# Polaris rzr ev



## major (Apr 4, 2008)

rancid0076 said:


> I have a rzr 800 and love it, so I decided to build another . So I got a rzr frame and Suzuki samurai axles , and I'm wanting to run a warp 8 or 9 in it. Stock hp is about 107 in the new 1000 and want to be on par. Was hoping to find a motor with a output at both ends to connect to both driveshafts without needing a transmission. Does a motor like this exist.


Yes, some versions have a rear shaft extension. But you'll need a gear reduction from motor speed to wheel speed so using opposite ends of the motor for a dual drive is seldom if ever done, not to mention the need for differential speeds on the wheels.


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## tylerwatts (Feb 9, 2012)

If the samurai axles have high enough gearing (aftermarket) then you could potentially run the motor like this. But only off-road as like major says it needs a centre diff for tight turning on hard pack surfaces. You could risk it with big knobbly tyres but your choice. 

Why do you want to run samurai axles? The rzr independent suspension is much nicer in my opinion and you can fit car diffs with high ratios and limited slip. Or even better a third centre car diff mounted with the motor transverse under the seat like standard. This would give you huge ratio choices then also with a centre and axle diff. Remember the front and rear must match or maybe be different if you run different size tyres but I don't recommend that and you wouldn't be able to run a limited slip centre diff in that case either. 

Sounds like a fun project however, and a warp8 is probably plenty motor. Lighter is better so I can't advise a warp9!


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## rancid0076 (Aug 2, 2012)

I will keep same size tire 31" tall and I want samurai axles because there about as light as a solid axle I'm gonna find. I want to run solid instead of ifs and irs because it will mostly be a rock crawler. But I plan to keep it as low as possible. So with some good long travel coilover shocks I think it should do ok in higher speed stuff. Also I figured most utv,s have some sort of aluminum or plastic roof panel to keep sun and weather off . Why not put a lightweight solar panel on top, Mabey even a flexible solar panel. Any thoughts


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## rancid0076 (Aug 2, 2012)

I just hope a warp 8 can compare to the. 103 hp gas version


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## tylerwatts (Feb 9, 2012)

I'm sure the warp will be fine. Have you thought about how to get drive from the motor to the axles? I'd say a diff in the centre with the motor attached would work best. You certainly can't fix shafts direct to the motor as you said initially for rock crawling. And ideally having a low range gear would be ideal. Best might be using a 4x4 transfer case to connect the motor to the axles then you have 2wd for high speed road use, 4wd high range for slippery high speeds (open diff) and 4wd low for rock crawling. Must be a unit that has a centre diff. A land rover has permanent 4wd with high and low range so no 2wd but no locked centre diff either. Something similar but lighter would be ideal. You could also use low/high changes as a 2spd transmission for acceleration to save running high amps either out the batteries or through the motor. 

Then I would say use a lighter Kostov k9 motor which weighs less and does higher rpm so decent speed in low and high gear.


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## rancid0076 (Aug 2, 2012)

Could I do a simple large sprocket on the driveshaft that would run to both axles. The motor would be just above or to the side of the driveshaft. With a smaller sprocket on the motor end. I'm trying to avoid a heavy tcase or transmission.


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## tylerwatts (Feb 9, 2012)

Sure but I would run the sprocket on a differential like kit car guys use. You need a centre diff for the rock crawling.

I had not thought of a chain/belt drive but it is a tidy strong solution. Something like a Harley primary drive would be perfect for the amount of torque and silent running. The chain is strong but a real hassle for mess of lubricant and also noise.


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## tylerwatts (Feb 9, 2012)

Actually rancid, you could run 2 smaller motors, one each direct to a diff at each end. But for crawling you will need. High gearing. Which will be tricky. Unless you use a whole diff with pinion gear reduction and then a chain/belt to the diff input for extra reduction. So 3:1 on the diff plus 2:1 on the belt gives 6:1 and so on. Large scope for high ratio. Say a 4.2:1 Subaru limited slip diff with 2:1 belt drive would make about 45mph cruise speed with low ratio for crawling without too much current through the motors. I'd wonder whether PMDC motors would be enough with 300A input for good wheel torque. Needs the numbers crunching but that would be a. Light package with good power. Not 100hp high speed power but certainly the low speed drive and loads of torque for crawling. 

