Twin motor UTV

[atait1]

Hello everyone

New here and new to ev's. Live on a farm in New Zealand and getting sick of filling up our canam side by side wirh petrol seemingly every 5 minutes. It is only used for short trips but on steep country which makes it very thirsty

Looking to build a fairly low budget ev alternative. Don't want to cannabilise our current one so have been looking around for affordable(broken) options. Realise something like our canam defender would be relatively easy with a single motor driving the current gearbox but these dont seem to come up at an affordable price.

What do seem to come up cheap are the Chinese ones. Have my eye on a kymco 700. Issue with these is they use an integrated engine/gearbox which could be difficult to adapt an electric motor to and would likely end up heavier than necessary

Im yet to look at the machine and run a tape over it to see if my idea would actually fit but I was contemplating running twin motors, as close to each diff as possible, leaving the large space under the seats and between them(where the ice motor currently lives) for batteries. My research suggests it should work running separate controllers driven by a single throttle? But I havent managed to find a heap of info from people who have actually done it

Have my eye on the qs138 70h v3 with the gear reduction. One of which would be way too small I believe to get a 500kg machine up a hill but 2 might work? I think the gearing might work based on general utv diff ratios but can't find a number for this particular brand so would have to measure it

Any advice would be greatly appreciated whether my motor selection would work(with the controller that comes with them from qs? Or would i be better using a different one?) And also whether the dual motor thing might be a headache. Id hate to go buy this thing then just wish id paid a bit more for a canam etc.

Batteries would likely be leaf ones as I've used them for our off grid setup and they're affordable here

Thanks!
Adam

 

[offGridDownUnder]

Kia Ora.

I looked up your motor choice, and there is good information about it's output - particularly the torque.

What is the torque output of the ICE motor used now? You can compare that. Hill climbing with load is about torque. Sustaining speed is about power.

As well, do you know about the Grin motor simulator? There are options for custom motors, and you may be able to plug the specifications in and get useful answers. You'll need to know the gear reduction from the motor down to the wheels, but then you could enter that as a single IN:OUT pair for a mid-drive motor.

Note that you have the option to simulate two systems and add them, rather than compare them. In this way, you can simulate two motors, one on each drivetrain.

There is a fair bit of data to enter, but you can do it from your kitchen table as a start.

 

[atait1]

Thanks offgriddownunder. Had a look at that website and most of the custom input requirements were very foreign to me even ai didn't seem to have an answer for a couple of them! May just have to go the trial and error method!

 

[fechter]

You might be able to find an electric Chinese UTV for not much more than building one.
Two motors adds quite a bit of complexity. Best if you can get away with one.
Would a golf cart make it up your trail? Those might be pretty affordable. Replace the lead-acid batteries with Leaf batteries.

 

[atait1]

Hi Fechter

Unfortunately not they're proper rough steep farm tracks, need to use 4wd fairly regularly in the canam and difflock for tricky bits. A 2wd sport quad with aggressive tires might get most places and is the other option with far more people having done it before. Not much use if I shoot a deer though which is the most common use for the machine.
May be best just to wait for a utv more suitable for a single motor to come up

 

[pinkpanda3310]

I just did a quick search to make some comparisons. So forgive me if I got some specs wrong.

Canam defender power plants vary from 52hp, 57Nm to 94hp, 95Nm , range +160km

Kymco power 45hp, 55Nm , range +190km

Leaf car battery 360v , 100amp continuous 200+ peaks

Qs138 70h rated 3kw continuous with peaks +20kw (4 to 33hp) 72Nm , input up to 96v.

x2 qs motors = 8 to 60 hp (note running at 60hp will likely give you hot motors)

Firstly, those motors are not compatible with that battery voltage. What controller are you expecting to use? If the controller cannot accept +300 volts AND limit the voltage going to the motor then you'll need to get fancy with your electronics.

If your goal was to build it then have at it but it sounds like your goal is to use it with a purpose in mind. I feel like you'll get frustrated with the time and money needed to build it. If you still want to go down that road i suggest doing a f@# ton of research first.

 

[atait1]

Hi pink panda

Wouldn't be using the complete pack from the leaf theyre 300kg+ we're running our off grid setup at 48v with 7 modules in series(although wish id left the pack as is with a hv inverter which seems to be done now) so could use 14 for 96v or a couple fewer if thats too much.

Thinking I might try the kymco with one larger motor and 2wd to start with and see how it goes. Potentially could hook a smaller motor up to the front diff at a later date for emergency 4wd? I guess a speed difference wouldn't matter if the wheels are spinning anyway?

 

[pinkpanda3310]

Ah, okay, you can make adjustments to the battery pack as needed. I'm guessing a qs180 90h might have a similar overall power to the stock kymco except the torque will be at the low end of rpm.

I'm don't really know about running a second motor at different power/ speed. That's a bit outside my knowledge.

 

[atait1]

Thanks for that. Think ill need gear reduction to direct drive the diff and the 180 doesn't seem to offer it. There's a 20kw rated 165 with gear reduction think that might go ok? Are there any other motors with gear reduction out of China worth looking at? Much appreciated

 

[pinkpanda3310]

Dr Goggle says the rev range on the kymco 700 is quite high... like very close to a qs180....? You may not need a reduction gearbox.

For reference, this go kart has qs165 v3. Note it is only being fed around 20kw from the battery/controller . Motor temperature gets to about +60°C from memory

 

[pinkpanda3310]

Other motors you could look at...

VTB (ventus bikes) Ryuga - high rpm , no gearbox

3shul GBX80 , has gearbox

SIA 200-50 , has gearbox (siacosys is same company as qsmotor, i think this is equivalent to qs180 but with gearbox)

There may be others but that's what springs to mind

 

[atait1]

Thanks pinkpanda

The kymco engine has the benefit of the gearbox though? Was hoping to direct drive the diff. Will definitely measure the diff ratio before making any decisions on motor choice. The sia 200-50 looks good and it's not too expensive for its size