QS205 (50H) v3/v2 and Kelly KLS7230S battery questions

[StevieB-FPV]

I have a question, and I'm a complete noob so please forgive me in advance. I want to build a ebike on an old moped frame. From my research, I'd like to run a QS205(50H) v3 or v2 and Kelly KLS7230S. My question is about the windings and KV on the motor and the battery and what the best battery would be for this combo. I have a 20s6p battery with the following specs:

74v 27ah - 21700 cells
Discharge, Peak 200A
Discharge, Constant 60A
Discharge, Standard 55A

Will the 60a constant discharge cause me any problems with sag or anything? I read somewhere that the controller constant should be double what the battery constant is? Did I get that right? The KLS7230S does 120a constant so I should be good, I think?

And regarding motor, I'd like to get up to 100km/h but I know that will be hard given the frame and suspension components are pretty heavy coming in at around 150lbs. Which KV and winding would be best?

Thanks in advance, this forum has been extremely helpful!

 

[john61ct]

Have you actually loaded the pack at those rates to see how it performs?

Is it self-built from known-good cells, ordered from a reputable seller?

Or are the numbers just the usual cheap-chinese vendor lies?

Only the former will answer the V sag question.

One of the three components has to be the weak link or bottleneck, personally my preference would be make it the controller.

With this combo, it would likely take a bigger very powerful pack to make that happen.

So besides temperature-limiting, I would make sure you can limit the controller amps, to avoid over stressing the pack and maintain acceptable range.

Unless you have good data display and self-discipline over your throttle usage.

Of course ignore all that, if you're happy with "tons of fun" runs that only last a few minutes.

100km/h is a heck of a lot, is the frame etc built to really handle that safely in your area's road conditions?

Legal issues, cops' attitudes?