In the past, I used to always leave one battery in my cameras.

I have a set of photography and videos cameras including some Canon, Panasonic and Sony.

I currently use them every few weeks, sometimes every few months, maybe I used them more often in the past. I usually recharge all batteries just before some events when I know I will use them.

During COVID lockdowns, I almost didn’t use them at all and that’s where everything started going wrong. The batteries stayed inactive in bag in a room that could sometimes get cold… And I had to re-set all the dates (and, if I remember well, all settings had been reset on some of the cameras but not all). The batteries were all still working but they started having weird behaviours (like discharging very fast, or my Canon camera suddenly claiming that one of my commonly used Canon batteries was counterfeit…). So, I replaced most of the batteries by now.

When purchasing some new batteries, some seller recommended me to keep the batteries out of the cameras when not using them and re-charge them every 3 months or so, so that they don’t get completely empty. This indeed helps dealing with some batteries being empty at the time I want to pull out a camera and use it (if I kept them inside camera). But also, now, on all of my cameras, almost every time I want to use them after a few weeks/months, I need to re-set the time again, and again and again. (I think that most other settings remain as set.) (But this also simply happens if I remove the battery and then want to re-shoot something and place back the batteries, after a few minutes, I already need to set the time again.)

So, I don’t remember exactly how this works and what would be the better way to keep all aspects in mind…

  • In my memory components may have a secondary small battery to run clocks and so on (I know PC motherboards have one), maybe I need to have these replaced? So, should I sent them to some workshops to do that?
  • If these secondary “clock batteries” exists as I suspect and they’re in poor state (which I assume), could it explain a faster drain of a battery that remained inside an inactive camera?
  • Should I leave a battery in each camera or should I not?
  • Other?
  • 1
    \$\begingroup\$ Good answers below, but I just wanted to add one comment... I just recently bought an Anker power bank and while glancing through the user guide that came with it, I noticed this: "To preserve battery lifespan, use and recharge at least once every 4 months" \$\endgroup\$
    – osullic
    Commented Oct 7, 2023 at 13:56
  • \$\begingroup\$ Thank you. This matches the seller's advice to recharge them every 3 months ( every 3 or 4 months being roughtly the same). \$\endgroup\$
    – TTT
    Commented Oct 8, 2023 at 13:43

2 Answers 2


A lot of cameras use lithium button cell batteries for memory (like the Canon 60D/5D, Sony CyberShot still and VX video models, etc). Some are user replaceable; some require service (or more involved teardown). If the memory battery is meant to be user replaced it is generally described in the owner's manual, such as this depiction for the current Nikon D6.

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Even if it is not meant to be user replaceable, or described in the manual, it may be relatively easily replaced. In that case there's often a "How To" available somewhere, such as for the Canon 5D II. With older cameras it may be more cost effective to DIY or upgrade rather than sending it out for service.

Many newer cameras use a capacitor instead... If it uses a capacitor then you need to leave a battery in the camera to maintain the capacitor. If it uses a button cell then there is no drain if the battery is left in the camera (and turned off).

All batteries self discharge, all batteries have a lifecycle (number of cycles), and all have a minimum charge. Many chargers will not attempt to charge a battery that has fallen below the minimum. The battery is not (necessarily) damaged/bad, but it is effectively useless unless you find another way to rejuvenate it and get it to take a charge.

Some batteries (NiMH) will develop "a memory" and will loose capacity/capability if always used within a smaller range (i.e. recharged early)... so those are generally best maintained by letting them discharge rather than keeping them fully charged or recharging early. Most modern Li-ion batteries are best stored at ~ 50% charge.

Ideally managing/maintaining batteries can be rather complicated/involved. Personally, I leave Li-Ion camera batteries in (block style); and I remove or disable NiMH batteries (AA/button style). I use the approved charger (camera) or a smart charger (AA), and I just to my best to make sure they never get too low (rotate them occasionally with spares).


I leave a battery in the camera. Removing batteries was a good idea with alkaline batteries that could leak, but chargeable batteries rarely do so, and camera batteries (by opposition to "naked" AA batteries) are enclosed in a plastic container that makes them even less susceptible to leakage.

AFAIK on some cameras the internal "battery" is just a capacitor with enough capacity to last a couple of days at best (so you can charge the battery outside the camera).

This table gives you the self-discharge rates of battery types...

  • \$\begingroup\$ Thank you. The guy who told me not to leave the batteries in was precisely talking of lithium batteries, because the camera would always slowly drain them, and these batteries reportedly get somewhat damaged when discharged to zero. Slightly out of topic but, right, I replaced all alkaline AA/AAA type batteries of any devices in my place with Panasonic Eneloop Pro. I saw customer-standard alkaline ones leak so often and damage stuff that I don't even understand why people buy them and why they're still more in shops... (+ on the long run, anything re-chargeable ends up costing less). \$\endgroup\$
    – TTT
    Commented Oct 7, 2023 at 1:20
  • \$\begingroup\$ Lithium batteries also self -discharge pretty quickly according to this, much faster than the camera drains then when turned off. \$\endgroup\$
    – xenoid
    Commented Oct 7, 2023 at 7:22
  • \$\begingroup\$ Thank you. Will if that is true, it's weird that I see a huge difference between batteries being nearly empty if left in cameras, and batteries remaining almost full went left out of cameras... Something else may be at work there? \$\endgroup\$
    – TTT
    Commented Oct 7, 2023 at 9:14
  • \$\begingroup\$ A lot of older cameras use lithium button cell batteries for memory (like the Canon 60D/5D, Sony CyberShot still and VX video models, etc). Some are user replaceable; some require service (or more involved teardown). If those batteries wear out/go bad the camera will lose clock settings anytime the main battery is out/dead. Many/most newer cameras do use a capacitor instead... \$\endgroup\$ Commented Oct 7, 2023 at 12:05
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    \$\begingroup\$ I do not think that a 2-3% self discharge rate (of the usable capacity) is higher than the parasitic drain of a typical camera that is using it for memory retention (capacitor maintenance). But it is far higher than in a camera that is using a lithium button cell for memory retention instead (i.e. no parasitic drain). \$\endgroup\$ Commented Oct 7, 2023 at 12:16

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