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Zenith SupersPORT battery rebuild

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  • GiGaBiTe
    replied
    The picture of the inside of the battery shows some circuitry with what looks like some sort of regulator. Once the batteries are recharged, a good charging circuit will maintain a float charge.

    Where I get the 15v from is the total voltage of all of the NiCD batteries in series. The battery circuitry is going to put out somewhere near that to keep those batteries charged, or it should anyway.

    The reason the lithium battery pack would never be fully charged is if the existing battery circuitry only puts out 15v, and the lithium batteries expect 16.8v, you're not fully charging them and will lose a lot of capacity. I'm making assumptions of how the battery pack works since with the bad batteries, you can't see the full charge voltage.

    Leave a comment:


  • thenzero
    replied
    Originally posted by GiGaBiTe View Post

    For NiMH batteries, I'd just get name brand. Energizer, Rayovac or Westinghouse. They're more expensive, but you only have to buy them once instead of experimenting with the Ebay lottery. Walmart, Home Depot and Lowes have their house brand NiMH batteries for garden lights in capacities between 1000-2000 mAh for AAA and AA sizes. C and D cells will have higher capacities, but I don't regularly buy those.
    I see.


    Oh dear heavens no, don't attach Lithium batteries directly to the existing charge circuitry, you MUST use a Lithium battery protection board unless you want a fire or exploding batteries. To clarify my above post, build up a battery pack with a Lithium battery protection board and then attach the output of the battery protection board to the existing charging circuitry in the laptop. This way would better ensure that the laptop didn't do anything funny from getting unexpected behavior from the battery.

    Just be aware that since regular lithium ion / polymer batteries voltage doesn't match up with NiMH, so it may cause the batteries to wear out faster. A 4 cell battery board will give you a voltage of about 16.8 volts, which is 1.8v higher than 10 NiMH batteries at full charge, so the Lithium pack would never be fully charged. Lithium Iron Phosphate batteries (LiFePO4) would give you 14.4v in a 4 cell pack, which is just under the max 15v charge, which would work better. You would need a different charge protection board though. Don't use LiFePO4 batteries on a regular lithium battery board or they'll be grossly overcharged and go on fire or explode.

    ok. Thanks for the info. Still a little fuzzy on the point about the 15V though, why would the lithium pack never be fully charged? I don't think the laptop itself does any regulation of the battery at all.

    Leave a comment:


  • GiGaBiTe
    replied
    Originally posted by thenzero View Post
    Copy on the ebay batteries. Do you have an alternative source you recommend?
    For NiMH batteries, I'd just get name brand. Energizer, Rayovac or Westinghouse. They're more expensive, but you only have to buy them once instead of experimenting with the Ebay lottery. Walmart, Home Depot and Lowes have their house brand NiMH batteries for garden lights in capacities between 1000-2000 mAh for AAA and AA sizes. C and D cells will have higher capacities, but I don't regularly buy those.

    Originally posted by thenzero View Post
    On the li-ion batteries I posted, are you saying the charging circuitry that's there will charge them ok? Or that it won't hurt to leave it there but still charge the batteries with a li-ion charger?
    Oh dear heavens no, don't attach Lithium batteries directly to the existing charge circuitry, you MUST use a Lithium battery protection board unless you want a fire or exploding batteries. To clarify my above post, build up a battery pack with a Lithium battery protection board and then attach the output of the battery protection board to the existing charging circuitry in the laptop. This way would better ensure that the laptop didn't do anything funny from getting unexpected behavior from the battery.

    Just be aware that since regular lithium ion / polymer batteries voltage doesn't match up with NiMH, so it may cause the batteries to wear out faster. A 4 cell battery board will give you a voltage of about 16.8 volts, which is 1.8v higher than 10 NiMH batteries at full charge, so the Lithium pack would never be fully charged. Lithium Iron Phosphate batteries (LiFePO4) would give you 14.4v in a 4 cell pack, which is just under the max 15v charge, which would work better. You would need a different charge protection board though. Don't use LiFePO4 batteries on a regular lithium battery board or they'll be grossly overcharged and go on fire or explode.

    Leave a comment:


  • Mad-Mike
    replied
    Originally posted by thenzero View Post

    Copy on the ebay batteries. Do you have an alternative source you recommend?

    On the li-ion batteries I posted, are you saying the charging circuitry that's there will charge them ok? Or that it won't hurt to leave it there but still charge the batteries with a li-ion charger?
    On the subject of LIthium Ion (my .02)

    Well, I know this for a fact looking into rebuilding my NEC Versa batteries with LiIon - it's not exactly safe since Lithium Ion are the explosive ones and they need a special charge management that's different from that of NiMH and LiIon. I have been messing with the whole idea of using Power Banks inside of old laptop battery casings since the LiIon charge management is located inside the banks. I'm doing some carefully curated experiments with this to see if it's a rebuild option. I did see that my Versa could charge the Power Bank (!!) - I tested the input voltage with a VOM, about 4.95 vdc - so it trickle charges properly. Those packs are around 5vdc each. The actual batteries themselves are around 7.2vdc rating.

    Leave a comment:


  • thenzero
    replied
    Originally posted by GiGaBiTe View Post


    Yeah you can use smaller cells, just be wary of random Ebay batteries, they are often fake. Usually the capacity is a lot lower than advertised. You can get a battery tester to be sure, and some smart chargers can do it as well. 2300 mAh is pushing the upper limit of NiMH at that cell size, so i'd be a bit wary of them.



