18650's from a laptop battery pack.- Mtbr.com
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  1. #1
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    18650's from a laptop battery pack.

    I am looking at building external battery packs using 18650's from IBM Laptop battery packs.

    Would anyone know if these batteries are protected or will I need to integrate a PCB?
    Will it hurt the batteries if I use a PCB and they are protected? Will the two protecting circuits cause any issues?

    I have noticed with laptop battery packs. Even if they will no loger charge in the laptop, when cracked open 4 of 6 cells are still good and hold a charge.

    I am looking at making a few 4 - cell packs (running in parallel) so I always have power on hand.

    Any info would be greatly appreaciated.

  2. #2
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    there is a PCB that protects the cells within the pack, but it isn't autonomous from what I understand (doesn't really work without a laptop connected).

    I've had no problem running 18650 cells from an old dell pack though. I ended up with 2x 3S-4400mAh packs that I'm happy with. I run them unregulated, because I own a balance charger that ensures they are balanced at 4.2V, and I run a Bflex with low power warning, so it's not a problem to not run the PCB.

    I just cut the old PCB out of it, and used the cells as needed to build my new packs.

    assuming you've got around 12 cells like my pack had, you can make 3x 4S1P packs (14.4V, 2150mAh), or one 4S1P and one 4S2P, or one 4S 3P pack.

    just remember you need to solder to the tabs that are welded to the cells, and you need to be careful not to get the cells too hot whilst soldering, and not short them out at all.

  3. #3
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    Bryguy17,
    ThanX for your reply.

    I got quite a few batteries as I've taken a few packs apart. Benifits of working in IT.
    I am looking at creating 4 or 5 1S4P's so I have extended run times on both my torches.

    What charger do you use? I have a cheap TrustFire from DX, that I particularily do not TRUST. I was looking to get this CHARGER..

    So if I run 4 x 16850 parallel and have a proper charger, I do not need a PCB? I was looking at adding this PCB if needed.
    Last edited by Absolute3.0; 07-14-2009 at 05:49 AM.

  4. #4
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    Please keep posting your laptop-battery-salvaging results here.

    I am also new to the whole DIY lights scene.
    I have ordered 2 of the DX P7 Bike lights (sku.25149) and now anxiously await delivery. In the meantime I have been lurking around these forums and starting to come up with some ideas for my own DIY projects.

    I am also in IT and have started to gather up some old laptop batteries for my future projects.
    I am interested to hear your success rate with salvaging these 18650's. Most of the laptop batteries I can get my hands on are really dead. Like they have been lying in a store room for years. Will I be wasting my time on these, or is there still a chance of finding some good cells inside?

  5. #5
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    Hey Brad,
    Welcome... I'm faily new here myself.

    I have tore open four battery packs and check each battery with a Volt Meter and find that usually 4 of 6 batteries are good. I did have one 5 yr old Dell pack that were all dead.
    I would not say that it's a waste of time, you will find a few that will take a charge. I have noticed that if I get 2.5V+ on a battery it will take a charge, if it has less, It won't.

    My best find so far was an IBM T60 Extented battery pack (9 cells) and 8 of them were good. And to top it off they were Sony Brand.

    I have found Sony's, Panasonic's and one with no name but has a red plastic coating.
    The only down fall of these laptop packs that I have found is that the batteries are only rated at 1800Mah.

    The main reason that they will be better off built into multi packs.

  6. #6
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    OK
    Thanks for the info.

    Most of the batteries I can get my hands on are from HP laptops. So far I have opened one up which had light green Sony cells inside.
    I have a few more HP batteries to still crack open & have now asked some colleagues to send their old batteries my way in future. I work for a large IT company. I am pretty sure I will have a steady supply of newly deceased batteries very soon.

    I still need to get a charger though so can't really do much until then. I haven't managed to find a local supplier for Li Ion chargers (in South Africa). I may have to order one from DX, which will mean another long wait for the delivery...

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