jerrysimon
10 W
- Joined
- Oct 19, 2009
- Messages
- 82
For the last two years on my ebike i.e. 2500 miles, 500 charge cycles I have been using the pack shown below. Its a 10.5 mile round commute and I can always carry a second battery if I need to go further.
As a novice I constructed it simply myself from single cells building two 6s1p packs connected in series and protected with a 15 amp fuse. I did include balancing leads as well. I had previously used Lipos in my RC hobby before but wanted to use LiFeP04 A123 cells for worry free unattended charging at home and work.
The pack was contructed and balanced initially using a Turnigy charger/balancer, but for the best part of two years has just been bulk charged with a generic 36v, 1.6amp SLA charger and not balanced. I have a Celllog which I used to watch each 6s1p pack the first few months but stopped using it after the cells remained very well balanced. I tended to charge it at work and after the return journey when I got home. It has pretty much been used every working day for the last two years and has been very much a charge and forget pack. It was really done as a test to see if these cells needed balancing. Anyway in the last few weeks I have had to change two cells that died one from each 6s1p pack. It now seems to be running fine again. I think given it cost me £60 to make and the way I have used it, it has done remarkably well ? I have another newer pack which my daughter has been using and I tend to now balance that every couple of months or so. It will be intersting to see how it compares.
I have brought some more cells (from the same ebay seller sz_ohmygod btw) and wondered if I should fit a BMS to see how much better/longer it might perform. Alternatively I could start balancing it say every month/60 charge cycles. I fancy using a BMS though just to see how all three battery use strategies compare.
Anyway the question is I have been looking at a few BMS units and these seem the two I have come down to
8S LiFeP04 BMS (same as Cell Mans ?)
Or their SMART 5-13s one
Maybe its just over complicating things and a monthy balance would increase the charge cycles before failure. It would be nice to see if I could get 1000+ charge cycles out of this little battery though
Regards
Jerry
been
As a novice I constructed it simply myself from single cells building two 6s1p packs connected in series and protected with a 15 amp fuse. I did include balancing leads as well. I had previously used Lipos in my RC hobby before but wanted to use LiFeP04 A123 cells for worry free unattended charging at home and work.
The pack was contructed and balanced initially using a Turnigy charger/balancer, but for the best part of two years has just been bulk charged with a generic 36v, 1.6amp SLA charger and not balanced. I have a Celllog which I used to watch each 6s1p pack the first few months but stopped using it after the cells remained very well balanced. I tended to charge it at work and after the return journey when I got home. It has pretty much been used every working day for the last two years and has been very much a charge and forget pack. It was really done as a test to see if these cells needed balancing. Anyway in the last few weeks I have had to change two cells that died one from each 6s1p pack. It now seems to be running fine again. I think given it cost me £60 to make and the way I have used it, it has done remarkably well ? I have another newer pack which my daughter has been using and I tend to now balance that every couple of months or so. It will be intersting to see how it compares.
I have brought some more cells (from the same ebay seller sz_ohmygod btw) and wondered if I should fit a BMS to see how much better/longer it might perform. Alternatively I could start balancing it say every month/60 charge cycles. I fancy using a BMS though just to see how all three battery use strategies compare.
Anyway the question is I have been looking at a few BMS units and these seem the two I have come down to
8S LiFeP04 BMS (same as Cell Mans ?)
Or their SMART 5-13s one
Maybe its just over complicating things and a monthy balance would increase the charge cycles before failure. It would be nice to see if I could get 1000+ charge cycles out of this little battery though
Regards
Jerry
been