What range do you want for the vehicle? What is your budget? How much does a stock rzr weigh?


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## rancid0076 (Aug 2, 2012)

I would like a range of 20-30 miles , the stock rzr weighs just under 1000lbs , but I'm not planning to use the transmission and transfer case . So I think I can save some on weight. The axles are 4.32 gears and , so I'm trying to figure out what tooth sprockets I should run to get a top of around 65mph. I will 30-31 inch tires. Also would agm batteries be ok for this. What volt should I be looking at running with a warp 9.


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## tylerwatts (Feb 9, 2012)

Will you run a centre diff then off the warp? You won't need sprockets. Attach the warp to a centre diff and run drive shafts off the diff to each axle. The ratios may not work then though. But with those big tyres you could maybe do it.

Assuming 6000rpm Max for the motor, 31" tyres are doing 705rpm (650revs/mile) plus a bit for dirt traction loss gives 750rpm. Multiply by diff ratio of 4.32 gives 3534rpm input to the axle diff so you need 1.7:1 centre diff ratio which is a bit low. Using smaller tyres helps, but 30" won't be much better. 
Assuming good traction and a 2.8:1 centre diff ratio will give 2979 axle rpm and 8805 motor rpm at 65mph with 30" tyres. 

Running 28" tyres would mean a diff ratio of 1.78:1 so not much better. Either lower the axle diff ratios or go AC. 

Can you lower the axle ratio? Are there any other choices? 

Also, lead won't get you this performance or range you need. Must be lithium and at a good voltage for high speed. I'd say a Soliton jr with max number of 40ah or 60ah cells and limit the battery current rate. The Soliton will then convert higher volts to more amps at low speed for torque and revert to high voltage for top speed. Unless you run a lower voltage motor so you don't need as many cells for the vehicle speed. 

Would you consider an AC drive? These rev high so will give you torque and top speed!


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## major (Apr 4, 2008)

rancid0076 said:


> I would like a range of 20-30 miles , the stock rzr weighs just under 1000lbs , but I'm not planning to use the transmission and transfer case . So I think I can save some on weight. The axles are 4.32 gears and , so I'm trying to figure out what tooth sprockets I should run to get a top of around 65mph.





tylerwatts said:


> Assuming 6000rpm Max for the motor, 31" tyres are doing 705rpm (650revs/mile) plus a bit for dirt traction loss gives 750rpm. Multiply by diff ratio of 4.32 gives 3534rpm coming out the centre diff so you need 1.7:1 centre diff ratio which is a bit low. Using smaller tyres helps, but 30" won't be much better.
> Assuming good traction and a 2.8:1 centre diff ratio will give 2979 axle rpm and 8805 motor rpm at 65mph with 30" tyres.
> 
> Running 28" tyres would mean a diff ratio of 1.78:1 so not much better.


The analysis from tylerwatts has me confused. I don't know why he is talking about high motor RPM. So let take a look at rancid's post. I assume the stated ratio of 4.32 is from the rear end input to the wheel. Then:

A 31 inch tire has a circumference of 97.3 inches = 8.1 ft.

It will make 650 revolutions per mile.

At 65 miles per hour (mph) it needs to make 42250 revolutions per hour.

Divide by 60 minutes per hour to get 704 revolutions per minute (RPM) for the wheel.

Multiply by the gear ratio (G.R. = 4.32) to get 3042 RPM input to the rear end.

3000 RPM is a good target speed for a 9 inch DC motor at top vehicle speed. So take that number to the motor performance characteristic curves along with your estimated vehicle load and determine the minimum needed voltage.


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## tylerwatts (Feb 9, 2012)

That was the exact calculation I made major, but on the assumption rancid will run a centre diff. 
Can anybody confirm it is practice to run rock crawlers with locked/no centre diff? I'm confident it is not ideal. So I am calculating on having a centre diff also. 

Additionally, I suggested using a transfer case as you would have good low speed torque and good high speed power. 

Maybe we would design this vehicle differently, and neither be wrong, but I am sharing my opinion. And I am a designer, and qualified mechanical engineer so thinking of optimal use for the vehicle and drive system. 

