At my house, we use a lot of AA batteries. Not only do several of our son’s toys use the batteries, but so do both of our baby monitors, our Wii remotes, our television remotes, and several wall clocks. Not only that, my wife’s breast pump runs on AA batteries as well, enabling her to pump in places where an outlet isn’t available (like on a long car ride when our children are asleep).
I did a count recently around our house and found that there are 36 AA batteries in use around our home (plus ten more in the breast pump, but I won’t count these for this purpose). Some of these are replaced frequently (even as often as monthly), like those in the Wii remotes and in my son’s self-propelled school bus toy – others are replaced rarely (less than annually), like the ones in the wall clocks. My estimate is that in an average month, we replace 10 AA batteries.
Because of our heavy battery usage – 120 AAs on average in a year – we were interested in finding an alternative to this expense, and we found that an investment in good rechargeable batteries up front will save significant money over the long run.
Let’s walk through this step by step. In order to do a fair cost comparison, I’m going to use prices from Amazon.com – a bargain shopper will be able to find better prices on specific items, but by using the same source, we can do a fair and valid price comparison.
Annual Cost of Non-Rechargeable AA Batteries
Since in a given year we burn through 120 AA batteries in our house, we obviously buy them in bulk in the largest packages we can. We’ve also tried many, many different brands of AA batteries and we’ve found that for our use, we almost always get the best bang for the buck from e2 Titanium batteries. They don’t have the longest life among the ones we’ve tried, but my wife and I have both observed that they have a very long life for the dollar.
So what do these batteries cost? You can get a twelve pack of e2 Titanium batteries on Amazon.com for $7.77. Since we use 120 per year, these batteries cost us $77.70 per year.
Startup Cost of Rechargeable AA Batteries
In order to effectively use rechargeables for our AA battery usage, we need to replace all 32 batteries with rechargeables, with four batteries to spare so that we can swap in fresh ones immediately and then put the empty ones on the charger. We’ll also need to invest in a charger.
After researching rechargeables, I found that almost every source recommended using eneloop rechargeable batteries because they don’t become weaker after many recharges and, more importantly, they hold their charge very well while just sitting there. I’m also investing in a quality battery charger that will last forever. Since I want these batteries to be a seamless replacement for our old AAs, I’m willing to buy the best.
As a result, I selected GE/SANYO eneloop AA batteries, which are available for $11.20 for a set of four on Amazon. Since I need 36 batteries, this is a startup cost of $100.80 for the batteries.
For the charger, I followed recommendations and selected a La Crosse BC-900, which not only charges batteries, but actually completely discharges them before beginning a charge, extending the number of recharges that you can get out of a battery significantly. Unfortunately, there’s another big cost here – $47.94.
Thus, the startup cost for our rechargeable battery use is $148.74. I recognize that I could cut some corners here and reduce the cost by buying other rechargeables or a lower-end charger, but the goal is to make the transition from disposable AAs as seamless as possible.
Maintenance Cost of Rechargeable AA Batteries
I put the charger on my handy Kill-A-Watt to see how much electricity is actually used in a recharge – and I was surprised. The battery recharger ate up 0.02 kilowatt-hours per AA battery recharged. Since I would be recharging 120 AA batteries in a given year, the recharger would eat up 2.4 kilowatt-hours per year. With electricity costing $0.10 per kilowatt hour these days, that means the charging cost per year for the rechargeables is $0.24.
Comparing the Two
Let’s look at this year by year.
In the first year, we would spend $77.70 on non-rechargeables. Simultaneously, we’d spend $148.74 on startup costs for our rechargeable batteries, plus $0.24 for recharging, giving a total cost of $148.98 for the rechargeables. Ouch – after one year, the non-rechargeables are way ahead, being $71.28 cheaper.
In the second year, though, the rechargeables get their revenge. The non-rechargeables cost $77.70 again, giving us a total cost over the two years of $155.40. The rechargeables just add another $0.24 onto the pile, making for a total cost over the two years of $149.22. Thus, after two years, the rechargeables are $6.18 cheaper, even after that huge initial investment.
Each year after that, the cost investment in the rechargeables is $0.24, while the non-rechargeables cost $77.70 – an annual savings of $77.44.
For us over the long haul, the rechargeables are clearly a good investment over the long term.
Let’s look at it another way. In the examples I used above, the rechargeable batteries cost $2.80 each and the non-rechargeables cost $0.65 each. Beyond that, there was also the startup cost of the charger itself – I used a very high-end charger in the example. The best way to spread out that cost fairly is to divide the cost of the charger by the number of rechargeable batteries you purchase. So, for that $47.94 charger above, my cost per battery for my 36 batteries was $1.33, giving me a total cost per battery of $4.13 per battery. At that rate, I have to charge up those batteries 7 times to match the cost of the disposable batteries. For me, that will take just about two years on average (some will be charged more often, some less, but that’s the average) – after that, this will turn into a great investment.
What’s Better For Me?
Let’s look at the numbers in general.
The more AAs you use in your home in total, the higher your rechargeable startup cost will be. This is because you’ll need to buy more high-quality rechargeables to rotate into the mix as the old ones wear out. You might want to just get rechargeables for the items you use often in order to reduce this number, but it’s really worthwhile to just get rechargeables into all of the places in your home where you use AAs.
On the other hand, the more batteries you use up each month, the quicker the startup cost will be recouped and you’ll be profiting from the investment. If you have a lot of heavy-use items that go through batteries like a child goes through candy on Halloween night, then this number is rather high and it’s worthwhile to dive into rechargeables.
The best way to determine if this is worthwhile for you is to keep track of how many AA batteries you replace over a long period – say, six months – and how many AA batteries you have in your home. The easiest way to count batteries is to buy a giant jumbo pack of the AAs and write the date of purchase on the back, then note the day you use up the last of the batteries – this will give you a good idea of how many AAs you use in an average month.
Here’s a thumbnail calculation: divide the number of batteries you waste in a given year by the number of batteries total in your home (plus a few for backup purposes). For us, that would be 120 divided by 36, or 3.3. That’s how many times you’ll recharge (or replace) an average battery in a year, and the higher it is, the more you’ll get out of a battery charger. My suggestion is that if your number is over 2, look seriously at getting high quality rechargeables into rotation. If it’s more than 4, you should definitely get good rechargeables in rotation.
I’m personally convinced that any household that has even a single device that uses a high quantity of batteries should look seriously into rechargeables. It takes some time to overcome that initial investment, but after that the savings is quite nice – it’s basically batteries for free.