I Nuked my BGX

[biknut]

Meet Nuke




I bought this bike in late August. BG-X.


I liked the bikes looks right away, but what really caught my eye was how much possibility it might have above, and beyond the low cost choices the manufacturer make in order to sell it for $1800 shipped. I'm at a point in my life where I'm having as much fun customizing my bikes as riding, which is handy this time of year.
This is the plan,
Roll my own 72v battery, Thermo Nucular F24 controller, with uLight accessory, 5000w motor, keep the look as stealthy as possible to the stock look.
So this is how it stands today.
Over the last 2 months or so I build a 72v battery to fit inside the stock shell using Samsung 50S cells. 20s 4p with an 80 amp bms. is the most that will fit in the shell. I've already converted all the wires on the controller, and finalized the controller mounting today. I hope to finish the motor wires later this week. after that I'm planning to lace the stock purple rim on the new motor. I plan to be finished with the whole project by the end of February.

 

[neptronix]

Dang, how's the ride quality on it with that great suspension?

 

[biknut]

Dang, how's the ride quality on it with that great suspension?

It rides very well even though the front forks are just low cost spring forks. The Works Performance shocks were in my parts pile from my Sportster riding days. The primary spring is over sprung for the weight of this bike, but the shorter secondary spring works better than the stock shocks. They both were leaking when I puled them out of the pile, but I was able to buy rebuild kits and referb them. Overall the BGX is more stable at high speed than my Stealth Bomber, but the steering is a lot slower. The feet forward riding position is very comfortable even with the low seat height. The ride is so layed back that I already lost one cell phone that flew out of my pocket pedaling across an intersection.

 

[neptronix]

Sounds cool, i think that long wheelbase has a lot to do with the handling characteristics. Also the fork angle.

The ride is so layed back that I already lost one cell phone that flew out of my pocket pedaling across an intersection.

Yeah same problem as i have on my semi recumbents. I feel like storage compartments is a necessity!

 

[99t4]

...keep the look as stealthy as possible...

Depends your definition of stealthy.

 

[biknut]

I worked on a lot of little details today. I just noticed I need to cut the side cover a little more. Those big 7g wires are a little crowded. The motor phase wires are cut to length. Tomorrow I can start soldering.

 

[biknut]

Not soldered yet, but this is the look I'm going for.

 

[99t4]

Looks good. Are you going to house them into an outer loom?

 

[Tony01]

Hey biknut when you first bought this I sort of had a feeling you’d be modding it soon enough.

A 5000w motor will be too big and heavy. I think you should get a 3000w it will be good to over 20kw depending on the wind. Also a good time to go to 17” wheels which could be the same OD if you go skinny tires as 20” fatbike. The nuc 24f is capable of 28kw and is an amazing choice but a wiring nightmare.

Remember, always plug ground in first or disconnect last on nucs. I made a separate tiny ground wire on my battery build along with the large qs8 connector just for this.

Also you MUST have an isolated power supply for any peripherals like the uLight. I just used a regular switching 110vac power supply 12v10a.

 

[biknut]

Looks good. Are you going to house them into an outer loom?

yes, but I need to leave a little bit unbound so they're easy to deal with when I have to change a tire. I go through a lot of tires.

 

[biknut]

Hey biknut when you first bought this I sort of had a feeling you’d be modding it soon enough.

A 5000w motor will be too big and heavy. I think you should get a 3000w it will be good to over 20kw depending on the wind. Also a good time to go to 17” wheels which could be the same OD if you go skinny tires as 20” fatbike. The nuc 24f is capable of 28kw and is an amazing choice but a wiring nightmare.

Remember, always plug ground in first or disconnect last on nucs. I made a separate tiny ground wire on my battery build along with the large qs8 connector just for this.

Also you MUST have an isolated power supply for any peripherals like the uLight. I just used a regular switching 110vac power supply 12v10a.

I'm glad you know something about the nuc because I'm not familiar with it at all, especially the uLight. I was laboring under the belief that the controller supplied 12v to the uLight? Or do I need a converter to give the uLight 12v? Or is the uLight a converter? Don't worry I'm probably a month away from trying to power it up.

