# Another E-ATV build



## copperheadroad69 (Nov 27, 2013)

I'm still trying to get my head wrapped around building an electric ATV. I have searched the forums over and over and I find that everyone has such varying criteria it's hard to gauge. 

I have a Yamaha Warrior I want to use as a donor, after engine removal and some lightening I'd like to have it in the 180lb weight range to begin. I weigh 200lbs.

My needs are straight forward, I simply want an inexpensive rout to get my feet wet in the E-ATV experience. I am simply looking for a build that can travel maybe about 7-10 miles at about 10MPH. No excitement just forest transportation. Does anyone have any suggestion on my minimum requirements? Would one of these Chinese kits be out of the question? http://www.monsterscooterparts.com/36-volt-1000-watt-motor-controller-throttle-kit-standard.html Would it power the ATV, what would it get me?

Batteries, capacity?

This may be a very redundant post for which I apologize but it's just a lot to decipher. Thanks!


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## tylerwatts (Feb 9, 2012)

Budget? I'd recommend to get started get a small forklift pump motor and altrax controller and deep cycle batteries, or simpler would be an old forklift with torque control drive or similarly an electric golf cart to strip the motor, controller and batteries from. 10mph is fine but torque will be required for forest use so will eat up efficiency. I'd suggest working from 500wh/mile, maybe more, and double that for a lead acid battery pack. So 10 miles is 5kwh doubled is 10kwh which is big. 

Maybe I'm being excessive with the efficiency. Can anybody suggest from experience? 

If you have high enough gearing and modest acceleration then you can probably reduce the consumption given the light weight of the vehicle, so going to 300wh/mile is 6kwh pack which at 48V would be 125ah cells x 4. Not excessive. See what you can get your hands on locally first at a lie cost as this will dictate alot how you do things.


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## major (Apr 4, 2008)

Hi copp,

I suspect you'd be disappointed with that cheap Chinese motor kit. Maybe look at doing something like this guy. http://www.equadsandkarts.com/equad/default.htm On the battery; 300 (or 500) Wh/mi is like the energy usage for EVcars. A slow small EV might be around 100Wh/mi. So for 10 miles figure 1 kWh. Depending on the quality of the build, terrain, conditions and battery type, double that at least. Look for maybe 2 to 3 kWh.

My little eTractor can do 10 mph and I'm pretty sure will go 10 miles. It uses an old 6" diameter floor sweeper motor, Curtis 1204 and 3 kWh battery. 

Search for electric ATVs on google, evAlbum, etc to see what others have done. Small EV builds like this are an excellent way to get into the DIY EV hobby.

Good luck,

major


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## copperheadroad69 (Nov 27, 2013)

Thank you guys! What Are some options for 2-3kWh battery supplies? In terms of lead acid you would simply be looking at 4 smaller car batteries would you not?


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## tylerwatts (Feb 9, 2012)

Lead you would want at least 50% more capacity IF you only draw 1c (equivalent of the rated ampage) from them, so volts x amp / hours = P x 1.5. If you are going to want more current for torque in tricky or sticky terrain, read mud, rocks, steep climbs etc, then you need to double the capacity so P x 2.
Therefore at a reasonable 48V you need 125ah batteries for 3kwh of useable range. So 4 125ah ish deep cycle batteries or traction batteries like from a forklift or golf cart. 

This is why I suggest using all the drive from a cart, everything is there for your needs...


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## major (Apr 4, 2008)

Try 16 LiFePO4 cells at 40Ah.


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## tylerwatts (Feb 9, 2012)

That also but a bit pricey for a learning build especially with a modest range like that.


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## major (Apr 4, 2008)

tylerwatts said:


> That also but a bit pricey for a learning build especially with a modest range like that.


A list price for a 125Ah AGM is $260. So times 4 is $1040. At $1.25/Ah, the LiFePO4 would be $800.

The 4 Pb-Acid batteries come to 300 pounds. 16 LiFePO4 cells come in at 52.8 pounds.


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## tylerwatts (Feb 9, 2012)

I apologize Major, and Copper. Your reasoning is sound and would be my preference also. I was only a bit hung up on recycling a golf cart for low cost and learning. The LiFePO4 cells would offer good performance and Max 2.5kwh which would mean more realistic 2kwh for longevity of the pack but with that weight may be plenty. 

Copper, I'd recommend using small pick-up all terrain tyres for less resistance than quad knobblies to help the range. And a good gear reduction to mean you don't need too much current to get decent tractive torque at the wheels.


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## elevatorguy (Jul 26, 2007)

I converted a Warrior as my second ev, I used lead acid batteries and some used parts from ebay etc. I used 75AH batteries and built it for speed and power for fun factor.
If I did this today I would used Lithium and am looking into some used batteries to replace the 6 year old AGMs, it would cost me twice as much but they could last 2-3 times longer and a lot lighter.
I think mine weighs about 500 pounds, with about 200 from the lead batteries.


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## tylerwatts (Feb 9, 2012)

Have you got a build thread or blog or pics anywhere to show us please? Thanks


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## elevatorguy (Jul 26, 2007)

tylerwatts said:


> Have you got a build thread or blog or pics anywhere to show us please? Thanks



http://www.diyelectriccar.com/garage/cars/218

http://www.evalbum.com/preview.php?vid=1174

I never had a blog on that build, I probably have a few more pics


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## tylerwatts (Feb 9, 2012)

Elevatorguy that looks like a great toy. What range do you get typically? Why do you state in the garage a peak of 3kw if the controller can deliver about 30kw?! What performance does the quad give in limited mode? How is this mode set please? Are you looking at lithium batteries for the upgrade? Would you mind sharing the upgrade build in a thread please? Lots of info for copper and others (myself one) and you seem to have excellent real world experience in using it also. 
Regards
Tyler


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## elevatorguy (Jul 26, 2007)

tylerwatts said:


> Elevatorguy that looks like a great toy. What range do you get typically? Why do you state in the garage a peak of 3kw if the controller can deliver about 30kw?! What performance does the quad give in limited mode? How is this mode set please? Are you looking at lithium batteries for the upgrade? Would you mind sharing the upgrade build in a thread please? Lots of info for copper and others (myself one) and you seem to have excellent real world experience in using it also.
> Regards
> Tyler


I guess that was a typo, the real number would be about 23kw, limited by the batteries sagging at 450 amps. The limiting is done by switching a 5k resister into the potbox circuit and limiting to 50%. This is good for first time drivers and economy.
When I do an upgrade I will blog it like the car, but it may be a while as other projects are in the mix as well.
I am looking at 100AH lithium to replace the batteries. and a charger 
As for range, I would guess 10 miles, with no odometer and offroad driving.
I checked current at 80 amps at about 20MPH, so that may be about right.


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## evluv (Feb 28, 2014)

Thanks for the info - I am planning a similar build to this. Short range, just for fun around the yard, and no noise, so the neighbors don't complain!


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