Buying first Mid drive Kit Help

suggy

Pedelecer
Oct 21, 2019
47
2
Hi everyone I am looking at getting my first mid drive conversion kit after having a crappy hub motor which was ok on the flat but not good on the hills.
I am quite a big bloke so probably need a bit of power and also on average when I go out on my bike I do about 25 miles.
I Also do not want to break the bank. I have only looked at the bafang 750w mid drive is this any good but I am stuck at which battery to get.
Any help most grateful.
 
Last edited:

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
Your hub-motor can probably give you a lot more power without stressing it. If You go up to 48v from 36v, you get 33% more torque, power and speed. Another thing you can do is increase the current. At 36v, you can go as high as 22 amps, which will give you a nearly 50% increase in torque, assuming that you have a normal 15 amp controller.

Tell us exactly what you already have, and we can give you more precise advice.
 

suggy

Pedelecer
Oct 21, 2019
47
2
Thanks for the reply I don,t have anything yet I will be fitting the kit on a Carrera crossfire 2. I have looked at this kit.

with this battery 48v 13ah
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
3,993
Basildon
That battery looks a bit weak to me - only 20 amps continuous. a standard BBS02 is 18 amps, so that doesn't leave you any headroom. You need one rated at at least 25 amps. eclipse have some very nice batteries. they cost more because they can do what's required for a BBS02.

How much do you weigh?
 

KirstinS

Esteemed Pedelecer
Apr 5, 2011
3,224
899
Brighton
Have to agree with the battery comments from vfr. I have had nothing but trouble from no name chinese cells (which make up a relatively cheap battery as you linked)

Buy cheap , buy twice is a a near certainty would be my view
 

suggy

Pedelecer
Oct 21, 2019
47
2
Good advice thank you think i will go for the motor and the battery from eclipse bikes
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,918
8,533
61
West Sx RH
In my view and practical use of 29E cells, ideally you need something better then 4p of 29E with 25a max controller discharge if you want the cells to last.
 

Nealh

Esteemed Pedelecer
Aug 7, 2014
20,918
8,533
61
West Sx RH
You need proper decent 10a + cells tbh, and the more cells in parallel the better.
The controller rating of 25a max means you need a battery that can deliver 30a plus without to much bother, although cells are rated you want to consider only applying half the current if possible for longevity/life cycle. You need to look for at least five cells in parallel in a battery.

Which cell/cells are better is like a piece of string.
Samsung 25R are highly rated but rare to find in ready built batteries.
Sam 30Q if not abused have a average life cycle but do deliver power and capacity, but if abused suffer.
LG MJ1 are pretty good.
LG M29.
Panasonic BD or GA.
Sony VTC5 or 5A.

LG MH1 possibly in 5 or 6p, although 10a rated suffers damage at that level but is good up to 7a max each, if treated well and discharge is kept to 1c max then cycle life is very good 92% capacity/500 cycles & 86% capacity/1000 cycles.

Not hard case options so not for evryone.