On Fri, 27 Jun 2014 14:46:19 +0100, Martin Brown
wrote:

On 27/06/2014 11:59, David.WE.Roberts wrote:
I have an 'Energizer' brand replacement battery for my Nikon camera.

Model ENEL9
Li-ion 7.4v 1000mAh (7.4Wh)

Left it in the camera unused too long and it is flat and won't charge.

If they get too low voltage then the self protection won't let you try
to recharge it. A better outcome than having it explode or catch fire.

Anything obvious I can do to revive it, or just dispose of and replace?

I still have the original battery so the camera is working.


Since it's a single cell "battery", all the battery management
circuitry can remain in the phone or camera itself, Allowing the
battery to just be a simple 'battery'.

The likes of a 3 cell laptop battery contains additional circuitry to
eliminate the risk of a battery fire either due to overcharging or
else from over depletion (an over-depleted condition is _not_ good for
the health of a Li Ion battery so needs to be avoided at all costs).

However, it the voltage hasn't dropped very far below the lower
limit[1], you might be able to feed it a sufficient charge from a
100mA source for a few minutes sufficient to raise the battery voltage
to an acceptable level for the camera or phone's charge controller
(but be vigilent of any signs of overheating, at least for the first
time you manage to revive the camera or phone charging circuit's
interest).

[1] Unfortunately, I only have the lower limit voltage figure of 2.4v
per cell discharge cut off to go by. I'd guess that if the voltage has
dropped to 2 volts or less, it's 'game over'. If you're looking at a 1
volt or lower open circuit reading, the cell can be regarded as
finished without any lingering doubts.

http://en.wikipedia.org/wiki/Lithium-ion_battery#Battery_life

offers some detail on this.
--
J B Good