Battery Pack question

Discussion in 'Electronics & Electrics' started by TonyR, Jan 2, 2020.

  1. TonyR

    TonyR Member

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    I have an Energizer battery pack with two USB charging ports. If I connect a phone, or a tablet or any two phones/tablets everything works as advertised.

    However, I also have hearing aids with rechargeable batteries and a holder which charges them through USB. If I try to charge these with the battery pack they start charging, but stop after a few seconds. I thought that this might be because they have a "no data" cable, but the same thing happens with a normal cable.

    I discovered that if I charge the phone and the hearing aids, one in each port, they both charge successfully, but only until the phone is fully charged. Then the hearing aids stop charging.

    So, I am speculating that "normal" devices like phones and tablets somehow talk to the battery pack, saying "Give me more" until they are full, then they stop. When the battery pack gets the "more please" request it supplies power to both ports. The hearing aids don't do this, so when the other device is full the pack stops sending power.

    Can anyone confirm this, or otherwise explain why the hearing aids won't charge normally?

    Thanks

    Tony
     
  2. slavewone

    slavewone Member

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    Yes. I’m thinking it’s similar but opposite to cheap phone charging cables not working on newer phones as they aren’t passing the new communication between phone and charger.

    https://electronics.stackexchange.com/questions/252995/dumb-power-from-usb

    I’ve resorted to a LiPo to USB adapter to let me slow charge old/basic devices on a 5200mah 2S2P. The adapter will drain the LiPo so I’ve got a conservatively low voltage alarm plugged into the balance plug. For everything else, off the shelf stuff just works.
     
  3. dakiller

    dakiller (Oscillating & Impeding)

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    I think the issue is that the hearing aids don't draw much power at all while charging and the output voltage regulator isn't seeing enough load and is switching itself off, so that the idle power the regulator uses doesn't flatten your battery.
     
  4. OP
    OP
    TonyR

    TonyR Member

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    Thanks. I suspect that the low power requirement is the cause. Since the pack has to not draw any energy when in standby mode it just shuts itself off.

    It isn't a worry, I was just interested in the "Why?" rather than the "What can I do about it?".

    As an aside ... If anyone is thinking about rechargeable hearing aids - don't bother. My old replaceable battery ones had a life of about a week between battery swaps. These ones last less than 24 hours between recharges. They died on a long trip (SYD to Shanghai via Bangkok) and they were close to running out yesterday when we lost power for 24 hours.
     
  5. koss

    koss Member

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    Lots of powerbanks switch off when the current draw is too low. Easy to test, put a second device on it so it draws more and stays on, and see if the hearing aid keeps charging.
     
  6. OP
    OP
    TonyR

    TonyR Member

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    That is exactly what happens. The hearing aid keeps charging until the second device is fully charged.
     
  7. callan

    callan Member

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    I have the same problem wity my paperwhite kindle: it will stop charging about 1/2 way on most battery chargers.
    FWIW I'm %99 certain THIS charger from JB is quite happy with my paperwhite, so it should be for your hearing aid. It also just uses 2x 16450 batteries so you can goose up the capacity yourself if you like :)

    Oh, and I got the charger below from Officeworks a while back. It's little (2600mAh), but should have plenty to charge your hearing aid. It has a on-off switch rather than "auto-detecting" when the device is charging. For some reason it takes ages (about 5h) to charge though, which is a downer. Keep an eye out for it.



    20200102_150404.jpg

    Callan
     
    Last edited: Jan 2, 2020
  8. OP
    OP
    TonyR

    TonyR Member

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    Thanks

    I'll have a look into those two.

    I had a look around and have found my old hearing aids which have small (312) batteries and last a week before the batteries need replacing. I'll use them as my backups when the power goes out again. Not looking forward to Saturday :(
     
  9. callan

    callan Member

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    Good luck. I don't think anyone is looking forwards to this Saturday. As Chief Inspector Friday always sais.. Mind how you go..
     
  10. merlin13

    merlin13 Member

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    There was a long Thread on this type of problem not too long ago, thus.

    Following on from that - build a dummy load for one of the ports (LED light perhaps?) and run your low-drain item on the other. Fiddle the high-power drain such to be enough to keep the powerbank running.

    You'll burn/waste power but it'll keep an annoying powerbank charging your other device.

    Messy kludge, but if Needs Must...
     

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