    I would leave the existing circuitry in the battery pack alone and just attach the new batteries to it.
    Copy on the ebay batteries. Do you have an alternative source you recommend?

    On the li-ion batteries I posted, are you saying the charging circuitry that's there will charge them ok? Or that it won't hurt to leave it there but still charge the batteries with a li-ion charger?

    Leave a comment:


  • GiGaBiTe
    replied

    Originally posted by thenzero View Post
    What about something like this?

    https://www.ebay.com/itm/12Pcs-1-2V-....m46890.l49286

    I think these have a similar capacity and same voltage as the nicad cells. They are physically smaller but I could just pad them, no?
    Yeah you can use smaller cells, just be wary of random Ebay batteries, they are often fake. Usually the capacity is a lot lower than advertised. You can get a battery tester to be sure, and some smart chargers can do it as well. 2300 mAh is pushing the upper limit of NiMH at that cell size, so i'd be a bit wary of them.

    Originally posted by thenzero View Post
    Here's a dumb question, could I pull out the circuitry and just house something like this in there?

    https://www.ebay.com/itm/2800mAh-14-...-/292901019641
    I would leave the existing circuitry in the battery pack alone and just attach the new batteries to it.

    Leave a comment:


  • thenzero
    replied
    (Note: some other enterprising fellow posted somewhere that this thing can take a voltage anywhere from 12-18V, if memory serves. The power adapter is 16.5V and the laptop doesn't complain about low power until the voltage dips below 12V).

    Leave a comment:


  • thenzero
    replied
    Here's a dumb question, could I pull out the circuitry and just house something like this in there?

    https://www.ebay.com/itm/2800mAh-14-...-/292901019641

    Leave a comment:


  • thenzero
    replied
    What about something like this?

    https://www.ebay.com/itm/12Pcs-1-2V-....m46890.l49286

    I think these have a similar capacity and same voltage as the nicad cells. They are physically smaller but I could just pad them, no?
    Last edited by thenzero; May 4, 2021, 02:06 PM.

    Leave a comment:


  • GiGaBiTe
    replied
    Originally posted by Timo W. View Post

    NiCD cells have 1.2 volts. So 10 of them will give you 12v.
    Fully charged voltage != working voltage. NiCD and NiMH batteries fully charged are about 1.5v. When being discharged, they will fairly rapidly drop to 1.2v and remain there for most of the discharge cycle before suddenly dropping off a cliff in voltage.

    Same principle for Lithium Ion batteries, the fully charged voltage is 4.2v, which will drop to a lesser voltage and hold that for most of the discharge cycle before falling off a cliff.

    Leave a comment:


  • Timo W.
    replied
    Originally posted by GiGaBiTe View Post
    10 NiCD batteries in series would be closer to 15v fully charged.
    NiCD cells have 1.2 volts. So 10 of them will give you 12v.

    Leave a comment:


  • GiGaBiTe
    replied
    10 NiCD batteries in series would be closer to 15v fully charged.

    Rebuilding that pack with quality NiMH D cells is going to be eye watering expensive. It'll be $65-70 in just batteries and more for the nickel strips to connect the batteries together. You can either spot weld them or solder them, whichever you prefer.

    LiFePO4 batteries might work using four in series to get 14.4 volts on a battery protection board. The circuitry for that battery looks very simple and may not complain about the slightly different voltage. You'd obviously want to double the lithium batteries up to have eight batteries with two in pairs to give you a higher capacity. But this would still be eye watering expensive.

    Leave a comment:


  • thenzero
    replied
    7F91FB4E-67E4-4726-A9F7-2AD2CA1A1BD9.jpeg Here are some pictures of the battery pack in question.
    1272469D-9235-4AD5-B136-40912EFE1B53.jpeg 83FC75AB-A03C-4297-9BCE-62F9793EB689.jpeg

    Leave a comment:


  • thenzero
    replied
    Great info, thanks a lot.

    FWIW, there are ten D-size looking cells: two packs of four and then two extras for a total of ten, apparently in a serial arrangement. I believe the output was intended to be 12V based on what I've read, which would make sense if there were ten 1.2V cells in serial (right?).
    Last edited by thenzero; May 3, 2021, 03:19 PM.

    Leave a comment:


  • GiGaBiTe
    replied
    Since NiCD batteries have been banned in many parts of the world due to creating hazardous waste, NiMH is a good replacement. The charging characteristics are almost identical and NiMH batteries have greatly increased capacity compared to the older NiCD type.

    Another option is to convert the battery pack to lithium cells with a charge protection board. The easiest lithium battery to use would be lithium iron phosphate (LiFePO4) since it has a fully charged voltage of 3.6v, which is evenly divisible by 3 NiCD/NiMH batteries. This means you can replace three NiCD cells with one LiFePO4 battery, or two in parallel for increased capacity. This may or may not be beneficial depending on how many batteries are inside the existing battery pack and their arrangement.

    Normal lithium polymer/ion batteries have a maximum voltage of 4.2v and wouldn't really work. The only two issues going with LiFePO4 batteries is cost and hard to find charge protection boards. Since the charge voltage and characteristics are different from a normal lithium polymer/ion battery, you can't use a normal battery protection board, and have to use one specifically made for LiFePO4 batteries.

    Leave a comment:

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