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4.5v or 6v for a 5.6 battery

Discussion in 'General Electronics Discussion' started by Squizzy, Aug 19, 2021.

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  1. Squizzy

    Squizzy

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    Aug 19, 2021
    Hi, I've been looking for days for a charger of a hair trimmer Babyliss E709E but unfortunately I couldn't find one with the exact voltage (5.6v), thus I bought an adjustable AC/DC charger with multi voltages that can go for 1.5/3/4.5/6/7.5/9/12V.
    So my question, which voltage is it safer to use on a 5.6v battery, 4.5v or 6v?

    These are some images of what I have:
    [​IMG] [​IMG] 235433532_835297213819341_6608584168285756903_n.jpg 236217033_872693813654248_1346808607048004812_n.jpg
     
  2. Sunnysky

    Sunnysky

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    Jul 15, 2016
    4.5V will not charge it enough and 6V may over charge and kill the batteries with heat. Use what is specified. 5.6V current limited to 80 mA
     
    Squizzy and davenn like this.
  3. Martaine2005

    Martaine2005

    3,661
    996
    May 12, 2015
    Do you still have the original charger?
    Perhaps it's a simple fix.

    Martin
     
    Squizzy likes this.
  4. Sunnysky

    Sunnysky

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    128
    Jul 15, 2016
    If you could add a series diode to the 6V, that might do for now. If you don’t and use the 6V, you’ll be looking for a new shaver this year.
     
    Squizzy likes this.
  5. dave9

    dave9

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    Mar 5, 2017
    What battery does it use? 5.6V is a strange voltage for 1 x Li-Ion or 3 x NiCd or NiMH and too low for 4 x NiCd/NiMH, so it looks like the charging depends on the very low 80mA current to end up trickle charging it, in which case you'd want the 6V but would want a series resistor (worst case, ideally a better charge strategy more appropriate to whichever battery config it uses) to limit current. A diode in series to drop a little voltage might be good too, particularly if you aren't diligent monitoring it to unplug when fully charged.
     
    Squizzy likes this.
  6. Squizzy

    Squizzy

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    0
    Aug 19, 2021
    I looked every where couldn’t find the exact voltage as it needs, I found an original charger for 44$ which is not worth it with the fact that I bought this trimmer for 60$, I’d rather just buy another one.

    And for the 80mA, I did some research, found it only takes what it needs so the amps aren't really the issue (Can you confirm this information)

    I’ll consider that
     
  7. Squizzy

    Squizzy

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    Aug 19, 2021
    The original charger fell on the floor that’s how it stopped working, and right away I opened it (broke it :(), but I didn’t notice any damage.
    I still have it though

    239066994_271372917819724_2150340367527192519_n.jpg 237661338_547511369796752_4135687477429208256_n.jpg 239341748_236511958367688_94577415182766940_n.jpg
     
  8. Squizzy

    Squizzy

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    Aug 19, 2021
    Idk I didn’t open the trimmer since it’s still working, charging with the 4.5V but it doesn’t last long on the battery, attempting to add a series diode, otherwise I'll use it as is until the battery dies or burns out and then eventually, I'll buy a new one :D
     
  9. dave9

    dave9

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    Mar 5, 2017
    A diode in series will get pretty close starting with 6V but I'd still want a series resistor and what but about what you wrote above, found it only takes what it needs, can you link to this info? Do you have access to the battery while it is charging, so you can determine the battery config, and measure what it is doing once it reaches what should be a fully charged voltage?

    I suspect that it keeps slowly cooking the cells at 80mA even when finished charging, otherwise why would they limit the current that much if it had an integral charge termination circuit? This would be consistent with the cheaper circuits for 3 x NiCd or NiMH.

    Keep in mind that if this circuit was cooking the cells all along, and if you do have 3 x cells NiCd or NiMH, and if you leave it charging long enough, AND if (heh, a lot of ifs) there is no polarity protection in series already to lose a fraction of a volt, then 4.5V input direct to the cells, should eventually fully charge 3 x NiCd or NiMH, so I wonder if the cells themselves are degraded from old age and hard charging cycles.

    If on the other hand it uses a Li-Ion cell, then it should definitely have a charge termination circuit, but it seems like a bad design then to artificially limit charge current to 80mA.
     
  10. Squizzy

    Squizzy

    5
    0
    Aug 19, 2021
    Thank you for the precious informations although I have a limited knowledge in this field but that helps a lot, I'll post new updates as soon as I open it.

    This is a link for the info that I posted earlier https://askleo.com/same-voltage-but-different-amperage/

    2021-08-24_003946.jpg
     
  11. dave9

    dave9

    1,154
    311
    Mar 5, 2017
    A laptop is a bit of a different situation in that they don't ever trickle charge the battery at the end. Well it is "probably" a different situation, that your trimmer probably doesn't have much of a sophisticated charging circuit which is why it's depending on this oddball voltage power supply to charge it, and why it's so current limited.

    Since I suspect this charger is carefully selected in order to mate with the built in batteries to get the job done as cheaply as possible, the best end result would be to current limit your charger PSU, and measure what it is doing all along, how much current is being delivered, and knowing (finding out) what batteries are in the trimmer, gives some expectation of how much current it should need to top them off, or plot the change in voltage as that will also give a hint, especially as the batteries age and their remaining charged capacity decreases.

    In other words, it helps greatly to have all possible info available ahead of time, when dealing with an atypical design.
     
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