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Reverse trike, need advice for motor, batteries and controll

Posted: Wed Nov 12, 2008 1:05 am
by agniusm
Hi everyone. So here i am with electronics skils (most in computing) welding experience and strong will to build simple and as cheap as posible 2 seater to go to work and back.
My idea is to build EV reverse trike with side by side seats. I want to use parts from scooters (wheels, suspension etc.)
I need to travel around 8 to 10 miles one way where 1,5 miles is up the hill. I can recharge at work.
i would be looking around 40mph speed. i need this wehicle to carry two people.
Is there any one who could advice a motor, battery capacity and type, maybe brand and controller for such application? considering that i dont want to spend fortune as i'll be getting parts from car breakers. I am located in Northern ireland.
Thank you for reading and yourtime.

Posted: Wed Nov 12, 2008 8:57 am
by MalcolmB
Hi Agnius

Sounds like a good project. Have you any idea of the projected weight of the trike and what sort of acceleration you want. 40 mph is easily achievable but how fast you want to get there naturally affects the motor and batteries you should use.

There's actually an Etek motor for sale on ebay right now (Item number: 280284100690) that might be suitable. This is the same DC permanent magnet motor I use in my bike, which reaches just over 50 mph with decent acceleration. If you could keep the weight down and fit a decent fairing then 40 mpg should be no problem.

If you ran this motor at 60V then five 50Ah deep cycle (lead acid) batteries should get you the range you want comfortably. They would weigh roughly 100 kg. You can often pick up Curtis controllers relatively cheap on ebay if you keep your eyes open.

How steep is the hill you need to climb?

Posted: Wed Nov 12, 2008 9:34 am
by agniusm
H. Thanx MalcolmB for the replay. I am not concerned about acceleration. 2 persons is about 120kg. I want some cover as well. I will use 40x40mm box section for framework, scooter wheels and suspension. Mabe AGM batteries would be better an are mor dense?

Posted: Wed Nov 12, 2008 10:25 am
by MalcolmB
Yes the batteries I use are AGM (absorbed glass mat) and deep cycle (they're not mutually exclusive). They tend to be expensive, but again you can sometimes find good quality ex UPS batteries on ebay that still have a lot of life left in them. I bought a few of these (Item number: 180221264009) a while back and they're still in good condition. They would make a decent starter pack.

Posted: Wed Nov 12, 2008 2:37 pm
by agniusm
Would it be better idea to use pulleys and belts instead of chain as in Cirbin V13R? Dont want to bother you too much but can you advise on exact kit to go after in terms of motor and controller? Thank you for the info

Posted: Wed Nov 12, 2008 3:49 pm
by MalcolmB
I'd look closely at fitting a belt drive myself, though it's really a matter of preference. Chain drives have the advantage of being readily available, fairly cheap and easy to set up. Belt drives are more expensive initially but quieter and cleaner, which goes nicely with electric drive.

The belt drive from a Kawasaki 250 or 450LTD would work well, but only if you're using a small rear wheel, i.e. scooter size, since the reduction is only around 3:1.
Medway sells sprockets and belts for use on go-karts that would give you a reduction of up to 4:1, possibly higher. You would need 8mm pitch 30mm wide belt as a minimum.

As for motors and controllers, I can't really recommend a particular combination if you're trying to do things on a budget, as it's usually a case of buying what happens to come your way. The Lynch-type permanent magnet motors such as the Agni, Mars, Lemco, Perm or Etek I mentioned earlier are compact and lightweight. Power is limited to around 15-20 hp peak or 5–8 continuous. If you want more than that then you should probably look for a series wound DC motor, which occasionally come up on ebay. For the speed you want, a motor that can run at 48–72V should be ample. Once you've found a motor you can start looking for a suitable controller.

PS. is a great place for inspiration and to find out what components others have used for similar projects.

Posted: Wed Nov 12, 2008 10:25 pm
by nino500
I have a spare curtis 48-72 volt controller, if you're interested.

See my post in for sale for details. It would be happy running an etek or similar.


Posted: Thu Nov 13, 2008 1:45 pm
by agniusm
Hi there. I found this site selling dc motors :
What do you think about 1000W 48V motor?
Wahat is dependant on voltage of the motor? Speed? The higher the voltage the higher speeds achievable?
If i woud use 36V motor means that i can gel 3 100-120AH batteries? Would that make sense or i miss out something?
I think that my planed vehicle would not weigh mor than 300kg. So what motors i would need to look at. That etec motor whent for whoppy 300+ pound which is too much to spend for me. These motors(see link) are sold for 179$ which is good for me but i dont know if that would be wnough for my application. What kind of wattage i should be looking at. Thanks again you guys for support and info.
Probably would go for chain instead of pulleys and belt drive.
I decided to use motorcycle back end with larger wheel and swing arm + suspension. The front i think that i can get something small like fiat sinchuento or whaterver you call it steering suspension.

Posted: Fri Nov 14, 2008 12:04 am
by MalcolmB
Yes, that Etek went for more than I expected. Seems like electric vehicles are becoming more popular, which is good in general but makes it more difficult to find cheap parts.

Running a 300 kg trike at 40 mph on a flat road is likely to take around 5 kW, give or take a kilowatt or two. Then you need a little headroom for acceleration and hill climbing. I'd suggest a motor with a minimum of 10 kW peak output. The 1 kW Unite motor just isn't up to the task. It could probably get you up to 40 mph for a few minutes if run at higher voltage but would soon burn out.

Roughly speaking, voltage governs motor speed, and current determines torque. You can sometimes pick up cheap series motors from ebay or from scrap yards that break fork lift trucks. Good luck!

Posted: Fri Nov 14, 2008 12:36 am
by agniusm
Ok. Whatabout these two:
for example that 48v one combined with this controller: 300amp one at 48v and thes 4 batteries: Link to ebay

Would this would make more sense? If i calculated correct (48V*125A=6000watts) 6kW motor. I would probably spend more money cause one week is 15 pounds petrol which makes 840 pounds per year so it would be a good investment. I have mesured the distance and it is 15.5 miles to work and back so 7.75 miles one way :)