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Because of design constraints I need to charge a 2S Li-Po battery over its balance connectors using a single-cell charger IC (e.g LTC4002). In order to allow the user to interrupt the charging process before the battery is fully charged, it makes sense to charge both cells alternately so that they are not significantly unbalanced after the interruption. The switching would not be triggered more often than every few minutes.

How harmful is such behaviour for the particular battery technology? Would you suggest some other charging process under my constraints?

Thanks for your help!

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  • \$\begingroup\$ What switching rate are we talking about? You may be able to see the effect of equivalent parallel capacitor which may make aiming for a specific SOC, probably 100 % to be slightly off. I doubt it would be a problem in practice. \$\endgroup\$ – winny Sep 2 '18 at 16:59
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The battery doesn't care if it's charged in intervals, even if you were to switch at a frequency >1Hz. The switching circuitry might be more difficult to implement than just using a 2S charging IC in the first place, however.

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  • \$\begingroup\$ I am happy to hear that. But if I use a 2S charging IC I need another boost converter to charge the battery over USB (which is one of my constraints). Additionally I need to do balancing by myself as most ICs cannot do this. I will think about those two options once more. Do you think one option is significantly better than the other? \$\endgroup\$ – Nejc Deželak Sep 2 '18 at 14:37
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    \$\begingroup\$ @NejcDeželak An even better option might be to use a 1S battery and a step-up converter in whatever device is powered by that battery. That's how it's done in most cases as it eliminates the need for a higher-voltage charger, balancer, and protection IC. You can get complete step-up modules really cheap. \$\endgroup\$ – Jonathan S. Sep 2 '18 at 15:55

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