Building an EV that can handle the dirt

Open for any sort of non-technical discussion regarding EVs
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BushBryony
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Building an EV that can handle the dirt

Post by BushBryony » Tue, 28 Oct 2014, 03:41

I live in the bush and want to switch to an electric vehicle, but none of the commercial models seem to be at all suited to dirt tracks or bootloads of stuff. Does anyone know if there's a fundamental problem with converting an AWD wagon to electric? Or do you have any suggestions about models that would lend themselves to conversion?

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jonescg
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Building an EV that can handle the dirt

Post by jonescg » Tue, 28 Oct 2014, 04:11

Outlander PHEV? Otherwise some all wheel drive SUVs have been converted like a RAV4.

I ride my Honda Blackbird up some pretty rough tracks, and it's OK with it despite not being made for the job... to a point anyway.
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Richo
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Building an EV that can handle the dirt

Post by Richo » Tue, 28 Oct 2014, 20:42

One of the issues I see is most of the conversions are still DC.
The DC motors are open so will get full of dust, dirt, mud and water.
Not good.

So if you were planning to convert an AWD wagon for off road then I would suggest an AC motor.
Without putting anything(batteries) in the back wagon area you would have plan carefully to be able to get 100-150km max range out of it.

It still isn't practical to change to 4 motors.
You will need to used the existing gearbox+transfer box.

It's more likely that any pre-2000 Subaru would be fine.
Just dont expect WRX performance out of it without spending oodles of dosh.

Other than that it's pretty much like any other conversion.
So the short answer is NO but the long answer is YES.
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BushBryony
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Building an EV that can handle the dirt

Post by BushBryony » Wed, 29 Oct 2014, 01:40

Thanks, I'll chase those leads.... didn't even know EVs could be AC! Are commercial models generally AC? I assume if you built a dirt proof housing (ha! no such thing) for a DC motor it would overheat?

The next challenge will be how to charge it off a standalone solar system. Why don't EVs have panels on the roof and bonnet? I guess the amps wouldn't be there, but surely it would help?

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Building an EV that can handle the dirt

Post by Gabz » Wed, 29 Oct 2014, 03:41

BushBryony wrote: The next challenge will be how to charge it off a standalone solar system. Why don't EVs have panels on the roof and bonnet? I guess the amps wouldn't be there, but surely it would help?


Nissan leaf actually has one it chargers the 12 volt battery it's on the spoiler somewhere.

your right there isn't enough room to make viable enough that you don't need the grid.

ford made a concept
http://insideevs.com/ford-c-max-solar-energi-concept/ but it has to move during the day and some sort of solar concentrator to charge the car fully

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Building an EV that can handle the dirt

Post by 4Springs » Wed, 29 Oct 2014, 13:33

You could put a snorkel on a DC motor I would think. It just needs to let plenty of air in and out. But there are many advantages with using AC. The biggest disadvantage is the cost of the controller used to drive them. I think all modern commercial EVs would be AC wouldn't they guys?

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Building an EV that can handle the dirt

Post by Bennothemad » Wed, 29 Oct 2014, 13:48

Maybe a snorkel would work, but you'd have to have the entire motor encased in a watertight box which would probably:
A. Not be as watertight as intended
and B. cause a heap of overheating issues going slow.

I think the added complexity of putting the engine in a watertight box with a workable cooling system would make you wish you had an AC motor.

...Maybe if you had an extraction fan to create low pressure in the motor box,assisting ram air at low forward speed; and a non-return valve to stop water ingress from the extraction port when it's submerged - which would be tricky as you'd have to do a lot of math to get a spring with the correct K value to not close up at low speed but to still close when water is trying to come in. It would also be susceptible to foreign object damage due to the nature of its location and intended function - you'd have to inspect it on a regular basis for spiders, and every time it was submerged.

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Building an EV that can handle the dirt

Post by BigMouse » Wed, 29 Oct 2014, 19:38

Yeah, all modern EVs are AC. Even in the 90's they were AC. The only people using DC are DIY'ers because of the easy availability of forklift motors (hint, you can also get AC forklifts).

I posed the question on here a while back about Subarus as EV candidates. Apparently the configuration of the transmission/engine block interface is such that it necessitates a very big/deep adapter plate. The flywheel is recessed relative to the mating surface of the engine block, not protruding like most cars. If you're skipping the clutch, you might not have to worry as much about it.

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Building an EV that can handle the dirt

Post by T1 Terry » Wed, 29 Oct 2014, 21:47

Jack Rickard had a conversion on an SUV using twin DC motors that he force cooled using electric turbo units into an adapter that otherwise sealed off the air intake/brush end. Adapting this approach to a snorkel air intake, a sealed motor compartment with air exit vents higher than the intended deep water crossing level could work well for a DC motor. The pressurised motor compartment would keep the dust out, the same way as pressuring a caravan to keep it dust free.

