After seeing different types of 18650 pack builds I have been thinking about protection.
I am going to build a 14S6P pack for my E-bike using Panasonic NCR18650PF 2900mAh - 10A.
This will be used with a 60amp BMS and 30amp controller.
After looking at the current/temperature curve for this cell I sure don't want to ever pull more then 10amps per cell.
To avoid this happening (in some case I can't think of yet) using a PTC fuse would be great.
Problem with a PTC fuse is that, if a problem does accure, you can't find it!
So the Tesla style fusing comes to mind but that makes a blown fuse very permanent.
That is when I thought of combining the two options.
The PTC fuse as cell overcurrent protection and a 1A tesla style fuse with diode as inrush protection, in paralel.
With this setup you can never pull more then 10amps per cell due to the PTC and if a cell dies the fuse will blow at 11Amps.
Price wise I am not bothered since it is around 10,- extra for the entire pack.
(100x PTC = 9,- / 100x Fuse = 1,50,- /100x Diode = 1,50)
I this "overkill crazy", "does't work crazy" or just "brilliantly crazy"....?!