Bafang M620 upgrade?

[Cybersnow]

I have a nice stepthrough e bike with an M620 motor. I am still finding some tough pedaling on very long and steep upgrades. I noticed today, (on line), that there is a company that can modify the output of a fully functional M620 from a 1,000/1,500 watt motor to (IIRC) to 1,500/2300watts. Does anyone have any experience with beefing up the M620?

 

[keithj69]

What company are you talking about?

 

[Cybersnow]

Watt Wagons, 966 Watertown St., West Newton, MA, 02465

 

[Tom@WashDC]

I have a nice stepthrough e bike with an M620 motor. I am still finding some tough pedaling on very long and steep upgrades. I noticed today, (on line), that there is a company that can modify the output of a fully functional M620 from a 1,000/1,500 watt motor to (IIRC) to 1,500/2300watts. Does anyone have any experience with beefing up the M620?

Yes. It woud involve upgrading your controller (40amps+ nominal), and a new battery as your battery will need to have a BMS (40amps nominal) with a higher amperage output, and you'll need higher voltage 52V-60V. You'll probably want more Amp Hours too as you will obviously burn more energy on your ride.

What kind of bike do you have? What kind of transmission?

 

[Cybersnow]

Zen Photon Ultra Motor Bafang M620 1000 W motor tuned to 52 V, Provides160 Nm Torque. Battery Long Lasting 52V, 1040 Wh, 20Ah UL 2271 Certified battery with Samsung 2170 cells offers extended range (upto 90 miles or 150kms)
Transmission is a Rohloff, but will go to chain drive and an 11 speed Sram.

 

[m@Robertson]

I don't think this is a motor power issue.

I use a 160 Nm BBSHD on a cargo bike to get up 16% grades, complete with a load of groceries or gravel bags for my back yard. I don't have issues with the motor having more than enough power to let me pedal up easy if I want to (usually I try and work for it and get some exercise, but I need a break too sometimes and want the bike to take over). I have my bike set up to output about 1000w on PAS9 pedal assist, and if need be, I can instead use the throttle and pour on roughly the full 1750w (peak output goes down as the battery drains). Plus, I have built BBSHD bikes starting in 2018 and have consistently had the same results with the power/effort issue.

So... considering your motor is beefier than the BBSHD (able to handle sustained output for longer thanks to its much larger stator etc.) and has the same torque output on paper at least, I have to wonder if what we are really talking about here is not the motor's problem at all. I'd think we are taking more about gearing the bike. Or using the gears properly.

Going up a steep hill with a cargo load, I am going up to maybe 10-13 mph at an extreme on throttle, with a steady pedaling speed in the 8 mph range, and that 8 mph would equate to light effort at worst. Front chainring is a 42T and rear is typically going to be three cogs in from the lowest gear, which is 34T and leaves lower gearing available. My typical preferred cadence is in the range of 70-75.

Also I have used 11s SRAM drivetrains on two of my bikes and can say they work great with a BBSHD and 160 Nm, but you should take care with the rear cassette, for which you have very limited mid-drive-friendly options. I use Sunrace CSMX80 11s which has mostly steel cogs. A Sunrace CSMS7 is 11s pinned-together steel and I use it on a couple of other bikes but it is limited to 42T which is as far as my SRAM derailleurs can go. A much better choice, believe it or not, is a Microshift Advent X 10s with a pinned-together hardened steel cluster, using an 11s chain (Shimano Linkglide chain is the new low-cost kid on the block versus a KMC11e which is more than double the cost)

If you've got a Rohloff on it, I would THINK thats got enough range in it to at least match what you can give yourself with a derailleur.

 

[m@Robertson]

Also if you are doing hills and going to a cassette system, you'd better make the cassette body steel or that 160Nm motor will eat into an alloy body like its made of cheese. Thats the reason you buy pinned-together cassettes too. They distribute the force better across the cassette body. I use DT Swiss 350 hubs. Preferably the Hybrid version that comes with the steel cassette body already, but you can do a regular DT 350 Classic and then buy the steelie as an upgrade. SunRingle hubs supposedly have steel bodies and are really good at handling torque. My Surly BFD came with Salsa hubs that had a steel cassette body and came with the CSMS7 cassette factory stock.

 

[Cybersnow]

It is funny that you mention BBSHD. I have 2 other ebikes one with a bafang 750W mid motor add on and another with the 1KW BBSHD kit added. Both if those bikes are lighter and seem to be much more powerful than the new bike. I guess I am spoiled as the BBSHD is powering a Salsa Via and I have hit 35 mph on the flat. The problem with the bike is with tire size as most of the roads around here are dirt and mixed gravel and can get very steep. Another issue is weight, the salsa weighs about 55lbs and the Photon is hitting about 75lbs. The current bike can get up the hills using the max pwr of 1500 watts but at a speed of maybe 8 mph.

