How fun is a High powered Mtb E-bike

[dogman dan]

Sounds like he wants fast, so no big deal with that. But 24s is a LOT. And that motor is fast. a 36-72v range controller would allow running at 10s 36v, 15s 52v, or 20s 72v. Get a high amp one, the fast motors need amps. You're still going to exceed 40 mph at 20s.

Riding that motor slow is quite possible, on the flat or easy hills. You just tickle the throttle, pedal along with it, and don't give the motor enough watts to make any heat. Efficiency might suck on the uphills, but if you are only offering it a few watts, the motor covers can shed the heat fast enough to have the motor reach a max temp that is not that hot. Don't try to ride it slow up really steep hills. You want to charge up those steep hills fast enough to keep the motor in it's more efficient rpm. If you plan on steep hills, I'd say get the HT version.

With the right controller, you have the ability to run at 36v, which will give you speeds much closer to the riders around you than being stuck at 100v.

It's quite possible to make an ebike that does two of three things, but a does all three is tough. I have lots of fun on ebikes that use very slow motors. Not much top speed, but the power is there if you need it on a steep hill. It's the way to go if slow riding is a priority. My approach gives me much more throttle controll on twisty trails that cannot be ridden faster than 15 mph.

What I'm trying to say is there is a reason some of us have three, four, or even more ebikes clogging up the garage. Each one does one thing really well. Build your fast bike to satisfy that itch. Then look into a featherweight lower power bike for riding with your buds. Or even two, so you can hand them one.

 

[HombreNeuvoElectro]

A good speed Ebike is certainly fun. My new build takes me to 32mph without any assistance from me, but it is like anything, what is amazing initially becomes the norm after a short time. Any now i can understand why some many members continue to build new a faster ebikes.

I have only travelled 120miles on my new build but the best moments to date are

See a lycra is the distance, tearing up behind him at 30mph with bags on my back and raingear on, at the last moment before overtaking my trick is to hit the brakes to cut the motor and cruise past without a sound, then open the throttle again when past .... priceless ev grin

 

[arkmundi]

What I'm trying to say is there is a reason some of us have three, four, or even more ebikes clogging up the garage. Each one does one thing really well. Build your fast bike to satisfy that itch. Then look into a featherweight lower power bike for riding with your buds. Or even two, so you can hand them one.

If only I was rich and could afford a garage and a bike to satisfy my every fantasy. I suggest best compromise between speed and torque, knowing its a compromise.

 

[EdwardNY]

I am a bit worried about my build being too powerful now. I thought that if I made an ebike that was able to reach high speeds, I can also drive slower without any issuses. Just give the bike less throttle.

Now you bring up a lot of points here.

So with a 24s battery, will I really be forced to drive above 30MPH all the time or risk the motor burning up? Is 24s really too much?

have any of you ever built a pack with too much voltage and wanted to lower it?

Can I just take out a 6s pattery pack and knock the voltage easily down to 18s and be able to run at slower speeds more efficently? Is this even possible without changing the controller?

 

[snellemin]

My EVG bike runs on 24S and will do 20mph without overheating with a Magic Pie motor. It climbs hills with a kids trailer with no problems and that is with a 12 fet controller and 3 speed switch. I can also let it go and get close to 50mph out of it and for sure faster with better quality lipo's. Once in a while I ride it off road as well.

My only headache is the sensitivity of the throttle at the max speed setting. I tried getting a soft start installed inline with the throttle, but didn't workout so good with Lyen controllers vs the Ebay controller.

 

[wesnewell]

I am a bit worried about my build being too powerful now. I thought that if I made an ebike that was able to reach high speeds, I can also drive slower without any issuses. Just give the bike less throttle.

Now you bring up a lot of points here.

So with a 24s battery, will I really be forced to drive above 30MPH all the time or risk the motor burning up? Is 24s really too much?

have any of you ever built a pack with too much voltage and wanted to lower it?

Can I just take out a 6s pattery pack and knock the voltage easily down to 18s and be able to run at slower speeds more efficently? Is this even possible without changing the controller?

Don't worry about it. I run mine at 10mph 95% of the time. Yes, you may lose a little efficiency, but it's nothing to worry about. Your assumption of just using less throttle is correct. Where you might burn up the motor would be giving it too much throttle going up steep hills for long periods of time. but that can happen with any voltage.

 

[dogman dan]

I think I tried to explain it, but it might have been in another very similar thread going right now.

What you cannot do is stall the motor for long. Stalling is running the motor too slow, like up a crazy steep hill, or towing several skateboarders, and giving it the full power. The slow speed relative to the throttle setting is the problem. Once the motor stops turning, or slows enough, it becomes a space heater like inside your toaster. Windngs glow red pretty soon. The power is going entirely into heat if completely stalled.

If you are on flat ground and not towing, then you only need 100w to run 10 mph. So if you are giving the motor 100w, then the motor is not slow relative to the power you give it. The motor will continue to run reasonably efficient at that low speed.

There is a catch 22 to slow riding though. Every start is a stall for a second or two. So in a situation like riding in a crowd can heat up a motor fast. I run dogs with an ebike, and once off leash they stop to smell constantly. So I stop. They run about 7 mph. So it's start stop, start stop, every 100 yards for a mile or two. It hammers the motor and heats it up very fast. But since I never am giving it all that much throttle, the motor heats up, but never overheats.

