Hello from Texas - E22 M620 Build

[hornetraider]

Hello everyone. I am in Dallas. Used to ride pretty frequently in the late 2000's. Rode a cheap mountain bike through my college years to all of my classes, and haven't been on a bike since.

I am building one myself with little/no build experience on bikes and very little electrical knowledge. The main components are:

Bafang m620 Ultra Motor UART (Can't decide on 48v or 52v)
E22 Carbon Frame

I don't have anything else spec'd out yet but am trying to get all of my ducks in a row before pulling the trigger on everything. The frame should be here late this year/early last year, so figured I'd start an account and ask all of my questions ahead of time.

 

[Xezzare]

E22 is the frame I'm quoting from dengfu's site , also I asked them to quote me the M620 motor kit ... just a day ago they replied saying M620/M600 motors only come in CAN versions ... I'm not planning to adjust any settings or fine tune OEM specs so I guess I will be OK with OEM settings .... if you don't mind me asking where do you purchase your frame + motor $ ... I'm from San Antonio TX ... I have built many mtbs/road before and service them no issues and by looking Rob Rides/Neeko videos eMtb is really not that complicated ... the interesting part will be to learn how to service the motor and where to get replacement parts years from now .

Hope all goes good with your new build
Cheers
Cesar

 

[hornetraider]

E22 is the frame I'm quoting from dengfu's site , also I asked them to quote me the M620 motor kit ... just a day ago they replied saying M620/M600 motors only come in CAN versions ... I'm not planning to adjust any settings or fine tune OEM specs so I guess I will be OK with OEM settings .... if you don't mind me asking where do you purchase your frame + motor $ ... I'm from San Antonio TX ... I have built many mtbs/road before and service them no issues and by looking Rob Rides/Neeko videos eMtb is really not that complicated ... the interesting part will be to learn how to service the motor and where to get replacement parts years from now .

Hope all goes good with your new build
Cheers
Cesar

Hello fellow Texan. I am planning on getting the UART version of the motor from Green Bike Kit. I haven't ordered the motor yet but see that it is available on their site.

Edit: Wish you lived closer to help put this monstrosity I'm planning together!

 

[Xezzare]

Cool....if you decide to Post your build I will follow up your progress since you are ahead of me.

 

[Ford Prefect]

If you have any update, I would be interested! GreenBikeKit & Frey.bike both seem to have UART configurable m620 motors in stock, at the moment???

Given the critical need to balance dual battery packs before connecting them, I'm not a strong proponent of paired battery packs...

I personally don't believe batteries under 675Wh are of much use as a transportation option. I've ridden quite a variety of ebike systems & honestly the smaller units weren't worth the expense & weight, for me. At about 6'10" & 250 pounds, I went with two individual 1008Wh/48V×21Ah packs (seventy-eight Samsung 35E cells, 13s6p) & after one year swapping back & forth between them I'm convinced of something I already kinda knew about that whopping big g510 motor core: It would prefer a higher voltage.

My huge self, would get more miles per watt-hour from the m620 at 52 Volts (or 60!), than I do at 48 Volts... presuming of course the discharge rate per cell were the same. No luck finding a Dorado pack with 14s6p, just yet.

5p just isn't enough for 30A from what I've seen: The battery seems to sag even faster, high-C discharge rated 21700 cells or no?

Theoretically, at peak charge, I'm told a "52V" 14s6p pack of 18650 cells, should(???) still be safely within the input voltage limits set for the 48V×30A controller... Without increasing its Wattage draw beyond the original 48×30, the stock controller could supposedly make use of a fully charged 52V pack, provided the pack isn't drawn down below that pack's nominal Voltage? (I'm certainly not planning to do this, just hoping to confirm why someone's build would work as reported...)

If I could find a 14s6p pack that fit my frame, I'd definitely go for a 52V controller. The m620\g510's KV:RPM ratings, favor higher voltages than most ebike motors. The 60V builds aren't over-volting that motor core; the 48V builds are under-volting it.

