Important facts you need to know about your camera’s batteries.

We’ve come a long way since the early days of digital cameras when AA batteries were the norm and you were lucky to get more than 50 shots from each new set. Today, rechargeable lithium ion batteries have replaced all the previous types because they accept more charge, hold their charge longer and provide more accurate information about how much power they retain. It’s also safe to recharge them when they’re partially discharged.

How a camera uses power depends on the type of camera and its components. All cameras use battery power for their electronic displays as well as operations like opening and closing the mechanical shutter, metering exposures and driving the autofocus motor(s) and stabilisation mechanisms in the camera and/or lens.

In mirrorless cameras, much of the power is used by the electronic viewfinder, which means battery capacities tend to be lower for mirrorless and compact cameras than DSLRs with optical viewfinders. Batteries may also be smaller in mirrorless cameras to make them more compact and lighter than DSLRs. The table below compares two cameras from the same manufacturer with a similar sensor size and resolution.

Nikon Z50 Nikon D7500
Physical dimensions 127 x 94 x 60 mm 136 x 104 x 73 mm
Body weight 450 grams 720 grams
Battery EN-EL25 EN-EL15a
Battery weight Approx. 73 grams Approx. 95 grams
Battery capacity 320 shots/charge 950 shots/charge

Shows the differences in physical size between a typical mirrorless camera (the Nikon Z50) and a DSLR (Nikon D7500).

How long should a camera battery last?

Rechargeable batteries have a limited life, which is influenced by the way they are handled and stored and the number of times they’re recharged. It’s impossible to provide exact figures that cover all the different sizes of batteries on the market but, as a guide you should expect a camera battery to last at least five years – provided it’s been handled correctly and wasn’t initially faulty.

Batteries are still available for many DSLR cameras that were first released over a decade ago. A check of several online forums found many contributors reporting rechargeable lithium ion batteries ‘still going strong’ after eight to ten years. Some older batteries that have been heavily used are not accepting the same amount of charge – but they’re still usable.

After a few hundred cycles, a battery may fall below half capacity and, if so, it should be ‘retired’. These batteries can be kept as emergency back-ups and used only when needed.

It’s not a good idea to let your camera’s batteries fully discharge because if recharged from flat the cells might become unstable and overheat. Your camera will indicate as soon as the charge becomes low enough to need recharging.

Batteries self-discharge over time, and will ‘die’ if they’re left unused in long-term storage through a gradual voltage drop. For lithium-ion batteries the average rate is around 2–3% per month so when buying batteries, it’s wise to check when the battery was made to make sure it really is new.

You can often find add-on battery grips available for cameras at the top end of a manufacturer’s range. Most will accept two batteries, which can double the shooting capacity of the camera’s single battery. Grips can be available for both DSLR and mirrorless models.

High-end enthusiast and professional cameras can often accept an add-on battery grip that accommodates two batteries, thereby doubling the camera’s shooting capacity.

How to prolong a battery’s life

Lithium ion chemistry prefers partial discharge to deep discharge, so it’s safe to recharge camera batteries at any time. You can also leave a battery with less than half its full charge on charge overnight, although it’s best to avoid charging longer than necessary wherever possible. Batteries last longest if they’re only topped up when a recharge is needed. If you’re in a rush and the battery is not fully charged it’s safe to use; it needn’t be fully charged every time.

Keep at least two batteries at hand and when the camera’s battery becomes low on power, exchange it for a fresh one. Labelling the batteries with the date on which they were purchased makes it easier to keep track of them and offers a quick indication of their age.

Most modern cameras display battery status data via icons on the monitor screen that show the level of power remaining. When the icon is fully coloured, the battery is charged; half the icon coloured shows the battery is half-charged. When there is no coloured in-fill, the battery is depleted and the camera should remind you to re-change it.

Some cameras also provide information on when to calibrate the battery and when a new battery is required. Battery chargers will usually show when the battery is fully charged by changing the colour of the indicator light or switching it off. Some will also indicate when it is partially discharged, low or depleted.

Battery performance can be affected by excessive heat and cold. High temperatures tend to accelerate chemical reactions and, in rare situations, batteries may explode. This is very unusual with camera batteries but has occurred with larger laptop batteries.

Low temperatures slow the reactions down and this might affect camera performance. Although most batteries can cope with sub-zero conditions, when shooting in cold conditions keep spare batteries inside your coat, close to your body so they remain relatively warm.

