When I read all your answer I think I do a really really bad explanation of my needs!
I will try to explain how I will use it (I just ask you to trust me about my usage
A classic day for me will be :
- acceleration with 1000W maximum then cruising @ 45kph (PAS mode)
- I have 1 stop on my way to work -> big power to have some fun (full power for 5 seconds). I'll do that 2/3 times per battery cycle.
- when I reach 45kph -> cruising @ 45kph (PAS mode)
What I will not do :
- high speed @ 70kph all day long
- high power everytime
Please don't say it is a shitty usage or I will not use it this way. Just consider this is the way I'll use the bike
Wheazel wrote:I think you should do either one of two things to improve your chances for a successful project.
1. Change the frame to something that will not be a rubbery snake when riding with 10kw and all the extra weight.
2. Ditch the idea of 10kw and reconsider what you actually need. What are you going to use 10kw for when riding 45km/h all day long?
I am riding my cargobike almost every day, and it can cruise just fine at 45km/h.
I use 600-1000W most of the time. and have the limit set around 2,5kw for heavy hills etc. This is a heavy bike with 20+kg of batteries, still leaves regular mopeds behind no problem.
Over 6000km in one year speaks for how reliable and usable it is, and its still far from perfect.
10kw on a regular bike will most likely be gimmicky, unsafe, and a pretty shit bike in the long run. After the initial hype, you will realize how lackluster the complete package is.
What I actually need? Almoast nothing, 1000W is more than enough.
You are speaking about extra wheight. But I'm 65kg. I'll add 20kg to the bike. I don't think it is worth than a fat guy riding a classic bike on hill down.
Why will it be shit bike on long run? With good setup it should react exactly the same as my old bike. With a good center of gravity it should be fine. Isn't it?
Chalo wrote:I think you'll go faster than 100 kph unless you make some mistake in matching motor speed to road speed. If your battery voltage times the kV of your motor equals more than 130 kph at the wheel, then I think you'll get at least 100 on the road.
I think pedaling doesn't do very much at speeds over 50 kph. So you don't need gear ratios for higher speeds than that.
I think heavy bikes are less fun than light ones, and your performance target requires a heavy bike.
I recommend 2 ply Maxxis Hookworm tires if you can get them. That's a much stronger casing than necessary for a bicycle, maybe strong enough for what you have in mind.
72V on a 4T mxus 26" gives 70kph. You can check ebikes simu. Maybe it is not the best motor, I don't know that. I know a guy with the same motor/power and the motor goes great. Maybe it can do better, I don't know.
i'm looking for acceleration, not top speed. That's why I choose this one. I think 3T on a tiny rim would be better but I don't want it.
dogman dan wrote:
Well,, practice riding 40 mph on just the front wheel. That's what happens when you hit a bump you didn't see in time, with no rear shocks. It's really fun.
This is no joke, it does happen. Ripping up a tire in 45 min happened to me too. This is one reason I got the welder, and started modifying frames.
Making them longer, and stiffer, and able to handle a smaller wheel without making the headset angle funny or having the pedals strike the ground. My bike looks funny, but no cop here thinks it's an illegal home made motorcycle with pedals. Adding rear suspension is also possible.
Get a steel frame like that to start with, then do the welding to modify it to take a moped size tire, stiffen it, and lengthen it enough so it won't want to stand on it's front wheel at 40 mph quite so easy. Yes, you'll wheelie off the line fine, but just think again about the other end of the blast, the 40 mph stoppie.
Go measure a motorcycle, that's the length you need for a homemade motorcycle, not a short wheelbase MTB with no rear shocks. .
That's good advice.
But this is for a 40mph/70kmh cruising speed right? Beacause I've done almost 10.000km at 45kmh with no problem.
I don't really care about max speed. The power is just for acceleration.
flat tire wrote:That's a lot of power, I think you could ride a regular bike frame but things will break. You want full suspension for sure, my last bike was front suspension only and did 44 mph top (70kph) and it was a very rough ride even standing. I think bike tires are ok if you're careful, especially if you keep them at high pressure for higher speed.
It's a good build though, don't let people stop you from trying it. I understand the concern with police and you're right, anything but bicycle wheels would be a complete no-go.
Hello Fabien, @20C the 25R will reach 95.2(℃) and 106(℃) @25C.
Also don't forget that is a 3.27V and 3.18V voltage sag, then the maximum output power (before controler/motor/transmission loss) will be around 7650W.
Then your 20s6p pack will last 150 cycles if it doesn't burn before or if you dont crash yourself with such a bad frame and whells.
Good luck frenchie !
Edit: I think you don't need a BMS as your pack is sentenced to death in a few months
Yes you are absolutely right about the sag. That's my biggest concern!
20C is more than my needs. I need 10C (=25A). If you have the same number (t° and sag) for 10C I would really appreciate it.
I think it will be something like 3.3V. So 3.3*20*150 gives 10.000W (I know it does not work exactly this way). Will it be enough for power wheelie?
As I saif 10.000W is for only a few seconds. I hope for more than 150 cycles as I will cruise at 10A (700W).