea. Using some insulation material covered with aluminum foil
or just painting the pavement with white paint will have some effect. Still, this is heavily limited cooling as
there already is some airflow below the battery. No airflow above it.
There will not be heat transfer from battery to pavement (less than 1%) as there is no noticeable radiation.
Painting parking spot with white will have durable effect of not heating the battery with hot air
(warm air raises). White color reflects up to 95%, aluminum theoretically 99%. 4% is not noticeable.
Short range EVs <30kWh -- Medium range: 30-60kWh -- Long range: >60kWh
Charging: Trickle <3kW -- Normal 3-22kW -- Fast 50-100kW -- Supercharging >100kW

yujungchang
Posts: 35
Joined: Fri Apr 26, 2013 10:44 am
Delivery Date: 07 Jan 2013
Leaf Number: 023949
Location: Sacramento, CA

Re: DIY - Improving battery cooling - active cooling

Tue Mar 22, 2016 4:02 pm

I wouldn't open that cover to the cabin, unless some type of filter is in between. If you just wipe the surface of the battery with your finger, you'll see how much black dust accumulated on that. Also when you turn on the AC, the hot air flow through the top of the battery as well and that will lead it to the cabin if you open it up. I attached a thermo sensor to the top of the battery through that hole and can see temp raised up few degrees when AC is on. That means you can't use the car's AC to cool its battery through that hole, the cold/hot air will just neutralize themselves and energy wasted without any benefit. You can feel that small amount of warm air with your hand from that hole when the AC is on.

I did buy a small room AC and small 120V AC 6" fan, intended to hook them up through a 6" alum duct. The idea is to extend the room temp sensor to the beginning of the duct and turn on the fan when the room AC kicked in. However looking at the degradation of my battery, it is not worth any effort to save it and the best bet for me is to replace it through battery warranty(if I'm lucky). Now I do regret baby sit the battery and drove with the max efficiency for that first 2 years. :(
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4rd: Sept 16, 45.8k, 42.19AHr, SOH64, Hx43.06
3rd: May 16, 42.5k, 45.70AHr, SOH69, Hx48.86, OBC failed Dec 15, 130+QC,1440+L2
2nd: Oct 15, 34.0k, 51.58AHr, SOH78, Hx60.88
1st: Oct 14, 24.5k, 55.68AHr, SOH84, Hx70.57

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