A little bit about my 2008 YZ250F Electric Conversion

[DonCox]

I've shown some of the pictures of my conversion in other posts on here, but here is a little more. I started this build after having had my KTM 250F Electric conversion for quite a few years. I helped a buddy in Florida build his version of a 2014 YZ electric, but around the specs of the ALTA, so I was itching to build another electric also around the ALTA specs.
I wanted more HP, 50hp seemed like the number. More battery, so I copied the ALTA battery. I am at a different a different voltage, but 20S21P with Sony VTC6 cells, would give me 72V nominal 630A 63AH and about 4.5KW of battery. A bike with aluminum frame and better handling, so the 2008 YZ25F. Here is a recent picture.

I have literally 1000's of images, I recorded this build with a lot of pics. Here is a list of the main pieces I am using on this build ME1302 motor, Kelly 72701 Controller, battery mentioned above. A primary gear reduction under the cover in the picture of 1.5239 using gears out of a KTM 450SX, since I had these parts. ( 21 to 32 gears) I used 3 gears out of that gearbox and the output shaft for my jack shaft. This has worked out quite well, but I am going to have it built by a machine shop from start to finish. This is a prototype that I put together with the help of various machine shops, and my own tools. You may notice that my aluminum welding is not professional grade.
I wanted to have the batteries easily replaceable , which I have accomplished. I have 3 packs 20S7P 210A each. Each pack has it's own BMS and own 10A charger port. I use 3 ea 10A chargers for a total of 30A at 110VAC.
In the picture above you see the cover for the right battery which comes off with 2 Dzus fasteners. In the Airbox you can see a little of the battery box behind the shock reservoir.
I built the 3 battery packs myself, and I have many videos of that build. So far the packs are holding up real well. I'm getting about 195A out of each pack. We went on a 15 mile desert ride ( I live 2 blocks from the desert here in Lake Havasu City, AZ) over the holidays, with a lot sand washes, and the battery was still at 75V which is about 60% battery left.
The controller has been a learning process. Kelly has helped, but it is typical Chinese poor manuals, and equal info in the email train from them. But it works now. It seems like all the controller vendors aren't to enthusiastic about making an electric motorcycle. ASI seems pretty proprietary, Kelly has sketchy info and explanations. Sevcon don't seem to be reliable, and Curtis I don't know too much about yet, but my friend in Florida is getting a special one from them, but the current is slightly limited. The Kelly does seem to get me close to 600A. With their most aggressive MAP it is whiskey throttle crazy . With a tamer MAP the power comes on better with power later.
Here are a few more pictures and I'll post more later. This project took about a year. I retired in Mar 2020, and have been quarantined to my garage all year. It's been a great outlet for me.

 

[VINSANITY]

That is an awesome effort - so after a 15 mile ride in sand you had 60% battery left - that seems like much better range than the Alta - I typically get 20 miles range before the Alta starts blinking.

How long to charge the 3 packs at 110?

I am toying with a similar build using a 2006 KX 250 chassis - the frame is chromoly so can be welded easier - it’s a modern perimeter frame so should handle well.

One thing I did on my electric bike ( motoped similar to a Sur Ron ) is I had a battery case 3D printed from plastic - it bolts to an aluminum base buts very sturdy and you can do things with the shape that is not possible with metal.

Thinking I would copy the drive train / battery / controller combo you came up with as I personally like the idea of using off the shelf components.

Well done my friend

 

[VINSANITY]

One other question, what does it weigh

 

[DonCox]

Thanks for the comments @VINSANITY. I have a 3D printer, but it doesn't do that big. I have to find someone to copy what I have and 3D print it. Same with the gear reduction, I am going to use the same gears, and have a machine shop build it and possible offer it up for others to buy. This motor rocks, it is the same motor SSE uses, but at 96V. The ride had a lot of sand washes, but not all. I'm taking it to the local track this weekend, I'll let you know how many laps it does.

 

[DonCox]

260lbs

 

[DonCox]

I can pop out one battery pack and still have great power and run a shorter race or time. Each pack weighs about 19lbs

 

[VINSANITY]

Pretty impressive performance and a nice clean package.

FYI - I actually had the battery case printed in Russia, they were great to work with, they took some pretty crude sketches I made into drawings that I could review, they printed and shipped it all at a pretty reasonable price.

I haven’t got the chance to do the final install yet due to broken wrist - damn Alta power got me.

It would probably be best the get your battery case 3D scanned so that drawings can be generated from the scan.

Here is my application - it’s a Motoped (Sur Ron but better) - it’s super tough and you can modify it as technology evolves. It’s a 72 volt X 200 amp controller so about 14,000 watts - 115 pounds so very good power to weight - battery is 42 amp/hr so good range - it’s not Alta performance but for what it is its a lot of fun - IMO two of these batteries would work pretty good in an MX build like yours - one on each side so they can be easily swapped out.

 

[DonCox]

It looks like you found the battery factory. Litespeedbike.com looks like they have a lot of choices, and might be able to build to suit. I saw the ANT BMS after I already had mine installed. I like the ability to adjust the max Voltage. Each of my 3 packs peak at slightly different voltages, even though They are the same manufacturer of the BMS. They balance when all are connected, But I can't adjust mine. Are those battery covers the ones you had 3D printed.
Your bike looks really awesome. I got to ride a SurRon a couple weeks ago it was fun and easy to ride. Yours looks a little more robust.
Too bad on the broken wrist, I think a lot of us can sympathize on that... I done both, one twice. But they can still twist a throttle...

