MSC Engineering YZ conversion ready for track testing

[Mark911]

Wanted to share my progress on the YZ125 conversion project.

My goals were simple (in no particular order) - 1) Lighter than the Alta by at least 25lbs 2) No thermal limiting issues 3) Minimal change in CG location to retain handling 4) No frame mods, completely reversible conversion 5) Enough energy to last 15min moto at expert level 6) Use commercially available motor, battery cells, controller and BMS 7) Ability to charge immediately after moto at 20amps without inducing thermal issues 8) 40-45 hp and 80ft/lbs.

Here's the result -
Conversion specs
Motor - DHX Hawk 40 72v, watercooled.
Controller - Sevcon Gen4 size 6 72-80v 550amp
Battery Pack - MSC Designed and built all copper bus bar watercooled 72v nominal 3.9kw/hr Sony VTC6
BMS - ANT 450plus amp

Mechanical specs
Roller - 2006 Yamaha YZ125
Forks - Factory "works" all aluminum 52mm WP forks and triples
Shock - WP Trax Shock
Swingarm - Late model KTM and linkage
Wheels - KTM Racing
Brakes - Factory KTM oversized front caliper and twin piston rear caliper with LHRB
Weight - 246lbs

What about my goals? Some items are clear based on testing already completed. 40-45hp is not going to happen....there was a slight misunderstanding in motor specs which makes this impossible with the current battery pack. My inertial chassis dyno says 35 hp and 65ft/lbs is where it's at right now. I'll need to do some side-by-side testing with my Altas for a final judgment. Missed my weight bogie by about 5 lbs, however, no weight savings heroics were attempted. I'm sure 5 lbs could be lost quite easily (but the Alta can do the same thing!!!). The watercooled battery pack is working beyond expectations during use and charging, but it's not summer, so . . . . . . . The size of the motor (very small dia) and battery pack (relatively short) fit between the stock lower rails and secondary head tube support tube quite easily. Only minor penetration into the gas tank area resulted in very little change in CG. The original fwd/aft weight bias was retained. Run time (race time) has yet to be fully tested.

Interesting tid-bits - The original design called for a single water pump and cooling circuit. However, the difference in operating temperatures between the battery pack and the motor/inverter is significate enough to dictate separate systems. Therefore, the bike shown (and weighed) has two electric pumps and individual radiators/plumbing. This obviously adds weight and complexity but I feel it'll be essential in keeping pack temps in check during the hot summer months. Also, the Sevcon size 6 controller is a MASSIVE beast. There are other controllers available that I feel will do the job and are much smaller/lighter (about 5-6 lbs). The issue would then be thermal, as the shear size/weight of the Sevcon helps in this respect. The trade would be the additional weight to watercool the smaller/lighter controller(s). More info TBD as track testing gets underway.

 

[Philip]

Awesome, Mark!

What's the new name of your bike? KTMAHALTA?

@DonCox

 

[bayodome]

I saw your post on FB, @DonCox. Really cool stuff. If I still lived in SoCal I'd be more than willing to help you out testing, photos, video...whatever. Really hope you keep moving forward with this build and others. If you're willing to put it in the hands of a local pro and get some video going, that would help promote the bike immensely. I'm happy to throw a few names and phone numbers your way if you're interested.

 

[Mark911]

Don, thanks for the offers. I'll probably be asking Matt Cerami to do some test riding for me. He's just fresh off healing from surgery due to a getoff at Day-In-The-Dirt this year. He's very familiar with my Altas having practiced and raced on them many times. The past few days of rain are the issue now. Soon, however.

 

[Rix]

Top notch work Mark, I really like this set up. Liquid cooled battery pack is off the hook. Should be able to quick charge @ 2c or so without any dramas I imagine.

 

[VINSANITY]

Nice work - big fan of using readily available components as it is easier for support and future upgrades.

A few questions:

Does it charge using 240 or 120 - also how long to charge from empty

Assuming battery is not set up to easily swap out for charged spare due to water cooling - is battery swap possible

What display are you using if any

For faster trail riding any idea what range you would expect - I typically get 20 miles on the Alta, maybe a little more depending on conditions

 

[Mark911]

Top notch work Mark, I really like this set up. Liquid cooled battery pack is off the hook. Should be able to quick charge @ 2c or so without any dramas I imagine.

