Are the batteries genuine Canon brand batteries or are these 3rd party batteries?
Four years is starting to get "old" for a battery.
Please switch on the camera, press "Menu" and then navigate to the tab that has the gold wrench icon with 3 dots (there are three pages of gold-wrench tabs... denoted by have 1, 2, or 3 dots next to the wrench.)
The top option on that page is "Battery info." Please select this and tell us what you see.
It should tell you the remaining capacity of your battery as a percentage.
It should also tell you the number of shots that were taken with that battery after the last full charge (it will call this the "shutter count" but it's not the camera body shutter count... it's just the count on that battery AND only since the last full charge.)
Lastly, it should tell you what the recharge performance is for that battery. A new battery will display 3 green boxes. An older battery will display 2 yellow boxes. A very old battery that needs to be replaced will show just 1 red box.
As batteries age, they do wear. They'll hold less of a charge then when new. Genuine Canon batteries are usually pretty good about having a low self-discharge rate. Some of my 3rd party batteries could be charged and put on the shelf... put into a camera after a month of non-use, and already show significant drain (especially when they got older.)
I realized a general trend that my genuine Canon batteries seemed to age a bit more gracefully than my 3rd party batteries (I got more years of use out of them and they held a charge better when sitting around on a shelf not being used).
But... four years is getting old for a rechargeable battery. They may simply be getting to a point where it's time to replace them.
The 60D doesn't have anything that would continue to draw down power when the camera is switched off *IF* you are using Canon brand lenses. Technically the on/off switch is just a software switch and when you switch the camera 'off' it doesn't really cut power... it just puts the camera into an extended sleep mode. I have heard of 3rd party accessories and sometimes 3rd party lenses that drain down the batteries of cameras even when off... and the (frustrated) owner eventually stumbles onto realizing that it only happens with a certain lens.
If you use any 3rd party products (products that use power such as lenses, battery grips, etc.) then those could be responsible for the drain even the batteries are fine (but at four years old, I doubt your battery info panel is telling you that you still get 3 green boxes in the recharge performance status).
Tim Campbell
5D III, 5D IV, 60Da
