Daily Dose of Common Sense

They have always been a good idea, but the tough economic times have made more people than ever look into using rechargeable batteries instead of single-use batteries. Once a mystery, we now all routinely use special-purpose rechargeable batteries in devices like cell phones and digital cameras. Like anything else, however, knowledge is power (pun intended), and even a few simple facts can help a lot.

First, let’s deal with the most important issue: safety. NEVER try to charge a single-use battery. Those warnings are not from some overly cautious lawyer; fire and explosions are real dangers. If you don’t believe me, search for battery fire on YouTube and you’ll see that these innocuous-looking little devices are not to be misused. Electricity and chemistry can each be dangerous on their own, and together they are even more so.

Similarly, never use any kind of rechargeable battery that has been damaged in any way. Likewise, don’t try and jury-rig anything; use things as they are intended and according to the instructions. We technology professionals have a humorous acronym for this: RTFM, which stands for (polite version) Read The Freaking Manual! While our arcane knowledge may seem a mystery to most people, and some of us do indeed have a knack for gadgets, it’s mostly due to the fact that we read the darn directions!

Now, lets get to those helpful facts.

First, take the time to find out the chemistry of the batteries you use, as that dictates how you should use and recharge them. The choice is whether to keep the battery “topped-up” as much as possible, or whether you need to mix things up more in order to avoid the (frequently misunderstood) memory effect.

In general, lithium (Li) chemistry batteries are better off if you keep them fully charged as much as possible. Most internal and special-purpose (by which I mean they only fit into one model or brand of device) batteries these days are Lithium based. So, keep your cell phone plugged in as frequently as possible and you’ll get the longest life out of its battery. Ditto goes for lead-acid batteries, which are most often found in your car and the external UPS you use for your computer, which is why both are constantly “trickle charging” the battery.

Some special-purpose batteries still use nickel (Ni) based chemistry, and all general purpose (standard sizes like AA, C, D, etc.) do. While the new Ni-MH batteries exhibit less of a memory effect than their predecessor, Ni-Cd, it’s still there. The thing to avoid here is repeatedly using the device for the same amount of time after a charge (say 10 minutes) and then recharging it afterward. Pretty soon, the device thinks the battery is low after 10 minutes.

How you prevent this depends on the batteries. If it’s a battery pack, you can only practice avoidance. Deep discharging will likely do more harm than good. If they are individual batteries (general purpose rechargeable D cells, let’s say), then you can deep discharge them, but only either in devices that use only one battery, or in a charger that discharges first. If you want to know why, here’s one good site: http://www.greenbatteries.com/

All that said, the best advice is still: READ THE INSTRUCTIONS! Every device or battery/charger combo will TELL YOU what the best usage strategy is.

Assuming I haven’t frightened or annoyed you by now, you’ll be happy to know that replacing single-use batteries with rechargeable ones can save you some serious samolians. Let’s take a AA battery as example. You can get a rechargeable AA for about $4, whereas if you buy wisely, a brand-name AA can be had for as little as $.50 (although many of us wind up paying more because of an impulse purchase at the checkout line). So, after 8 charging cycles, the battery only costs you the electricity you use to charge it, which amounts to a few pennies or less. Even if it were a nickel, and even if you only got 50 charging cycles out of the battery (100 or more is the norm), that’s at least $18.90 you’ve saved, a 372% Return-On-Investment. Try getting that from your mutual fund manager!

Our final handy fact: When buying rechargeable batteries, the specification that matters is the capacity, expressed as mAh or Ah units. The bigger the number, the longer the battery will last in the same device. So, besides less tangible factors like the reputed quality of the brand, etc., the only reason to pay more for a given battery is if the capacity specification is higher.

Lastly, it’s still a good idea to keep some fresh single-use batteries on hand for devices you will need in an emergency. If the power is out, you can’t charge your radio batteries to find out when the repair crews are due. http://www.ready.gov/america/getakit/

Photo courtesy of Flickr: moria

This entry was posted on Monday, September 21st, 2009 at 2:01 pm and is filed under Technology. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.