# What design considerations for extreme temperature climates?



## electricdominic (Apr 3, 2012)

Bump :beer:


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## Ziggythewiz (May 16, 2010)

Houston is extreme temps for people, but Phoenix would be more extreme for a machine.

Any form of cooling relies on the difference between your equipment and ambient. It won't be possible for you to keep your stuff under 120 F, but keeping it under 200 F won't be much harder than it is elsewhere.

You'll probably want to route your AC to your battery box(es).
Also, don't undersize anything as larger things take longer to heat up and can dissipate heat better.

What are your performance requirements?


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## piotrsko (Dec 9, 2007)

my $.02: if you need to be comfortable, the car should be comfortable, too. Although at 120 degrees, the only thing that should happen is that you hit thermal limits really fast and you can't really transfer heat as good as on a 70 degree day. We did radiate heat into space on the satellites, but it took relatively huge heat sinks.

beer helps, but my car gets drunk way to fast to be useful.


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## tomofreno (Mar 3, 2009)

electricdominic said:


> I live in Phoenix, AZ where we can have 30+ days of 110F days and we average 169 days of 90F and over. Sometimes in the summer the low temp doesn't even get below 92F. So my garage usually stays in the high 90s on those nights.
> 
> I see water heaters for EV's. I presume these are for cold climates. However....
> 
> What design considerations should I take into account for Phoenix's extreme temps?


 I would be concerned about the cells if you use LiFePO4, since I've read the electrolyte breaks down at 50 - 60 C (122 - 140 F) and coats electrodes with LiC4, LiCFx,... causing a loss in capacity and higher cell resistance. The later exacerbates the heating problem due to increased internal power loss.


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## mizlplix (May 1, 2011)

I am in Queen Creek (the Phoenix East Valley area).

My battery boxes are lined with 5/8" plywood and sealed (for insulation). They have 3" diameter, screened air inlets in front, with 3" turbine ducted fans in the rear to pull cooling air over the batteries (they run charging and driving). Ditto for the winters. (insulation works both ways). An insulated pack just off the charger is really good-to-go thermal wise, here, winter and summer. I just slap duct tape over the air inlets for winter (and shut off the fans driving) or run the fans in summer.

I anticipate no problems at all with over heated batteries, but I am installing thermisters in each battery pack in one of the interconnect bus bars to give me a representative thermal indication. 

I have an AC50 system and Curtis 650 amp controller. There again, anticipate no heat issues, although the controller IS water cooled and I feel it would be marginal on just air alone..

A friend has a curtis 500 amp controller/8" motor combo that is air cooled...He is running on the edge controller wise even with a 1" heat sink with 4" fins, mounted in the car grille area.

Charger wise, they need a fan on them. Either get one with a fan or buy a stand alone fan for it. I have had charger shut downs in the summer heat, even in the shade without forced air.

We are not dealing with 130C water or 700C exhaust temperatures anymore. This is a lot easier to deal with.

As in everything here, it is not so much the ambient that is the issue, it is the heat transfer speed with the cooling media sitting at 110-120 F. that hinders cooling.

Miz


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## Conelrad (May 23, 2009)

I am glad you started this thread. So much of the country and so many folks have no knowledge of our climate and what it does to things.

From paint advice to gardening, what they say and think just doesn't fly out here. 

Snowbirds (AKA winter visitors) come out here for the good weather, maybe driving a black car with black seats and no A/C. Then a few figure on making it permanent, and wonder why nobody would take their car as a trade-in on a golf cart...

Our biggest draw, other than propulsion, is the HVAC aspect of a car for at least 9 months of the year. Compressing refrigerant is indeed a necessary way of life when the natural daytime ambient in a locked car is about 160F.

Living here all my life, it seems normal. Soldiers from out here going to the Middle East find the climate no big deal.

I always pitied drivers with 60's vintage Brit cars...boilers on wheels.

Dennis in Hidden Valley, 35mi S. of Phoenix.


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## bjfreeman (Dec 7, 2011)

Then there is Death Valley. Swap Cooler work the best.


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## Conelrad (May 23, 2009)

Evaporative coolers are very viable other than in July & August. The relative humidity goes too high for them to work.

Usually they work alongside an AC unit, called a 'piggyback'.

A swamper in a car would be tough with all the movement.

DG


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## bjfreeman (Dec 7, 2011)

over 60 yrs ago we had a swamper on the rider-side of our Buick, when we lived in the Mojave Desert.


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## Conelrad (May 23, 2009)

I remember those on cars then. Looked a lot like my mom's vacuum cleaner hanging out the window.

Nobody thought they were adequate, more trouble than they were worth. Salt streaks down the side of your car, always having to add water. Sitting at a light, they stopped working. Absolutely worthless in July/August.

As soon as AC was factory available, they disappeared off the landscape.

I'll pass.

DG


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## piotrsko (Dec 9, 2007)

actually they didn't disappear, the bug guys still use them, sort of. When A/c takes 10 + HP out of a 50 hp max engine, there isn't a lot left. But it is also a fashion statement, too.


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## mizlplix (May 1, 2011)

They are easy to make, you can convert an old Electro-lux vacuum cleaner housing. I have seen several.

Miz


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