2019 KTM 450SXF Factory Edition Conversion to Electric Street Legal

[DonCox]

I just finished this build and I wanted to share the build, because I think this is one of the easiest frame/models to convert, with minimum modification. None to the frame , only plastics are modified. This is a 2019 KTM, but I believe the GasGas and Husky will be almost identical., 2018-2022, in particular, but 2014-2018 also. I find the 450 frame to be the best. ( the lower tubes are 1/2" wider, and this allows motor to rear sprocket alignment to be right on. the 250 and 150/125 are narrower, and require just a little bit more work.
The first 2 pictures are the before and after. The finished bike is like the Stark EX , street legal with lights, and a 12V system, but with the advantage, a possibility of a quick change battery.
We found this bike pretty cheap(it was rough) and sold the motor and everything not needed for more than we paid for the bike. That purchased the battery for us. We had Amorge build us a 20S12P Molicel P42A cells, and an ANT smart BMS, with Open Discharge. They built the metal box and all. Just the shipping time is a little slow. There are now better cells that can be used and a good price.
I will include pictures of the motor build here tonight, and I will expand into the rest of the key parts. There are a million ways to skin this project, This is the way I do it, and I have built or helped build over 20 bikes, and these methods work, and have proven very reliable.
Lithium-King.com makes the motor mount. This is very important to be really solid, and certain steps must be followed to ensure that. This electric motor wants to turn the wheel and get itself out of this frame, so don't skimp on this part. The mount from Lithium-King.com is made for this frame/ bike and motor. Their universal mount should not be used with the slotted bolt and the system not welded in the rear. The torque is tremendous on this bike. I am not the best welder, but my welds work, I hope you can post better looking welds.
This is the motor mount from Lithium-King.com, it is made of 1/4" 6061 aluminum, and the upright legs in the back are the back battery tray mounts. We don't want the battery to touch the motor so as not to transfer heat from the motor to the battery. Each major component has Heat issues that need to be addressed. The motor makes a lot of heats and can usually withstand that in our use. The battery can overheat, and that is why we use an open Discharge system in the battery, and don't want the battery touching the motor. The smart BMS is used to charge the cell groups, and give us a visual of the battery condition. The Controller monitors for low Voltage condition, and slows us down at 65V and off at 59-60V. The discharge of the battery is straight out of the battery, with a 400A fuse at the controller. Some people have asked for 400A Fuse right at the output of battery before the Disconnect switch. This does make sense.
The mount, bolts across the main mount bolt at the bottom of the frame, with spacers to make it a solid mount point. (Using the stock KTM bolt there). On the swing arm bolt we use a 1" aluminum tube with a 17MM (correction) center ID fit to the whole width. You need to align the motor sprocket edge with the rear wheel sprocket edge, and the chain centers on the plastic guide pad on top of the swing arm.. Make sure the rear wheel is perfectly aligned in the swing arm. ( alignment spacer on each side are as accuarately equal as possible). I will stop here for today, more to follow and ask any questions. You notice in the pictures we do cut the top mount off of the motor for more battery space. I use a Sawsall with a long blade.

 

[halg]

Looking forward to more info!

Mainly, would you be willing and able to share the exact dimensions of the battery?

I'll be in battery planning mode soon. I am pretty sure I will target a 20s12p like this one. Based on my research so far, it seems like around 612 cubic inches of volume is required for such a battery. I'll create a post soon seeking info about battery dimension information so I don't clutter this thread too much. But, getting another data point on the volume I need to target would be great.

EDIT: US people like me must annoy the rest of the world who uses the metric system. Metric or imperial dimensions work. Especially if that is how you communicated the dimensions to amorge.

 

[DonCox]

The Battery subframe is also 6061 Aluminum 1/4" thick and 2" wide with the top mount of the motor cut off so it can clear the motor by 1/4". It mounts to the lower skid plate mounts in the front, but could be made to work coming up to the bigger mounts in the front. You can see that the battery clears those mounts in the front. With the bottom tubes level, the battery tray sitting at 30 degrees. The next pictures are of the battery tray, that is bolted to the battery subframe in the front and rear. You can see by the guides that the battery comes in and out from the left side of the bike. You can see the rear right guide is a little angled to guide it in easier. The battery tray is 1/8" aluminum, not particularly 6061. With the battery in place you can see the clearances front and back to all the original mounts. I did a 2017 KTM 150SX and with a lot of mounts removed, we got a 20S16P battery in this space, but it was tight. With 20S16P and Molicel P50B cells it is 80AH. This 2019 build is around the quick change battery system. The last picture of the battery mount is the left side retaining piece. It bolts into place with 2 x 8mm bolts. There will be 2 straps over the top of the battery with latching tension buckles. The strap is made of 1 1/4" by 1/16" strap. For alignment in the front I split the strap to go on the existing mount in the 8mm hole in the frame mount. (You can see the hole in IMG_7258, and the split straps in IMG_7282.) All the power and charge cables come out of the top left side of the battery. The latching straps can exert up to 1320lbs of pull. There is also a locking in place pin, if you look closely at IMG_7270 or IMG_7071, which I did lock.
The build specs I sent to Amorge were just hand drawn, they responded with a draft of what they could do, and we went with it. I cannot put more than 20 images (and I have) in so I will get into the battery ordering itself tomorrow.

