Balancing series packs is indeed important. This is why laptop batteries have
all those pins on their connectors, and why hobby type batteries have balance
charge connectors. Although they are different chemistries (laptop and
16450/18650 batteries are typically Li-Ion while hobby type
The biggest mistake you can make if you plan to use them in series not to
equalize them before use. They come in different state of charge. Maybe
close if from the same lot but not close enough and I do not count on the
equalizer. I start with a discharge to 2.5 V and charge two at a time in
I built a switched capacitor balancer. It takes some time to balance a wildly
out-of-balance pack but does a great job of maintaining balance during charging
and discharge. I run the balancer during pack charging and discharging. I
tried it charging an 8S LiFePO4 pack with 7 fully charged
