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I tried to salvage 18650 batteries from a dead laptop battery, in the process I peeled off and scratched the metal casing a little bit with my utility knife (see attached image below), Other than that batteries work fine (Cells read 4.01v), Is it safe to keep using them? I'm planning to cover the open area with electrical tape.

Thanks in advance for answering

18650 battery

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    \$\begingroup\$ Cant answer that..it would be an opinion and I for one am not willing to tell you it's fine then have something bad happen. \$\endgroup\$
    – Trevor_G
    Commented Aug 28, 2017 at 18:00
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    \$\begingroup\$ New shrink wrap "rolls" are available online. \$\endgroup\$
    – winny
    Commented Aug 28, 2017 at 18:12
  • \$\begingroup\$ use them outside or in a cast-iron pan for the first cycle or two... \$\endgroup\$
    – dandavis
    Commented Aug 28, 2017 at 19:32
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    \$\begingroup\$ If the laptop battery was dead, what makes you think any of the cells are good? \$\endgroup\$
    – Matt Young
    Commented Aug 29, 2017 at 2:29
  • \$\begingroup\$ Thanks for answering. I'm aware there is a level of risk I'm just trying to minimize it, I tested them, 4 cells have a voltage reading of 4.0v the other two 0v. What temperature is recommended to use with the shrink wrap? \$\endgroup\$
    – bran
    Commented Aug 29, 2017 at 16:10

2 Answers 2

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Yes its casing is not punctured. Cover it with tape and keep a closer look on it the first time you charge/discharge. I would still use it. What level of risk you are willing accept is up to you.

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  • \$\begingroup\$ Thanks for answering, the casing is not punctured, Do you know how strong is the metal casing? I will use the cells to make a power bank. \$\endgroup\$
    – bran
    Commented Aug 29, 2017 at 16:14
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Be very careful! That scratch is very near to the positive pole, and if those 18650 are the same as all the others that I have used, the bare metal that you have exposed will be the exact same as the negative pole (I.e, the entire metal casing is negative, the small flat top or button on top is positive). So if anything connected to the positive touches that bare metal you will be effectively creating a short and will be in trouble very soon!

Shrink wrap made to seal these 'mistakes' would be the safest. Electrical tape always seems to fall off at the wrong time.

Good luck!

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  • \$\begingroup\$ Thank you for answering, do you recommend to peeled it off completely and seal it with shrink wrap again or just seal it on top of the current pink wrap? \$\endgroup\$
    – bran
    Commented Aug 29, 2017 at 16:17
  • \$\begingroup\$ I would just seal it on top. \$\endgroup\$
    – Filek
    Commented Aug 30, 2017 at 1:39

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