How to measure battery power

[Speedfinder]

As batteries age they store less. So Im wondering how to measure how many % power my ageing LP-E19 is capable of storing.
If its fully charged it shows full on camera display. I need to know as I spend long times waiting on wildlife which usually goes from nothing happening to its all happened so I need to leave the camera turned on all the time.

 

[koenkooi]

Go into the battery menu, that has a ‘recharge performance’ indicator for all batteries you have used in the camera.

 

[koenkooi]

I was slightly confused, the LP-E6 bodies can track batteries, the LP-E19 don’t have serial numbers, so you can only view info on the battery that is in there:

 

[Speedfinder]

Go into the battery menu, that has a ‘recharge performance’ indicator for all batteries you have used in the camera.

Great , thanks for that. I was (obviously) not aware of that function.