I am a battery dependent hobbyist - Cameras, radio control devices of all sorts (cars/trucks/helicopters/drones/planes/still & video transmission gear/etc. etc.) power tools, lawn tools, you name it, I have a battery powered version. Have gone from all types of non rechargeable to all rechargeable and to units/systems with dedicated batteries. For my devices that utilize Li-on batteries (I'll stay with the camera gear for simplicities sake) I use a simple process of checking each device monthly, turning on, run for a bit/shoot a couple pics, check functions, check battery level. When the battery level for one falls to the 40% or below It gets a recharge. If it is one I'm not using very often, it gets approx. an 80% charge (but if it goes to 100% before I check it that's ok). If it is a high usage camera (camera of the moment) it gets full charge. Same goes for the batteries that are on the shelf/in the case on "stand-by", and these generally don't need to be checked as often (say quarterly). Scheduled "cycling" of the battery/device is your best bet.

I rarely charge anything in the camera, to many years with Li-po batteries have tainted my methods - all it takes is a direct short, bad setting on a charger, and trouble can visit. Even with Li-on, a bad charge could give you problems you never imagined.

Depending on the devices static drawdown rate (battery depletion in the unit, not turned on), some don't need to be checked as often (every other month or quarterly), and you learn which ones over time. If I can't remember, I use a notepad kept with the gear, or you could do a spreadsheet if you have so many its hard to keep track. Li-on batteries perform well and from my experience are generally quite safe (I didn't say perfect) and can be counted on to perform as predicted. I've had no camera gear failures with Li-on, I did finally lose my Toshiba laptop battery after 8 years, so I bought cells and rebuilt it...still chugging along. I have a couple of li-on's that aren't as good over time now, but no other signs of failure/leakage/swelling/etc. Now, if you have Li-po batteries in any devices, they require greater care, but then they are generally used for high current applications (running four brushless motors at very high amp draw, for instance) and they tend to run through very tough usage cycles....and have a shorter lifespan. Misused Li-po's can be dangerous (check out youtube lipo battery explosions). Li-ons can also catch fire, but the instance is usually an extremely low percentage...usually caused by the charging device, or a short of some kind (cell phone meltdowns/explosions).

NIMH batteries are generally safe, will deplete over time, so they need to be checked and cycled also, should be stored in the 60-80% range. NiCad batteries are very dependent on regular checking and cycling, and that is part of why they have fallen out of favor (they are just not as good).

Non rechargeable batteries - we all have experience with these...yes they will eventually fail and usually goo comes out - never pretty. Do remove those for storage.

I have never (yet) had a cameras internal battery fail, or not come back to life, in all my years with digital (or otherwise)….I'm not sure if its my methods, dumb luck, or what. Some of my bridge cams and P&S have sat for months at a time, no battery, no power, but have come to life with a charged battery.

insman1132 wrote:
Why not just recharge the battery in any camera, that remains on the shelf most of the time, every 3 months?? Especially easy to do if you can charge the battery while in the camera. I set my outlook calendar to pop up every 90 days with a reminder. Just a suggestion!! Simple and straight forward!

When batteries do fail - if you are like me, I rebuild them, and I have a lot of experience at it, so its an easy deal (usually getting the case open without damage is the worst part). For those who do not know how, you can learn, or just properly dispose of the dead rascal. Either way is ok.

Sorry for being long winded, but if anyone has questions or concerns, please respond. Long story short - they worka whole lot better and longer with a little "maintenance".