The Li-ion Pack has 4 18650 lithium-ion batteries with a soldered Balancer and XT60. On my ISDT charger, the read out voltage for each battery cell is:

  1. 3.17V
  2. 3.18V
  3. 3.29V
  4. 2.93V

Whenever I try to charge the Li-ion Pack, I get:

  • "This operation is not supported"

My Question: How can I bypass this using my ISDT charger?

Auline 14.8V 4S 18650 2600mAh


  • $\begingroup$ Could you link to the product you're talking about? I haven't ever heard of the LionPack. $\endgroup$
    – ifconfig
    Nov 15, 2020 at 0:24
  • $\begingroup$ @ifconfig I believe it's a Lithium ion battery. I've seen both "Li-ion" and "lion" as abbreviations. $\endgroup$
    – Jacob B
    Nov 15, 2020 at 0:27
  • $\begingroup$ Sorry about that, I just added the product links. $\endgroup$
    – DroneDome
    Nov 15, 2020 at 0:32
  • 1
    $\begingroup$ @DroneDome it might not be charging because of a safety feature built into the charger. If there are cells with 3.17v and 2.93v in the same battery, that could mean there is a problem with one or more of the battery cells, which could be very dangerous. If the battery is new, I would recommend contacting the seller and asking if they can replace the battery. $\endgroup$
    – Jacob B
    Nov 15, 2020 at 0:39
  • $\begingroup$ @Jacob B, I thought you can discharge a lithium-ion as low as 2.5 - 2.7v and still be able to salvage it? And yes, the battery is new $\endgroup$
    – DroneDome
    Nov 15, 2020 at 1:11

1 Answer 1


Note: This answer does not consider whether this is a 'good idea', as there can be safety concerns with over-discharged lithium batteries (e.g. see this question.)
I aim here to address the 'how' of the question, but you must decide if you consider the risks acceptable (for this battery, or others in the future) and follow all the usual charging safety measures.

It looks like the charger in question supports unbalanced charging, so you may be able to set the battery to charge in unbalanced mode which should ignore the per-cell voltage. In this case, I would set the charge current as low as possible and charge somewhere very fireproof - in case the low cell voltage has caused damage - and plan to stop the charge once the faulty cell has exceeded about 3.1V. You should then be able to try balance charging again.

However, the charger may check the sum of the individual cell voltages for the unbalanced charging mode and could therefore still decide that the total voltage is too low.


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