Battery for 48v 500w rear motor geared ebike conversion kit?

harryS

Well-Known Member
These Paypal protections, while auppossedly friendly to the buyer, are full of trap doors to catch the newbie. Be sure to watch the clock when you raise a dispute. If it expires, the seller wins.

If I increase the controller amp from a 38a to say 50a, how will that change the performance, if at all? Everything else stays the same.

Depends on your battery BMS, Mine will shut off if asked to push more than what they were rated for,
 

Clyde

Active Member
I've seen several packs lately with the BMS set to 50 amps continuous, with peaks to 150 or so. There shouldn't be any problem running these with a motor controller that only draws 30a continuous and 90a peak, should there?
 

JES2020

Active Member
These Paypal protections, while auppossedly friendly to the buyer, are full of trap doors to catch the newbie. Be sure to watch the clock when you raise a dispute. If it expires, the seller wins.



Depends on your battery BMS, Mine will shut off if asked to push more than what they were rated for,
So if the BMS will handle the higher amps do I get more power and speed from the motor with higher amps?
 

AHicks

Well-Known Member
It's about avoiding a bottleneck between the battery and the motor. Once you source a controller that can handle anything the battery can put out, anything bigger has what a lot of people call "head room", which amounts to excess capacity. My own thought there is a little head room never hurt a thing.

In your example, 38a vs. 50a the 50 would have no downside - unless the case that contained it was much larger than the 38a making it inconvenient to mount.

On my bike, which has a 1000+w motor and a 35a controller, I have a little concern regarding the 14ga wire used internally within the battery. I think anything over about 20a is pushing it. For that reason, I have limited the power to the motor to 20a electronically, which this controller (a KT type) is able to do. In this example, this controller has 15a headroom as it is able to handle 15a more than it will ever be used for. This means it will be nearly impossible for this setup to overheat or burn out the controller, because the controller components are so much sturdier than necessary. -Al
 

JES2020

Active Member
It's about avoiding a bottleneck between the battery and the motor. Once you source a controller that can handle anything the battery can put out, anything bigger has what a lot of people call "head room", which amounts to excess capacity. My own thought there is a little head room never hurt a thing.

In your example, 38a vs. 50a the 50 would have no downside - unless the case that contained it was much larger than the 38a making it inconvenient to mount.

On my bike, which has a 1000+w motor and a 35a controller, I have a little concern regarding the 14ga wire used internally within the battery. I think anything over about 20a is pushing it. For that reason, I have limited the power to the motor to 20a electronically, which this controller (a KT type) is able to do. In this example, this controller has 15a headroom as it is able to handle 15a more than it will ever be used for. This means it will be nearly impossible for this setup to overheat or burn out the controller, because the controller components are so much sturdier than necessary. -Al
Never thought about the battery wires getting too hot !
I have a 21 a battery but I'm not sure what controller comes with the Calibike kit. But as I understand it, the battery amp is the limiting factor as long as the controller has "head room". Which is what I needed to know.
Thanks
 

Thomas Jaszewski

Well-Known Member
If I had to buy a 48V pack today, I would go to these guys. It's $80 shipping for $460 total,

I have two 2014 36v EM3ev batteries. Still pretty good but only 12-15A motors.
I've bought a few packs from U.P.P. on aliexpress. I always upgraded to better cells, but I don't think their BMS boards are very good (no balance circuits). Starts at $280, and costs $100 more for name brand cells, So it's $380 shipped

UPP can upgrade ANY detail. Including BMS. I always bought a spare from them with the battery.

Some sellers pricing reflects the service they provide.
 

Thomas Jaszewski

Well-Known Member
I have a 21 a battery but I'm not sure what controller comes with the Calibike kit.
They used generic Chinese batts. Was a UPP repair and warranty station briefly. Bad service but nice fellow. I think he bit off more than he could chew. Battery repair isn’t for the faint!
 

JES2020

Active Member
They used generic Chinese batts. Was a UPP repair and warranty station briefly. Bad service but nice fellow. I think he bit off more than he could chew. Battery repair isn’t for the faint!
Yeah I get that feeling too.
It takes a certain personalty to be good at customer service. I used to be a landlord, so I know a little about the subject.

I understand UPP now gives the option to buy high grade batteries, for a premium of course.
This is my first ebike, so next time, hopefully in a long time, when this battery dies, we will have a whole new load of options for batteries.
 

Thomas Jaszewski

Well-Known Member
Yeah I get that feeling too.
It takes a certain personalty to be good at customer service. I used to be a landlord, so I know a little about the subject.

I understand UPP now gives the option to buy high grade batteries, for a premium of course.
This is my first ebike, so next time, hopefully in a long time, when this battery dies, we will have a whole new load of options for batteries.
It's ALWAYS been an option. Buyers just didn't ask. But in our experience the failure rate was unacceptable. Personally, all I bought are fine, but we paid out most gains honoring warranties that they wouldn't. Kinda like Bafang. Guaranteed to be delivered. Period.
 

JES2020

Active Member
As I gaze into my crystal ball, I see many more sources for high quality batteries in the near future.
EVs ARE the future !
The amount of research going into batteries is at an all time high!

I also see a boom in EV aircraft, which is of particular interest to me, as a pilot.
 
I was thinking about this from my Newbie "jigsaw puzzle" perspective and wondered whether the following could work together:

1) a 250W-350W controller that states on it that it is a "24v/36V/48V controller"
with a
2) 36V 350W hub motor
using a
3) 48V 10Ah battery (for 350W or 500W)
Would this work together?
Or would the battery have to be limited to a 48V 10Ah battery for 350W?
I have both 1) and 2), but I need to get a battery and would prefer a 48V 500W battery if possible. So I wondered if the controller would automatically limit the wattage for the hub motor to 350W.
Any thoughts on this would be greatly appreciated.
Thanks!
 

Clyde

Active Member
Don't confuse the wattage rating of your motor with the watt-hour capacity of your battery. If the motor draws 36v and 20a continuous then you need a 36v battery capable of 20a continuous. Battery capacity is a whole other issue.