Why is cell balancing important for my R/C battery packs but not for some of my power tool or laptop battery packs?

Under what conditions can you use serial connected Lithium cells without load balancing?

I have disassembled several battery packs from different manufacturers (Bosch, Makita, Ryobi, Panasonic, Acer, Asus and more) and found some without any circuitry for cell balancing.

EDIT: Rephrased the question to be less categorical.

  • \$\begingroup\$ It might have something to do with the speed at which R/C battery packs are charged and discharged. I don't know of any laptop or tool battery that is charged at 4C or discharged at >10. \$\endgroup\$ – DKNguyen Apr 6 at 20:25
  • \$\begingroup\$ Possible duplicate. Although there are no accepted answer yet. \$\endgroup\$ – Unknown123 Apr 6 at 20:59
  • 1
    \$\begingroup\$ This generalization is absolutely unfounded. All multi-cell laptop batteries have either a multi-pin connector (and the balance is done by laptop mainboard), or some huge balancing and managing circuitry is built into "smart batteries". Ryobi "ONE+" does have serious managing circuitry inside, I just happen to have one open. \$\endgroup\$ – Ale..chenski Apr 6 at 21:25
  • \$\begingroup\$ By "any circuitry", do you mean you did not even find taps that ran out connections between individual cells to a connector? Because I would expect these to be present in the battery pack, but expect any balancing circuitry to be in the charger itself, not the battery pack. \$\endgroup\$ – DKNguyen Apr 7 at 1:18
  • \$\begingroup\$ Power tools at least use lower capacity, high current batteries, and for packs of batteries that require less balancing to be safe, large companies have the option of buying and binning millions of batteries to make tightly matched sets, or paying a factory to do so. \$\endgroup\$ – K H Apr 7 at 2:08

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