I'm sure it'll take 2C charging but it'll need to be a 240v charger for sure.

 

[Mark911]

Nice work - big fan of using readily available components as it is easier for support and future upgrades.

A few questions:

Does it charge using 240 or 120 - also how long to charge from empty.

Assuming battery is not set up to easily swap out for charged spare due to water cooling - is battery swap possible

What display are you using if any

For faster trail riding any idea what range you would expect - I typically get 20 miles on the Alta, maybe a little more depending on conditions

110/120 is good for about 20 amps and it'll charge to 95% in about 45 min (final 5% and balancing takes longer). I haven't got anything more powerful for that voltage, but I'm sure at 25-35 amps it'll charge pretty fast.

Yes, it's possible. With some "dry break" hose fittings.

The only gauge I have right now is a small battery monitor showing voltage.

Range is so dependent on the rider and conditions I can't say for anyone but myself. The way I trail ride I'd say its good for at least a couple hours of stop and go tight/slow trail work. The faster the trail/road the faster the pack will deplete. I'll need to do a distance test soon. However, remember, my goal was not range but weight. The pack I have is about the energy equivalent of 3/4 of an Alta pack. Hopefully, only enough to make it through one moto with 90% power. If it does better I screwed up and left some weight on the table.

 

[F451]

Very impressive, nice work.

Why did you go with all the KTM bits (wheels, WP suspension, KTM swingarm/linkage, etc) vs keeping the stock YZ bits?

 

[Oded]

wish I lived in the US. I'd order one of Marc's conversions for my son in no time.

 

[privateer703]

Just out of curiosity, if the stock YZ components were kept (forks, wheels, swingarm and shocks) what would be the cost of the conversion components?

 

[Mark911]

Very impressive, nice work.

Why did you go with all the KTM bits (wheels, WP suspension, KTM swingarm/linkage, etc) vs keeping the stock YZ bits?

Basically, I wanted to upgrade and except for the swingarm, had all those items already (bought for my Altas).

 

[Mark911]

Just out of curiosity, if the stock YZ components were kept (forks, wheels, swingarm and shocks) what would be the cost of the conversion components?

The motor alone is almost half the cost of a used Alta. However, the company (DHX) is almost ready to release their new product line of more economical high performance motors.

 

[testus191]

Mark, in your post you said something about a misunderstanding on the motor/battery combo. Can you elaborate anymore on this?

Also, I’m very anxious for more info on the Peregrine and Kestral production models coming out. Do you have any insider info you could/would be willing to share? Are the power outputs going to match up with the Hawk series models? Know of any increase/decrease in weight? Availability and any idea at a scale/percentage in cost reduction we will see?

Killer job you’re doing on the YZ build! Electro is putting in my quote for some QS motors. Going to start there for my first build with a Sevcon I picked up cheap. Hope to struggle my way to getting things spinning and learn the ins/outs of all this stuff beyond the “textbook” realm of learning and understanding that is the internet. Then move on to something that is hopefully much more competitive with ICE bikes.

The specific power and energy of cells I feel is all we are really lacking. Another decade and I think we will be close. 50hp, 50mi, and sub 240lbs will be the day! Full day of trails, MX, or XC racing on one charge.

 

[Mark911]

Mark, in your post you said something about a misunderstanding on the motor/battery combo. Can you elaborate anymore on this?

Also, I’m very anxious for more info on the Peregrine and Kestral production models coming out. Do you have any insider info you could/would be willing to share? Are the power outputs going to match up with the Hawk series models? Know of any increase/decrease in weight? Availability and any idea at a scale/percentage in cost reduction we will see?

Killer job you’re doing on the YZ build! Electro is putting in my quote for some QS motors. Going to start there for my first build with a Sevcon I picked up cheap. Hope to struggle my way to getting things spinning and learn the ins/outs of all this stuff beyond the “textbook” realm of learning and understanding that is the internet. Then move on to something that is hopefully much more competitive with ICE bikes.

The specific power and energy of cells I feel is all we are really lacking. Another decade and I think we will be close. 50hp, 50mi, and sub 240lbs will be the day! Full day of trails, MX, or XC racing on one charge.