Again, it is my opinion and advice only. Not the only way to do things...


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## major (Apr 4, 2008)

tylerwatts said:


> That was the exact calculation I made major, but on the assumption rancid will run a centre diff.
> Can anybody confirm it is practice to run rock crawlers with locked/no centre diff? I'm confident it is not ideal. So I am calculating on having a centre diff also.
> 
> Additionally, I suggested using a transfer case as you would have good low speed torque and good high speed power.
> ...


All I said was your post confused me


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## major (Apr 4, 2008)

rancid0076 said:


> What volt should I be looking at running with a warp 9.


O.K. rancid,

Let's look at this question. You figure out all that gear crap so you can run the Warp9 at 3000 RPM for your top speed of 65 mph. So to figure out the minimum voltage you need you will have to calculate the motor load at 65 mph. How much power does it take to drive at a steady 65 mph? For example let's say it is 25 hp. So you know the motor RPM you want is 3000, calculate the torque. hp=torq*RPM/5252. So the motor load will be 43.8 lb.ft. Now find a performance curve for the Warp9. 










Now follow the horizontal scale out to 43.8 lb.ft. Draw a vertical line there and read where it crosses the RPM curve. That would be 2500 RPM right? But you want 3000 RPM. The 2500 RPM point is at 72V on the motor. To get 3000 RPM at that load, you need to proportion up the voltage by (3000/2500). That means you need 86.4 Volts to the motor. That would be the motor voltage on the Warp9 to get 25 hp at 3000 RPM.

Now, motor controllers work by reducing the voltage from the battery to the motor. So you should not try to use a battery exactly of 86.4 Volts. Use a higher voltage. You'll also need a higher voltage than 86.4 in order to accelerate to that speed under load in a reasonable time.

So a 96 Volt battery would be the minimum I think suitable. 120 Volt would work and you could even go higher because the controller can be used to limit the motor voltage. This all depends on how you design your system and select components like the motor controller, battery and charger.

I hope that shows you how to decide on the system voltage. You'd use the same procedure if you decide to run the motor at 4000 RPM, which is O.K. Or if you calculate it requires 35 hp; just adjust the figures and do the math.

major

ref:
http://evolveelectrics.com/PDF/NetGain/WarP 9 Torque Curve.pdf


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## rancid0076 (Aug 2, 2012)

Ok what about a fwd car transmission mounted sideways with a ev motor , to run both drive shafts to both axles , that would lower my gears and also give me a overdrive in 5th, mabey like a geo metro.


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## tylerwatts (Feb 9, 2012)

Major, I apologize again sir. Rpm/mile should read revs/mile... a proportional value to the tyre size. Post edited. 

Rancid 
I do not think you want a big transmission for the sake of adjusting ratios. Rather strap a belt/chain drive onto a diff and gear up the motor to the axles. I'll sketch it out...


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## tylerwatts (Feb 9, 2012)

This is the setup I mean. To reduce your gearing. 

May I ask whether you would consider an AC drive? A HPEVS AC50 would be ideal and would run up to 8000rpm meaning you could simplify the drive by using a complete centre diff and mount the motor transverse under the seats bolted direct to the input flange. Shall I sketch this? 

Have you got pictures of the chassis and space to work with?


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## rancid0076 (Aug 2, 2012)

Is there a lower cost forklift motor , that would work for my application . Mabey down the road get a better motor


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## rancid0076 (Aug 2, 2012)

tylerwatts said:


> This is the setup I mean. To reduce your gearing.
> 
> May I ask whether you would consider an AC drive? A HPEVS AC50 would be ideal and would run up to 8000rpm meaning you could simplify the drive by using a complete centre diff and mount the motor transverse under the seats bolted direct to the input flange. Shall I sketch this?
> 
> Have you got pictures of the chassis and space to work with?


 And that is exactly what I'm thinking with a. 630 chain and sprockets


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## major (Apr 4, 2008)

rancid0076 said:


> Is there a lower cost forklift motor , that would work for my application . Mabey down the road get a better motor


Hey, I'm not recommending any of these, but right now in the classified on page 1 there are several; an 8" and a couple 6.6" for under $500 each. http://www.diyelectriccar.com/forums/forumdisplay.php/classifieds-4.html


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## tylerwatts (Feb 9, 2012)

That would work just as well. I'd suggest if the 8" were a good motor to run it at 500A maybe, depends on the spec.