How to preserve battery power

If you’re out on location and don’t have a fully-charged spare battery, there are a few practical things you can do to maximise the number of frames you can capture with the remaining charge:

  1. Don’t leave the camera powered-up when you’re not actually using it. Most cameras will switch off if the controls aren’t used after a specified period of time (which can be set in the set-up menu).
  2. When photographing static subjects, such as landscapes and posed portraits, try not to activate the metering until you’re ready to shoot. This isn’t practical when shooting moving subjects but keep it in mind that continuous re-focusing drains power from the battery, and avoid unnecessary re-adjustments wherever possible.
  3. Turn the camera off when it’s not being used, particularly if the screen is illuminated. Screens can draw a lot of power from the battery. There’s also the chance you might press a button inadvertently and activate the camera if you’re walking around with the camera switched on.
  4. Image stabilisers also draw power from the camera. Leaving IS switched on will deplete the battery, particularly if you are using a super-telephoto or extended-range zoom lens. Switch off the stabiliser whenever your shutter speed is fast enough to avoid camera shake.
  5. Hunting for focus in low light or low contrast situations also consumes battery power. Switch to manual focus or use the manual focus over-ride to focus the lens.

Third-party batteries
To the best of our knowledge, no camera manufacturer makes its own batteries; they source them from specialist manufacturers and re-brand them. Accordingly, ‘alternative’ batteries from third-party manufacturers are available for most digital cameras (as well as many other electronic devices).

Alternative batteries with different brands from the camera come in different configurations. Some are sold alone, while others come with a matching charger. Some are also offered as twin packs.

It’s not uncommon to pay more than $50 for manufacturer-branded batteries, especially the relatively small, low-capacity batteries used in compact digicams and entry-level interchangeable-lens cameras (ILCs). Higher-capacity batteries for advanced DSLRs and ILCs usually cost more than $100; sometimes much more.

There are a few issues with buying third-party batteries. First, you have no guarantee of the same levels of quality control as the branded batteries provide. Secondly, even though the battery might fit into your camera and be able to provide it with power, it may not be able to be recharged with the charger supplied with the camera. Problems can also occur when recharging batteries via a USB cable.

If the manufacturer’s battery fails during the warranty period both it and your camera will be fully covered. But while a third-party battery may be covered by a limited warranty, any damage to your camera won’t, so you’re running a risk. That said, a check of online forums showed many contributors reporting good performance from third-party batteries.

Our advice to potential purchasers would be to buy batteries from a reliable re-seller, such as your local camera shop, so you know the battery is fit for purpose and you have some recourse if anything goes wrong. If buying online, check the price; if it’s too good to be true, the product is likely to be defective.

Auction sites offering products with no box or manual, no warranty or documentation, are usually selling counterfeit goods. These products consistently fail to meet stringent safety standards and can pose serious dangers to the end user. Buying cheap is just too risky to contemplate.

Identifying faulty batteries

Lithium batteries that have become damaged and unstable have been known to ignite fires. Look for the following signs that indicate a damaged battery: bulging and or discolouration, squashed, deformed or spilt casing and leaking fluid. If your battery shows any of these signs, it should be replaced immediately.

A number of major retailers in Australia accept spent batteries for recycling, among them Battery World, Ikea and Officeworks. Most council offices also provide a collection service for a range of batteries. You can find nearby collection points at the Recycling Near You website.

Travelling with batteries

While it’s generally safe to travel with equipment containing batteries, most airlines (and governments) impose regulations on travelling with batteries. Qantas permits each passenger to carry up to 15 portable electronic devices powered by lithium-ion batteries with capacities up to 100 Watt hours. This includes cameras, camcorders, small drones, computers and medical devices and the devices must be for personal use only. Devices containing lithium-ion batteries over 160Wh (such as the batteries used in commercial cameras, professional drones and remote control aircraft etc.) are forbidden as passenger baggage and must be sent as freight.

Note that the US and UK have implemented new travel requirements that restrict the carriage of electronic devices larger than a smartphone in the cabin of inbound flights from some Middle Eastern airports. Check the requirements of the airline you are booking with.

Shows the current airline regulations for carrying devices that use lithium-ion batteries and spare batteries.

The batteries that power phones, laptops and cameras are usually under the 100 watt-hour (Wh) rating and it’s safe to carry them in your hand luggage, either in the device or in a carry-on bag.

Spare batteries must always be carried in hand luggage. Some airlines have a limit of two spare batteries per passenger. Place them in individual plastic bags or protective pouches, or  tape over the terminals to protect them against short circuiting.

Don’t travel with fully charged batteries. Keeping charge levels at 40-70% will maintain the particles that store energy in their most stable state, minimising the risk of overheating.

Article by Margaret Brown –  see Margaret’s photography pocket guides  

Excerpt from Photo Review Issue 84

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