12kW upgraded E-Grom with ASI BAC4000

I have noticed that E-Groms are becoming more popular so I decided to share my bike here. I was $1200 shipped to my door and came with a 2000W YuyangKing controller, QS hub motor, and 72v of lead acid batteries.

My modifications:

1. ASI BAC4000, running 150A battery, 250A phase
2. 1.5 kWh of Toshiba SCiB Lithium titanate in a welded sub-frame that bolts onto the stock battery connection points. Nominal 78v
3. Tyco LEV200 contactor paired with a ZEVA smart precharger
4. 120v DC/DC converter
5. Cycle Analyst HC with a .25mOhm shunt in a 3d printed mount where the stock display fit.

All of the above fits in the faux gas tank (except for the battery and CA). The battery is still a work in progress, and I hope to secure some leaf modules to replace the low energy density LTO, as I am only getting about 18 miles of range right now. I am also toying with the idea of putting a qs 138 3000w motor in the swingarm, but SiaEcosys on Aliexpress just sent me a motor with what seems to be bad bearings.

Hey, awsome project. Where did you get the 120V dc/dc converter??

Thanks!

I found the DC/DC on eBay:
https://www.ebay.com/itm/222860367230
It's non-isolated, but hasn't given me any issues

TorgueRPM said:

Thanks!

I found the DC/DC on eBay:
https://www.ebay.com/itm/222860367230
It's non-isolated, but hasn't given me any issues

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I will check it. Thanks

Starting my own e-grom build. I'm worried about top speed not being enough to keep up with traffic as stock these things top out around 40-45mph. I note your battery voltage didn't go up that much, was the ASI controller enough to bring that top speed up into the 60-70mph range?

marsrover said:

Starting my own e-grom build. I'm worried about top speed not being enough to keep up with traffic as stock these things top out around 40-45mph. I note your battery voltage didn't go up that much, was the ASI controller enough to bring that top speed up into the 60-70mph range?

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Hey, I'm the guy from esk8.news. Definitely not enough to get to 60mph

marsrover said:

Starting my own e-grom build. I'm worried about top speed not being enough to keep up with traffic as stock these things top out around 40-45mph. I note your battery voltage didn't go up that much, was the ASI controller enough to bring that top speed up into the 60-70mph range?

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MarsRover-

My experience is that hub motors are limited in top speed by battery voltage. If you have the same QS 72volt 2000w hub motor I have on my E Grom, then different controllers are unlikely to push your top speed much without higher than 72 volts. I am getting 35 MPH out of my stock grom but with Nissan Leaf batteries , a bigger motor and an ASI BAC8000, I should be doing 70MPH soon. Please post about your project and I have a post on this forum about my build

roadpupp said:

My experience is that hub motors are limited in top speed by battery voltage. If you have the same QS 72volt 2000w hub motor I have on my E Grom, then different controllers are unlikely to push your top speed much without higher than 72 volts.

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Actually this is incorrect, controllers matter tremendously regarding top speed.
You are right to say that voltage is the primary way of getting higher speeds, but the other way is to get a controller featuring flux weakening. This feature artificially lowers the back EMF of the motor, allowing it to reach much higher top speeds.
What that means is that if you get a controller capable of doing flux weakening, then you will be able to reach 60mph with a 10 inches wheel setup, a 2000W motor and 72V battery. That's what my old scooter was able to do.

Sorry for the mis information!

From what I've read, some motors' designs make field weakening less efficient than others, sometimes so much so that field weakening is not the best way to go about reaching higher speeds. It depends on the motor

Hello. I have a similar project but with the BAC8000. Can you explain me how you connected the Zeva precharge/12V DCDC/Tyco/Battery positive to controller?? From where you get the 12V to the Zeva precharge? Are you using the native ignition for the controller or you just switch on the 12V to activate the relay and turn on controller? Do you use a main disconnect braker?? If you can make it like a diagram it will help me a lot. Thanks in advance.

The 12v system is turned on by a switch on my handlebars. Then when I turn the key switch the smart precharger prechargers the controller caps and closes the contactor automatically after they are charged. This is the website with the wiring diagram: https://www.evwest.com/catalog/product_info.php?products_id=299

TorgueRPM said:

The 12v system is turned on by a switch on my handlebars. Then when I turn the key switch the smart precharger prechargers the controller caps and closes the contactor automatically after they are charged. This is the website with the wiring diagram: https://www.evwest.com/catalog/product_info.php?products_id=299

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Ok. I know how the precharge works. So, you turn on the controller when the main contactor closes after the 12V key switch? Do you have the controller ignition (key in or pin 9) wired directly to the contactor? Or you have another switch to bring B+ to the Key in or Pin9??

I have the keyswitch pin wired directly to B+ on the controller, just another ring terminal on top of B+. The controller turns on when the contactor closes.

Thanks!