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MazdaMatt 01-22-2009 02:18 PM

EV S10 project budget forcast?
I am tossing around the idea of an S10 conversion. They are a cheap truck that I can easily gain access to and I can sell the unneeded parts for the cost of a truck.

I'm interested in figuring out the base cost (motor, batteries, controller) and the feasibility to cover my needs. Building costs can be considered later.

80km/h for 50km round trip to work
Factoring reality, i could deal with 70km/h, but should account for 60km just in case.

I would LIKE to do a direct drive to lose tranny
I can probably get my hands on whatever final drive gives highest speed for lowest rpm

So step one: what is the tallest final drive?
Step two: What motor has a continuous rpm rating with reasonable tires to go 70km/h
Step three: How many amps?
Step four: how many batteries?
Step five: is DIY controller feasable for me (computer engineer)

Please hep me stay organized and we'll work on each step, one at a time. So... Truckers - what are my options for S10 final drive?

Daox 01-22-2009 03:23 PM

I'd look through EV Photo Album: Our Electric Cars on the Web and take a look at what others built to find something similar. The s-10 is a popular conversion. Typical costs range from a few thousand and up.

Alain St-Yves 1996 Chevrolet S-10 King-Cab
Kent Barnes' 2001 Chevrolet S-10
Wayne Anderson's 1987 Chevrolet S10
Charles Clark, Jr.'s 1994 Cheverolet S-10
Scott Davis' 1994 Chevrolet S10
Mike White's 1982 Chevrolet S-10
Eric C. Krofchak's 1984 Chevrolet S-10

MazdaMatt 01-22-2009 04:25 PM

Thanks, Doax. I will browse through those. I have noticed that S10s are popular, that's why i'm interested in them... not that i'm a chevvy guy :p

MazdaMatt 01-22-2009 04:29 PM

I had a quick click through - not one of those is direct drive. What's up with that?

Ryland 01-22-2009 11:12 PM

their are kits out there just for the s10 so you can buy it all off the shelf and just put it together.
to do a direct drive would make it really clean and allow you to move the electric motor back a bit, but would it change your motor requirements to something that is harder to get? I don't know off the top of my head the gear ratio of the rear end of an s10, or the drive shaft speed at 65mph.

Daveedo 01-22-2009 11:50 PM

2nd gear in an manual transmission s10 is usually around 2:1 (it varies somewhat depending on year and model of transmission). Most EVs tend to use 2nd gear all the time. So if you go with direct drive then you will essentially be in 4th gear which is usually 1:1. To deal with this you'll need to swap to a rear end gear ratio that is about double what stock is. stock is anywhere from 3.08 to 4.11 so you'll need to find aftermarket gears in the 6:1 to 8:1 range which is a major problem.
The pinion ends up with way less teeth which equals less gear contact which means it will break much easier. I see this all the time with offroad rigs swapping in 5.29 5.87 or higher numerical gear sets. They simply are weaker than the lower numerical sets due to the ever shrinking size of the pinion gear (torque multiplication is murder on the axle shafts too). Now think about how much instant torque an electric motor puts out compared to an ICE...SNAP! Axles and pinions likely won't last long if you couple the changed gear ratios in the rear with a direct drive electric motor.

One other thing about the ratios...friend of mine has had many dodge diesels. The ones with 3.29 (or was it 3.23 or 3.08?) gears had higher GVWRs than the exact same model of truck with 4:10s. This is due to the strength issue. Also, this same friend was complaining about breaking his 4:10 dana 70 rear end under normal hauling usage. He swapped in the lower (numerically) gears to try to avoid breakage again.

An option for you is to run very small and short tires which will look better if you lower the truck anyways and run the highest (numerical) gear set that came from the factory (likely 4:10s). The combo of these two things might get you where you need to be gearwise without the aforementioned problems.

MazdaMatt 01-23-2009 08:30 AM

Daveedo, you've got it backwards. Offroaders use high numbers so they can spin up their motors and keep the wheels slow. I need to keep my motor slow and spin up the wheels. Here's what I guesstimate based on an advertisement for a Warp motor I saw the other day... Continuous 5krpm. Given 1:1 to the wheels, a 26" tire (0.66m, i'm going metric), the circumference is 2.07m, so i'd be going 1014m/min ~= 60km/h... so to go 80km/h i need 1.3 wheel revs per motor rev, so that would mean a 0.75:1 real axel... i think i'm in the "that doesn't exist" territory. Crap.

Okay, new thought - why do people leave it in gear? Why i can't I shift gears like a normal car? Is it the "unloaded" overrevving between shifts? Could i just drop throttle, depress clutch, change gear, slip clutch in, get back on throttle?

Daox 01-23-2009 09:41 AM

Most guys don't have a clutch, so shifting is slower and not as easy.

MazdaMatt 01-23-2009 11:41 AM

So why no clutch?

Daox 01-23-2009 11:47 AM

Namely two reasons.

1) motors aren't made to handle the thrust pressure from the clutch
2) easier to make

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