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## tylerwatts (Feb 9, 2012)

Rancid. That 8" ADC would be good, 500A and 144V is normal running. If you get fancy with forced air cooling you could run higher amps .


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## rancid0076 (Aug 2, 2012)

What kind of hp do you think could be made with one of those


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## tylerwatts (Feb 9, 2012)

Well assuming an 80% efficiency through the motor, if the controller is outputting 144V and 500A. P = V x A that makes 57,6kw or about 70hp. Don't be put off, you'll have more torque than any rzr and the delivery is something else so where a combustion engine only has peak power for a few rpm when you change gear and the average power over the useable power band is a fair bit less. Plus you won't be wasting time changing gears etc. I'd say you need about 60% bhp of what the ice had which will normally equate to 50% more torque than the ice. 

I'd check the garage section and evalbum to see how hard guys are pushing these motors.


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## Dustin_mud (May 22, 2012)

I have been planning a Ev crawler for a few years now and been into hardcore crawling for a very long time, if you want to crawl it you really should run a t-case. If your pulling axles from a Sami then use it's t-case, it small, light, and is a divorced so no need for any trans or adapter. Also they make a low gear kit to make the low range down to a 8 to 1, so you can have higher gearing in the axle with a 1to1 high and 8to1 low for crawling.


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## rancid0076 (Aug 2, 2012)

<P>well I just picked up a sidekick tcase, with a 1.81-1 low range, and 1-1 high. They offer 4.24-1 kits. But it doesent change my high gear. I can get the axle gears down to 5.83. So if I'm not crawlin what would my top speed be in either high or low.im going to run only 31" tires.</P>


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## rancid0076 (Aug 2, 2012)

<P>would I need to run around in low range all the time or do I need to find a way to gain a 2-1 reduction still for my 2-1 reduction for my high range or a 2-1 reduction before it enters the tcase, lowering high and low gears. Wish I could find a 2-1 box to run in front of the tcase so I could permenently lower everything.</P>


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## Dustin_mud (May 22, 2012)

Like I said before get the sami case, go on zukikrawlers and trade the kick case you have. With the sami case you can run the 6to1 low and still have a high gear witch the gear kit lowers it just a bit too. Just seems like it would fix some of your problems.


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## rancid0076 (Aug 2, 2012)

just got a samurai case there light and compact


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## Dustin_mud (May 22, 2012)

Good deal, now hit up trail gear for a set of gears.


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## rancid0076 (Aug 2, 2012)

<P>so with the 6.5-1 transfercase gear upgrade wich also lowered high range by 20% from 1-1. And running 5.83 axle gears and 31" tall tires.can anybody estimate whatmy top speed with a ev motor may be , I'm hoping with all this and the light weight of the nature of the rig I can skip on having any transmission. Hoping it will accelerate pretty well on a high volt system. Any advice </P><P> </P>


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## tylerwatts (Feb 9, 2012)

Sorry rancid, I posted a long calculation but it seems to have vanished. It is the transfer ratio times axle ratio times circumference proportional to Max motor rpm. I'll calculate it properly again, but it was about 40mph only, at 6000rpm. Don't waste money on the extra ratios for the low range in my opinion.


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## evluv (Feb 28, 2014)

There was a guy on minibuggy.net who used a Civic 5 spd transmission turned sideways to drive a front and rear axle. The transmission, all stripped down, bellhousing shaved off, and driven by a chain, only weighed something like 50 pounds, could handle the power, and was cheapish and easy to find. Just an idea


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## rancid0076 (Aug 2, 2012)

So with my 1.8-1 t-case high range gears and 5.38 axle gears, and 32inch tires, and running a warp 9 motor. Can anyone give me an idea of top speed and how it may accelerate on a 144v system.


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## Jeremyfc1 (Feb 5, 2016)

i run an electric samurai and have found that high gear in the trans is only good for road use and low range im in first or second the whole time i am off road i am running twin 6.7 chain driving the transmission all stock sami drivetrain i originally was going to just run the transfer case direct drive but found there was not enough ratio to truly crawl


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