Misbehaving 5d2 battery

Any cure for this?

One of my (original Canon) 5d2 batteries has started a habit of suddenly going dead, usually in the middle of live view with the mirror open.

It then only wants a couple minutes charge, or so it tells the charger, but the next morning you can charge it all day long before full. Then it pretends to work until the circle completes.

If it's over a year old you may need to buy a new one

Let me add to that: most lithium ion batteries ago dead after 1 year, maybe two. Some will last for 3 years if you are lucky. Camera batteries are no exception, it's just the nature of the beast. Luckily the 5D2 batteries are still manufactured and still readily available (and they will be for a long time). You may want to get a chipped 3rd party battery if you don't want to pay Canon the outrageous cost for a new one.

uOpt wrote in post #16352236
Any cure for this?

One of my (original Canon) 5d2 batteries has started a habit of suddenly going dead, usually in the middle of live view with the mirror open.

It then only wants a couple minutes charge, or so it tells the charger, but the next morning you can charge it all day long before full. Then it pretends to work until the circle completes.

Is it an original battery or 3rd party?
How old is your battery?
What's the usage like?
Does it see continuous use or more storage than use?
How do you store the battery, for how long and do you store it fully charged?
How do you normally charge your battery?

All these things will affect battery performance and life. Under normal use and maintainance, all Li-ion batteries should last 2-3 years.

Depending on your answers above, you may be able to rescue your battery.

It's one out of 3 of my original Canon batteries. I don't think it had other use and storage than my other batteries and if so - less. Couple years old, maybe 3.

It's not a case of bad recharge performance. It suddenly goes from 90+% full to so dead it can't close the mirror.

Try to recalibrate your battery. You need to slowly discharge your Li-ion until it reads 0v (when the protection circuitry kicks in and cuts off the internal circuit). The reserve voltage is still about 6.5volts. Then use the canon charger and charge it to full again. In some cases, you may need to repeat twice.

I've been using my originals and 3rd party since 2008 and it still works almost 90% capacity.

Aswald wrote in post #16352320
...You need to slowly discharge your Li-ion until it reads 0v...

How is this done? Normal camera usage, live view, etc?

amirshakoor wrote in post #16352345
How is this done? Normal camera usage, live view, etc?

When the 5Dmk2 reads min battery left, the actual voltage left in the battery is still about 7volts. You need to take the battery out and discharge it like how is described in my previous post.

I was surprised how much energy the LP-E6 can actually store! I've done recalibration on original Canon LP-E6, BP-511, NB-2HL. Also performed recalibration on the Wasabi 3rd party, same models with good results.

uOpt wrote in post #16352304
It's one out of 3 of my original Canon batteries. I don't think it had other use and storage than my other batteries and if so - less. Couple years old, maybe 3.

It's not a case of bad recharge performance. It suddenly goes from 90+% full to so dead it can't close the mirror.

When you buy a camera it doesn't come with 3 batteries. so the question is were did you get it?

Places like Amazon, and ever Newegg, was selling counterfeit batteries before, they can look like original.

plus 3 years, depending on use, could simply be end of life for that battery.

If you are in the habit of recharging batteries before they are really flat, some will remember this and expect it all the time. Do try not to recharge until the battery in question is truly flat.

Sometimes I use my camera with one charged battery in the grip and one uncharged, until both go flat, to ensure the uncharged one gets totally flat. Then I repeat the process, swaping battery roles.