Batteries and Battery Level Indicator

Just a heads up for those with BG-E2 battery indicator problems. I've been using a BG-E2 grip (gold indicators) on a 20D for almost 10 months now and it has worked flawlessly. Last month I noticed my charge level dropped to half within 20 shots of a newly charged battery. Taking out and putting the batteries back in full charge reappeared but only temporarily before going back to half charge after a few more shots are taking. After doing this a few times it got to a point where half charge appeared on power up even after I reinserted the batteries or removed and reinstalled the BG-E2.

At first I thought the problem was with the BG-E2 but when I removed the grip from the camera and put the batteries directly into the 20D I get the same problem. So now I'm thinking there's something wrong with the body.

Since I bought the BG-E2 I've been using the same set of generic BP-511A and it seemed strange that this problem would appear all of a sudden. This morning I decided to put in a Canon OEM BP-511. With only one battery in the grip I've shot about 140 frames and am still showing a full charge. I'm yet to do any longer term checks but fingers crossed the problem is with the generic batteries rather than the camera or grip.

So the batteries are 10 months old...?
They should last longer but sounds like they have died and can no longer hold a charge. Have they had heavy use?

Thats the problem with unofficial batteries but they are cheaper so you can get new ones

The generic batteries are holding up fine. I've run a voltmeter on them and when fully charged they show about 8.70 volts. They are currently holding about 8.30 volts and that's after approx 150 frames being shot. But for some reason they're triggering the camera's low battery warning while the OEM ones aren't. They don't have a name on them but are made in Japan which should be better than the rubbish ones coming from China or Taiwan. Should have mentioned that in my original post

The battery level will drop when under load. If they have dropped a cell they could read correctly off load but will be low when any load applied.

After a year, it's quite possible for Li-Ion batteries to start wearing out. As evandavies asks.. "Do they have a lot of use" ?

The more you charge and discharge a Li-Ion battery, the faster it wears out. If they did have more than average use, it's possible they are near the end of their lifetime. 10-14 months is par for a well used battery.

When they're on their last leg, they show a full charge much faster than 'normal' when plugged in to a charger, and of course the batteries discharge much quicker when you use them.

Useage was about 4,000 frames. Always recharged after a reasonable amount of shooting (some times when the battery indicator showed half charge, other times when it was still showing full charge). I would estimate that the batteries have been placed in the charger and charged approx 15 to 20 times. Come to think of it I have never run the batteries to a full discharge.

I think I might see what happens if run them to fully discharge. Any way of discharging the batteries without using them in the camera?

Discharge them fully. Then recharge them fully. It might take a few times but a lot of time this will clear up any "memory" problems if possible.

You might also consider a Canon Battery. The ones I have now will go 300 frames raw before slowing down. You get so used to the time that I often forget the spares.

Volts tell you how much power a battery, like a bucket of water in a well at the top. Ampreage tells you much of that power is available. Like the size of the bucket at the to of the well. More amperage longer running time.

I have three Canon batteries. Two are over a year and a half old and going strong. The other is from the D5 and it is a powerhouse.