Setting up my lithium pack so it is balanced to the point where I can charge 3.5 volts and then terminate the charge. What I have found is that my charge is pretty much dead on balanced up to around 3.5 to 3.55 volts. Beyond that batteries will jump to 3.7 to 4.1 volts within 30 minutes. Up to 3.5 volts the charge takes about 5 hours. Slow and steady. So 3.5 is the start of the upper knee rise. It only takes about 30 minutes for some to jump. This is the reason we need to terminate at like 3.55 volts so no battery will jump beyond 4 volts. Since it only take 30 minutes or so for 34 batteries to jump from 3.55 to 4 volts that last bit of charging is really giving you very little.
My charge this evening started at 15 amps and I terminated at 12 amps. I did not turn down the amps at 3.55 but I could have and never have pushed a battery to 4 volts. So a good lithium charger could go into cv at 3.55 and hold that until amperage went to zero. That would just about right.
34 lithium 100 AH Hi-Power. I started the charge at a standing voltage of 3.1 after my run. Terminated when one battery hit 4 volts. Like I said earlier, up to 3.55 all 34 were pretty much dead on 3.55 maybe a few at 3.57 then 30 minutes later one peaked 4 volts. Some were close many were 3.76 or so. So the safe way is balance on the low end so most of the batteries are close to the same at the end. In the super low end you will also find varying voltage ranges.
Find the spot where they are all balanced cleanly and cut off discharge and terminate charge at those points to keep your batteries safe. BMS FREE.
For me I had no choice but to take my time and balance out a pack. Slow but well worth the knowledge I have gained.
Pete
I will try to exceed 25 miles at 55 mph next run and remain in my safe zone.
My pack is small so this will be a big test of range and it will be cold too. No battery heating except from discharge heating. I will be keeping my motor at as high of rpm as possible to keep my driving battery amps down.
