18650 from old Apple iMac

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18650 from old Apple iMac

I recently joined this forum and I’m really amazed with some of the stuff I’m learning in such a short period of time. Flashlights are turning into my newest addiction. I saw a couple threads where people commented about tearing apart old laptop batteries for the 18650/26650’s inside, and just a few minutes ago I saw it again, and decided I might as well do that.

I tore apart an old apple iMac battery back. I have two iMacs, one wouldn’t hold charge, the other did. I don’t know which one was which….

Is there any way to tell how many mAH these batteries are rated for, or the volts or watt output? Or any way to tell if they’re any good, short of charging them and trying them…?

6 batteries altogether in a school bus yellow wrap, according to the sticky thread they should be protected batteries because they have a rib that runs the length of them, and vent holes in the top. They say “LG Chen” on the top and written lengthwise it says “ICR18650s12067209607ccq2c03306”

I apologize in advance if there’s a thread here that already goes into detail about checking batteries out, I haven’t found it, and didn’t spend much time searching lol..

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Can you see what the voltage and capacity rating of the battery pack itself is?

We can divide those values by the number of cells in series and parallel to see how the individual cells are rated.

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it just says model: a1008 10.8v

assembled in taiwan

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well that’s not good, google says it’s only a 4400 mAH battery pack

so individually the batteries would be 1.8v/730 mAH

those are pretty much trash aren’t they?

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Are you sure it’s an iMac, not a MacBook? What’s the model number and the year that it was sold? I think googling the model number would tell us some battery pack specs.

zoom zoom wrote:
well that’s not good, google says it’s only a 4400 mAH battery pack

so individually the batteries would be 1.8v/730 mAH

those are pretty much trash aren’t they?

If that’s the case, they are 3.6V at 2200mAh each. 3 in series, 2 in parallel for a total of 6.

You should measure the individual voltages of the cells. Anything under 2.5V is permanently dead. Sometimes a few bad cells can cause the entire the battery pack to stop working in the laptop, but the rest can be salvaged.

The individual cells don’t have protection, so you still can short them out or overdischarge them. Be careful when you’re tearing them apart!

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it’s an iBook, sorry for the confusion. It’s been so long since I’ve messed with them…

that’s good news if they are 3.6/2200. I have two on a charger, watching them, I’ll get my voltmeter out and check them all out.

Is there anything I can check besides voltage with a multimeter?

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You should check their voltages before you charge them. If they’ve been sitting at low voltages for a long time they are permanently damaged.

As for other tests, you can check their capacities using a charger that has a discharge function or by putting them in a flashlight on measuring the runtime.

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If what your saying is true then all these batteries are probably junk. The two that have been sitting on the charger for the last hour (right before I started this thread) read 3.46V, the other 4 are 2.12/2.14/2.14/2.25

I’ve been tossing around getting a 4 slot lcd display charger, not sure which one I want to buy, do you know if either of these has the discharge function you describe?

http://www.ebay.com/itm/NEW-NITECORE-D4-Digicharger-For-AA-18650-14500-18350-16340-10400-Li-ion-Ni-MH-/291148278673?pt=Battery_Chargers&hash=item43c9ca2b91

http://www.amazon.com/dp/B00OCCNBOE?psc=1

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zoom zoom wrote:
If what your saying is true then all these batteries are probably junk. The two that have been sitting on the charger for the last hour (right before I started this thread) read 3.46V, the other 4 are 2.12/2.14/2.14/2.25

I’ve been tossing around getting a 4 slot lcd display charger, not sure which one I want to buy, do you know if either of these has the discharge function you describe?

http://www.ebay.com/itm/NEW-NITECORE-D4-Digicharger-For-AA-18650-14500-18350-16340-10400-Li-ion-Ni-MH-/291148278673?pt=Battery_Chargers&hash=item43c9ca2b91

http://www.amazon.com/dp/B00OCCNBOE?psc=1

They’re probably all worn out after hundreds of cycles in the laptop. I’m assuming there’s about 1000-1500mAh left on those cells, but I wouldn’t recommend using them because sitting at low voltage can damage the cells.

Common 2 or 4 slot chargers don’t have discharging capabilities. Check out the Opus charger: http://budgetlightforum.com/node/33914 as well as others I’m sure members will suggest.

If you get into serious battery testing, a hobby charger like the Accucel-6 or the iCharger 106B+ will suit your needs.

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I don’t necessarily agree that cells need to be pitched if they sit below 2.5v (i have had good luck to 2v and my understanding is that the dangerous reactions don’t happen until ~1.5v but given how old and used these packs must be, I wouldn’t screw with them.