Speak EV - Electric Car Forums banner

1 - 4 of 4 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter #1
Hey everyone, I am looking for some advice/help with custom building an electric motorcycle. This will be my first and I want to do it right, so before I jump into buying the wrong components I would like to see if anyone has past experience that can steer me away from making bad decisions.

I haven’t chosen the donor bike yet although I want a modern racer look such as an R1,R6, GSXR, CBR. I want to pack as much voltage as space will allow, 48V-72V. I have been looking at many other conversions on instructables and YouTube trying to learn the components involved. Which to me seem like the battery’s, motor controller, motor, twist throttle, charger (on,off board), and a main contacter.

I have been looking at where to purchase all these items from and the best variation possible for a decent range and speed. I have not found a supplier for the battery’s as yet as I don’t no if I want lithium-ion or AGM battery’s. I understand a BMS will need to be in place for lithium.

So my first question - AGM or Lithium? If lithium, can anyone recommend a supplier for the battery’s and BMS.

I have looked at Alltrax controllers as they seem to be very popular amongst EV conversations however Carl Vogel’s EV convertion book suggests a few other types available. Some include regenerative braking and others do not, I would like to incorporate regen into my conversion.

Can anyone share their experience with motor controllers and advice for choosing the right one from a reliable supplier?

I have found a motor on eBay a Motenergy ME0907 Brushless DC Permanent Magnet Motor, 48V, £375. Without choosing battery’s however I am reluctant to purchase the motor just yet.

But can anyone suggest a better motor, perhaps using brushes? Suppliers? How does regen effect the motor, does it have to be a specific motor for regen?

Thanks for looking, great full for anyone’s advice.
 

·
Registered
Joined
·
2,208 Posts
Best advice would be don't do it. DIY is likely to cost more and be unreliable. If you persist then AC motor and lithium are a must.
 

·
Registered
Joined
·
3,083 Posts
Are you trying to make something that will just kind of go along or something that will try to live up to the looks?
The very easiest way to do it if you just want movement and looks is to get a ride on scooter/ev bike already made and switch the parts over - though most of the low cost ones are slow and low range.
You could of course up the range considerably by adding more batteries and if you're not fussed about fast that's probably the way to go.
Speed is the problem. It's very easy to make a very fast ev of any kind since even relatively small motors can be spun up to some decent power. The problem is then supporting that in a relatively small package. There is little point in slapping on an 80kW motor on if the 8kWh battery only then allows 10 mins riding.
On the other hand there's not much fun in having a 200 mile range if it will only do 30mph.
The problem with bikes especially is their dimensions don't allow you to have both unless you want to spend a lot of money so there has to be a fairly large trade off between money, power and capacity.

For instance four 12v batteries would give your 48v. At 100ah each you're going to struggle to get many more on the bike and that only gives 4.8kWh so even a 10kW motor (roughly equivalent to a 125cc) will last less than half an hour at full tilt.

Good li-ion's are the only way to get decent range and power but that will still be relative and costs then spiral massively.
 

·
Registered
Joined
·
692 Posts
Having built my own electric bike, I can say that it is a minefield. I used 18650 cells from laptop batteries (54.6v bottom balanced with no BMS) and a small brushless motor (2kw). At the time I only wanted it for fun, so 30ish mph around town seemed to look good and I didn't want to spend too much on it.

After building it, I immediately regretted not getting a bigger motor. I mot'd it and took it for a run around town. It could be best described as a glorified mountain bike. It is great fun and funny to see people's faces when a motorcycle passes them with no engine noise, but us bikers are all about power and speed. I'll be revisiting it again soon to make it "go".

With the motor you have, the only option would be lithium. The amount of lead to drive it would make it feel the weight of a Honda goldwing.
 
1 - 4 of 4 Posts
Top