# EVirgin spitballing bike idea AGAIN



## Woodsmith (Jun 5, 2008)

Hi and welcome to the 'mad house'!

I don't think those little electric bicycle controllers will be any use to you.

36V x 136A = 4896W

Increasing the voltage is a good place to start anyway. 48 or 72 volts will both be nice. Or you can go higher. It all means the current reduces and the motor speed goes up, within reason, so you can look at different gearing options.

There are some reasonably good controllers out there to play with but you will need to make sure that they are good solid 'built for an EV' controllers. Ignore the bicycle ones and the ones that are small scale machinery controllers. Always ask here before laying out your money in case you are about to buy a 'lemon' of a controller brand or type.

You can also build an Open Revolt controller kit from Paul and Sabrina. There are some very good reviews and feed back about it.


Have you seen Yabert's bike thread?
A very neat package.

Also Todd's bike, 'Scrape'.

The forum member Jozzer converts motor bike to EVs in the UK and so may also have a mine of info that will be useful. He has a preference for Agni motors.

Good luck.


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## DaveyG (Apr 9, 2013)

I did scan thru Yabert's build, and looked alot at Todd's scrape build. Thanks for the link and the math concerning the controller, so I will definitely be needing a controller bigger than 1000w! Like 5-6x bigger! I will look for something higher capacity. Thanks!


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## Yabert (Feb 7, 2010)

Hi Dave
Your equation is almost impossible to resolve.
Long range (relatively) + highway speed + very bad aerodynamic motorcycle ≠ low cost
The aerodynamic play an important role for a motorcycle at high speed.


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## DaveyG (Apr 9, 2013)

Yabert, thanks for pointing that out, I figured if it ends up being only capable of 35-40mph and 10-15 miles range, I would be able to live with that, and just toy with it, maybe put the knobby tires back on and keep it as just a plaything, maybe after proof of concept I can upgrade it to a bigger motor and better battery system in the long run. As far as aero goes, I did have a few ideas, once I get a proof of concept, I have almost all of the front fairings off of a Ninja 650 a friend had, he picked it up as an insurance claim, put all new fairings on it, and gave me all the fubar ones. So I'm thinking I can fab/fiberglass up some aero improvements down the road as the project progresses.


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## DaveyG (Apr 9, 2013)

How about a Curtis 48v 250A controller? Sure, it wouldn't be useable if I wanted to upgrade above 48v later on, but again, with the budget... Would it be able to get the full potential out of my motor? I know they aren't the very best EV controller out there, but for my purposes/setup would it be sufficient to start with?


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## Woodsmith (Jun 5, 2008)

I use a Curtis 1214 controller on my tractor. 36-48v, 350A.

They are fine as controllers, so long as they are used within their means. I have a large slab of 5/8" aluminium plate on mine as a heat sink and it quite happily spins the wheels on the tractor when hauling logs. Broken two trans axles already!

The only snag with my one, for a motorbike, is that it has to have reversing contactors and switches connected otherwise it won't work.
There are other versions that don't have this issue.

I also have two 1209B controllers that are 48-72v, 350A (IIRC) and they just have a power terminal and throttle pot connections. I plan to use one of those for my trike.


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## DaveyG (Apr 9, 2013)

Very cool thanks for the info! That will probably be the route I take for the time being. I'm very excited to see what this can turn into! (Even if it is just a 30mph for 15 minutes toy lol, it'll be a start to get my feet wet!)


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## Yabert (Feb 7, 2010)

If low cost is the main goal for the moment and if you only need proof of concept right now, I strongly suggest you to find an Alltrax 72v controller (ebay?) and a used forklift motor (6.7'' to 7'' diameter).
Both can cost as low than 500$ (up to 1000$) and if you add some crappy lead acid battery your bike will move. But be sure to remember than the low performance and range will caused by the bad battery.


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## DaveyG (Apr 9, 2013)

I think I will stick with 48v setup, with 36v motor for now, if it ends up being a waste, I'll put it on a bicycle, and save up for a more serious build. Main reason being the alltrax controller alone costing as much as the entire current budget. Thanks for the info and thoughts though, I will keep them in mind for future project plans.


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