Chinese Grom Clone with 8K QS Hub and Nissan Leaf G2 battery pack build

[roadpupp]

https://advrider.com/f/forums/electric-motorcycles.102/

Hey all-

Been lurking here since May when I ordered my E Grom from Belmonte Bikes. Since it arrived, I have done a few upgrades but have a ways to go. I will share my progress here and solicit any suggestions. Thanks in advance, this is a forum full of interesting projects!

So I started with a lead acid 72 volt system with a 2,000 watt QS hub motor.

Upgraded so far:
Honda Grom Forks
Aftermarket Shock
Brembo Single pot front caliper
SS brake lines
Machined Brake levers
Fender delete and integrated blinkers in rear brake light.
8,000 watt QS Hub
13” rear , 12” front - Pirelli Diablo Rosso tires
11 Nissan Leaf batteries (not installed yet)
80 amp Greentime controller (not installed yet)

Future upgrades: a better controller.

So I have been riding this thing stock for a few months and it is fun around the neighborhood but lacks the grunt I am looking for. Between this forum and ADV riders, there are a few people who have upgraded these bikes. The Honda Forks made a great bit of improvement and the Brembo single pot is better than the two pot chinesium front caliper that came on it. The tires also feel better but I am not pushing them on the stock power.

The forks bolted right up. The rear shock made for Groms also bolted up easily once I had the rear wheel off. Stainless lines took a bit of measuring but eventually I got them working well.

Hub motor.
This was about $550 Plus $250 shipping! from QS. It is made to work with 200mm drop outs so it is a direct replacement for the stock hub/wheel. One thing to note is the motor came with no spacers. I took the old spacers and had one machined (cut into three pieces) and I was able to mix and match the spacers to work on the new hub. I do have some concern that the slotted hub puts a ton of force on the keeper plates on the swing arm to keep from spinning under load. Perhaps socking down the nuts and spacers will provide more structure.

The rear hub with mounted 13” tire is quite a bit bigger than the stock one. The fender may need some fabrication.

Battery pack
I bought 11 cells from Tech Direct. They are used and I bought an extra incase I had a bad one. Probably should have bought pouch batteries on such a small bike. This weekend I am going to drop the battery box and see about expanding it an inch in width and 2.5 inches in depth. This will allow me to get 6 in the bottom box and 2 on either side standing on top of the others.

I will post pics when I am done.

Any feedback is appreciated. Still haven’t figured out a BMS for 20 cells (2 per leaf cell) but will try to get it running before I start working the batteries. Any suggestions for a BMS with 10 or 20 sensors is appreciated.

Charging to 85 volts through a $150 Lithium 72 volt charger.

 

[johnnyddn]

I've been trying to find low mileage salvage Leaf batteries but I haven't had any luck. Let me know how the batteries from tech direct hold up for you.

 

[roadpupp]

Will do. They are 7.6 volts and from Tech Direct. Fresh batteries are very hard to find.

 

[Dui ni shuo de dui]

8,000 watt QS Hub

80 amp Greentime controller (not installed yet)

Whuuuuutt???
Man, you have a 8000W QS motor, why would you install such a puny controller?
You can go crazy with this motor, it can take up to 1000A per phase!
(though I wouldn't recommend you such insane power on a small bike like this, stay on the safe side, 600A/phase and 2-300A battery would already be ridiculously fast)

I do have some concern that the slotted hub puts a ton of force on the keeper plates on the swing arm to keep from spinning under load

Yes, your concern is justified, those motors have a ton of torque and sometimes the plates can be destroyed (which is a problem since then the motor stator spins and ruins the phase wires).
On my bike the plates hold just fine, but on a friend's bike we had to machine a clamp out of 7075 aluminumin order to clamp firmly the axle to some point further on the swigarm. What puts the most stress on this is instant torque variations, if you like to start like a maniac from standstill then you might run into this issue. Your bike is lightweight though, so maybe you'll be fine without one, I suggest you to check regularly and to tighten the axle nuts hard.

Any feedback is appreciated. Still haven’t figured out a BMS for 20 cells (2 per leaf cell) but will try to get it running before I start working the batteries. Any suggestions for a BMS with 10 or 20 sensors is appreciated.

Go for the ANT BMS in 300A version. It will be good for lots of power (we tested it up to 600A battery, works fine), it's easy to hook up, easy to work with, reliable, it comes with bluetooth and a screen that displays all kind of info, it's cheap.... I have nothing but praises for this thing, really great product.
I'm impatient to see your battery build!

 

[roadpupp]

Thanks Dui!

I read all your posts. Really cool stuff you are fabricating to make your bikes great!

I should receive a Kelly KS-S mini controller 72v good for 300A for 20 sec and 120A continuous. I am just getting this project together and bought a few controllers as I was conceiving the bike.

I suspect I won't be happy until it will do wheelies! Thank you for the tip on the hub studs, I think we will need to add something more structural to keep the motor from spinning. I have some ideas.

Will definitely look into the BMS you recommend, .

Thanks for your comments!
Roadpupp

 

[roadpupp]

So I dropped the battery box, cut the bottom out and added 2-5/8" to the bottom edge and rewelded the bottom. The steel was so thin, we couldn't get a good bead so I settled for buttons every few inches. I will mount this and the wheels and make sure the bodywork fits and the ground clearance is at least workable.

Then probably JB weld outside/Silicone inside and Paint. Very little of it is visible but the button welds look like crap.

I was pleasantly surprised that 7 cells fit across the bottom. All 11 will fit nicely as long as the ground clearance is ok.
Needed thin plate steel and so this is how we cut it!

