Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Charge an emergency fan on AC or DC setting?

  1. Jul 12, 2013 #1
    I've an emergency fan with an AC/DC button on it, but its manual doesn't say on which setting it should be charged. I've tried charging on both settings, and it can be charged either way.

    On the back of the fan it reads:

    "AC 220/240

    The fan's box only says:

    "DC: Operate when power failure.
    AC: Operate by AC power directly"

    My question is on which setting (AC/DC) I should charge it for future use when there's a power failure? Thanks in advance!

    This is not a homework question.
  2. jcsd
  3. Jul 12, 2013 #2


    User Avatar
    Science Advisor

    The AC / DC switch probably selects the source of power for the fan motor.
    So it does not matter which is selected during charging of the internal battery.
  4. Jul 12, 2013 #3
    I see. Thanks for the reply!
  5. Jul 12, 2013 #4
    Also -the switch is most likely "after" the battery, so it has no effect on the charging circuit.
  6. Jul 12, 2013 #5
    I agree With Mr. Baluncore. The Switch itself selects the Power source(whether AC/DC). No matter on Battery charging.
  7. Jul 12, 2013 #6

    jim hardy

    User Avatar
    Science Advisor
    Gold Member

    That's assuming the charger's current capacity is more than the fan draws.
    It could be a trickle charger.

    Knowing no more than has been posted, I'd charge it on AC setting.

    But one experiment is worth a thousand expert opinions...........
    Try it overnight - run battery down and then see whether it'll charge back up with fan running in DC position ??
  8. Jul 12, 2013 #7


    User Avatar
    Science Advisor
    Gold Member

    I would just take it apart and have a look. The wiring should be straight forward.
  9. Jul 13, 2013 #8
    Well, I did that and it does charge fully on DC position. I'm also drawing this conclusion that the AC/DC button has nothing to do with the battery.
    Last edited: Jul 13, 2013
  10. Jul 13, 2013 #9
    That's actually not a bad idea. I'll do that even though I understand the AC/DC option has no effect on the battery.
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Charge an emergency fan on AC or DC setting?
  1. Ac & dc (Replies: 9)

  2. AC or DC (Replies: 4)

  3. Ac or dc (Replies: 6)

  4. AC to DC (Replies: 6)

  5. AC to DC (Replies: 4)