 

[m@Robertson]

I just took a look at the Photon Ultra and thats an awfully big front ring on the drivetrain. I'll bet the bike is geared more for speed on flat land and rolling hills. Thats what consumers tend to look for generally. Handling steep hills is kind of a niche. I bet the motor is bogging. You can put a smaller front ring on there and a smaller belt to match and that motor will spin faster and handle the hills better. I owned a Gates belt'd bike with an IGH and I would kill to be able to afford a Rohloff on all of my other bikes. Grease-free, maintenance free, dead silent and the belt lasts (almost) forever. Sure you need to service the Rohloff every 6 months to a year but thats no biggee.

I would try re-gearing the bike before giving it a brain transplant, and all of the money and uncertainty that entails. Since you say you can hit 1500w that sounds like you probably have a controller that is not hobbled. Probably 28 to 30a. Something to bear in mind is if you graduate to a 40a from say WW, and what you really have is a bogging/gearing issue, you're just giving the motor the ability to tear things apart instead of living within its means, so to speak.

I would also ask Zen directly what they think of your dilemma and see what they say. They may have a readymade front ring/belt solution available, or something else.

 

[Tom@WashDC]

Zen Photon Ultra Motor Bafang M620 1000 W motor tuned to 52 V, Provides160 Nm Torque. Battery Long Lasting 52V, 1040 Wh, 20Ah UL 2271 Certified battery with Samsung 2170 cells offers extended range (upto 90 miles or 150kms)
Transmission is a Rohloff, but will go to chain drive and an 11 speed Sram.

I have the same motor and Rohloff hub. 30 Amp controller, 48V battery. I cannot imagine having any problem climbing long and steep grades. Something else must be amiss. What is your transmission ratio (Chainring Teeth/ Rear Sprocket Teeth)? I was running 2.5 which had ridiculous climbing ability. Now I'm running 3.125 which is more balanced between climbing and crusing.

 

[Cybersnow]

Maybe I am used to a quicker bike? I will try to slow down on the hills and let the bike do most of the work.

 

[Tom@WashDC]

Maybe I am used to a quicker bike? I will try to slow down on the hills and let the bike do most of the work.

I've got a BBSHD too, on a Fat Tire Bike. You do realize that you are going to have to work harder with the ULTRA becuase it's torque sensing and there is "no free lunch". The BBSHD has cadence sensing which is going to power you up to speed whether you are pedaling hard or easy. BBSHD is a lot less work than the ULTRA.

 

[greeno]

You think you’re frustrated with your bike because of “lack of power” if you send it to WW you will be frustrated because of “lack of bike modified in a timely fashion”.
just change your front chainring to a 42 or so and you’ll be just fine.
I thought the Archon guys ( controller software ) split up.
and shut it down as far as reprogramming goes, but I haven’t been following WW for awhile.
Take the easiest and cheapest option and see where that gets ya.
Good luck.

 

[Cybersnow]

I've got a BBSHD too, on a Fat Tire Bike. You do realize that you are going to have to work harder with the ULTRA becuase it's torque sensing and there is "no free lunch". The BBSHD has cadence sensing which is going to power you up to speed whether you are pedaling hard or easy. BBSHD is a lot less work than the ULTRA.

Thanks for the advice! I will stay away then. Will finish riding out this year with the bike I have.

 

[smorgasbord]

I've got a BBSHD too, on a Fat Tire Bike. You do realize that you are going to have to work harder with the ULTRA becuase it's torque sensing and there is "no free lunch". The BBSHD has cadence sensing which is going to power you up to speed whether you are pedaling hard or easy. BBSHD is a lot less work than the ULTRA.

One can tune the ULTRA (M620) to require almost no torque to output high power, of course. And a 52Volt Ultra produces a lot of power.
My guess is the OP with an Ultra and Rohloff either has a problem in the motor or hub (or dragging brakes or something), or is simply not using a low enough gear.

 

[Cybersnow]

Max wattage on the M620 on this bike is 1500watts. The same as my BBSHD.

 

[greeno]

The BBSHD is max rated for 30a period or 1500w.
The M620, G510, Ultra which are all the same can be configed up to 2200w which would be about 45a.
When I built up my buddy’s battery I used a BMS rated for 50a even though 99% of the time he is in lower power settings but his battery is good to go if he needs it.

With an Ultra and a Rohloff on the rear you should be able to crawl up a telephone pole with that thing.
You get more max wattage output at the higher rated unit but still only get the 160 nm that it’s rated for.
Utilizing a 52v platform compared to a 48v system allows you to use less amperage at the same wattage output.

Longer battery life, more range.

 

[Cybersnow]

Interesting, how do I configure the N620 for 2200watts? The display shows a max of 1500.

 

[Cybersnow]

Make that M620. Phone keys are so small

 

[greeno]

You need the dealer software to initially set it for max wattage.
You do it with a programming cable going directly to your motor controller just like you can adjust multiple settings like Penoff and Frey.
Of course your controller protocol needs to be the older UART not the CAN buss type which is pretty much mostly availible now.
You can still get the UART 52v units from GBK and do the mods yourself but that’s a whole nother thread.
Then you need your supply battery configured for the higher wattage draw.
BMS, wiring etc.
Then you get two levels to chose from.
You can change up/dn from the higher wattage unit.
But on the lower unit your stuck with just the lower scale.