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Building an EV that can handle the dirt

Post by Bluefang » Thu, 30 Oct 2014, 00:27

Or you could build the car using BLDC systems. 4 motors, one per corner is the ideal solution. Water cooled BLDC motors are available and so are controllers capable of powering those motors to peaks of ~100kw. If you want i am more then happy to help you with a build or even do it for you at pretty close to cost price. Even going for a positive pressure air cooling system would be relatively easy as T1 Terry suggests.

Either way the cost of batteries for the range is probably going to be the highest cost.
Solar pannels on EVs are for climate control fans.....thats about all they are useful for at that size. :) I have one on my 1974 Merc 450SLC.
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Building an EV that can handle the dirt

Post by jonescg » Thu, 30 Oct 2014, 00:31

Four motors means four controllers right? Could add up, but the smaller the motor the cheaper the controller.
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Building an EV that can handle the dirt

Post by Bluefang » Thu, 30 Oct 2014, 00:39

Doing around 50kw per motor system would be around $3000
Trying to get to 100kw per corner $5000
Full variable regen and high efficiency
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Building an EV that can handle the dirt

Post by BushBryony » Thu, 30 Oct 2014, 14:53


Solar pannels on EVs are for climate control fans.....thats about all they are useful for at that size. :) I have one on my 1974 Merc 450SLC.[/QUOTE]

Damn. Sometimes our car sits for days in the sun between town trips. Are the batteries for an EV like house batteries, in that you really need to whack them with some amps to get them to 'float'(full charge)? Can you trickle feed them over longer periods?

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Building an EV that can handle the dirt

Post by BushBryony » Thu, 30 Oct 2014, 14:58

Bluefang wrote: If you want i am more then happy to help you with a build or even do it for you at pretty close to cost price. Even going for a positive pressure air cooling system would be relatively easy as T1 Terry suggests.


Interesting. I certainly don't have the know-how to do it myself. So many considerations to weigh up!

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Building an EV that can handle the dirt

Post by Bluefang » Thu, 30 Oct 2014, 15:56

If you do play around with chucking a solar panel on the roof of your car i suggest just linking the pannel direct to the fan, dont try and run it to the car battery as it will be more likely a drain on the battery rather then useful, you only want it working when its sunny anyway. Use a brushed centrifugal fan as this will work even in shady areas vs a brushless fan that will only come on after a certain power is achieved and needs a higher start up current then running. I have a relay that switches it off when driving.

EV lithium batteries can accept any charge you want to send them, they can quite happily be trickle charged, but please realize that a electric car will take about 3x the daily energy usage of your house to go 100-150km. Could be more of less depending on how much solar you have vs your actual house usage.
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Building an EV that can handle the dirt

Post by Richo » Thu, 30 Oct 2014, 21:04

Most cars are not setup for 4 motors in terms of structural mounting.
It can be done (in and ideal world) but you WILL need deep pockets.
Which is why I said it's not practical.
So the short answer is NO but the long answer is YES.
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Building an EV that can handle the dirt

Post by Bennothemad » Thu, 30 Oct 2014, 23:45

Really, is anything about converting from ICE to EV practical? "Practicality" and possibility increase in direct proportion to your bank account.

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Post by T1 Terry » Fri, 31 Oct 2014, 03:29

Bennothemad wrote: Really, is anything about converting from ICE to EV practical? "Practicality" and possibility increase in direct proportion to your bank account.

Image I think that line belongs as your signature, never a truer statement made
My big bus project, even though it will be a hybrid, will be solar powered, 3kW acting as a summer roof, but being our hose on wheels means we can park up for 3 days or more to recharge.
you could connect thin film panels in a small grid to power the 12v aux battery and use that to power a 240vac inverter to trickle charge your EV battery using upper and lower voltage level control for the inverter to protect the battery from damage in place of any other form of solar regulator, basically a direct connection to the battery. It's highly unlikely you would ever reach fully charged on the EV pack this way so it would be a form of dump load regulation.

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Building an EV that can handle the dirt

Post by BushBryony » Fri, 31 Oct 2014, 14:37

Thanks everyone for your kindness to an ignoramus, and your generosity with information. I'm going to go away and mull over what I've learned. The short trips, the watts and time needed for recharge, the size constraints and the big cost are all things I need to weigh up.... the stakes are higher when your nearest neighbour is a kilometre away and you might need to get out in a hurry before a bushfire comes, for instance. I'm going to see what I can learn about chip fat conversions.

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