# Heavy rain + EV = ?



## Tony1M (Feb 21, 2009)

Please forgive me if this is not the correct forum to post this question. If it is not, I hope a moderator will move it to one where it is.

Our 2.2-litre Accord's engine compartment sometimes gets wet when we drive in heavy rain, hit puddles, etc., and sometimes snow gets in there, too, when snow is light and fluffy. 

I understand that H2O + electircity don't mix very well. 

What effect, if any, does significant moisture have on an EV's components - batteries, motor, and the rest? More specifically, can you drive an EV around in a heavy rain storm, as you can with an ICE? Should one take any precautions at all?

Should one try to somehow make an EV's engine compartment "weather tight"?

Thanks.


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## Technologic (Jul 20, 2008)

Tony1M said:


> I understand that H2O + electircity don't mix very well.
> 
> What effect, if any, does significant moisture have on an EV's components - batteries, motor, and the rest? More specifically, can you drive an EV around in a heavy rain storm, as you can with an ICE? Should one take any precautions at all?
> 
> ...


Well certain components can probably be fine with some weather on them...

Really though controllers etc should be kept in decently weather tight "boxes". Boxes for car batteries (plastic boxes and stuff) work just fine for this purpose.

In general a lot of EV components can get wet without major issues... Just want to keep them off the charger, any BMS, or controller... the leads are small so treat them how'd you'd treat any traced circuit board (like a computer)


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## Tesseract (Sep 27, 2008)

Tony1M said:


> ...
> What effect, if any, does significant moisture have on an EV's components - batteries, motor, and the rest? More specifically, can you drive an EV around in a heavy rain storm, as you can with an ICE? Should one take any precautions at all?
> 
> Should one try to somehow make an EV's engine compartment "weather tight"?...


Excellent question! One of the things I noticed about every existing DC controller out there (including the Zilla) is that they have absolutely no "Ingress Protection" (see: http://en.wikipedia.org/wiki/IP_Code ). I don't think it's necessary to protect against full immersion (well, unless you like to drive through floods...) but anything mounted under the hood should be able to withstand incidental (splashed/sprayed) water. In other words, rated for IP54 at a minimum.

Same with every DC motor I have seen being used in an EV (I have not seen them all, obviously, so there's a disclaimer for you). The stator is made of steel and though it is typically dipped in lacquer of some sort, it will rust like hell if water, especially salt water from de-icing, gets into it. Likewise, the brush/commutator can get all scratched up from grit... Fortunately for the motors, anyway, you can buy or fabricate cover bands to fit over the ventilation holes with a single exhaust port on one end and a blower on the diagonally opposite. This cools the motor effectively AND creates positive pressure inside it to prevent incidentally ingress of water/salt/grit/sand.

Just my $0.02 on this...


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## Greenflight (Sep 13, 2007)

Yeah, it is a good idea to have some splash protection. I didn't go to the trouble of waterproofing my engine compartment but I did put a little extra thought into component placement. I've driven my truck in pretty heavy rain and deep snow without any problems whatsoever.

The more thorough your waterproofing is, chances are your car will be more reliable.


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## Tony1M (Feb 21, 2009)

Thanks for the replies, guys.

The reason I started this thread is that I live in Edmonton, Alberta, which is a place that has hostile weather, to say the least. For example, as I sit here typing this message, it is -26C (-14F) and the low for the next two nights is going to be -29C. 

When it warms up a bit, the roads will get extremely slushy with salt-laden puddles, ruts, etc. Ugly, ugly, ugly, for any vehicle.

On the other side of the weather coin, it can get well above 30C (86F) during July and August.

I short, Edmonton is a place where automobile "torture tests" could be conducted. The fact that our 92 Accord has survived (albeit with my careful maintenance) is a testament to Honda's engineering and manufacturing ability in 1992. (Sadly, new Hondas are not built to anywhere near the same quality and reliability standard.)

Anyway, I would love to buy or build an EV, with Lithium, but before taking that expensive plunge, I must determine as best I can whether an EV could practically survive in Edmonton's weather conditions. We have an attached, insulated garage, but it is not heated, and I really don't want to change that. It sometimes gets below freezing in there. 

How practical do you think it will be to operate and maintain an EV in Edmonton's weather conditions? Please keep in mind that my wife and I are not masochists.

