BP-511 Charge

[CM]

Anyone know how long a BP-511 maintains its charge when off-line?

I put my backup battery in my camera tonight and, despite the battery condition indicator being OK, I only took one exposure before my EOS 300 died. I reckon the battery was last charged almost 18 days ago.

[Kenski]

Anyone know how long a BP-511 maintains its charge when off-line?

I put my backup battery in my camera tonight and, despite the battery condition indicator being OK, I only took one exposure before my EOS 300 died. I reckon the battery was last charged almost 18 days ago.

Where did you have the battery laying?

It could of discharged because it could of been shorting out and you didn't know it... There are alot of things that are conductive and you just don't know it... 18 days is a long time for it to discharge slowly if it is a poor conductor....

[dsze]

There are times when I leave some of my 511's in the bag for 2-3 weeks without using/charging them and then when I do put them in the camera, they only last a short while.

Its slightly concerning that your camera indicated a full charge and yet the battery died. Did the camera indicate a low batt. before turning off? I know that the batt. sometimes has to be in the camera for a few minutes before the camera will give you a true reading, but...

-daniel

[robertwgross]

Lithium ion rechargeable batteries are pretty good, in general, as compared to the old NiCd batteries and stuff like that we had before.

A normal lithium ion battery will take a good charge and hold it without much loss. It is normal to have 1% of self-discharge per day. So, even after a few weeks of idle time, it should be good, but not perfect.

However, then there are lithium ion batteries that are not normal. In some cases, these are batteries that have been recharged a lot, like more than 300-500 times. In some cases, they were marginal spec batteries to begin with and were sold cheaply. In some cases, they were improperly recharged. In some cases, the regulator chip (hidden inside the battery case) has failed and now represents a slow short to the actual lithium battery cell. For whatever the reason, they are no longer normal, and they won't hold a good charge very long. Expect 10-50% self-discharge per day.

If they get too funky and don't work to your expectation, then put them in a battery recycling program and move on.

---Bob Gross---