The standard voltage for the DHX Hawk 40 was 96v at the time I ordered mine, which was awhile ago. They advertised that they could do custom voltages as well, so I ordered a 72v option to match my planned battery pack. DHX sent me the spec sheet for the 72v version for my approval before processing the order. The specs looked great, apparently too great. As is turns out someone simply copied the specs for the 96v version and changed the nominal voltage. So, when I thought I only needed 450 motor amps (rms) to make 50hp I actually needed almost 600 (over 800 battery amps) . My pack simply cannot make that kind of current at 72v. This was never discovered unit many months later when I had the bike on the dyno.

From everything I've been told, the new product line will be as good as or better spec wise than the Hawk series. The Hawk series was hand built in-house and consequently very expensive. The new series incorporates all the engineering and production innovation but with some minor changes to make it more suitable for production. The first couple pre-production units should be arriving at DHX soon and I hope to get my hands on one shortly.

The Sevcon is a good unit and they been around long enough to have a decent used market (as you discovered). You'll need the CAN adapter and DVT software to program the unit. There's several companies that offer them as a package.

I agree with you battery tech assessment, at least for big bikes. The smaller 50s and 65 sized bikes seem to be a good fit right now.

Good luck on your build!

Cheers.

 

[riverin]

The standard voltage for the DHX Hawk 40 was 96v at the time I ordered mine, which was awhile ago. They advertised that they could do custom voltages as well, so I ordered a 72v option to match my planned battery pack. DHX sent me the spec sheet for the 72v version for my approval before processing the order. The specs looked great, apparently too great. As is turns out someone simply copied the specs for the 96v version and changed the nominal voltage. So, when I thought I only needed 450 motor amps (rms) to make 50hp I actually needed almost 600 (over 800 battery amps) . My pack simply cannot make that kind of current at 72v. This was never discovered unit many months later when I had the bike on the dyno.

From everything I've been told, the new product line will be as good as or better spec wise than the Hawk series. The Hawk series was hand built in-house and consequently very expensive. The new series incorporates all the engineering and production innovation but with some minor changes to make it more suitable for production. The first couple pre-production units should be arriving at DHX soon and I hope to get my hands on one shortly.

The Sevcon is a good unit and they been around long enough to have a decent used market (as you discovered). You'll need the CAN adapter and DVT software to program the unit. There's several companies that offer them as a package.

I agree with you battery tech assessment, at least for big bikes. The smaller 50s and 65 sized bikes seem to be a good fit right now.

Good luck on your build!

Cheers.

The standard voltage for the DHX Hawk 40 was 96v at the time I ordered mine, which was awhile ago. They advertised that they could do custom voltages as well, so I ordered a 72v option to match my planned battery pack. DHX sent me the spec sheet for the 72v version for my approval before processing the order. The specs looked great, apparently too great. As is turns out someone simply copied the specs for the 96v version and changed the nominal voltage. So, when I thought I only needed 450 motor amps (rms) to make 50hp I actually needed almost 600 (over 800 battery amps) . My pack simply cannot make that kind of current at 72v. This was never discovered unit many months later when I had the bike on the dyno.

From everything I've been told, the new product line will be as good as or better spec wise than the Hawk series. The Hawk series was hand built in-house and consequently very expensive. The new series incorporates all the engineering and production innovation but with some minor changes to make it more suitable for production. The first couple pre-production units should be arriving at DHX soon and I hope to get my hands on one shortly.

The Sevcon is a good unit and they been around long enough to have a decent used market (as you discovered). You'll need the CAN adapter and DVT software to program the unit. There's several companies that offer them as a package.

I agree with you battery tech assessment, at least for big bikes. The smaller 50s and 65 sized bikes seem to be a good fit right now.

Good luck on your build!

Cheers.

Using a bac8000 would solve this problem no? 450 battery amp and 800 phase amp.

 

[testus191]

The standard voltage for the DHX Hawk 40 was 96v at the time I ordered mine, which was awhile ago. They advertised that they could do custom voltages as well, so I ordered a 72v option to match my planned battery pack. DHX sent me the spec sheet for the 72v version for my approval before processing the order. The specs looked great, apparently too great. As is turns out someone simply copied the specs for the 96v version and changed the nominal voltage. So, when I thought I only needed 450 motor amps (rms) to make 50hp I actually needed almost 600 (over 800 battery amps) . My pack simply cannot make that kind of current at 72v. This was never discovered unit many months later when I had the bike on the dyno.

