YZ250 build

azeus17

10 mW
Joined
Jun 16, 2022
Messages
34
Hello everyone! This is my first post, but I have been snooping around for several weeks gathering info for my build. My 9 year old son and I recently modded his Razor MX500 and we got the build bug! Now we need to build something for me. I picked up a 96 yz250. I plan to put a QS 138 70h v3 motor in it and build a 20s8p, or maybe 10p, depending on space, out of Molicel 21700 p42a cells.

The one thing I am having trouble narrowing down is the controller. The guys at QS are suggesting the Votol EM200. I asked if they could provide the EM260 and they said “it is not ready for market.” I told him I have seen it used in other builds and for sale on other sites and he just replied that it needs hardware and software updates. I saw another recent CRF build where the guy used a BAC8000, which seems like a good option. To be honest, my head is spinning. If anyone has a suggestion, I would be all ears. I want to get as much out of the motor as possible, while still being safe and not killing it.
Thanks in advance for any input and all the help so far!
 
Hi,

I have ordered the same motor with the gear box, for my Sur Ron my Sur Ron use a Fard Driver ND 96530, with this controller the battery setting for the Sur Ron is 260 Amps and the Phase amps 460.

This controller as more power output then a Bac 4000 and the phase amps are a bit lower then the Bac 8000, But I plan to used the QS138 70H V3 with the Sur ron or another motocross to do the same conversion like you did with your full size motocross, my battery pack is 12P 20S Lishen LR2170LA cells with about the same specs of a Molicel P42A.

Ariane
 
i think a fardriver controller would be best, from what ive seen they seem relatively easy to setup (compared to other options). I am going to be using a qs 180 90h and fardrive 721800 in my build.
 
Thanks for the replies, guys. Programming the controller seems the most daunting task to me after reading lots of build threads. It seems that either half the thread is discussing controller set up, or it is not mentioned at all. I have not looked into a fardrive, so I’ll start doing that now.
 
IMG_20220611_221154_501.jpg

This is my Crf450 Enduro build using the same QS v3 motor, Fardriver 96v 850 controller and a 28s10p molicel battery I'm currently in the process of building.I think this setup for my application should be nice and light yet still very powerful for more Slow technical stuff with bursts of power for hill climbs.For Mx track type riding I would maybe go for a bigger motor.Lots of information out there on my motor and controller if you ever get stuck👍
 
azeus17 said:
Thanks for the replies, guys. Programming the controller seems the most daunting task to me after reading lots of build threads. It seems that either half the thread is discussing controller set up, or it is not mentioned at all. I have not looked into a fardrive, so I’ll start doing that now.

Your welcome, but I'm not a Guy and I have no plan to be one of them soon or later, I'm a women, good day!
Ariane
 
Im sure most people(like myself) was replying to the GUY who made the post.Good day to you sir whoops madam :wink:
 
speedy1984 said:
This is my Crf450 Enduro build using the same QS v3 motor, Fardriver 96v 850 controller and a 28s10p molicel battery I'm currently in the process of building.I think this setup for my application should be nice and light yet still very powerful for more Slow technical stuff with bursts of power for hill climbs.For Mx track type riding I would maybe go for a bigger motor.Lots of information out there on my motor and controller if you ever get stuck👍

I think that can be a very nice enduro setup too :thumb:
Maybe I would have gone for a few more parallel cells, like 15 or so, for lower ir.
But that is more a hunch than real knowledge.

I must have missed the build thread..
 
j bjork said:
speedy1984 said:
This is my Crf450 Enduro build using the same QS v3 motor, Fardriver 96v 850 controller and a 28s10p molicel battery I'm currently in the process of building.I think this setup for my application should be nice and light yet still very powerful for more Slow technical stuff with bursts of power for hill climbs.For Mx track type riding I would maybe go for a bigger motor.Lots of information out there on my motor and controller if you ever get stuck👍

I think that can be a very nice enduro setup too :thumb:
Maybe I would have gone for a few more parallel cells, like 15 or so, for lower ir.
But that is more a hunch than real knowledge.