Thanks again.


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## Voltswagen (Nov 13, 2008)

Tesseract
Thanks for that explanation of "cover bands" and forced air cooling.
I had early on in my build floated the idea here of enclosing my motor in a large clam-shell and fan forcing cooling air thru it which could be plumbed to the passenger cabin for a little heat.
This would cool the motor and thereby reduce the amp draw and also protect the motor from road splash.
But many here panned the idea saying it would heatup the motor for various reasons I couldn't understand.
Now that I know its available commercially.....despite their objections....I will fab one of my own.
Thanks for that -
Roy


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## Duncan (Dec 8, 2008)

Hi Tesseract,
Just want to put my tuppence worth on waterproofing,
I worked in production engine test for many years and I came up with a strategy

-Unless you can waterproof something so I can go scuba diving with it - Don't

What I found was that the problems were not water so much as retained water
The best solution was lots of drain holes and nothing that would retain the water.

Most forms of waterproofing simply retained the water and caused failures


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## Tony1M (Feb 21, 2009)

I don't think that waterproofing has to be what most people think it is. I think all that's really needed is some sort of tightly-woven, long-lasting fabric that could be installed at the bottom of the engine (motor) compartment, between "the weather" and (not touching) the motor and other electronic components. 

The fabric would simply block (catch, "filter") and even absorb, big and small water droplets from the air and, when it is saturated, shed them to the road by simple capillary action (as a water-soaked rag does when it is hung up to dry). In theory, the wetter the fabric gets, the fewer airborne droplets it will allow to pass. 

In all weather conditions, even heavy rain, the engine compartment _should_ remain free of droplets, but still well-ventilated (although very very humid). 

When the heavy rain stops, the fabric dries. 

One could test this theory quite smiply by directing the ouput of a garden hose, (adjusted to a "spray" pattern) at a high-thread-count bed-sheet that is hanging vertically. A person standing on the other side of the sheet _should_ remain relatively dry, while the vast majority of water _should_ cascade off/through the hose-side of the sheet to the ground. (I leave this test to the lucky warm-winter-climate folks.)

Dust is a comletely different matter, but components should be less dirty than they would become without the fabric installed.

Sound good?


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## Greenflight (Sep 13, 2007)

Dust isn't a huge concern... Unless you have relatively large particles getting into the contacts of your main contactor you shouldn't have any problems. Electronics can take a surprising amount of crud... I've taken a lot of electronics apart and I can say that my car's engine compartment, after 4,000 miles of driving, pales in comparison to your average laptop motherboard as far as the amount of dust it accumulates. 

Figure in that most EV electronics use DIP through-hole parts vs. the SMT parts with absurd pin spacing found in consumer electronics, and it's easy to see that most of the stuff in your car is pretty resilient.

I use forced air cooling directly to my motor and I haven't had any com problems either.


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## aktill (Jun 18, 2008)

Ewww...Edmonton? My condolences...  (Howdy neighbour)

There's at least one person that's operated an EV in Edmonton, and one in Calgary. Definitely doable, just plan on insulating your batteries and doing a bunch of water sealing.

I'm building one myself, and plan on pretty extensive weatherproofing. The first stepup will be laying up a fibreglass floor for the hood, which I'll be starting in a short while. I can let you know how it goes.

Good luck!
Adam


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## Tesseract (Sep 27, 2008)

Duncan said:


> ...
> -Unless you can waterproof something so I can go scuba diving with it - Don't..


That is definitely a valid argument, Duncan. IP54 is probably not good enough for under-hood use in a vehicle... Whether it is worse than no ingress protection at all probably depends more on luck than anything else. That said, IP67 would be much better for the automotive environment as it'll withstand some immersion, just not scuba diving depths!. You pay a huge cost penalty for any connectors that are sealed to IP68, though, while the alternative of putting in weep (drain) holes will result in accelerated corrosion from atmospheric pollution/humidity unless conformal coatings are used, and those have their own pathologies depending on the type.

Still, I won't disagree with you that there is merit in *not* sealing an enclosure...


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## JRP3 (Mar 7, 2008)

I'd say "seal" it enough that splashes can't get on anything but allow draining at the lowest point and some protected air flow. A belly pan/splash pan can serve double duty by smoothing the airflow as well as water protection.


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