# Electric MZ!



## aminorjourney (May 16, 2008)

Hi folks. 

Well, finally got agreement from my other half to have a bike licence so now happily have my CBT.

A friend is giving me a dead MZ ETZ 250, so I'm planning a bike conversion.

48V, Agni 95... Did think about a controller with regen, but space is at a premium of course. 

Thoughts?

It'll go nicely with my 96V CityStromer... still getting 25 miles on a charge on 7 year old batteries 

Nikki.


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## AmpEater (Mar 10, 2008)

Budget?

Unless you're stuck with lead I'd go 72v. Will increase top end, and acceleration by allowing you to use more of a gear reduction, as well as less stress on the motor.

The Kelly controllers are very compact and allow for regen. I have a 72v/500a w/ regen than is less than half the size of a 72v/400a curtis it replaced. You want to oversize them to account for the "generous" ratings


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## aminorjourney (May 16, 2008)

AmpEater said:


> Budget?
> 
> Unless you're stuck with lead I'd go 72v. Will increase top end, and acceleration by allowing you to use more of a gear reduction, as well as less stress on the motor.
> 
> The Kelly controllers are very compact and allow for regen. I have a 72v/500a w/ regen than is less than half the size of a 72v/400a curtis it replaced. You want to oversize them to account for the "generous" ratings


Budget will initially be rather small - but then the project will be a long one as I just don't have the time or a lot of spare cash...

But, I do want to do it right. 

72V could quite easily be okay, especially if I went for 1/2 U batteries. 
But, to be honest, the more I drive EVs the more I'm convinced that the way forward it high voltage low current, so 72V would be preferable anyway.

Nikki.


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## AmpEater (Mar 10, 2008)

aminorjourney said:


> Budget will initially be rather small - but then the project will be a long one as I just don't have the time or a lot of spare cash...
> 
> But, I do want to do it right.
> 
> ...


Sounds like you do want to go with lead then. The smaller the vehicle, the more sense LiFePO4 makes. Though you could easially fit 6 1/2u-1 batteries on pretty much any frame. I'd try to squeeze in 6 U-1s if you can. Peukert can really suck. You are right on track with the voltage/current trade-off. 72v is about the highest you can go before you run into difficulty sourcing cheap, off the shelf controllers.

How much is that agni? $1200 or so IIRC? If budget is your main conern you could save about $800 by going with an etek, or brushless etek. Perhaps even enough to afford lithium? 20x 40ah thundersky lifepo4 would only cost $1000 and would beat the pants off 72v of 18ah lead acid. You might sacrifice a little peak torque but if your bike weighs ~100lbs less than it would still be faster, much better range.


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## mattW (Sep 14, 2007)

Hi Nikki, welcome to the site.
I'm a big fan of your EV cast podcasts, so it is a privilege to host you on our humble forums. 

I agree with the previous comments. You could probably save money by going with say a Mars 0709 (Etek) rather than the Agni motor right up front. 72V will be better than 48V, even if it means more, smaller batteries. If you can afford the upfront cost, lithium has the potential of paying off in the long run due to the longer cycle life and needing a smaller pack once the lower weight and better Peukert.

If you do go with a Kelly controller, make sure you get one a couple of notches above the current rating you actually want. As stated above as they have a reputation of being a little 'generous' with their current ratings.

If you still have money left over after that then I would go with the Agni motor, but you will notice a bigger difference going from 48V to 72V or lead to lithium than you would going from an Etek style motor to a slightly smaller, more efficient motor. 

My never ending motorcycle conversion has a 48V 60Ah thundersky pack, a kelly controller and a Mars motor (or it will when I finally get it on the road).


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## genawin (Oct 1, 2008)

Hello Nikki, i think we will have to have a chat , maybe you might like to come over and have a look at my latest project. please don't choose the MZ because it's free , a lot of undesireable things are free , if you choose the right bike it could save you a lot of time and money and you are more likely to end up with something desireable.
Hope your well Martin.


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