Mid Drive Electric Bike Lover

[middriveebike]

I love to build ebikes.
I am curently using a 48V 450W brushed Mid Drive Electric bike that was built with ebike conversion kit.
The battery I used is NiMH. This is a rare choice because most people either go cheap to use the AGM or go expensive to Li.
I am using NiMH 4500mAh cells in parallel and series to build 48V 18Ah battery pack.
It is definitely not recommended, but that's what I have.
I look forward to use 48V 500W chain reduction brushless kit in the future, but for now, I will stick with my brushed kit until it breaks.
How is everyone doing?
I am from Toronto Canada and would like to see about the difference of ebike here than that of Canada.

 

[Deleted member 4366]

Welcome. Any chance of some photos of your bike and the battery?

 

[middriveebike]

My bike is the first bike in the gallery. The one with most pictures and with a front basket.
Ebike Gallery


I used the black battery in the following picture. It is a 4500 mAh NiMH battery pack.

I put 4 in parallel to form a 18Ah pack and connect 4 together to achieve 48V.
I will try to take a picture of my battery pack tonight.

 

[Richard_M]

It is a 4500 mAh NiMH battery pack.

I really like the sound of this. I've been keeping an eye on the price of NiMH and even at Tesco's (other superstores are available), they're getting really cheap. Yes, they're a bit heavier but no BMS required and a really simple CI charger.

Keep the posts coming and good luck with the project.

 

[middriveebike]

...they're getting really cheap. Yes, they're a bit heavier but no BMS required and a really simple CI charger.

Since the maximum capacity for each cell is 4500mAh, in order to have something like 18Ah, you will have to connect them in parallel. This complicate the matter when you are charging. Most of the NiMH chargers out there for 12-18V and with a charging current of 500mA. You are going to need a special charger for this unless you want to disassemble all cells to charge.
Plus the continuous discharge current from my battery is not enough. You need to have at least 2-3 cells connect in parallel in order to get enough current.

However, on the other hand, NiMH is good for different temperature compared to Li batteries.

 

[Streethawk]

The problem with NIMH is they drop their voltage a lot under load, you would need at least 48v to get the same power as a 36v lithium based pack under peak load.