I must have missed the build thread..

Yeah this is one of two battery packs im building for this bike.Next pack will be 24s12p.Life is far to busy for me atm so decided against doing any type of build thread.Tbh though this type of setup has been done many times already in the past.Thanks :thumb:
 
Ariane said:
azeus17 said:
Thanks for the replies, guys. ...

Your welcome, but I'm not a Guy and I have no plan to be one of them soon or later, I'm a women, good day!
Ariane

Maybe you aren't aware of the fact that "guys" can be used for both, men and women.
Might be a difference between Canada and other English speaking countries.
 
Ariane said:
azeus17 said:
Thanks for the replies, guys. Programming the controller seems the most daunting task to me after reading lots of build threads. It seems that either half the thread is discussing controller set up, or it is not mentioned at all. I have not looked into a fardrive, so I’ll start doing that now.

Your welcome, but I'm not a Guy and I have no plan to be one of them soon or later, I'm a women, good day!
Ariane

Sorry, no offense intended. I did notice your profile pic after I posted, but hoped “guys” would be taken in the sense of “everyone”. Either way, thanks again!
 
speedy1984 said:
IMG_20220611_221154_501.jpg

This is my Crf450 Enduro build using the same QS v3 motor, Fardriver 96v 850 controller and a 28s10p molicel battery I'm currently in the process of building.I think this setup for my application should be nice and light yet still very powerful for more Slow technical stuff with bursts of power for hill climbs.For Mx track type riding I would maybe go for a bigger motor.Lots of information out there on my motor and controller if you ever get stuck👍

Very nice! I wanted to go with a CR/CRF for the aluminum frame, but I could not find one reasonable priced in my area. No MX riding for me. I’m hoping to be able to get a couple hours of fire road and single track riding.

I am interested in your battery. Do you know what the dimensions are? Any pictures from the build? I don’t think I’ll be able to make mine as tall due to the different frame designs, so I’ll probably have to go a little wider.
 
Because I know everyone likes pictures. Here’s our project when we brought it home and after my son stripped all the plastics. We have not ordered the motor yet, and assume it will be a while, so I had a full scale model of the motor 3D printed to use for mock up. It has to be printed in two halves and will be glued together.

AB590FA0-C09B-47A0-A3CB-FC53268A4438.jpeg
DFF22D50-3D4B-44EA-8929-5DED83C88E09.jpeg
23C0AAC8-8A0E-4265-89F1-CE5D30024A6F.png
 
How does this motor mount look to you experienced builders? It seems to be inline with the swingarm, but does have about an inch it could move back, with some additional fabrication. In this location, I am able to utilize an existing mounting location on the frame. If I move it, it would require new tabs to mount to. For the second mounting point, I am planning to run some supports from the swingarm bolt, down to the lower right bolt hole you can see on the motor. Is that enough support, or do I need more,
E04C4DD3-5F73-43A3-AA6D-24B335D7855C.jpeg
 
Thanks for the feedback. Just so we are clear, the sprocket was printed with the motor and is represented by the black circle that I highlighted here in red. That is too high? Moving down would be fairly easy, so just checking. 62E4FE97-9C52-4C95-B5D2-EE2BC0957FE7.jpeg
 
Work has been continuing slowly. Most of my time has been spent learning CAD so I could design parts and have them 3D printed for prototyping. I designed motor mounts, controller mounts and a spacer to fit in the area on the swingarm bolt where the combustion engine used to mount to. I managed to get the motor mounts printed, attached to the motor and in the frame.
My goal was to not have to weld anything and so far so good.
IMG_7269.jpg
IMG_7273.jpg

I cut the mounts out of steel plate and everything lined up great.
IMG_7286.jpg

I have decided to mount the controller in the airbox location. Fits nicely and out of the way.
IMG_7272.jpg

