Tuesday, January 19, 2010

Why does my battery charger flash ?

Recording this for other users, as well as smarter computers that can read.

Item (object, device, appliance):
Energizer 15 min AA - AAA battery charger.
(includes AC adapter as well as car adapter, and usually sold with a set of decent NiMH rechargeable batteries.
[In 2009, decent energy storage amounts for the AA package is 2000mAH to 2400mAH.]
Car charger is convenient when you are going somewhere with e.g. your camera and realize you don't have extra charged batteries.)

Usual action:
Put from 1-4 batteries in,
plug in charger,
LED displays as red while charging.
If there is a problem (battery won't hold charge, bad voltage, inserted wrong, etc), LED will flash red and charger turns off.
When batteries are hot (this includes during charging), the fan runs.
When charging is finished, LED turns green. The fan usually continues running an additional 8-10 minutes.

If LED is flashing, the usual strategy is to remove one or more batteries so a smaller set can be tested, then attempt to charge again and determine by isolation whether there is indeed a problem with one or more of the batteries.

However, it has been empirically determined that this often results charging being successful (i.e.: without flashing red LED).

Action in this episode:
Put two batteries on the left side, after a minute or two, the LED starts flashing.
These were the batteries I had in my mouse, and discharged over a period of a couple weeks.
Unplug AC adapter, remove batteries, insert batteries in two right slots, plug back in.
Result: batteries charge to completion.

  1. charger is wrong: does not sense voltage/charge consistently.
  2. device model of how batteries operation is not right: a charge of the battery may change its characteristic faster than expected
  3. one or more of the charging slots on the left have an issue.
  4. each slot may have different operating characteristics.
Further tests to be conducted.

The ideal charger would be able to supply more info about batteries (display charge curve, etc), be transparent in operation (what is your charge strategy?), sense/display battery type (and perhaps even recognize specific ones, or let you assign), do deep charging, download updates / upload recorded data.

Are there any specific app/lets that provide more info?

Send me your stories and battery links.

2010.01.30: Two batteries in the left slots did not cause the charging.
These two batteries were Energizer brand. I now notice they are different; 2450 and 1700mAh. Maybe that's why they didn't last so long in the Magic Mouse.