As well as on our first prototype with the rear-wheel Bafang drive with a power of 350W, and on the second with the mid drive motor Comp C17 of the same power, e-bike batteries 48V, capacity 13Ah were set at the initial stage of tests. These batteries were assembled from cells 18650, with a capacity of 2600mAh. As a result, such a battery requires 5 x 13 = 65 cells; therefore, the casing with such set of cells has big overall dimensions and weight.
On 650 km mileage, we decided to test our bicycle with the mid-drive Comp C17 working at 250W / 36V mode. For this purpose, e-bike battery 36V with total capacity 13Ah was made from 50 cells (10S/5P) of a standard size 18650 and with 2600mAh capacity. The first tests already showed that our second prototype with the mid drive is capable to pass in the active mode about 60 km on one charge with such battery, and in case a rider has weight more than 100 kg. In our opinion, it is a good result; however, we consider e-bike battery to be the most effective, in other words, the easiest, capacious and compact.
We decided to try to make independently and test battery 36V / 14Ah, made of cells 18650 with 3500mAh capacity of the Samsung company. Also, taking into account that the bicycle mileage on one charging will grow to 70 km, and in economy mode – to 100 km.
The necessary voltage and capacity can be received, using only 40 cells (10S/4P), so our battery will become more compact and light, having the best characteristics at the same time. As usual, the problem occurred, where we expected it least of all. It turned out that the cases of e-bike batteries, manufactured in Southeast Asia, usually are expected on 60 cells in most cases. As a result, with such casing, we could receive rather easy, but at the same time a half-empty dimensional bay, besides it suits our bicycle frame in design a little.
At the moment, we tried to make a few test cases of e-bike battery containing only 40 cells and a compact board of the BMS controller. Both in terms of convenience and general design, both round and rectangular casing batteries, made of the aluminium shape, well proved to be. I hope the upcoming version of Avial e-Bike prototype, which is now made for the installation of rear-wheel 250W, will be made for the installation of rear-wheel 250W, will be already equipped with our self-produced battery.
In detail https://avialbikes.com/news/avial/