I bought this bike to customize. A couple of things, I love the look of it as it is for the most part.. Love the big giant tires. They're actually the exact same size as my 97 road king. I bought this 5000w motor. This same motor comes in a 3000w too. I wouldn't bbe surprised if the only difference is 3T vs 4T wind or some other trickery. It's only rated for 135 Nm. I'm thinking that's not that much for 5000w. I also noticed this motor is noticeably lighter than the 5000w QS motor in my Stealth. At any rate this motor is lighter. The stock motor put out a little over 2000w, and went almost 40 mph. so I'm not really expecting this motor to be a lot faster then the stock motor.
Another consideration is it's not going to be subjected to more than 80 amps. I have a 80 amp bms, and my battery may be able to handle that much.

 

[biknut]

This is what I did today. All the motor wires are done now. After this I have to think about what I want to do next. I need to disassemble the stock wheel wheel, and find out if the rim is double wall like the one on the new motor. If it is I'm good to lace on the new motor. If it's not I may just run this rim for a while. The only thing I don't like about the rim is it's only 3 inch. The stock rims are 4 inch, and they're purple.

 

[Tony01]

I was laboring under the belief that the controller supplied 12v to the uLight? Or do I need a converter to give the uLight 12v? Or is the uLight a converter?

Yes the controller does provide power to the uLight but it’s only 3 amps at 12v. I forgot. I remembered why I used a separate power supply for it, it’s because my headlight was drawing 7 amps and I wanted to be sure it would run brake light and turn signals as well. Actually I had only head and brake light thru nuc then turn signals on a separate 12v system, which had other stuff on it too like my j1772 controller.

Motors are rated differently by different vendors. Some rate them in continuous, some rate the same motor in a higher continuous power, some just rate them in peak.

The motor in your stealth looks to be a qs205/50h which is a 3000w rated motor. Usually with QS original ratings you can push 6-8 times their continuous in peak power. For example mine a 3.5t 3000w rated qs205/50h I pushed 24000 watts peak and around 8000w continuous with the statorade and heatinks.

There are different vendors of the same QS motors and they will sometimes call a qs205/50h a 5000w motor. Their qs273 was the 5000w and that ones 15lbs heavier, but you can push over 35000 watts I’ve heard.

The motor you’ve got looks to be a 1500-2000w rated continuous motor and is sometimes sold as a 5000w peak motor. That’s enough for a light bike, bicycle tires, and for cruising. The nuc is the highest quality controller you can buy for this range IMO, but the far drivers and em controllers sold in bundles by qs are cheaper and easier to wire up.

 

[biknut]

Yes the controller does provide power to the uLight but it’s only 3 amps at 12v. I forgot. I remembered why I used a separate power supply for it, it’s because my headlight was drawing 7 amps and I wanted to be sure it would run brake light and turn signals as well. Actually I had only head and brake light thru nuc then turn signals on a separate 12v system, which had other stuff on it too like my j1772 controller.

Motors are rated differently by different vendors. Some rate them in continuous, some rate the same motor in a higher continuous power, some just rate them in peak.

The motor in your stealth looks to be a qs205/50h which is a 3000w rated motor. Usually with QS original ratings you can push 6-8 times their continuous in peak power. For example mine a 3.5t 3000w rated qs205/50h I pushed 24000 watts peak and around 8000w continuous with the statorade and heatinks.

There are different vendors of the same QS motors and they will sometimes call a qs205/50h a 5000w motor. Their qs273 was the 5000w and that ones 15lbs heavier, but you can push over 35000 watts I’ve heard.

The motor you’ve got looks to be a 1500-2000w rated continuous motor and is sometimes sold as a 5000w peak motor. That’s enough for a light bike, bicycle tires, and for cruising. The nuc is the highest quality controller you can buy for this range IMO, but the far drivers and em controllers sold in bundles by qs are cheaper and easier to wire up.

Thanks for the info Tony, I can use all help I can get. I think 3 amps will probably be adequate for my bike. I'm only planning a headlight, and taillight with brake light. I'm going to toss the turn signals on the pile.

