Crystalyte controller 36 or 72V battery

[rogerax]

Hi,

I wanna go 50 km/h with my bike. Travel distance 20km. The plan is to buy a crystalyte HS3540 and Infineon controller 36-72V, 40A regen and a Cycle Analyst, from Crystalyte Europe. A little expensive, but I believe running “high power” controller at a little bit lower current would be a robust solution?


Regarding battery, I see to alternatives. I have one almost new 36V/10Ah Li ion battery.


1. Buy one more 36V/10Ah battery (same brand), connect in series and run 72V/10Ah.
2. Buy one more 36V/10Ah battery (same brand), connect in series and run 36V/20Ah (topspeed reduced to 40km/h, I believe)
3. Buy a new 48V/15 AH.



Since I can buy the 36V/10Ah battery locally in Sweden, that will be cheaper than buy a new 48V/15 Ah. To be able to go the distance I want, top speed and maximum current must be reduced in the controller with the Cycle Analyst, at least in the 72V case.


Which solution is to recommend, pros and cons?

/ Roger

 

[dogman dan]

Hmm, I'd say the first thing is ditch the 40 amps controller, unless you plan on a future battery that can handle it.

IMO, that controller will need a completely new battery, and it would have to be higher c rate than a typical 10 ah 36v ebike pack. So you'd need 3 new batteries of that type to run that controller without murdering your batteries.

Or as you say, start from scratch, but with a higher c rate battery such as headway, A123, or RC lipo. You'd definitely have your performance with 72v 10 ah of 20 or 30 c lipo. But you'd have the extra vigilance required to safely charge and store the more volatile lipo battery.

However, a 72v 20 amps controller should get you to 50 kph. Or limit amps with the CA. A smaller controller should be cheaper than a big one limited by CA. It would still be a bit of a push for those batteries, but 72v 10 ah would be only using 2c discharge rate to get 20 amps.

C rate is how you measure the discharge ability of a battery. Very likely what you have now is 2c, so 10 ah can do 20 amps max. And idealy, you'd not max it for more than a few seconds at a time. RC lipo with 30c, could handle your proposed controller with ease. It's what I run with my 40 amp controllers for high performance riding on dirt trails or racetrack.

If you bought 48v 15 ah of a 2c battery, you'd still need to limit to 30 amps, or preferably even 25 amps. Likely you'll like 72v best, even if you limit it to 20 amps.

 

[rogerax]

Ok, dogman. Thanks for the info. I'm sure you're right. Ebikes.ca have a Infineon controller 36-72V, 25A regen. Cheaper, smaller but propably still good for 50kph. Seems good to me. I think I would like a CA to get a overview of the system and limiting current etc.

The battery I have now is 10s LiPo 36V 10Ah. (AE7288195PMHRE). Cant find any c rate of this, so dont know if buying one more and connect in series, would do the job.

http://www.rpc.com.tw/en/polyme_d.asp

R

 

[dogman dan]

That link goes to many batteries. Do you know the c rate of yours? I see that they do sell some with higher discharge rates. If yours is 10c or more, then go for the 40 amps.

2-3c is more typical of batteries intended for ebikes, since most ebikes have 15-20 amps controllers.

Typical ES kook thinks 20c is weak though.