rnlcarlov
Posts: 22
Joined: Wed Apr 13, 2016 8:30 am

Re: Passive cooling ?

Mon Jun 12, 2017 6:27 am

Of course I wouldn't reccomend a portable Chademo charger as an alternative to regular Chademo public stations. But in many countries the Chademo coverage is insufficient for the range of the triplets, so there's that. I'm still on the "wait and see" phase, since payment on quick-charge station is scheduled to start in my country soon. Depeding on the price we have to pay, a portable Chademo could result in some savings. Combining that with cooling during "slower charging", faster charging on 7 or 22kw AC charging stations and adjustable output (for charging in some old places where 14A trips the breaker, it becomes rather tempting for me.

You got your car for 7k? :shock: Sounds like a nice price (depending on the remaining Ah, of course)

Aerowhatt
Posts: 315
Joined: Wed Jan 28, 2015 1:52 pm
Location: Albuquerque NM

Re: Passive cooling ?

Tue Jun 13, 2017 6:23 pm

So I've been looking at the main battery exhaust blower and wiring, etc, in the shop manual. Looks doable to add in a relay to run the blower powered by, perhaps the onboard charger 12 volt relay activation. That way when the charger shuts down (and the DC to DC shuts down too ) so does the fan. Also it needs to be installed so that it doesn't interfere with normal operation of that blower, QCDC etc. Or trip any error traps. So next is to look at it from every angle and hopefully catch any trouble spots before they are actually encountered. "dumb" systems are so much easier to mod than "smart" ones. At first blush it looks totally doable and could even include an ambient air temp function so it only runs when the ambient air is cool enough to make a reasonable difference.

Aerowhatt
2014 cool silver ES, acquired new 4/2015
2014 Labrador Black Pearl ES, acquired new 3/2016

rnlcarlov
Posts: 22
Joined: Wed Apr 13, 2016 8:30 am

Re: Passive cooling ?

Thu Jun 15, 2017 11:23 am

Aerowhatt wrote:. "dumb" systems are so much easier to mod than "smart" ones.


I hear ya. Can you imagine if we could do the same to stuff to EV cars as people do in electric motorcycles? Custom battery packs, chargers, et cetera.....

PV1
Site Moderator
Posts: 2803
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Location: Pittsburgh, PA
Contact: Website

Re: Passive cooling ?

Sat Jun 17, 2017 7:30 am

The thing to watch for when trying to run the pack fan is that the cabin HVAC has the battery damper flipped and the vents set to the floor. Otherwise, you're not going to get much airflow through the pack.

Although not really passive cooling, I have removed the servo that controls the battery air damper and just leave it set to the battery full time. I never use the floor vents (when I do, it's easy to reach down and flip the lever), so anytime I want to send air through the battery, conditioned or not, I simply set the airflow to the floor. These last few days, I've been splitting the A/C, 75% to the battery, 25% to me.

Sometimes, in the winter, I can do double duty (warm the battery and cool the cabin) by cracking a window open, turning on the recirculator, and send all air to the battery. This draws the warm air in the cabin through the system and into the battery, which also pulls cool outside air into the cabin. This is what I do on those 40F days when the inside of the car is 80+. Free heat nets increased regen with a warmer pack :ugeek: .
"Bear" - 2012 Diamond White Pearl ES with QC - 2/21/2013
Solar-powered since 10/10/2013

"Koorz" - 2012 Cool Silver Metallic ES with QC - 1/5/2015

Driving electric since 2-21-2013.
3 years with the i-MiEV and loving every mile!

rnlcarlov
Posts: 22
Joined: Wed Apr 13, 2016 8:30 am

Re: Passive cooling ?

Sat Jun 17, 2017 7:49 am

PV1 wrote:The thing to watch for when trying to run the pack fan is that the cabin HVAC has the battery damper flipped and the vents set to the floor. Otherwise, you're not going to get much airflow through the pack.

Although not really passive cooling, I have removed the servo that controls the battery air damper and just leave it set to the battery full time. I never use the floor vents (when I do, it's easy to reach down and flip the lever), so anytime I want to send air through the battery, conditioned or not, I simply set the airflow to the floor.


That's my setup, too. I'm not sure if I said this here already, but in my case I just connected the car to a public Chademo charger, unplugged the power to the servo while the system was sending air to the pack, and now it's locked in the battery position. If I plug the servo again it should go back to its position. It's not a solution so flexible, but I don't use the foot vents, either. Actually, once I turn the AC to the battery, I always get some cold air on my feet. More than I would like, too. The vents are not 100% sealed.

Aerowhatt
Posts: 315
Joined: Wed Jan 28, 2015 1:52 pm
Location: Albuquerque NM

Re: Passive cooling ?

Thu Jun 22, 2017 11:06 am

PV1 wrote:The thing to watch for when trying to run the pack fan is that the cabin HVAC has the battery damper flipped and the vents set to the floor. Otherwise, you're not going to get much airflow through the pack.


A good reminder. I assumed anyone deep into this thread would remember that, but likely a reckless assumption ;)

Aerowhatt
2014 cool silver ES, acquired new 4/2015
2014 Labrador Black Pearl ES, acquired new 3/2016

Aerowhatt
Posts: 315
Joined: Wed Jan 28, 2015 1:52 pm
Location: Albuquerque NM

Re: Passive cooling ?

Thu Jun 22, 2017 11:26 am

rnlcarlov wrote:Actually, once I turn the AC to the battery, I always get some cold air on my feet. More than I would like, too. The vents are not 100% sealed.


That's interesting, On my car it is a very good seal. No discernible airflow out of the floor vents when in Battery vent mode.

It's hitting 105 F here today and I can keep the hottest cell under 91F if I work at it. Frankly though, the temperature management system is less than stellar. If you let it get ahead of you, it just doesn't move enough BTU's fast enough to play catch up. That's partly why I want to find a practical automatic way to cool (as much as the environment allows) for hours on end at night and while charging at night. Starting the driving day as cool as possible is critical to success in holding down the temps overall.

The cabin fan cools it's motor with the air that it is moving (like most blowers). So the higher it is set to run air through the restricted duct to the battery the more heat it adds to ambient air temp before sending it to the pack. It produces significant heat with all of that back pressure! In that sense pulling ambient air through makes more sense. However the battery exhaust blower is not well suited to the task for a number of reasons. :roll:

Aerowhatt
2014 cool silver ES, acquired new 4/2015
2014 Labrador Black Pearl ES, acquired new 3/2016

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