Llecentaur
Posts: 240
Joined: Thu Dec 27, 2012 7:56 am

Re: Passive cooling ?

Thu May 30, 2013 2:06 pm

My Czero does not have AC but it does have the battery fan. Would you think that charging at high amperage like 14A would harm more the battery pack of a car without AC ? Of course not in winter but in a mid-European summer never reaching extreme temperatures more than a few days a year.

siai47
Posts: 363
Joined: Fri Jun 14, 2013 5:54 pm

Re: Passive cooling ?

Fri Jun 14, 2013 6:11 pm

I have a I-miev with the battery warming option. I thought it was pretty useless in Florida but I found a good use for it. It works by directing air from the heater floor vents into the battery when the temperature is very cold. However, on my car I removed the actuator (one connector and two screws) which you can see from the drivers side, under the dash just above the console extension. Once removed, you can move the white plastic lever that will divert air that would normally flow from the floor vents into the battery. Putting the HVAC mode selector knob in the floor/face position you can direct cooled air from the A/C to both the cabin and the battery. Now you have "active" cooling!

Llecentaur
Posts: 240
Joined: Thu Dec 27, 2012 7:56 am

Re: Passive cooling ?

Sun Jun 16, 2013 10:50 am

Thank you for the info. Combined with a Webasto diesel heater, this could become a passive warmer for winter driving in order to improve battery performance.

I could not find the connector, would you kindly post a picture ?

Thanks

siai47
Posts: 363
Joined: Fri Jun 14, 2013 5:54 pm

Re: Passive cooling ?

Sun Jun 16, 2013 3:13 pm

You must have either the quick charge option or the cold weather package to have this part in the car. As I am new to this forum, I don't think I can post pictures yet (there is no "advanced" option available). However, if you get your head into the drivers footwell and look in the opening above the console under the dash, you will see the actuator mounted to the heater floor duct (this is on a left hand drive car). There is a three wire connector plugged into it. It really works well as it is dropping the temperature quite a bit in the battery enclosure. I don't want to get it too cold as you don't want condensation to form inside. Condensation is a Florida problem, not a Phoenix problem and the temperature is easily adjusted with the A/C mode selector. I am getting another I-Miev tomorrow without either package and am going to see what is takes to change a standard car, parts wise, to one with this ability. Yes, in cold weather it would heat the enclosure. The I-miev draws air from the passenger compartment from a duct located under the passenger seat. This system just adds an additional duct to connect the heater and A/C floor vents to that existing duct. The actuator allows selection of the air from the system to blow on the floor or into the battery enclosure. If you want electric actuation, a switch will need to be added to supply power to select which position you want the door inside the floor outlet housing to be in.

jaraczs
Posts: 114
Joined: Mon Aug 06, 2012 6:03 pm
Location: Somerset, NJ

Re: Passive cooling ?

Sun Jun 16, 2013 6:47 pm

Llecentaur wrote:I could not find the connector, would you kindly post a picture ?


I am posting pictures taken in October 2012 during some exploration of my base model iMiEV with winter package. I have not done any modifications regarding passive/active thermal management.
To siai47: Everyone can post pictures, it is just not simple process.
JoeS: Do we have instructions somewhere in this forum?
All: Please feel free to suggest/improve/correct part's description in pictures.
Picture 1 is taken from the footwell of the driver, aiming to the center:
Image
Picture #2 is the Center panel with one cover removed (driver's underdash cover is removed, too):
Image
Pictures #3 and #4 represent two stages of uncovering the center panel showing the battery duct inlet:
Image
Image
Picture #5 is some control unit:
Image
Picture #6 is taken from the passenger footwell showing control unit 1 and also pipes to/from heater core. Interesting to note that these pipes can be located without any disassembling, even while driving to check onset of heater function. It takes little practice:
Image
Last edited by jaraczs on Mon Nov 25, 2013 7:44 pm, edited 1 time in total.

Llecentaur
Posts: 240
Joined: Thu Dec 27, 2012 7:56 am

Re: Passive cooling ?

Sun Jun 16, 2013 9:34 pm

Many thanks !

I will check to see which parts I have.

siai47
Posts: 363
Joined: Fri Jun 14, 2013 5:54 pm

Re: Passive cooling ?