I noticed in the setup manual it implied there's a way for the controller to activate the brake light from the brake cutout signal, but I'm dot sure how to program it to do that.

 

[biknut]

I laced my stock purple rim on the motor today. i don't have a truing stand big enough for this wheel, so I'll have to do it in the swingarm.

 

[Vrooom!]

Why didn't you want tubeless motorcycle tires?

 

[biknut]

Why didn't you want tubeless motorcycle tires?

mostly because they weigh more, and cost more. You're right though, it's time to think about tires.

I made this simple tool to help me true the rim. Right side is lateral, and left side is radial. I'm almost done with it.

 

[rafalg]

Are you going to leave the cranks/chain, or get rid of that? It looks like it was put there by a lawyer, after kicking out the design engineer. I mean, this opening in the frame looks like it was originally designed for holding a battery, but then something bad happened and they released this strange hollowed out form - so now it's your turn to finish the project as it should be..

 

[biknut]

Are you going to leave the cranks/chain, or get rid of that? It looks like it was put there by a lawyer, after kicking out the design engineer. I mean, this opening in the frame looks like it was originally designed for holding a battery, but then something bad happened and they released this strange hollowed out form - so now it's your turn to finish the project as it should be..

I'm not really planning any changes to the frame, or pedals, but I do feel like I'm building this bike like it should have been if cost hadn't been such a big consideration.

 

[biknut]

Would there be a problem if I run my lights on 72v? Lights are available with built in converters that run 72v.

The other choice would be 12v. The only problem with 12v is it won't run my day time driving light.

 

[amberwolf]

You can use both if you like. Run the lights that have built in converters on traction pack directly, and the ones that won't on a DC-DC that can handle the full required power for the appropriate voltage.

If you want everything on the same voltage, then if you already have a light you want to use, that dictates the voltage of the rest of them. Otherwise you can replace it with one that runs at the voltage of the other lights you want to use.

I prefer 12v stuff, because I can find good well-built reliable DOT-rated (for real, not just labelled) weatherproof lights of all kinds, *and* I can also find non-rated stuff that just has a particular look, shape, or function that I also want in addition to the important ones.

My SB Cruiser thread shows some of the various options I've tried, and the Cloudwalker Cargo Bike thread has some others I haven't gotten to using yet. The CrazyBike2 and Delta Tripper and Fusin Test Bike threads show things I tried and mostly abandoned (some I'm still using but those are in the SBC thread).

If you need a DC-DC, make sure it is rated for as much more current as you can afford / have space for, so that you have some wiggle room if it's not really built as well as it's supposed to be or it's rating is a lie (not uncommon in the cheap ones), and in case you end up wanting to add stuff that needs more power (bigger lights, more lights, horn, accessories, air pump, etc).

You can also use a separate battery, either charged separately or with a charger that runs off the traction pack to keep it topped off, etc.

 

[biknut]

You can use both if you like. Run the lights that have built in converters on traction pack directly, and the ones that won't on a DC-DC that can handle the full required power for the appropriate voltage.

If you want everything on the same voltage, then if you already have a light you want to use, that dictates the voltage of the rest of them. Otherwise you can replace it with one that runs at the voltage of the other lights you want to use.

I prefer 12v stuff, because I can find good well-built reliable DOT-rated (for real, not just labelled) weatherproof lights of all kinds, *and* I can also find non-rated stuff that just has a particular look, shape, or function that I also want in addition to the important ones.

My SB Cruiser thread shows some of the various options I've tried, and the Cloudwalker Cargo Bike thread has some others I haven't gotten to using yet. The CrazyBike2 and Delta Tripper and Fusin Test Bike threads show things I tried and mostly abandoned (some I'm still using but those are in the SBC thread).

If you need a DC-DC, make sure it is rated for as much more current as you can afford / have space for, so that you have some wiggle room if it's not really built as well as it's supposed to be or it's rating is a lie (not uncommon in the cheap ones), and in case you end up wanting to add stuff that needs more power (bigger lights, more lights, horn, accessories, air pump, etc).