I have the battery mocked up. I decided not to build myself and am working with an experienced builder. He provided the 2D outline and I built into a full pack. Fits in the frame nice and does not stick out too far.
IMG_7270.jpg


A few questions I have been thinking about:
1. Has anyone located a good source for a 520 sprocket that fits this motor? I have seen the Mighte, but $100 for sprocket and shipping to the US seems like a lot. If I have to, I will, but any other options out there?
2. Contactors and precharge circuit...What is the current consensus? I have read that with a smart BMS, they are really not needed anymore. I plan on using an ANT BMS. I do like to be conservative, though, so is it still a good idea to have both contactor and precharge?

Thanks for all the help!
 
Looks nice. How’d it go?
For pre charge I think a loop-key with a precharge plug is ideal in its simplicity and being pretty theft proof..assuming they don’t know it’s as simple as bridging the contacts.

U could get a custom sprocket made cheaply abroad.

I wonder how well adhesives can replace welding
 
The build has not really moved much in the last couple of months. I had some travel for work as well as 2 weeks with family on vacation. I really need the battery to make some progress, but that is a pretty hefty bill, so I have been putting it off. I am hoping to be able to pull the trigger on it before the end of the year.

I did end up buying a custom rear sprocket from Electro & Co. Might end up needing another larger one, but will wait to test this one first.

I'm not sure what the comment about adhesive is for.
 
You were saying you didn’t want to have to weld anything and I wonder how well an adhesive can substitute

I find lifepo4 from batteryhookup.com or some other places are cheap.
 
Oh, I see. Yes, I do not want to have to weld. Plan is to utilize existing frame mounting holes/locations which I have been able to do so far.
 
Azues17, I think I can help you. a couple of quick answers. Here is a link to my bike build on a 2014 YZ250F. A lot of your answers might be there.

https://electricdirtriders.com/threads/yz250f-2014-build-with-qs-138-70h-v3-motor-and-450a-controller-part-1-and-part-2.2733/#post-33026

I am running 13 51 sprockets, 520 chain, QS 138 70H V3 motor and the EM260/2SP Votol controller. I bought it all from Electro and company. It comes programmed from them, and it is "Plug together and Ride" from them. It took me 5 days to build this bike, I have built 5 others this year. Here is the first ride of the Yamaha on the street.
https://youtu.be/N1lioYhFW3c

The battery for this is a 20S14P Sony VTC6 cells 18650 size (72V 420A, 42AH). For others I have built 20S8P P42A Molicels 72V 360A 72V (84v Max) 34ah, and a KTM 150X with 2 of those for 20S16P P42A Molicels.

I use Precharge resistors with the Votol controllers, and no switch arcing. it is a 1K 10W resistor, and you can see it in the pictures and also in the hand written schematic. I would recommend the Votol Em-260/2SP from Electro and Company, because it comes programmed, and it will and can do 450 battery Amps. The motors live so far. Here is the same combo on a 2004 CRF250 with the same motor/controller from Electro and Company at Glen Helen running 300A 72V (84V max).
https://www.youtube.com/watch?v=wpCnW2bwSnM&ab_channel=CasMoto

I run mine at the moto track at 250A most of the time, (mode 2) and bursts of 380A (my battery max right now) (Boost, or mode 3 the way it is set up now)
I will have video of this bike at the track soon. last time at the track, my memory stick was full when I got there and I did not know, here is the mud evidence of about 30 laps ( 10 on the first charge and every other ride was when the battery got back to 80% 78-80V.)
My battery is two packs, and I have 2 10A chargers, and 30-45 minutes bring it back to 80% +

IMG_3009[1] (1).JPG
 
Thank you! Lots of good information there. I will have to register for that site so I can view the larger pictures.

Has anyone used QS10 or QS12 connectors for their battery? I was planning on Anderson plugs, but these were recommended to me. The QS12 looks like it has a max amp rating of 320a, which would be enough for my application.
 
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