What would you do with 4000W power?


Well-Known Member
1) Isn't battery voltage a factor to counteract the back emf of the motor? I'd love to see a torque versus RPM curve for the ultra. 40mph feels like a good speed target for me, and I guess the human RPM matters too... That's a good point. I feel like my Juggernaut is running out of steam at around 30mph. I can comfortably get to 35mph when the battery is full and my top speed was 40mph on level ground, but I was at the limit of my leg speed. Definitely not sustainable.
1. https://wattwagons.com/blogs/news/archon-x1-controller - a couple of torque curves for the new controller.

2. 40mph on a bike is FAST! I would highly recommend recommend riding with better body protection gear, full face helmet etc. I have topsided on my motorcycle at 40 mph and it hurts like hell even with body armor and a full face helmet.

3. Using 52V pack versus 48V pack will allow you to get more assist for a longer time.

2) Isn't belt drive lower efficiency than a chain though? Are you saying the Rohloff is more efficient than the Shimano 3 speed IGH? That would surprise me since there are more gears in the Rohloff...
1. https://www.cyclingabout.com/belt-drivetrain-efficiency-lab-testing/ (belt versus chain)
2. http://www.cyclingabout.com/speed-difference-testing-gearbox-systems/ (hub efficiency comparison)

3) Is there a reason suspension bikes can't put the suspension pivot point concentric with the crank bearing? This would get rid of the need for a tensioner altogether.... I've never understood that limitation.
That is correct ....the pivot point for rear suspension is almost always offset from the bottom bracket. So you need some form of tensioner for the drive train - for both chain and belt.

4) Fully loaded I've been around 300lbs on the bike. I'm typically in assist level 5 doing 30mph on level streets. However, I'm pounding through curbs and launching off speed bumps at that speed. Max weight would be 250lbs'ish. These distances are only around 10 miles. My long distance riding is eco 3 averaging 20mph for 60 miles. I usually need to charge for a bit at the halfway point using a 48V 21Ah battery. There are many spurts of throttle on this trip, and there's a lot of starting and stopping. Terrain is half asphalt half gravel. I lose about 2mph for the same human effort in the gravel.
That is well within the design spec for the UC Pro. No problem.

On my Luna Stealth, there is a parking garage at work with a steep incline. I can get the belt to slip with the 500W peak of the motor and 250lbs from the rider standing on the pedal to get started from a stop (gotta stop and swipe a badge to get out). I find myself riding that limit of the belt slipping to get started. That's why I'm worried about 4000W going through the belt (although really it's the low speed torque that is more concerning).
Belt slipping? You need to tension it better - try around 43-44lbs. I ride with 2500/3000W all the time and have had no issues with slipping, even on inclines.

5) How configurable will the tuning be on the new controller? I wouldn't mind a bit less torque down low, and coming on more slowly than both of my bikes. There should be tuning tables for time domain and inclination levels and gearing? Could also compensate for total weight too.
It is pre-tuned for every motor. We have addressed the "torque coming on slowly" part with Archon.
We are working on adding ride profiles, and configuring assist per PAS level - will be a firmware upgrade available later in the year. May need a new display, but we are working on it.

6) For urban city riding, the ability for regen would be very cool too. I know on long rides it matters less but it would increase my urban distance by at least 30% and dramatically reduce the wear on brakes. I replace my pads every 500 miles because I'm always accelerating and stopping hard...
Regen occurs when the motor is spinning with the wheel. This way we capture the power when rolling freely downhill (or coasting).
Mid drive and regen dont mix (if at all). On a mid drive, when you coast, or are rolling downhill, the motor stops spinning...so there is no regen !

If you want regen, you probably want some form of hub motor.
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Just to be clear - my intention isn't to actually ride at 40mph...
it has more to do with being able to have more control over matching the speed of traffic that is going 25mph to 30mph. Maybe occasionally 35mph to reposition myself in traffic. I'd like to have headroom so that acceleration from 25mph to 30mph is quicker.

I agree about riding with more protective equipment. Last year a car pulled in front of me and I t-boned it at 26mph...so scary. Thankfully I made it out with only scratches on myself and the bike...the car had $7500 in damage. Nothing like an accident to remind you of how vulnerable our bodies are with all these metal machines flying around us. I frequently get rubbed by buses and pinched off into the parked cars...going faster reduces the risk of this quite a bit. I would have a daily near death experience when on my normal pedal bike (going around 16 mph). I'd like to lobby to have different laws for ebikes in the cities since there are more degrees to safety. Everyone always thinks speed kills, but all the impatience from drivers and incidents happen when cars are trying to get around bicyclists...if speed is matched, then the need for evasive maneuvering goes way down. I agree the impact onto the ground is worse, but guys are always riding downhill on normal bicycles going 50+ mph - which is even more crazy because it's downhill and the maneuverability is even less.

