You are here

Time to Change Your Batteries

We have several remove controls from the television, DVD, VCR, and amplifier. The remotes work more than one device. We use the TV remove for both the TV and the VCR. That leaves the VCR remove used only twice per year for the changeover to and from summer time. Unfortunately I left batteries in the rarely used VCR remote. You could have the same problem which is a good reason to have a Spring clean and then an Autumn clean of all your batteries.

Alkaline batteries last several years when not in use but they do not last forever. Alkaline batteries are the best choice for remote controls, smoke detectors, and several other uses because the batteries retain their maximum voltage output until almost dead.

Example Problem

The following picture shows one of the batteries from the infrequently used remote controls. The battery expired on March 2004, was still working reliably in October 2005 but was leaking in March 2006.
A corroded battery showing chemicals leaking out of one end.

Here is the end of the battery showing the corrosive chemicals that can destroy electronic devices. Fortunately I found the leak before the chemicals reached the circuitry in the remote.

The end of a corroded battery showing the chemicals leaking out.

Type of Battery

Manganese and other cheap batteries lose power quickly even when not used. Expect only six months out of cheap batteries. Some of that six months might have already expired in the shop before you buy the batteries. Added to the short life, the batteries lose their voltage evenly across their life.

Voltage is important in electronic devices but not in a torch. Cheap batteries are useful in frequently used large torches because the cheap batteries are the lowest cost source of electricity and you can still use the torch even when the batteries are weak.

Never use the cheap batteries in a smoke detector because you do not know when the batteries will fail. People tend to replace smoke detector batteries once per year and manganese batteries do not last a year, no matter how lightly used. Do not use manganese batteries in cameras because the manganese batteries drop their voltage too low for the camera a long time before you use all the power from the batteries.

The cheapest batteries have weak seals which means they leak very quickly after they lose power. The better batteries have stronger seals that last for months after the batteries die. The best seals appear to last six months after the expiry date but not 12 months. Buy good batteries and check them at least each six months.

Lithium Batteries

Lithium ion rechargeable batteries are in common use in mobile phones (cell phones in USA). The use once disposable lithium batteries are less common and are a poor choice in Australia because, compared to alkaline, they are 3 to 4 times the price but have only twice the power. Lithium batteries do not seem to have a longer shelf life, do not have better seals, and are poisonous when they do leak. Avoid lithium batteries. If you use them then check them monthly.

Low Power Devices

Standard remote controls and most other small electronic devices with unlit LCD screens use very little power. Anything with a backlit LCD screen will use lots of power when the screen is on. Anything with a motor will use lots of power including CD players and those iPods that use a hard disk instead of modern technology.

Smoke detectors use little power because there are no moving parts and the indicator light blinks on only for a fraction of a second at wide intervals. Clocks use little power if they do not have an illuminated display. Alarm clocks may use a lot of power if they have a loud alarm and you sleep through the alarm for several minutes each morning.

Low power devices can easily last two years on one set of batteries but how are you going to remember when to relace the batteries?

Replacement Schedule

Remembering the right time to replace the batteries is the main problem. Two years is too hard to remember. If you set a day once per year to replace batteries then you can associate the changeover with something else such as New Year. Smoke detectors usually have a once per year replacement.

Slightly higher power devices need more frequent replacement. Twice per year is the longest time between replacements based on the safety of the battery seals. The example shown in this article was safely sealed 6 months after the expiry of the battery but had leaked at 12 months.

A 6 month changeover schedule fits the daylight savings changeover. When you change your clocks from Summer time to Winter time or back to Summer time then change all the batteries around your home and office.

Old But Not Dead

What do you do with batteries that are old but not dead? You can move them from low power devices to high power devices.

All my remote controls use two AA batteries. I can move the old batteries from the infrequently used remotes to the frequently used remotes. The remaining power can then be used up before the batteries start to leak.

Do not mix groups of batteries. In a group of batteries the total power is limited to the power of the weakest battery. If you have a frequently used device that requires four batteries and you want to top it up from devices that use two batteries then you could mix two almost empty batteries with two almost full batteries and end up throwing the lot out before you use all the power.

You can go the other way and split four batteries into two lots of two.

Never mix types of batteries as you will get the worst of both lots. Do not mix alkaline with manganese or lithium. If you do mix them the power will be limited to the cheapest weakest battery.

Torches are less sensitive to weak batteries. I have lots of low powered devices that use two AA batteries. Where can I use the batteries when they are close to expiring but are not dead? I purchased some low cost torches that use two AA batteries and used the almost expired AA batteries in the torches. The torches will still light up when the batteries are no longer safe to use in clocks or anything where reliability is needed.

I also give the old batteries away to children for use in simple toys. They can wear out the batteries in one day of use and the parents can remove the dead batteries at night when packing the toys away. An old Alkaline battery can still have as much power as a new manganese battery which makes the old batteries good value for the children.

Rechargeable Batteries

Rechargeable batteries are great for frequently used devices but not for infrequently used devices. Rechargeable batteries lose their power while not in use and last only a couple of months. Recharge your rechargeable batteries at least every month even if not in use.

Clearly you would not want to go around the house replacing every battery every month. Keep the rechargeable batteries for the items you use every day. For smoke detectors and other devices that sit in a corner forgotten until an emergency happens, use alkaline batteries and check them every six months.

I use alkaline for clocks including clocks with moving hands because the type of movement uses very little power.

My mini disk recorder uses just one AA battery and I pack both rechargeable and disposable batteries for the recorder. If I am driving across country and dictating a book, I use the recorder for up to ten hours per day. The rechargeable batteries power the recorder most of the time and the alkaline batteries are a backup.

Solid state sound recorders use less power but sometimes have very expensive proprietary rechargeable batteries that make no sense at all. I will eventually replace my mini disk recorder with a solid state recorder when I find one that works on rechargeable AAA batteries, has inputs for all of my microphones, and plays modern Ogg Vorbis recordings as well as the older MP3 format. Even with the very low power usage of solid state recorders, I will keep spare alkaline AAA batteries for emergency use.

My rechargeable batteries are nickel-metal hydride (NIMH) batteries which are economical to buy and reliable. There are rechargeable alkaline batteries but they require special chargers, are unreliable and more prone to overheating. Pay the couple of dollars extra and buy NIMH. Some devices are designed to work with NIMH and will fail to work reliably with rechargeable alkaline.