first ev project simple questions

[marksch]

Newbie first build
I have been reading for a week and have some questions. I want to build a ebike to ride drive in California. It can be 1500w max with no peddles max speed is 30 mph. It is going to be a 2 seater with 3 wheels. My commute is 8 to 10 miles. The bike with riders should weigh in at about 400lbs max
I found a 1500w BMC brushless motor http://www.thesuperkids.com/15wabmcbrmos.html
Motor is 3800rpm @36v and 4900rpm @48v I do not have the torque. I will call on Monday to get the torque.
They also have a kit the 1500w BMC motor and a 72v 55a Crystalyte controller
http://www.thesuperkids.com/15wabmcbrmos.html
1.Will I get better performance out of a Kelly controller like the
KBL72101,24-72V,100A,BLDC Controller/With Regen
2. Is anyone on the forum using this motor? http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=22560&p=368442&hilit=motoped#p368442
This post looks like the same motor with custom winding.
3. What would be the advantage disadvantage between the Kelly and the Crystalyte controllers?
4. How do I calculate the gearing to get the bike to top speed?
5. How do I calculate battery size?
16s 36V 16Ah LiFePO4 Battery Pack
6. Is 16s 20s is this to do with the BMS?
7. Is ah amp hours?
8. Will a higher ah give you more distance?
9. Higher voltage will have more speed will it give you less torque?
With these simple questions I hope I can stop asking so many questions.
Thanks

 

[amberwolf]

16s 36V 16Ah LiFePO4 Battery Pack
6. Is 16s 20s is this to do with the BMS?

"s" is how many cells in series, and so how high the voltage is.

7. Is ah amp hours?

Yes.

8. Will a higher ah give you more distance?

Depends, but usually.

9. Higher voltage will have more speed will it give you less torque?

Speed: Depends on your motor/setup/gearing/etc.
Torque: nothing to do with voltage really, just how much current you put thru the motor and it's winding/etc.

 

[marksch]

Thank you Mr. Amberwolf

 

[McDesign]

I just received the same setup from TSK.

This weekend I started building a stretched "test scooter" that will have (up to) 72 volts of 6V / 12 AH SLAs. The center section is just a 24" long box, 6" wide and 4.5" deep, that takes twelve batteries. I charge (8) with a 48v charger and the other (4) with a 24, then reconnect them to go

I believe the gearing will be 15/80, and the motor at ~7000 rpm on a 12.25" wheel.

That appears to give 48 mph, which I don't think it will actually do without a good aero fairing.

Still, 72V at 55A is about 5.5 hp, so we'll see!

I need to see what mods to do to the controller to get to the 72 / 55 - it's supposedly possible - I'm gonna' look on here.

Forrest

 

[marksch]

Did I do the top speed calculator right.
3800rpm @ 36v
15/80 is 5:33:1 ratio
26" wheel circumference 81.68
speed of 59mph
this would be with no load.
I used this to do it

top Speed Calculator
http://49ccscoot.com/calculators.html

Did you got the kit with the controller? The kit states it comes with the 72v-55 amp controller.

Mark

 

[dogman dan]

Re the kelly 100 amp controller.

Yes performance will be much greater with the 100 amps, vs 50 amps. But not for long. 72v x 100 amps is 7200 watts! That should have smoke coming out of the motor pretty fast, unless you use something with at least a 5000 watt continuous rating.

You ask me, even that 55 amp controller is stretching things a bit. ( merely 3600 watts) You are talking about two people too, so expect max amps to be higher under load. Be interesting to see if you get away with it or not. A lot depends on the speeds you go, hills, etc. But since it's not a hubmotor, you could do things to cool it. Damn interesting motor for a chain drive dirtbike. 8)

Also, if you choose a high wattage setup, you will have to match it with a battery that can hack that kind of amperage discharge. So you might look into lipo or A123 or headways for the battery. Stuff like pingbattery won't do it for 55 amp controllers unless the pack size is huge.

 

[McDesign]

Mark - I did get the controller as well. And this is a scoot, so a 12.25" diameter tire.

One thing - that motor has a 17mm (~.674") output shaft size - no readily available sprockest or bushings fit that. I had a 15t 1/2" bore sprocket with a thick-enough hub, and had the shop bore it out today with a 43/64" (.671875")drill, and then touched-up the last coupla' thousandths with a roll of emery cloth - I still need to hand-file in a keyway.

Forrest

 

[marksch]

Forrest-How did you sprocket turn out?

 

[McDesign]

I still haven't filed the keyway - I'm thinking up a way to make a little jig.

Forrest

 

[marksch]

Hey Forrest, Did you get it put together yet. I just got my 1500w kit yesterday hope I have time this week to work on it.
Mark

 

[gogo]

Be aware that the Kelly specs quote 50A continuous motor current, and 100A maximum motor current. This equates to 50A or less battery current.

The Crystalyte 55A is refering to a battery current limit and it probably has about a 137A motor current limit.

The Kelly can be programmed with a PC/laptop. AFAIK, the Crystalyte can't be programmed.

 

[McDesign]

I haven't gotten it together - caught up in boring stuff at the moment.

Forrest