The basic problem with 24s and a fast winding motor, is that your lowest throttle setting you can select will still be pretty fast speed. I do this dog running with a motor that is not just slow, but extremely slow. So 10 mph might be just about the slowest you can go with a high speed setup. The throttle will seem to have two settings, 20 mph and 40 mph. Finding that tiny tickle that gives just 10 mph is tricky with a 40 mph club bike.

Again, it might have been that other thread where I said it, a three speed switch makes much of the problem dissapear. Select slow, and you still get the full range of throttle adjustments, but with a much lower top end.

 

[EdwardNY]

Did my first real drive today for around 15 miles. Ebike driving is just crazy. I was flying at 25-30MPh through parks, streets, sidewalks. Was going way too fast in a park and almost ran into a curb at a park.

This was more fun then I had with anything in a real long time. I honestly can not wait to take it out again. Unfortanetly it will be raining tomorrow all day.

I love speeding and this thing is like a constant downhill biking experience. My full suspension bike really handles well and even bad cement is no problem at speed.

I can just imagine what 72 or 96 volts would be like. I already can almost keep up with city traffic at 48volts.

My favorite riding is riding at high speeds through park trails. It is a real speed thrill to do this.

The only problem I had is I seemed to have used up my 12s4p 20AH pack in about 15 miles.

 

[electr0n]

I have the setup you mentioned you were considering in your original post. HS3540 running 24s 2p 10 amp hours, 99.5v fully charged. With a 3 speed switch you'll have no problems going slowly and throttle control won't be so twitchy trying to go slow. I rarely ride on the lower speed settings unless I need to get more distance from my battery pack. My bike easily keeps up with traffic and can pull away from stop lights faster than most cars.

I started out with something modest 48v 20 amp controller. I then gradually moved up to almost twice the voltage and over 3 times the amps and I'm pretty satisfied with the power for now. My bike is more motorcycle than bicycle like at this point. I can still pedal if I want but I've got enough power that I don't need to unless I want some exercise or to extend range. Mostly I use the pedals to help accelerate the first few feet by then I'm going fast enough that my pedal input is negligible.

I love beating all the traffic in the morning on the way to work. I can ride on the side of the road up to the front of the line during rush hour and stay in front or hop onto the sidewalk when it's too congested. Traffic is basically eliminated with the ebike. A bus ride to work takes me an hour. A bike ride may take 15 minutes. A car about 30 minutes give or take. To top it off no more insurance payments, gas, expensive repairs etc etc.

 

[EdwardNY]

Thanks for the reply elctron. I was wondering your top speed in your setup.

I was also wondering why you say it is more motorcycle then bike. Did your bike lose handling with your setup? I sometimes say my bike is more like a motorcycle because of all the power it has at 48 volts and how I can drive on the street keeping up with traffic.

I do the same as you, I will drive to the front of the cars waiting and then either drive on the sidewalk or go right through the red light. Having full suspension makes driving on the side walk no problem. Not sure if you would want to do that at 25MPH without full suspension.
It was nice setting off the red light camera today when I drove through a red light. I made sure there are no cars when I do this.

What controller are you using for your 24s setup?

 

[electr0n]

My top speed is somewhere around 80kph. I've had it as high as 87kph but my speedometer may be a bit off but not much. It's a rush going that fast let me tell you, although I'm starting to get used to it. I can't see myself trying to go much faster. Instead I will likely move to smaller diameter wheels for stronger acceleration.

I say it's more motorcycle like just because that's way I tend to use it since upgrading to this much power and capacity. When I had a smaller motor running at 48 volts and a 20 amp controller I'd be pedalling a lot more. The bike was slow enough that pedalling was more effective and I was also carrying much less usable amp hours so part of it was to conserve power. My bike still looks like a bicycle and feels like a bicycle, albeit a heavy one. When the motor loses power, for whatever reason, it can be discouraging to pedal it home specially on any type of an incline. So it is a bit of a trade off with power vs weight.

Yeah it's great being able to hop on sidewalks and go on bicycle paths or cut across fields etc that's one of the best aspects of the ebike. I'm using an 18 fet controller from lyen here on the forums. I've had it up as high as 65 amps battery current which peaks at about 70 amps max on 95.5v fully charged no problems.

Are you using your bike for fun or commuting etc? I initially was using my ebike mostly for fun but I always had the intention of it becoming a serious means of transportation and over time I ended up first parking the car in the driveway for almost a year before finally selling it. I am liberated.

 

[Punx0r]

I will drive to the front of the cars waiting and then either drive on the sidewalk or go right through the red light. Having full suspension makes driving on the side walk no problem. Not sure if you would want to do that at 25MPH without full suspension.
It was nice setting off the red light camera today when I drove through a red light.

I nip to the front of the cue and then wait for the lights to change - just like a motorcycle or fast cyclist. Jumping the lights or cycling on the pavement are both illegal here and create animosity towards cyclists.

Watch out if you habitually set off cameras. If you take the same route regularly don't be surprised if there is a cop waiting for you one day... There have been motorcyclists here caught in this exact way (with speed rather than red light cameras).