 

[DonCox]

You asked about the Battery charging on 120V. I have 3 battery packs, and I have 3 x 84V 10A chargers that are 120V. My RV has a 120V 30A out of the 5000W gen. It charges at about 2500W 84V x 30A About an hour from 74V to 84V. I have a 240V plug in my garage that I've wired into two 120V standard house outlets. They both work great.

 

[Philip]

Here are some pics of Don and his YZ250E!

 

[Dain_SSE]

This is the first one I've seen using a gearset off the ME1304 motor, cool!! Significant reduction is whats needed to really make that motor come alive (that or a 10/66 sprocket combo). Clean work and it appears to function well, nice job!

 

[VINSANITY]

When i see something like Don’s build which is a clean and straight forward layout, I am puzzled why OEM’s can’t figure out how to build one.

 

[Warren]

I guess it’s like KTM said current cost of battery’s makes the profit margin to low to be profitable. All about the $$$ make money not loosing it.

 

[F451]

When i see something like Don’s build which is a clean and straight forward layout, I am puzzled why OEM’s can’t figure out how to build one.

Same.

Besides the low profit margins mentioned above, think of the upheaval of the industry. Significantly less revenue for the dealers due to lower maintenance, way less maintenance item sales (air filters, filter treatments, gear oil, antifreeze, spark plugs, spare parts, etc). Less revenue for the OEM's selling parts.

Then you have the aftermarket getting decimated, no expensive exhausts, no jetting kits, no electronic computer tuners/reflashes (initially).

At some point the aftermarket would catch up and there would be all kinds of hop up parts, but they would be supplied by completely different companies, with just a few of the existing aftermarket companies being able to make the transition to e-bike aftermarket parts mfrs.

Of course it would take some time for all of this to happen as ICE bikes aren't going anywhere any time soon, but as soon as an Alta comparable dirt bike is released by one of the majors, and if it is less expensive, greater range, lighter weight, quick charger, quick change battery, they will very quickly replace regular ICE bikes.

I think there are a lot of people in the industry that do not want to see that bike developed and offered to the masses.

Its the only explanation I can think of.

 

[VINSANITY]

I think OEM that first to market could dominate and knock out competition.

Also like all electronics,electric cars and bikes will get out of date pretty quickly as batteries, controllers etc advance so people will want the latest and greatest.

Regarding the battery price maybe, but all other aspects of the drive train are cheap - mass production of batteries will quickly drop the price.

And lastly, I think there is ways to drop production cost of the bike itself - plastic sub frame (less complicated than the Alta, or more simplistic frame because of the drive train is relatively simple.

The OEM’s are lazy or scared or maybe not seeing potential new markets or groups that wouldn’t otherwise ride

 

[Bob Casper]

I am in the process of building a CRF250 E bike. I have done some ICE 500's and enjoy building different projects. A small bit of background shows I have zero electric motor, controller or anything voltage or amp related experience. I have been very fortunate to meet and develop a friendship with Don. He has mentored me so much in ebike related information. We speak pretty regularly about electric building and have some pretty fun old bench racing stories. I feel without Don's expertise and friendship, my project would be going forward much slower or possibly scrapped by now. I've ridden his really cool YZE and look forward to riding my own. Thank You Again Don

 

[Mark XEMX]

Great job on the Bike Don.
Thanks for all the help working on my bike project all these years as well.
I hope to release a teaser video of the YZ 2015 Build, hopefully by the end of the week. (it's being edited)

 

[DonCox]

I have been riding the bike almost every weekend , and it has been at least performing very reliably. I am still down on power, I need to explore other controller options. I can select different Maps on current response. The most aggressive MAP was too much down low and it would run out of power on top end ( on a track). So I upped the counter shaft sprocket 2 teeth from 12 to 14. But now on take off, it will overcurrent, (I think, since there are no codes that I can see, and it comes right back on. ) So I reduce the current output setting from 100% to 80% and now it doesn't overcurrent. Then this weekend I got in a drag race with an ALTA Mode 4 and a KTM 350EXC, newer, and I was 3rd.
My 3 battery packs each put out about 190A(to the controller when I run them independently, but all three together I only see 270A(to the controller). The motor should be capable of taking 600A plus. Every controller has some caveat. Too low on output current. Hard to program, reliability. My Kelly is at least the largest, so I have space. I may try the ASI BAC8000, but only 450A , I would like to try 2 of the Silixcon SL1620, but they won't sell them to us here in the US, plus pretty steep support costs. Using 2 of these I could split the stators. Anybody have some better ideas? At least Kelly has very good support, but they just don't put out the power. They are the heaviest at 12lbs and the largest. 2 Silixcon controllers weigh only 5-6lbs
My friend in Florida Mark XEMX, has not been happy with Sevcon, programming and reliabilty, he is currently trying a new Curtis one, but with only 450A.
My friend in OC, CA should get his ASI BAC8000 back in a while, so we can see how that works.
At least I can still ride what I have until I find a fix. I am doing some work on my older KTM Electric, It needed some repairs, long over due.

 

[Dain_SSE]

I'd recommend a Sevcon g4 s6, in my experience Kelly controllers are garbage and if they work at all half power is all they can muster. Programming a sevcon isn't any more difficult than a Kelly you simply have to bend over and buy the ixxat CAN-usb adapter. I am seeing 450A from the battery size 6 into an ME1304, 100V.

 

[enjoythesilenc]

I'll go in on a ixxat with anybody if its prohibitively expensive

I'm wondering if two votol 150s controllers might work on a split stator motor. I guess you can modify the shunt inside and trick it into dumping more amps. i think they might be voltage limited though. cheaper to experiment with...
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