Mon Jun 17, 2013 5:40 am

Yes, the picture marked "actuator" is the actuator in question. The quick and easy way to get instant cooling is to remove the connector and take the two screws out that hold the assembly to the heater duct. Manually move the linkage until the lower arm faces forward and you are done. When you want additional cooling to the battery, just select the face/floor position with the A/C unit running. Works the same way for winter if you want to add heat. I would also think it works best in the non-recirculation mode as it would push the most air out through the battery enclosure. In the winter, if you want floor heat, you need to reach down and move the linkage back until the lower arm is pointing up. One thing that is puzzling to me is how the battery internal fan cooling works with this system as supplied by the factory. When the actuator is in the normal position (floor vent open) the opening to the battery enclosure is blocked. When the battery fan comes on for it's self test when you plug in the charging cord, the actuator doesn't move to an open position. I am assuming in cold temps, or while quick charging the actuator is operated by the same signal that starts the A/C or heat depending on what is required. I still don't know what would cause it to move if just the battery fan was called for.

jaraczs
Posts: 114
Joined: Mon Aug 06, 2012 6:03 pm
Location: Somerset, NJ

Re: Passive cooling ?

Fri Sep 20, 2013 6:59 pm

Further to this topic, I came up with a proposal to upgrade thermal management of the battery with rather simple modification. The idea is built on the assumption that we know how to open the battery compartment inlet and if we run cool/warm air into the battery compartment, it is a good idea to return the air into the cabin to recover the residual cool/heat. Now we need to identify a suitable opening in the floor or make a hole in the frame. Inspection of the floor behind front seats and under the rear seats shows that there is a rectangular hole in the floor behind the central panel (see pics). The hole is plugged with a piece of rubber (5 x 4.5 cm) with cable for parking brake running through. It sits firmly and I have not been able to remove it without tools. When the lid above the rear engine was removed, the parking brake cable could be located as coming from the above the battery pack. In addition, the air outlet from the battery compartment is located in the back of the pack, near-center and it is facing front. The proposal would be to attach a suitable duct (perhaps 2-3 inch wide) from the battery compartment air outlet and connect it to the hole for the parking brake cable. The estimated length is 1 foot. The hole in the floor would have to be modified to allow the cable to go through without air leakage for the air return. The carpet inside of the vehicle would need to have openings as well. The metal shield on the floor (see pic) may need to be cut or lifted a little to increase the clearance so that the air can flow into the cabin. It is imperative, that in order to perform this modification, the battery compartment would have to be dropped, which renders the realisation difficult. This is a reason I cannot do it.
ImageImageImageImageImage

Things to further consider:
1) We may want to be able to control whether the air goes inside or out (damper?).
2) We may need to run the battery fan to improve the air circulation.
3) We may need to consider adding insulation between the battery compartment and the plastic shield under the vehicle.
4) If we install Webasto heater, such modification may become obsolete as the heat from combustion is rather cheap and the warm air can be vented out.

Don
Site Moderator
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Joined: Thu May 10, 2012 3:55 pm
Location: Biloxi MS

Re: Passive cooling ?

Sat Sep 21, 2013 6:07 am

Llecentaur wrote:My Czero does not have AC but it does have the battery fan. Would you think that charging at high amperage like 14A would harm more the battery pack of a car without AC
You'll never charge at 'high amperage' unless you have and use the L3 Quick Charge feature. The built in charger is only 3300 watts and since it's a 330 volt battery pack, that means it can't supply more than 10 amps to the battery pack. Since it's a 50 AH pack, you're only charging at about 1/5th C (C is 'Capacity' of the battery). For Lithium batteries, 1/5th C is a quite slow charge so you have little to worry about overheating the battery during normal charging

Don
2012 iMiEV SE Premium, White
2012 iMiEV SE, White
2017 Chevy Volt Premier
2014 Ford Transit Connect XLT SWB wagon, 14,000 miles
1979 Honda CBX six into six

Malm
Posts: 449
Joined: Mon Jul 22, 2013 12:16 pm
Location: Tábua - Portugal

Re: Passive cooling ?

Sat Sep 21, 2013 10:17 am

siai47 wrote:Yes, the picture marked "actuator" is the actuator in question. The quick and easy way to get instant cooling is to remove the connector and take the two screws out that hold the assembly to the heater duct. Manually move the linkage until the lower arm faces forward and you are done. When you want additional cooling to the battery, just select the face/floor position with the A/C unit running. Works the same way for winter if you want to add heat. I would also think it works best in the non-recirculation mode as it would push the most air out through the battery enclosure. In the winter, if you want floor heat, you need to reach down and move the linkage back until the lower arm is pointing up. One thing that is puzzling to me is how the battery internal fan cooling works with this system as supplied by the factory. When the actuator is in the normal position (floor vent open) the opening to the battery enclosure is blocked. When the battery fan comes on for it's self test when you plug in the charging cord, the actuator doesn't move to an open position. I am assuming in cold temps, or while quick charging the actuator is operated by the same signal that starts the A/C or heat depending on what is required. I still don't know what would cause it to move if just the battery fan was called for.


Can you measure, with canion, how much this process can cool the battery? Thank you for chairing this with us. In Portugal summers, we have some hot days and this should help to keep them cool.
Riding an i-Miev since 4/2011 in Portugal, 100.000 kms.

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