2008 Polaris outlaw 525s ev build

[Stupidcomputers]

Hi All,

I’m in my 40s and must be halving a mid life crisis or something. Recently re-discovered love for outdoors and ATVs after fixing up a nearly perfect condition 99 Polaris scrambler 400 4x4 and riding at WA state ORV parks.

Need a 2nd quad now and I’ve been frustrated with lack of EV options. So why not build my own? . I’ve built electric scooters in the past, but apparently they went to fast .

Anyways, I found a deal on some 4s 150aH sunwoda battery modules that looked like a perfect size for an ATV. Also stumbled upon a Facebook marketplace deal for a rolling frame of a Polaris outlaw and couldn’t pass it up. A bunch of research and ordering of parts means this project is motion! According to specs, this thing should be pretty decent to ride and felt I should document and share the build. We will find out!

Frame: 2008 Polaris outlaw 525s
Motor: QS 165v3 60h + gearbox
Controller: fardriver nd84890B
Battery: 6x 150aH sunwoda module 4s1p = 24s /88v 13.2kWh and 450 amp peak for 10s !
Bms: JBD 24s 200amp

 

[Stupidcomputers]

Starting to build the battery pack. Soldered bms wires to a plug for easy disconnect. Tabs are nickel and should be safe to solder to without damaging the battery. These modules are encased in an aluminum frame already and I planned to run 2 AWG to connect battery lugs in series.

They also have a nice silicon rubber adhesive layer on the bottom for cushion.

Planned to run threaded rod in each corner with spacer to secure battery pack to each other and the frame.

 

[Stupidcomputers]

Recent post regarding a Suzuki ltz400 build is inspiring me to try and mount the Qs165 60h motor close to the pivot end on the swing arm. Hoping to tuck it in front of the shock. Think it will fit?

I need the space for the battery modules. While each module is 14x6x4.5 in., 6 of them will add up.

It’s been about 20 years since I’ve welded so I bought an extra swing arm off of eBay for easy figment and to practice on. Plane to cut and drill a simple motor mount out 1/2 aluminum plate and then weld it to the swing arm.

 

[Stupidcomputers]

Progress! Battery pack build and charge test successful!

8 pin Deutsch water proof connectors for bms
Amazon Project Box size 200 x 120 x56mm. Just barely fit the jbd bms… wish it was slightly wider and longer.

No name 100.8v charger from AliExpress. Seems to work ok.

 

[Stupidcomputers]

Pro taper handle bars arrived. Looks much more familiar now! Clearly this frame had been sitting outside for awhile. Any advice on how to clean rust and discoloration? If this thing turns out to perform well maybe it would be worth taking it to some place that can repaint / re-powder coat.

Bonus pic of my Polaris scrambler I fixed up a few months ago from a craigslist deal.

 

[SlowCo]

Great project. I'll be following thread for updates. Good luck and enjoy building it.

 

[Stupidcomputers]

Making progress! Still waiting for the QS 165v3 and kit to arrive direct from siaecosys. In the meantime, my threaded rod and spacers arrived. Assembled 2 modules composing of 3x sunwoda VDA355 modules from battery hookup. These things seem like a crazy hot deal for what they are capable of given the energy density.

Battery pack will weigh 78.4 lbs x2 for a total of 13.2kWh of capacity.

Added some scrap aluminum pieces for temporary carrying handles.

Using m6x400mm threaded rod. Too small for pre-existing holes. Might upgrade to thicker rod or nylon spacers for rigidity.

1 1/4 inch aluminum spacers between each module leaving just enough space as to not compress the top plastic cover on each. Also every module has a nice 1/16 inch layer of silicon? Material to absorb shock on the bottom. Happy to answer questions! Or take advice on improvements in design!

 

[jkrienert]

Are the gray pads on the modules base thermal transfer medium? Maybe you could sandwich some aluminum sheet between models in the stack to help intercept and transfer heat out of the core?

 

[Stupidcomputers]

Pretty certain the pads are a silicon rubber material designed to reduce vibration. They don’t look like and thermal material I’ve seen before.

I’m trying to figure out what is the best sprocket size for this setup. I’m taking a guess and found a 520 size 12 tooth. Online images for the qs165 v3 60h indicate I should expect a shaft with 20mm od and 16mm id splines. This Niche sprocket from Amazon looks like it fits the bill. I am expecting massive torque from the gear reduced motor and I won’t want to damage the splines by using a loose fit sprocket.

I have no need to go faster than 60 mph and will need torque to climb WA mountain trails. How do you guys calculate estimated top speeds?

Here is my guess:

Top rpm @72V is 7500
2.37 built in gear reduction
12t 520 drive sprocket
38t rear sprocket
20x11x9 tire size

Online calculators say 59.4 mph top speed!

I will run at 88v nominal bumping the top speed slightly higher. Should I expect to be able to hit 7500rpm? This is my first time playing with these type of components.