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Cost Savings with Rechargeable Batteries
Rechargeable batteries can be a major cost savings in a household that has many battery-powered devices.
According to All-Battery.com, premium alkaline batteries will power your digital camera to take about 45 photos for a cost of $2.99. Rechargeable NiMH Batteries will take about 30,000 photos for a cost of about $18.98. This calculates to about $0.0664* per photo with the alkaline batteries and $0.0006 per photo for the rechargeable NiMH batteries. This makes the rechargeable batteries about 100 times less costly than alkaline batteries. The cost difference is staggering.
My all-time favorite rechargeable batteries are the Sanyo Eneloop 
batteries. They are the only rechargeable batteries that I have been able to reasonably use with a flash in my digital cameras. The new Eneloop batteries are rated for 1500 re-charges. They must be charged in the Sanyo Eneloop charger. (It is likely that another high-quality NiMH charger will work; I haven't tried it) For our cost purposes, I've taken the price from Amazon for a 4 pack of AA Eneloop batteries with the charger included - $15.94 (price as of 06-12-12). This would make each battery cost $3.99 (I'm ignoring the price of the charger; the cost of 4 AA Eneloops without the charger is $10.69, or $2.67 each. But since the charger is a must in order to get the maximum use of these batteries, the price with the charger is the most correct one to use for our purposes.)
According to the forum site, CandlePowerForums (www.candlepowerforums.com), the Eneloops will last about 3 hours, 57 minutes compared to 2 hours, twenty five minutes for an alkaline battery, when used in certain flashlights. In my digital camera, I have also found that the Eneloops last longer, but I have no precise data to offer as I have not kept records. So, for our purposes, just to be conservative, we will assume that the Eneloops and the alkaline batteries will last about the same length of time, even though there is good evidence that the Eneloops probably last almost twice as long.
Also, from the site, are the calculations showing that each recharge of the battery will cost about $.02 or less in electricity.
Here is the cost comparison:
Sanyo Eneloop - 4 - AA batteries and charger cost: $15.94 = $3.99 each**
Energizer Max Alkaline AA Battery, 24 count cost $9.61 = $.40 each**
Cost Per Full Battery Use:
Sanyo Eneloop - 1500 recharges + $.02 in electricity to recharge = $.007+ $.02 = $.027 (2.7 cents) per use of approximately 2.5+ hours
Energizer Max Alkaline - $.40 each = $.40 (40 cents) per use of approximately 2.5 hours
Comparison Cost in Total Battery Usage for a 4-pack of Batteries:
Sanyo - spend $15.94 for 4 batteries with 1500 recharges each. = $15.94
4 batteries X 1500 recharges each = 6000 charges x $.02/ea electricity to recharge = $120.00 in electricity.
Total = $15.94 + $120.00 = $135.94 for 6000 uses
Energizer Max - $.40 per battery use = $.40 X 6000 batteries = $2400.00
Total Potential Savings for Rechargeable NiMH Eneloops vs. Alkaline batteries= $2264.06
To realize this kind of savings, keep in mind that you have to keep track of these batteries and have a regular system for recharging them. You may need to buy a second pack of the Eneloop batteries so that you will have a fresh set to replace the set that needs to be recharged.
One feature I like about the Eneloops is that the battery itself is white - very different from most alkaline batteries and very easy to recognize. This nearly eliminates the chance that you will accidentally throw away the battery when it is discharged.
You will have to develop the habit of looking at the batteries in no-longer used devices or devices that you are getting ready to toss or give away. If not, you may end up tossing or giving away your valuable Eneloops.
There are other NiMH batteries on the market, of course, for example:
Amazon Basics AA NiMH 4-Pack (rated for 1000 charges) + Charger for $18.79
Duracell Value Charger with 4
AA NiMH batteries (rated for "100's" of recharges) = $16.30
However, for my uses I have not found another NiMH that compares to the Eneloop in power, longevity, ease of recharge, and total cost.
As a side note, I also have a charger that I use to recharge regular alkaline batteries. It works, but not as predictably and easily as the NiMH rechargeables. Often, though, the batteries are free: just ask friends and family to save their used alkaline batteries for you. They will look at you as though you are delusional (most people feel that alkaline batteries cannot be recharged), but they will still save their batteries for you. I'll post an article about recharging regular alkaline batteries soon.
Using rechargeable batteries is reliable, earth-friendly, saves significant amounts of money, and gives me a great feeling. Now that's the Fat Dollar way.
*based on 500 recharges of the batteries.
**prices from Amazon.com as of 6-12-12
References:
CandlePowerForums
http://www.candlepowerforums.com/vb/showthread.php?296552-alkaline-vs-eneloop-in-Fenix-LD20
All-Battery.com
http://www.all-battery.com/batterycost.aspx
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