Alfalfameister
New Member
- Joined
- Feb 21, 2020
- Messages
- 50
Ordered from Amy (Luyuan instead of Xuba) 32 280Ah cells. They're already in my country, so should be delivered to my home soon.
Here's my plan:
PLAN A: (all while slightly compressed using rigid plywood at the ends, and loooong hose clamps top, middle, and bottom part).
1. Parallel them and "balance" them au naturel overnight - not really balancing, just getting the voltages in the same ballpark.
2. Disassemble then connect them 2P16S, slap a BMS (the Xiaoxiang / Overkill version), charge them with my 48v charger (maybe at 20A? 30A? can do up to 60A) at XXX voltage (was thinking 56?) until it says fully charged OR one of the cells hits HVD.
3. Disassemble them, then parallel them again (32P) and use a benchtop power supply (20 amp rating, but plan on using only 16A) and top balance to 3.6 (am thinking to just 3.60 for margin of safety (in case voltmeters are off by that little bit) instead of 3.65? Am I wrong to forego the last .05v?).
4. Finally, re-assemble them to it's final configuration (2P16S) and slap on the BMS again (120A rated BMS).
Questions for Plan A:
- is Step 1 necessary?
- what voltage and current should I charge them for Step 2?
- for Step 3, 3.60 or go all the way to 3.65
PLAN B:
1. Connect them all at 32P, use benchtop power supply at 16A and either 3.60 or 3.65V and just wait about two weeks (assuming cells arrived at 50% SoC).
Same question for Plan B: 3.60 or 3.65v?
With Plan A, I expect to save at least a week to 10 days, but Plan B looks a lot more straightforward (just time required). I figured, I waited 2 months for the batteries, hope they can last 3500-6000 cycles or about 10+ years (DoD 70-80%, likely from 90% SoC to 20% SoC, and charge ratings 100A max (or less than 0.2C for a 560Ah pack) and discharge of max 120A, but 80% of the time, likely at only 30A), so waiting two weeks to top-balance them with Plan B should be worth the wait.
Comments, suggestions, criticisms welcome (just don't use harsh words if they're criticisms, haha).
Thanks!
Here's my plan:
PLAN A: (all while slightly compressed using rigid plywood at the ends, and loooong hose clamps top, middle, and bottom part).
1. Parallel them and "balance" them au naturel overnight - not really balancing, just getting the voltages in the same ballpark.
2. Disassemble then connect them 2P16S, slap a BMS (the Xiaoxiang / Overkill version), charge them with my 48v charger (maybe at 20A? 30A? can do up to 60A) at XXX voltage (was thinking 56?) until it says fully charged OR one of the cells hits HVD.
3. Disassemble them, then parallel them again (32P) and use a benchtop power supply (20 amp rating, but plan on using only 16A) and top balance to 3.6 (am thinking to just 3.60 for margin of safety (in case voltmeters are off by that little bit) instead of 3.65? Am I wrong to forego the last .05v?).
4. Finally, re-assemble them to it's final configuration (2P16S) and slap on the BMS again (120A rated BMS).
Questions for Plan A:
- is Step 1 necessary?
- what voltage and current should I charge them for Step 2?
- for Step 3, 3.60 or go all the way to 3.65
PLAN B:
1. Connect them all at 32P, use benchtop power supply at 16A and either 3.60 or 3.65V and just wait about two weeks (assuming cells arrived at 50% SoC).
Same question for Plan B: 3.60 or 3.65v?
With Plan A, I expect to save at least a week to 10 days, but Plan B looks a lot more straightforward (just time required). I figured, I waited 2 months for the batteries, hope they can last 3500-6000 cycles or about 10+ years (DoD 70-80%, likely from 90% SoC to 20% SoC, and charge ratings 100A max (or less than 0.2C for a 560Ah pack) and discharge of max 120A, but 80% of the time, likely at only 30A), so waiting two weeks to top-balance them with Plan B should be worth the wait.
Comments, suggestions, criticisms welcome (just don't use harsh words if they're criticisms, haha).
Thanks!