How would you build an AATV,(amphibious 6 wheeler)?

JRP3

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Greetings all. I'm contemplating an electric conversion of an AATV such as a Max, Argo, Attex, etc.
http://www.maxatvs.com/
They weigh around 700lbs, use anything from a 16-25hp briggs type motor, and a T-20 skid steer transmission and chain drive to the wheels. I'd be happy with 15 mph top speed and an hour or so of run time. I was considering an etek type motor, maybe a brushless etek or something, but don't know if that would be enough motor for my requirements. Maybe 36 or 48 volts, Alltrax or Curtis, Kelly for the brushless? I'm new to all this so please keep things dumbed down :oops: What are your thoughts?
 
That's pretty big. At least you should have room for batteries, although too many lead-acids and the thing won't float anymore :eek: .

The new Etek-R looks like it would be in the ballpark, perhaps two of them. You could possibly run two of them off a single controller. These just came out, so we don't know how reliable they are. The old Etek (if you could find any) or a Perm 132 are in the same power range, but are more expensive.

The Mars motor might work too, but the peak power would be a bit less. You cannot run two Mars motors off a single controller (easily). You would need two controllers if you went with dual motors.
 
Since this is my first EV I want to keep this simple, so I think I'll stick with 1 motor. I suppose ideally you could have 6 motors, one for each wheel, and get rid of the transmission and chain drives, but that might be a future project. Attex made an EV 6x6 back in the 70's and they claimed 4 hours run time with 6 12volt lead acids. I don't need 4 hours so I'm planing on using 4 12volts, haven't decided on amp hours yet.
I've seen brushless Eteks for sale but I guess they would be harder/more expensive to control?
 
That is a pretty big vehicle and for off road use you will need a lot of power/torque. you may want to look at a golf cart size motor. Here is one that is used as a replacement for the GEM car (it's a NEV or Neighborhood Electric Vehicle that goes 25 to 35 mph) and this motor is not too expensive.

http://www.electricvehiclesusa.com/product_p/mo-gem7.5-1.htm
 
Looks like that motor takes a special, (probably expensive), controller. Also it says it's a 7.5hp motor while etek types are higher than that, aren't they? Yes it's a heavy vehicle but can't I use gearing to over come that, since I don't need top speed?
Here's a link to the factory Attex, kinda short on specs:
http://www.6x6world.com/images/brochures/Electric-Attex%20-six-wheeler-1.jpg
http://www.6x6world.com/images/brochures/Electric-powerred-attex-6x6-amphibious-atv-2.jpg
 
JRP3 said:
Looks like that motor takes a special, (probably expensive), controller. Also it says it's a 7.5hp motor while etek types are higher than that, aren't they?
Etek is rated for 8hp continuous at 48 volts (20 HP Peak) so from a horsepower standpoint they are in the same ballpark a better motor than the GEM motor might be this D&D motor it is also 8hp continuous at 48 volts. You see these D&D motors a lot in golf carts and small electric cars.

http://www.electricvehiclesusa.com/product_p/mo-es-33.htm

It's not that I have anything against the Etek but I think that they may be better suited for smaller EV's like Scooters, Motorcycles, and small ATV's - Also it is sometimes hard to find the Etek (most suppliers are "out of stock" on the Etek).

Your AATV may run just fine with the Etek but you may burn out the motor quickly. I think that may be why fechter suggested using two of them.

Another option is the Perm-Motor PMG-132 (often called an Etek replacement) it is a little more expensive but it can be run at higher voltages. Problem is that you don't get 8hp until you go to 60 volts. Here are the specs on the PMG-132

Peak Efficiency:
2.2 KW @ 24 volts, 1080 RPM, 2.94 HP
3.5 KW @ 36 volts, 1700 RPM, 4.69 HP
4.74 KW @ 48 volts, 2300 RPM, 6.35 HP
5.97 KW @ 60 Volts, 2870 RPM, 8 HP
7.22 KW @ 72 Volts, 3480 RPM, 9.7 HP
 
Thanks for the breakdown. The PERM is a bit more than I'm looking to spend, plus the voltage issue. That D&D looks like a good possibility. The E-TekR looks good too, but I'd rather not burn it out if it's not up to the job. :oops:
 
Dammit, somebody test out that Etek-R! I want to know if it's up to snuff! :evil:

Seriously, though, that probably is one of your best options. Two of them, I mean. If one (I'm assuming it's at least close to the original Etek) is enough to move a 400lb motorcycle at 45mph+, two should be able to move a 700lb...thingy...at 20 with killer torque. AND two of them will be more powerful but cost the same as a PMG-132. You might be able to get away with one motor if you gear it right.

I would imagine (meaning I'm taking a WAG) that four or five 12V 100Ah batteries might be up to it.

How much does the engine (and associated parts) weigh? Figure you can replace the weight of the engine with an equivalent in batteries.

Though you're going to spend a lot on batts. Those 100Ah ones I mentioned were something like $220 at my local electronics place. Add in the two motors, controller, and whatever else you may need and you could well expect to pay over $2,000.

EDIT: Read the part about six motors being a future project!

Holy crap! :shock:

That's, what? 90,000W!? 120hp worth of motor on a 700lb craft!? I would expect over 100mph if you did that!
 
Holy crap! :shock:

That's, what? 90,000W!? 120hp worth of motor on a 700lb craft!? I would expect over 100mph if you did that!

