Hi!
I found genuine 10s4p packs of Samsung ICR18650-26F of only 90€ each(and 2.25€ per cell).I also had one same pack from a previous ebike build so I ordered 3 of these packs and I now have a complete battery pack for my e-moped.I have wired 2 of these in parallel and another 2 of these in parallel and connected the groups together in series to give me a 20s8p pack! I charge the parallel groups separately with 2 10s chargers while they are not connected in series so I think there are no issues with charging!
Each pack however has its own bms so I have 4 different bms's in my complete pack. This doesn't cause problems with the series packs,however I think there is a huge issue with the parallel packs.When I twist the throttle there is a voltage sag of around 5 volts which is pretty big for Lithium-Ion so I think a bms has cut off in one of the parallel packs thus only one of the 2 packs in the parallel group gives power.Also first time I ran this setup there was very little voltage sag(around 1 volt).
So my question is:Can somehow this setup work by just bypassing the bms's(and only using them for balancing) so they will not cutt off and cause problems or I need to just have 1 bms per parallel pack(also bypassed as I am certain it will not be able to handle the amps)
I think the best way is to have only 1 bms per parallel pack but this requires removing all shrink wrap and insulation,and connecting each parallel group of the 2 10s4p packs I had started with,together,so I will get a 10s8p pack at the end with 1 bms.Then I have to insulate the pack again.This is going to take a lot of time and also requires me soldering the parallel groups of each 10s4p pack together as I don't have a spot welder, which is pretty dangerous in my opinion
So what do you guys think? Can I just get away by bypassing the bms's of the parallel packs or I must keep just one bms per parallel pack?
Thank you for time!
I found genuine 10s4p packs of Samsung ICR18650-26F of only 90€ each(and 2.25€ per cell).I also had one same pack from a previous ebike build so I ordered 3 of these packs and I now have a complete battery pack for my e-moped.I have wired 2 of these in parallel and another 2 of these in parallel and connected the groups together in series to give me a 20s8p pack! I charge the parallel groups separately with 2 10s chargers while they are not connected in series so I think there are no issues with charging!
Each pack however has its own bms so I have 4 different bms's in my complete pack. This doesn't cause problems with the series packs,however I think there is a huge issue with the parallel packs.When I twist the throttle there is a voltage sag of around 5 volts which is pretty big for Lithium-Ion so I think a bms has cut off in one of the parallel packs thus only one of the 2 packs in the parallel group gives power.Also first time I ran this setup there was very little voltage sag(around 1 volt).
So my question is:Can somehow this setup work by just bypassing the bms's(and only using them for balancing) so they will not cutt off and cause problems or I need to just have 1 bms per parallel pack(also bypassed as I am certain it will not be able to handle the amps)
I think the best way is to have only 1 bms per parallel pack but this requires removing all shrink wrap and insulation,and connecting each parallel group of the 2 10s4p packs I had started with,together,so I will get a 10s8p pack at the end with 1 bms.Then I have to insulate the pack again.This is going to take a lot of time and also requires me soldering the parallel groups of each 10s4p pack together as I don't have a spot welder, which is pretty dangerous in my opinion
So what do you guys think? Can I just get away by bypassing the bms's of the parallel packs or I must keep just one bms per parallel pack?
Thank you for time!