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Posted: Wed, 28 May 2008, 02:56
by Jmags
Hi all,
new to EV's but have alot of off road experience in quads. Want to look at building / coverting a race quad to electric. Like I said B4, have no idea about electrics but current specs of a high performance quad with rider are as follows.
Mass = 270kg
Power = about 50 hp
Top speed: Moto X = about 110kmh, Range about 10km to 20km

           Desert = about 140kmh, Range about 150km

Mass of engine, fuel tank (full) and exhaust = about 50kg

Can anyone help out with what is required to do this? Advice, specs, parts, anything?


Posted: Wed, 28 May 2008, 04:12
by antiscab
whats the greatest mass you can put on a quad?
and 6.7" x91 and 144v curtis directly driving a diff would do what your looking for.
however the x91 weighs 40kg.
make sure you get an x91, not a L91, as the x91 has smaller windings, which are more efficient at lower currents than the L91. Also it can do a higher voltage (144v instead of 120v)
you will need to use lithiums, if service life isnt an issue use lithum cobalt polymer. sells these type packs. id suggest the 50AH cells. you will need a bms, they also sell this.

if you need closer to 2000 cycles to make it cost competitive, then use LiFePO4 such as thundersky from
theyre having a special on the 40AH units atm, so itd try and order something sooner rather than later.

for this sort of conversion, your looking at about $7k to convert if you use a 144v40AH battery (weighs 68kg). more if you need a bigger battery.

Id suggest looking at quads that come from the factory as electric. These always come with lead batteries, so have poor range. but they are cheap, and can be upgraded to lithium. have a look around
its another forum, but they discuss smaller EVs.
specifically, look for MountainChen, hes a chinese scooter manufacturer. He could probably point you in the right dirrection.


Posted: Sat, 14 Jun 2008, 16:32
by Jmags
Thanks antiscab. Is that motor AC?. I would like to run lite batteries. Weight savings are performance gains. I have not seen any performance oriented quads come out of china, just utility style quads which is not what I am on about. Just to give you an idea a typical race quad costs about $12k to $14k then most spend another $3k on hop ups and $3k to $5k on suspension. If you damage an engine you normally look at $4 to $6k repair bill. I think spending $7k on a conversion would be cool. I have a race quad in my shed that I can use for a donor. There a plenty of opps for a good quad with a damaged motor at the right price.

But it has to go like hell! That part is not negotiable! Image


Posted: Sat, 14 Jun 2008, 20:00
by antiscab
Ah the universal requirement "But it has to go like hell! That part is not negotiable!" lol

That motor is a series wound DC motor. As far as bang for your buck, you cant go wrong. that setup will give you approx 72hp peak

A slight change to my advice, id suggest the kelly 144v kelly controller from its cheaper and has more features.


Posted: Sat, 14 Jun 2008, 20:09
by Jmags
Is there a motor which is lighter and less HP? Say 50hp and 20 to 30kg? Some dimensions would be good also.


Posted: Sat, 14 Jun 2008, 20:17
by antiscab
i dont know of any motor between the etek 15hp peak units and the 6.7" series wound 72hp peak.
If you go for a smaller motor your efficiency will suffer, as will your continuous output.
The continuous output of the 6.7" is 16hp, if you go to a smaller motor you may run into heat problems.

Heres a link to the dimensions: