# Trunk cooling



## etischer (Jun 16, 2008)

I have my charger in the trunk, and on hot days it throttles back because the temperature inside the trunk is too hot. 

I have some small blowers I plan to install, but need to find a place that won't allow mist or dirt to get sucked in. 

I have a 90W 12V power supply I plan to connect to the AC input from the charging cord to power my fans. I can then use it as a backup DC-DC if my IOTA dies again. I also thought about a solar panel, since the fans only need to run when it is sunny out. 

What has everyone else done for trunk cooling? Do you find it better to blow hot air out, or suck cool air in, or both? I figure if I suck cool air in, I can at least filter the air, and know where the air is comming from.


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## ruspert (Jun 16, 2008)

To open the trunk lid would help.


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## dtbaker (Jan 5, 2008)

etischer said:


> I have my charger in the trunk, and on hot days it throttles back because the temperature inside the trunk is too hot.


mmmm, perhaps if you can create a duct to the charger intake fan from the side where it won't get much dirt/water splashed up to it, and just drill a couple small holes from box to vent outside... it would only come on when charger was running, and no extra fans or wiring required! The flexible dryer vent ducting is pretty easy to work with and tape using the aluminum 'duct tape'. You could add some 'swamp cooler' filter material, or perhaps use a small air intake filter like used for the heat/cool system.


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## EVfun (Mar 14, 2010)

If you can cut the hole in about where the pumpkin the the rear axle would be (on a rear wheel drive car) that is likely a very dry spot. It's real hard for the tires to toss water in that area of a vehicle. 

In general, look around under your car for areas in back where the sheet metal is pretty clean on the bottom. That is a good indicator that mud rarely if ever reaches the area.


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## etischer (Jun 16, 2008)

Well, this is what I came up with. I installed my 90w power supply and it runs the blower/fan mounted to the trunk lid. This basically inflates the trunk lid, and the hot air blows out some vent holes I drilled behind the license plate. It will be interesting to see if the paint stays cooler in the sun since it will have air flow on the back side. Here are some pics, still need to clean things up in the morning. 
























I get quite a bit of air flow pumping out these holes, enough to feel a breeze on my face.


I bolted the license plate on with some spacers. The holes should be well protected from the rain, if it's an issue I can always cut a metal frame to better seal against water spray. I have some conduit chase nipples in the bottom of the trunk to let air in.


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## JRP3 (Mar 7, 2008)

Might be worth putting some air intake foam or filter over the holes to keep dust from being sucked in when driving.


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## dtbaker (Jan 5, 2008)

JRP3 said:


> Might be worth putting some air intake foam or filter over the holes to keep dust from being sucked in when driving.



some kind of screening or filter would help keep MICE and bugs out too.


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## Matthijs (Jun 19, 2009)

JRP3 said:


> Might be worth putting some air intake foam or filter over the holes to keep dust from being sucked in when driving.


If I read it correctly the air is blown out of the trunk. So no air is being sucked in. Some foam or filter is off course still useful.


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## JRP3 (Mar 7, 2008)

I got the impression that air was only blowing out during charging. If so driving would suck air and dust in. Maybe pressure sensitive flaps that only open with positive trunk pressure


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## RKM (Jun 9, 2008)

My charger is located in the trunk also. I've covered the hole that was left when removing the fuel tank, with an aluminum mesh and a poly filter medium (above and to the right of the charger in the photo). It won't be perfect, but should keep rodents, bugs and dirt out of the trunk while letting it breath some fresh air.

I have a pair of 12V fans, controlled by a thermal switch, that will turn on at about 80F. These fans will run when charging or while driving. They are installed in the trunk mounted batt box. They should cool the trunk if it gets warm.

I had considered venting behind the license plate as well.

Rob


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## Dave Koller (Nov 15, 2008)

dtbaker said:


> some kind of screening or filter would help keep MICE and bugs out too.


Rats (pun intended) - Dan that was my first thought - I had to pull everything out to find the dead baby mice AFTER I sealed the hole from the clutch cylinder.. had it out for only a while and Momma mouse went in - I sealed it up then get in one day and see her in the back window - so I set an evil trap and got her - cleaned up all the mess she made .. week later = I get the smell URRRRH....

Her babies died and stink was awful - had to pull the seat to find the nest... Yep watch the mice!!


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## etischer (Jun 16, 2008)

Well, this is what I ended up with:
2 blowers mounted just above the air outlet from the charger. 

I enlarged the hole behind the license plate to increase air flow. 

The air flow comming out from behind the license plate is about what a 4" computer fan would blow with no back pressure. I think this will make a big difference. 

The fans run off a power supply which runs off the 120-240vac, it can also run off the 330vdc if I need a backup DC-DC. The power supply also energizes a relay which will disable my motor controller, I accidently drove off with the plug still inserted last week =)

I also added a relay to switch my Iota into 14.3 volt mode when the ignition is on, with the key off it gets set to 13.8v.


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## etischer (Jun 16, 2008)

I added one of these thermostats so the fan only runs above 80 deg F. 

Contacts are rated 15A 120VAC

Hoffman part number A-TEMNO
$44 on ebay.


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## O'Zeeke (Mar 9, 2008)

DT, I always thought you had a good reputation. We have Battery Management , but Reputation Management ?
Quote:
Originally Posted by *dtbaker*  
_mmmm, perhaps if you can create a duct to the charger intake fan from the side where it won't get much dirt/water splashed up to it, and just drill a couple small holes from box to vent outside... it would only come on when charger was running, and no extra fans or wiring required! The flexible dryer vent ducting is pretty easy to work with and tape using the aluminum 'duct tape'. You could add some 'swamp cooler' filter material, or perhaps use a small air intake filter like used for the heat/cool system._


Written genuine & good replied by you thanks.I am happy for your good suggestion
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## JRP3 (Mar 7, 2008)

Spam bot reported. So lame.


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