LOL, no, that would be insane. I meant 6 smaller motors. That's just a fantasy at this point since I've never built anything with even one electric motor.

Maybe I'll start out with on EtekR and see how that does, or the D&D. I can always add another if I really need more, but I'm really just looking to creep around the woods and haul some firewood. Depending on which 6x6 I find it could weigh only 400 or so pounds so a single motor would definitely be fine in that case. I just need to find the right 6 wheeler, but they aren't that common so I'll have to take what I can get.
 
Argocat on ebay.. http://cgi.ebay.co.uk/ARGOCAT-for-spares-or-repair_W0QQitemZ120209935165QQihZ002QQcategoryZ18449QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Too many wheels for ya?
 
Jozzer said:
Argocat on ebay.. http://cgi.ebay.co.uk/ARGOCAT-for-spares-or-repair_W0QQitemZ120209935165QQihZ002QQcategoryZ18449QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
Too many wheels for ya?
Yeah, moving 6 of them will be enough. Plus it's on the wrong side of the Atlantic for me, shipping would be brutal :mrgreen:
 
Uh, what are you wanting to be creeping around in the woods for??? :shock: j/k man. Good luck with your project. :lol: :lol:
 
Ok I'm re-thinking the Etek-R. I don't know if it will be enough for the vehicle. The original ICE in these machines only weigh about 100 lbs, so even with an Etek-R I'm only saving about 75lbs at most, with the D&D only about 50. Then toss in 2-3 hundred pounds of batteries and I'm close to 1000 lbs, then I want to be able to tow a trailer with a few hundred pounds of wood up a steep hill about 50 feet long. Also the rolling resistance of 6 balloon tires. Yeah, I think I need more motor :cry:
 
It depends on how fast you want to go. I'm sure an Etek will pull that thing fully loaded up a hill, but really slow with the right gearing. Of course "really slow" isn't much fun. Even the golf car motors might be a bit on the small size, but with the right gearing could push a tank.

A fully loaded golf car is going to be in the same ballpark weight wise. Lots of lead.

Any bigger than that, and you start getting into really expensive motors.

For something like that, some kind of multi-gear transmission might be needed. Low gear for climbing hills, high gear for flat or downhill.
 
I read what fechter said about using gears and then I began to wonder what kind of transmission a vehicle like this has? So I went back to the link and read that is uses a T-20 Skid Steer Transmission.

Well I had no idea what a T-20 Skid Steer Transmission was so I did a Google search and I found this webpage

http://www.oasisllc.com/english/max.htm

This site had some cool information and these pictures

Here are the general parts Looks like they use a torque converter between the engine and transmission
max_parts.jpg


Here is the transmission
max_transmission.jpg


The smallest engine that they use in this vehicle is the Vanguard OHV 14hp 4-cycle Twin Cylinder engine. Here are some of the engine specs. The power output is 14 hp @ 3600 rpm and it has 22.5 ft lbs of torque @ 2100 rpm

So you need and electric motor that can match or come close to matching those numbers. You might even be able to connect the electric motor right up to the existing torque converter.
 
Since I have nothing to do anyway and this 6 wheel vehicle sparked my interest I kept looking and found out that there is a Forum specifically for owners of these 6X6 amphibious vehicles. and on that forum I found this thread where someone was rebuilding one of those T-20 Transmissions and it even has pictures of the inside of one of those T-20 Transmissions. +

In case you're interested here is a link to that thread.

http://www.6x6world.com/forums/aatv-transmission-articles/1460-t-20-skid-steer-transmission-rebuild.html

If you are going to go forward with this project you might want to join this discussion group. They may be able to give you some more tech tips about this AATV.
 
Thanks, I'm already a member there and that's actually where I started talking about this idea. I came here to get more info on the EV angle :D AATV's do use a snowmobile type torque converter but I was thinking about removing that because of transmission losses and belt slippage, and just using fixed sprockets. That may not be a good idea, I just don't know for sure.
I may also have a line on a good deal on a bigger motor 8)
 
To further expand on what power is needed, I assume the power required is different since an E motor produces torque from startup whereas an ICE needs to get RPM's up to get torque. That's why I was thinking I don't need the torque converter.
 
Yup. They do, and lots more than an ICE.

If i were you I'd ditch the torque converter. Anything sized for a vehicle is very inefficient. As far as I know, the most efficient torque converter you can get today is the NuVinci, but that's made for bikes, and even some of the more powerful motors on here would break the thing. An Etek or Etek-R being far more powerful than even those. And remember, motor hp is generally more than engine hp.

Gearing an Etek low enough to go 15mph tops will really give you some pulling power. I don't know if it will pull a 1000 lb thing up a 50% grade (can you believe I used to have to drive up one to get to my house?) but I should think it would be more than enough for the flats and smaller hills.

I must say, that is a very odd transmission.
 
Actually that was a 50 foot long grade, probably more like 30%, narrow trail with a bit of side tilt too, but yes, it is a scramble. I did it with a 4 wheel drive Polaris and had to get a running start to make it all the way with the trailer full of wood :shock:
 
Holy crap, man. Is that a modified WarP? Definitely ditch the torque converter if it is, 'cause that might just snap it in two.

Incidentally, is that one of the ones that can be switched between series and parallel windings?

How much you land it for?
 
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