EddySPalm
100 W
I am in the final welding of my 11P 16S pack of 18650 cells (LG MJ1), and I am starting to wonder if I should go over the whole thing and weld even more nickel to the series connections, or mayve solder some copper wire to it (OR whatever you experienced pack builders might suggest!)
- I bought pure nickel strips from banggood.com. They are 0.1x8mm, and "rated" at 5A continuous
- The pack will be 60V, as you may have calculated already
- My motor is a QS 4kW hub motor, and the controller is a very capacle Kelly KEB70601. People say these motors are beasts and capable of much more than their nominal rated power, which is a plus, but of course one would have to accommodate this if one were to take advantage of it...
This is how I calculated my series connections:
1. 4000W/60V= 66.7A
2. 66.7A/5A per strip = 13.3 strips per series connection.
3. To give an example: some places I have only 5 cells making up a series connection. So what I did was calculate 13.3/5 = 2.67 strips on top of each other. Of course I rounded up to 3, so a total of 15 strips is making up the series connection. calculating backwards, this should be able to hold a continuous current draw of 15x5=75A. At no given place on the pack are there less than 15 strips making up a series connection.
But I am starting to worry about what bursts I will be seeing with my motor, and what pain they can/will cause to my battery pack? I've spent ages welding this thing together using my homemade welder, and I do not want to do the whole thing again. Nor do I want to ride my scooter 1km only to find that my battery pack is a huge bottleneck.
So I'm reaching out to you to see if you think I've underengineered my battery pack, or if you think it should be capable of handling bursts from acceleration up to say 150A (the BMS will have a 150A discharge limit, so this is what I will have to limit the whole system to anyway).
Project thread for the battery pack and the whole scooter is located here, for those interested in the looks of it:
https://endless-sphere.com/forums/viewtopic.php?f=10&t=89582
I will be very thankful for any input.
- I bought pure nickel strips from banggood.com. They are 0.1x8mm, and "rated" at 5A continuous
- The pack will be 60V, as you may have calculated already
- My motor is a QS 4kW hub motor, and the controller is a very capacle Kelly KEB70601. People say these motors are beasts and capable of much more than their nominal rated power, which is a plus, but of course one would have to accommodate this if one were to take advantage of it...
This is how I calculated my series connections:
1. 4000W/60V= 66.7A
2. 66.7A/5A per strip = 13.3 strips per series connection.
3. To give an example: some places I have only 5 cells making up a series connection. So what I did was calculate 13.3/5 = 2.67 strips on top of each other. Of course I rounded up to 3, so a total of 15 strips is making up the series connection. calculating backwards, this should be able to hold a continuous current draw of 15x5=75A. At no given place on the pack are there less than 15 strips making up a series connection.
But I am starting to worry about what bursts I will be seeing with my motor, and what pain they can/will cause to my battery pack? I've spent ages welding this thing together using my homemade welder, and I do not want to do the whole thing again. Nor do I want to ride my scooter 1km only to find that my battery pack is a huge bottleneck.
So I'm reaching out to you to see if you think I've underengineered my battery pack, or if you think it should be capable of handling bursts from acceleration up to say 150A (the BMS will have a 150A discharge limit, so this is what I will have to limit the whole system to anyway).
Project thread for the battery pack and the whole scooter is located here, for those interested in the looks of it:
https://endless-sphere.com/forums/viewtopic.php?f=10&t=89582
I will be very thankful for any input.