 

[OpaTsupa]

Following with interest.
Did you happen to weigh the empty chassis? What is the final weight?

Would love to see a video of it in motion if you have it.

 

[fmxxx666]

@OpaTsupa doncox has a ton of Videos already online on his Youtube Channel here is the Link: Donald Cox there are also ride videos of a KTM and other Bikes he build.

 

[DonCox]

Following with interest.
Did you happen to weigh the empty chassis? What is the final weight?

Would love to see a video of it in motion if you have it.

The final weight was about 240lbs with kickstand and lights.

The donor bike weighed 141lbs, ice motor stuff all removed,

 

[DonCox]

I will talk a little bit about the Battery. I sent a sketch of what I wanted and Amorge sent back a drawing of the idea. Back and forth a few times, and a couple quotes to get everything correct, and off went the payment. They at Amorge do a good job in a lot of ways, but once you have paid your money, you are in Limbo. No more communication. This is just there way. They offer air shipment and sea shipping for a lot less. I really think it is slow boat and fast boat. I know it is difficult to ship, specially Air Ship batteries, but 3-4 weeks to airship is not right. I order a lot from Aliexpress, a Motor, or a controller, and it usually take about 2 weeks from order to delivery thru DHL air from China, from order to delivery. Amorge builds the battery, and does a great job, but the communication during the build and during the shipment is zero. And once it leaves Amorge, it is 2-3 weeks to Air ship it here.
Enough about that, other than they make a good product at a good price.
Here is the sketch I sent them and then the image they sent back. The final quote sheet. The dimensions they quote are right on.
The label on the battery only states 220A continuous Discharge, but you can see on the quote that it is 220/550A BMS. That is the larger BMS to allow, I believe, a 50A charge. On Race setups we quote Open Discharge so the discharge MOSFETs don't heat the battery more while we ride. This build was not built for Racing only.
The battery is real nice with a handle on the top. I mention in the first chapter of this that this Battery is a 20S12P with Molicel P42A cells . This gives us a 50.4AH. If you had them put in Molicel P45B cells it would be 54AH, and the cost isn't too much more. They could also put in Molicel P50B cells to get 60AH. That is a 20% increase of your range for all the same weight. But these P50B cells are still quite expensive.

 

[Mastadon]

This thread is awesome. I just bought a cheap used Chinese dirtbike (Kayo k6 250) with the intention of a similar project when it eventually has motor or trans issues. It has a similar frame design to the Ktm bikes so I am going to watch this closely.

 

[DonCox]

This thread is awesome. I just bought a cheap used Chinese dirtbike (Kayo k6 250) with the intention of a similar project when it eventually has motor or trans issues. It has a similar frame design to the Ktm bikes so I am going to watch this closely.

If your ever up Lake Havasu way, get in touch before and you can try one of these out. They are all smiles. This is this guys first ride on one in this YouTube I posted. A friend in Florida builds these , Mark Peroni XEMX1.com

 

[DonCox]

Tonight I am going to show how I mounted the Controller and maybe the wiring.
The airbox lends itself beautifully to the Votol EM260S controller. Just remove all the parts of the air filter system until it is all just orange plastic. Some of these pictures are off a 2022 KTM I did earlier. After removing the air filter, just make the surface flat, open up the air filter hole to accept the cooling blocks, and mount a flat plate of aluminum 1/8" to bolt the controller on one side and the cooling blocks on the other. These are the first few pics.
After mounting it, you can see the 2 each 3x3" cooling blocks, make sure there is enough plastic removed to get those in. I also found that the air doesn't move in the air box, so I added a small CPU fan below the controller to get airflow thru the box. It sucks air thru the rectangular hole at the bottom of the airbox and a made a few other holes in that area to get good airflow. You can see the fan and the mount below the controller in IMG_6590 and 91. You can also see the DC to DC Power adapter with relay above the controller, and in IMG_6588 and 89. These are used to convert 72V nominal to 12VDC, to run the water pump, fan and lights if you want them. There is a harness that I get from China from the same people that make the controller , to wire all this in very easily.
The harness is made for this operation , it has all the connectors for headlight, taillight, horn, blinkers , etc. I will list most of the parts for this build. The Water pump is mounted on the left side where the radiator was. We only use one radiator on the right side. Right below the water pump on the left side, I also mount the charge port.
The battery feeds thru a QS10 connector to the Master ON/OFF switch on top of the tank with #4 copper wire and goes from there to the controller. I put a 1K10W resistor across that switch so the contacts don't get arced. I also install a volt and current meter in that area. The current meter reads up to 400A, and I can look at it and catch it on my Go Pro sometimes.
If you have any question , shot them my way and I will try to answer them. I will put together a list of a lot of the parts I use. It seem that Amazon carries a lot of it.

 

[Jim Beagle]

Hello Don, some really great info in this thread. I like the idea of a fan mounted in the airbox. At what power level do you typically need to add radiator cooling ?
Thx!
Jim

 

[DonCox]

I run most of the time at 72V 300A. The cooling is different on each bike. I believe it has to do with air flow and the outside air. In a closed airbox it heats up, with the controller outside not as much a problem. We ride in the summer out here, and it can be at 100 Degrees, this is tough on everything, me included. I would recommend cooling for all of our applications. We are pushing a lot of energy thru these devices, so it is going to create heat, and you don't want to be stopping in the middle of a race...