Battery Amps vs Peak Motor Amps (Kelly conversion)

[methods]

I am having trouble determining how to rate what Kelly controller I need.
I have been drawing around 80A – 100A battery Amps peak at launch. I may like to up that a little to something like 120A, but at least I want to be at the same level.

How do I calculate/guess what the peak motor current would be?
I did see a rule of thumb showing 3X – 4X but is that only at the instance of dead stall?

I was using a 5305 @ 100V, 7240 V2 with 4110’s and a soldered shunt

I am looking at this Kelly Controller: KBL12221H
http://www.kellycontroller.com/mot/Brushless-DC-Motor-Controller.html

I think it will cut out when I hit 220A peak motor current but I am not clear how that system works or how that will change my experience.

I want insane acceleration and I am done with the Crystalyte controllers.

Thanks,
-methods

 

[fechter]

It's hard to say exactly. If your xlyte was doing 100A, then you're going to need about 300 amps in a Kelly to get the same kind of launch. Once the motor builds up a little speed, the difference will be less, and unless you are racing, it may be better to reduce the stall current a bit to improve system efficiency.

 

[methods]

Of course you are correct. . . Dumping all that current off the line is counter productive. What I should really do is set it up so that power wont come on until the bike is moving at 3mph.

To get 300A (at over 100V) I would have to step up to the next class of controllers. This one is already the largest for the voltage range I want to run.

I guess I will give it a go and report back. Kelly has been very responsive via email.

Anyone know what the highest voltage an X5 has seen? I am considering adding another 6S pack to step up to 125V. High voltage should be fine by my estimation, so long as the current is kept in check.

-methods