I'm sure the safety discussion is a hot topic? I'm new to the forums :) I hope I haven't stepped on any toes, haha.

2) Thanks for sharing that data! It's interesting that the efficiency converges at higher output....that totally makes the belt worth it. Any concerns of heat into the belt at the 4kW levels? If the efficiency stays the same, then 48W into the belt and cogs is a lot of heat to dissipate...no concerns of the belt getting soft or anything like that?

6) I understand that the motor stops spinning when coasting, but the drive train doesn't have to be designed that way...All the freewheel clutches could be removed and then go to a Jeep 4x4 style differential lockout if you need to disconnect the motor? I understand the Bafang Ultra and its controller isn't designed that way.

The reason I don't like hub motors is because of rotational inertia, unsprung weight, and the lack of torque benefit from the gearing...totally not worth the tradeoff. And regen doesn't help long distance range - it would only impact urban range where charging at home more often isn't a big deal. I guess this is way off the topic of peak power though, hah.

Btw, thanks for all the insights - I'm really excited about the upcoming "Founders Series Superbike - Ultimate Commuter Pro". I really like the price of the City Commuter, but it seems the max weight, max speed, and lack of front suspension push me towards waiting for this new bike. I'd love to see pictures when you get your first prototypes. What color is the matte blue going to be?


New Member
Exess makes excellent bikes and they have the new controller in them. However, they only sell the 1600W version (30A max). There is no confusion there. They also only sell a battery that can do a max of 30A.

Watt Wagons sells the 3000w version - it is custom programmed for us, with a lot of other features , and comes with upgraded Battery and BMS. There is a cost to provide these updates.

Please let me know if this helps.
Thank you for the explanation, pushkar

Did you know you have pay extra and specify you want the upgraded controller from Excess, otherwise it is just the regular ultra
Here is the link, they up-charge $390 Euro's, sorry to say if you never paid it for it you never got it.
Upgraded Controller

Watt Wagons will be standard with no up-charge when they launch.

That's what i did!
I paid 12€ to ship the motor to them, 390€ for the controller, 80€ for repairing the damaged thermistor wire and 12€ for shipping it back to me. Total off almost 500€!
Like two month ago they where advertising the new X1 controller with 2300W continuous and 3000W peak. So i was thinking that i get that for my 500€. Apparently not and that's why i'm pissed.


Active Member
Thank you for the explanation, pushkar

That's what i did!
I paid 12€ to ship the motor to them, 390€ for the controller, 80€ for repairing the damaged thermistor wire and 12€ for shipping it back to me. Total off almost 500€!
Like two month ago they where advertising the new X1 controller with 2300W continuous and 3000W peak. So i was thinking that i get that for my 500€. Apparently not and that's why i'm pissed.
Hmmm..I don't understand I thought the upgraded Exess is equal to the X1 maybe the wattage is different, but they say 1600 watts max for their bike, Pushkar gives three options 1200/1600/3000 watt peak I don't see that with the Exess, so you should have the 1600W version like their bike says.

From their website
The result is a higher range when using the same power output or you can also use the higher effiency for more power output with the same power consumption.
But they don't tell how much it really is in wattage whereas Watt Wagons is more open about it.


New Member
My present ebike, with a 500 W hub motor, allows me to cruise along at 20 mph with moderate pedaling. I'm looking forward to riding my upcoming WW Superbike (see what I did there Pushkar) but I

have no idea what it will be like to ride an ebike with 2300W of continual power. I suspect it will a hell of a lot of fun, but honestly I doubt I would have any desire for more power and more speed.

Having said that, after riding a 2300W ebike for a year I may be interested in more power. Heck, after driving my V8 powered Mazda Miata for a year I started searching for ways to make the car faster.
V8 Miata? My 4 cylinder gets up and goes


New Member
if you have a 3000 watt motor but go out and ride it within the same activity/speed/torch levels as you would on a 750 would the battery drain more or the same netween the 750 and 2300?


New Member
If you have a 3kW motor, but only use 750W, then the battery drains at the 750W rate. This is always true.

The only remaining factor is the efficiency of the controller. How much power does the battery provide to the controller to get 750W at the motor?
At 90% controller efficiency, you're looking at 830W needed from the battery to produce 750W at the motor.
At 95%, then you are using 790W from the battery to create 750W at the motor.

So the only difference in battery drain 750W is if the controllers have different efficiency.

That said, I would bet the 3kW controller is more efficient at 750W. It might be less efficient at levels below 200W though...it would be interesting to see the efficiency curves of the controllers.


New Member
I just noticed this picture on their website:

Looks like all around better efficiency:


Curious what the efficiency delta is at ~200W of power for those trying to increase their distance...or what is the power level where the efficiencies intersect?