From everything I've been told, the new product line will be as good as or better spec wise than the Hawk series. The Hawk series was hand built in-house and consequently very expensive. The new series incorporates all the engineering and production innovation but with some minor changes to make it more suitable for production. The first couple pre-production units should be arriving at DHX soon and I hope to get my hands on one shortly.

The Sevcon is a good unit and they been around long enough to have a decent used market (as you discovered). You'll need the CAN adapter and DVT software to program the unit. There's several companies that offer them as a package.

I agree with you battery tech assessment, at least for big bikes. The smaller 50s and 65 sized bikes seem to be a good fit right now.

Good luck on your build!

Cheers.

Thanks for the insights! Bummer to hear about the miscommunication on the 40, hopefully they make it up to you with a hookup on the new motor. I reached out to DHX trying to get some of that production here where I work, unfortunately the parts Cameron sent me were not a good fit for us. Most were really stuff that needed to be laser cut. My boss didn't really want to spend the time finalizing the quote I put together. Maybe next time, would've been cool to be involved!

So at 800/600amps is 1.33, does that mean you intended to pull 450*1.33=600amps from your pack originally? Which I assume is what you're currently pulling max (600amps battery)? What kind of continuous draw are you getting off your pack with the water cooled plates?

I do have an IXXAT and DVT, old versions, and have had the controller talking to my laptop. Just don't have a motor, throttle, or anything else yet. Other than the DVT & Sevcon manuals, do you have any thing to help learn the programming?

Yeah, youth and pitbike sized bikes are pretty capable currently. Kids in that age, maybe a tad bit younger will likely grow up with mostly electric I think. The KTM Juniors Supercross at all the SX races are on the SX-E now.

 

[Mark911]

Using a bac8000 would solve this problem no? 450 battery amp and 800 phase amp.

The problem is not the controller, its my battery pack not being able to supply the required amps/voltage. I have a BAC8000 I'll be trying just for comparison, however.

 

[Mark911]

Thanks for the insights! Bummer to hear about the miscommunication on the 40, hopefully they make it up to you with a hookup on the new motor. I reached out to DHX trying to get some of that production here where I work, unfortunately the parts Cameron sent me were not a good fit for us. Most were really stuff that needed to be laser cut. My boss didn't really want to spend the time finalizing the quote I put together. Maybe next time, would've been cool to be involved!

So at 800/600amps is 1.33, does that mean you intended to pull 450*1.33=600amps from your pack originally? Which I assume is what you're currently pulling max (600amps battery)? What kind of continuous draw are you getting off your pack with the water cooled plates?

I do have an IXXAT and DVT, old versions, and have had the controller talking to my laptop. Just don't have a motor, throttle, or anything else yet. Other than the DVT & Sevcon manuals, do you have any thing to help learn the programming?

Yeah, youth and pitbike sized bikes are pretty capable currently. Kids in that age, maybe a tad bit younger will likely grow up with mostly electric I think. The KTM Juniors Supercross at all the SX races are on the SX-E now.

Cams a good guy, helps me a lot.

I can get 600 out of it without issue on an MX type track/duty cycle. Continuous I'll probably never test as it's just not a condition I'll ever encounter. When Bryan Haskell rode it he got the motor pretty hot and the pack was still around 45c. I put a higher volume pump on the motor side after that, lol.

I've got what little anyone can find on the internet. The Laptop I bought from a guy who loaded a bunch of macros, but I don't know how to run them.

 

[testus191]

Cams a good guy, helps me a lot.

I can get 600 out of it without issue on an MX type track/duty cycle. Continuous I'll probably never test as it's just not a condition I'll ever encounter. When Bryan Haskell rode it he got the motor pretty hot and the pack was still around 45c. I put a higher volume pump on the motor side after that, lol.

I've got what little anyone can find on the internet. The Laptop I bought from a guy who loaded a bunch of macros, but I don't know how to run them.

I understand, quite a dynamic duty cycle compared to cruising down the pavement, even dual sport type riding for that matter. That’s pretty impressive for temps on the pack! I’m curious to see how the longevity of it plays out running it that hard but keeping the temps down.