Right click for IMGUR video of a Plasma Cutter

 

[j bjork]

Thanks Dui!

I read all your posts. Really cool stuff you are fabricating to make your bikes great!

I should receive a Kelly KS-S mini controller 72v good for 300A for 20 sec and 120A continuous. I am just getting this project together and bought a few controllers as I was conceiving the bike.

I suspect I won't be happy until it will do wheelies! Thank you for the tip on the hub studs, I think we will need to add something more structural to keep the motor from spinning. I have some ideas.

Will definitely look into the BMS you recommend, .

Thanks for your comments!
Roadpupp

Still no use for this kind of motor with a controller like that.. You should probably been better off keeping the motor you had and just get a better controller. Are you sure those 300A is battery amps? In that case it could work, but be far from the motors potential. I am afraid it is phase amps..
This motor needs something like an asi bac 8000.
Maybe votol em 300 or something like that.

You are putting a garden hose on a fire truck.

 

[roadpupp]

I had a sense that the controller is the weak point but I have just installed the motor and haven't built the pack yet.

I requested a quote on the BAC8000 looks to be a good size.

Thanks.

Roadpupp

 

[j bjork]

No harm in trying it with the controller you have, but it would be a shame if you thought "is this it, not very impressive"
When you are no where near using the potential of the motor. But I think you need to do something about the dropouts, or maybe the whole swing arm. It is good to make like clamps, so the shaft is held tight in the swing. And just use the nuts to hold it in position.

Did you see the seller here on the forum? People seems happy with him. It seems to be a good idea to avoid ERT, just have a look in the vendor relations corner, or what it is called.

 

[John in CR]

Nissan Leaf cells need a bit of compression to get the most out of them and prevent them from swelling. Do you have all of the Nissan hardware that help you achieve even compression using bolts through the holes at the 4 corners without deforming the cans? Look up a pack teardown video to get an idea of what you need.

 

[roadpupp]

John-
That is a good point and one I didn't know about. Thanks! I was thinking of using threaded rod in the four corner holes. Now I definitely will. 4 of the cells will be used in two sets, so I will probably bolt those together but they won't have much compression. These are standing up on either side of the frame. The ones in the bottom of the Battery tray are squeezed to make 7 fit. I can run with 6 there and make room for endplates, or stuff 7 in and a small bit of foam and should have good compression.

Much appreciated! Keep the suggestions coming all. Finally have a Kelly KLS S and the battery box mod and the motor mounted, it is almost time for a test ride!

 

[Dui ni shuo de dui]

I should receive a Kelly KS-S mini controller 72v good for 300A for 20 sec and 120A continuous. I am just getting this project together and bought a few controllers as I was conceiving the bike.

Ah ok that's a bit better, but as bjork said, it is still far from your motor's potential.
Usually Kelly controller power ratings are phase Amps ratings, so I guess it should be around 120-150A battery. It isn't bad but it isn't amazing either.
If it's not too late and if your battery allows it, I suggest you to go for higher power.

Also, I'm not familiar with the leaf cells, how much amps can your battery setup reasonably deliver?

 

[roadpupp]

Dui-

Thanks
I just placed an order from the EU vendor here for an ASI BAC 8000 so I should have plenty of power soon.

Nissan Leaf G2 cells are listed as 66 amp hours and Maximum Continuous Discharge Current is listed as 130A. I have 10 or 11 cells that will be in Series. Website info seems to say they are a safe 10C discharge.

 

[Dui ni shuo de dui]

Nissan Leaf G2 cells are listed as 66 amp hours and Maximum Continuous Discharge Current is listed as 130A. I have 10 or 11 cells that will be in Series. Website info seems to say they are a safe 10C discharge.

I'm not sure what to think since two informations contradict each other.
Maximum discharge = 130A
C rating 10C = 66Ah x 10C = 660A.

I get that the first rating is continuous and the second one is likely to be peak but that's quite a big difference. At first glance it seems a bit weak to me.
Please try to find someone on the forums who knows the Leaf's battery better than I do, just to confirm that it'll be ok with the power you intend to draw from it. Would be a shame to beat the battery to death.

 

[JimVonBaden]

Welcome fellow ADV Rider inmate. Do you have a build thread on ADV?

Jim 8)

 

[roadpupp]

Jim-
Not yet. The project got stalled for a few reasons. I am back on it and will write it up when there are completed photos. Will post over at ADV rider then.

 

[JimVonBaden]

Jim-
Not yet. The project got stalled for a few reasons. I am back on it and will write it up when there are completed photos. Will post over at ADV rider then.

Great, looking forward to it!

 

[pwd]

Hello. Any updates?

 

[roadpupp]

All-
It's been a long time. Now an update!
I bought a powerboat in 2021 and got busy with that. Finally this winter I turned my attention back to the EGrom project. Deciding I didn't have time to get this going, I jobbed it out to my friends at Spark Cycleworks. They build hub motor mopeds and motorcycles and are experts at tuning the Far driver.

It should be back from them shortly! At my request, they stripped the wonky Chinese wiring out of it and upgraded it with their own light and power harnesses that are compatible with the Far driver. "Powerful Lithium" Built a 50 Ah, 72 volt custom pack with dual discharge capable of 540 Amps (38Kw peak). Paired with the 8000w QS 273 and the Far ND72850, that pack should make this thing rip!
Time and my interest in building a custom battery just killed me and left this bike non running for so long. I can't wait to hoon around on it this summer.

It has been fun to reengage with this project and see some of the crazy builds others have done using this platform in the last few years!

I will post more when I get it back and into shape. Will post ride and performance notes.