1. Forum
  2. Usenet
  3. SCI.ELECTRONICS.BASICS

  • How long to charge 9v nimh battery

    From AK@21:1/5 to All on Sun Dec 19 05:57:15 2021
    I have a 9V 180 ma discharged Nimh battery that I am charging at 25ma.

    How long will it take to charge?

    Thanks,
    Andy

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Allison@21:1/5 to All on Sun Dec 19 12:34:27 2021
    AK wrote:
    -------------
    I have a 9V 180 ma discharged Nimh battery that I am charging at 25ma.

    How long will it take to charge?


    ** What you have is a 180 mAh battery: h = hour.
    You do the math.

    ...... Phil

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Marco Moock@21:1/5 to All on Mon Dec 20 11:22:04 2021
    Am Sonntag, 19. Dezember 2021, um 05:57:15 Uhr schrieb AK:

    I have a 9V 180 ma discharged Nimh battery that I am charging at
    25ma.
    Isn't it 180mAh?
    milliampere hours and not only milliampere?

    How long will it take to charge?
    (180mAh)/(25mA)=7,2h

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Robert Roland@21:1/5 to All on Tue Dec 21 19:07:21 2021
    On Mon, 20 Dec 2021 11:22:04 +0100, Marco Moock <[email protected]>
    wrote:

    Am Sonntag, 19. Dezember 2021, um 05:57:15 Uhr schrieb AK:

    I have a 9V 180 ma discharged Nimh battery that I am charging at
    25ma.
    Isn't it 180mAh?
    milliampere hours and not only milliampere?

    How long will it take to charge?
    (180mAh)/(25mA)=7,2h

    For nickel based batteries, you normally add 40-50% to compansate for
    charging efficiency.
    --
    RoRo

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)
  • From Phil Allison@21:1/5 to Robert Roland on Tue Dec 21 15:03:22 2021
    Robert Roland wrote:
    ==============
    For nickel based batteries, you normally add 40-50% to compansate for charging efficiency.


    ** The OP posted a question from some test he had to do.
    So no such correction factor is needed.

    For slow charge (8hr) rates - 40% might be OK.
    But absolutely not for fast charging, or the cells will cook.


    ..... Phil

    --- SoupGate-Win32 v1.05
    * Origin: fsxNet Usenet Gateway (21:1/5)