You can also use a separate battery, either charged separately or with a charger that runs off the traction pack to keep it topped off, etc.

Thanks for the reply amberwolf. I think you answered my question for me. If there's no reason not to go 72v on the lighting I'm inclined to keep it independent from the controller.

The uLight accessory with still play a major role in this build, because it does more than power lights. All the wires to the accessories on the handle bars go down through the frame to the side covers. The uLight is soo small I can keep it in the side cover and hook the brake cutouts, and throttle too it. All the wires for the lights will be in the side cover too so that should make them easy to rewire the lights. The only exception may be the brake light. I think the brake light might be able to trigger off the brake cut outs.

 

[amberwolf]

The uLight accessory with still play a major role in this build, because it does more than power lights. All the wires to the accessories on the handle bars go down through the frame to the side covers. The uLight is soo small I can keep it in the side cover and hook the brake cutouts, and throttle too it. All the wires for the lights will be in the side cover too so that should make them easy to rewire the lights. The only exception may be the brake light. I think the brake light might be able to trigger off the brake cut outs.

If the controller and uLight "communicate" then if you have brake switches for the controller, I'd expect that it would pass their state on to the uLight.

If not, there are a number of ways to add that functionality. I have two different methods implemented on SB Cruiser--the left lever is *just* for regen braking control (no mechanical braking), and provides analog control over the Phaserunner regen braking of the rear wheels (thru the Cycle Analyst), as well as switching the brake light on. The right lever *only* does the mechanical front brake, and switches the brake light on.

Both of them have a switch that is wired to trigger a relay setup (to isolate the lights from the control system; they're on different batteries too). I'm using three separate relays because it made it possible to trigger just the lights without regen, but if you only want to trigger the lights when ebraking also happens you only need one. In my case, each relay is SPST. Two of tehm have coils wired in parallel; these are for the regen braking part. The third's coil is separately energized, so it can turn the brake light on separately.

The regen-only brake lever has a switch built in, as it's "just" a regular ebrake lever (from an ATV, IIRC), cabled to a cable-operated throttle that controls the regen amount. (a relay engaged by that lever switches between my regular throttle and this one during regen so that braking is just the usual fast instinctive/trained control, and not the complicated throttle-hand-controlled method that isn't natural and requires extra actions taking more time and brain attention). Pulling this lever turns on that switch that turns on the brake light relay (as well as the regen-control relays).

My front mechanical brake lever uses a microswitch with a wheeled lever on the disc brake caliper, setup as Normally closed, and is held open by the caliper being in it's usual position. When i putl the lever far enough (just barely, not even enough to begin braking) the caliper pulls away from the wheeled lever, which turns the microswitch on, closing the relay that turns the brake light on. (I tried a number of switch methods on the lever itself, but none of them worked out for various reasons--the microswitch method has worked great for a few years now, though I did have to replace the switch once, probably from internal corrosion as I used the absolute cheapest switch I could find. instead of one rated for the conditions )

 

[biknut]

I've been waiting for this fancy freewheel spacer for over 3 weeks. It's a really nice one. Too bad it's about 1/4" too wide. So much for the best layed plans and stuff. I ended up using 4 conventional bottom bracket spacers to correct the chain line. The freewheel only screws on to about 3 threads, but since I don't pedal much that's enough for me.

 

[biknut]

Next my plan is to use the stock wiring harness. All the wires on the handle bars come down into the side cover where my controller, and uLight is located. So far I've identified the 3 throttle wires. The on/off light switch wires, and the brake cut out wires. Also left and right turn signal wires, but I'm not planning to run any turn signals.

I've decided to run my lights on 12v through the uLight. Since my battery is a little on the small side at 20ah, I don't really need to be burning the daytime driving light all the time anyway. This slightly complicates my headlight hookup. The stock headlight is 48v. I bought a new headlight that looks exactly like the stock one, but it will run on 12v, everything except the DRL. The problem is I'll have too change the plug, which means I'll need to identify the wires which are probably going to be different color than what I have. I'll have to think about how to do that for a minute.