Running lower than the motor's most efficient Voltage, requires more Watts per RPM, meaning way higher amperage draw for the same speeds! It also means more waste, more heat. An m620 moving the same load at the same speed, tends to run cooler at 52V than at 48V. More efficiency plus more performance; what's not to like? I see no advantage to building a 48V m620, if you can build a 52V instead.

I wouldn't want less than 20Ah for a 30A controller. Generally speaking, bigger Wh is better... but when it comes to the Bafang m620 Ultra, I'd sooner choose a 14s6p than a 13s7p!

If you can get hold of a 52V controller & pack with >20Ah for an E22 frame, I say do it!

If you're average size or larger, for an adult US male, I'd recommend the very largest internal volume rear shock you can get: Springs are one thing, but big weight needs big damping, & m620 ebikes weigh plenty before we throw big riders on them.

I wouldn't buy a non-configurable ebike motor controller.

In particular, Bafang's default configuration on the m620, is... wrong. Not "less than ideal", it's literally uncalibrated.

Frey's latest config I've seen, at least sets a safe baseline for the pedal torque sensor & such essentials. Even so, the config I find most suitable is profoundly different in a dozen ways.

Spoiler: A note about the state of Bafang firmware for the m620

It's also worth noting that the m620 controller's firmware seems to reject any settings where the "KeepCurrent" for any Speed00/Speed20/Speed40/etc range is set higher than its "MinCurrent". This is backwards, as the MinCurrent is a floor value, below which KeepCurrent cannot actually drop. As seen on the older Pedal Assist tab, KeepCurrent should be a value between MinCurrent & max. With the current firmware, the KeepCurrent for each Speed00/etc range, can only equal MinCurrent. Unfortunately, without a firmware update from Bafang, I see no way to fix this. From what I've seen, the CANBus versions are locked with this issue still present. (If I find time in the shop with a camera, I shall send Johnny at Bafang's USA service dept, a video illustrating the config issue visually.)

 

[Paulquattro]

Welcome to the site

 

[mjcother]

Watching this, as I am in the same boat. I want to build a bike that won't stand out as much as a surron on the public roads and paved bike paths... I am highly technical and experienced in mechanics, but zero knowledge in component selection. I wanting to get the E55 or E56(with shipped battery) and I am OK with CANbus version of the 620 as the programming tools will become available eventually... shock/fork, wheels, etc will be selected with the 'great deal on last years fairly high end product' to be somewhat budget conscious. The little things are my concern, getting the right fitting components without spending hours on each part.... in the process of crawling the "Dengfu E22 Frame Thread" and a few others..

 

[Ford Prefect]

Watching this, as I am in the same boat. I want to build a bike that won't stand out as much as a surron on the public roads and paved bike paths... I am highly technical and experienced in mechanics, but zero knowledge in component selection. I wanting to get the E55 or E56(with shipped battery) and I am OK with CANbus version of the 620 as the programming tools will become available eventually... shock/fork, wheels, etc will be selected with the 'great deal on last years fairly high end product' to be somewhat budget conscious. The little things are my concern, getting the right fitting components without spending hours on each part.... in the process of crawling the "Dengfu E22 Frame Thread" and a few others..

"I am OK with CANbus version of the 620 as the programming tools will become available eventually..."

It's been years already. I wouldn't hold my breath (or stake any money) waiting for the BESST tool to restore configurability that has been taken away.

Based on the git readmes, attempts at reverse engineering access to the CANBus controllers, did not seem to get very far before throwing their hands up, either.

Bafang makes good ebike motors but I can't say the same for firmware/software. There are old mistakes which have yet to get fixed, even on new units.

At this point, I'd be somewhat surprised if they update anything for existing units. Honestly, they seem to be hoping most of the market won't want to tune anything.

Personally, I find Bafang's motor controller configurations need to be tuned, to work as well as other brands.

Again, the m620's g510 motor itself is great relative to what's on the market; the uncalibrated stock config really lets it down though.

If the only option were a CANBus controller (it's not, UART are still available), I could only recommend swapping the stock controller for an aftermarket one - which wouldn't fit inside the case.