Cant decide on 36v or 48v mid drive motor

[JaredT]

Hi guys,

After reading so many threads on this topic i still cant decide on whether to get the Bafang BBS02B 36v or 48v mid drive motor.

Here is my situation. I hv been using a ready made ebike with 36v 250w rear hub motor (using a small 7.8ah batt). The speed is locked at 25kmh. Occasionally, i would need to climb some steep hills with it and the motor is not strong enough to help me get up the hill with PAS 3 ( i wanna conserve battery). On flat ground, i usually would only use PAS 1 (again to conserve battery due to the small 281wh capacity), so i ride hard most of the time. But when it comes to climbing hill, it becomes pretty hard even with PAS3.

So now, i am planning to build my own ebike using the Bafang mid drive 36v or 48v 500w motor. I will get either a 15ah or 17.5ah battery with samsung cells.

My question is whether do i really need a 48v motor instead of 36v to help with the hill climb occasionally? I will only be using the pedal assist and not use the throttle at all as i still want some exercise.

If i choose the 48v motor, then i would need to get a 48v battery as well which will cost more. I rather use a 36v one and get a bigger amp battery for longer mileage. The dilemma is just that i would need some extra power to help with the hill climb occasionally.

Appreciate your views. Thank you

 

[flat tire]

36v will work

 

[JaredT]

36v will work

Thx!

 

[spinningmagnets]

I will ALWAYS recommend 48V over 36V. There are several reasons. One is that you can use a 48V / 52V ebike battery to power a 48V inverter (60V max input) to produce 120V AC during a power outage...

 

[Drunkskunk]

The 48v motor will climb better, have more power, more speed for the same amp limit on the controller.

The same wattage battery should cost about the same regardless of voltage. Lets say you have a 36V 17.5AH battery made of 2500mha cells. that would be 70 cells. (10S 7P). A 48v 12.5Ah battery made from the same cells would also use 70 cells. (14S 5P).

I would always recommend the more powerful option. You can chose to use less than the full power you have available, while still having it available for those rare times you need it. You don't have the option if you chose the low powered setup. In your case, there is absolutely no advantage to lower volts. the weight is the same, the range is the same. But one has more usability.

 

[JaredT]

The 48v motor will climb better, have more power, more speed for the same amp limit on the controller.

The same wattage battery should cost about the same regardless of voltage. Lets say you have a 36V 17.5AH battery made of 2500mha cells. that would be 70 cells. (10S 7P). A 48v 12.5Ah battery made from the same cells would also use 70 cells. (14S 5P).

I would always recommend the more powerful option. You can chose to use less than the full power you have available, while still having it available for those rare times you need it. You don't have the option if you chose the low powered setup. In your case, there is absolutely no advantage to lower volts. the weight is the same, the range is the same. But one has more usability.

Thx Drunkskunk! That make a lot of sense. I was for a bottle form factor battery and couldnt find a real one with 17.5h. Now if i use a 48v motor, it is a lot easier to get a bottle with 12.5ah or more!

 

[NeedForSpeed]

I’d look at it like comparing a 4 cylinder engine to a 6 cylinder, even though this is an arbitrary comparison. You’d always be fine with a 4 cylinder, but a 6 is just much nicer. Go with the 48/52

 

[kcuf]

bbsxx originally 24-36v

do not believe bafang

modified internal gearing

for 48v


if you actually pedal

48v may seem too fast

using full voltage rpm

for any meaningful leg input


something to consider

but 52 is my choice

 

[tomjasz]

I’ve been riding BBS01 36V for 5 years. I have several 48v bikes too. I’m a conservative rider, not interested in higher top speeds as much as cost and efficiency. My newest build, a GD will be powered by my new EM3ev 36v 17Ah Reention cased pack. I get great mileage and decent performance.

My 52v batteries were a waste IMO. Marginal improvement over 48v and usually premium priced. Not what the cool kids do, but I found riding at high speeds, beyond typical bike speeds, means cages took more left turns into my path. They see. BICYCLE, not 35mph eBike.

My BiXPower 36V (29V ~ 45V) DC to 110V AC True Pure Sine Wave AC Power Inverter serves me well. Not clear on how 48 has an advantage there either.

 

[Ford Prefect]

bbsxx originally 24-36v
do not believe bafang
modified internal gearing
for 48v
…

Funnily enough, this is exactly what EM3EV claim on their page.

 

[dogman dan]

It depends on your total weight. If your bike, battery, cargo and you will weigh 400 pounds or more, you'd definitely need the 48v on the hill. But if less, 36v will climb, just a bit slower, and in your lower gears is all.

A little goes a long way with mid drives, since you can actually switch to low gear. So the voltage choice for a load under 300 pounds depends only on how fast you'd like to go up that hill. Since you plan on riding in the lowest assist anyway, why choose 48v at all? Unless you will weigh 400+ pounds.