Rechargeable Batteries: Myths Exposed
Ever wondered about all the truisms thrown around about rechargeable batteries, like putting batteries in the freezer makes them last longer? What about the old saying “it’s best to slowly recharge a battery.” In this article we’ll expose some of the myths that surround rechargeable batteries, and their basic capacity ratings.
1. Putting batteries in the freezer prolongs their runtime. Sometimes it’s just not worth the trouble. For instance, alkaline batteries stored at room temperature self-discharge at a rate of less than two percent per year. Storing alkaline batteries in a freezer or refrigerator barely slows down the self discharge. Use your storage space for food items!
However, if you store your NiMH batteries in freezing temperatures you’ll see positive results. NiMH batteries kept at freezing temperatures retain over 90% of their charge for a full month. It makes sense to store them in the freezer. If you choose not to freeze them, consider storing them in a cool place to minimize their self discharge. Why? At room temperature [around 70 degrees Fahrenheit] NiMH and NiCD batteries self discharge at a rate of a few percent PER DAY. Therefore, storing them at lower temperatures slows their discharge rate in a dramatic way.
Consider alkaline batteries again. If alkaline batteries are stored at a high room temperature, they lose the basic capacity rating pretty quick. At 85 degrees Fahrenheit they lose about 5% per year. At 100 degrees they lose up to 25% or more per year. If you live in a hot climate store your batteries in a place with a controlled climate. This should prolong their runtime.
2. It’s best to recharge batteries slowly. Manufacturers design some batteries for a quick charging. Sanyo, POWERhaus, and GP make their batteries with a rapid recharge by design. Of course, you will want to use specifically
designed chargers that will rapidly recharge NiMH cells. This means that quick charging NiMH batteries will reduce their basic capacity rating.
You have a greater chance of decreasing the life of a NiMH battery is you use an “overnight” charger instead of a smart fast charger. Some folks think these chargers are the same. They are not. Overnight chargers depend on the user
unplugging them after a set number of hours. When the user forgets to unplug the overnight charger the battery continues to charge longer than it should. Overcharging drastically reduces the life of a battery. Make sure to use a smart
fast charger.
Still, some folks will cry “foul” and champion slow charging. If you’d like to get really technical, then yes, slow charging a battery will likely increase its charge a bit more than one that has been rapid charged. However, the difference is tiny and is usually not even noticeable.
3. A battery capacity of 2,800 mAh delivers a current of 2,800 mAh for at least an hour. If you read this article on rechargeable batteries you know that assigning battery capacities is not a great practice to follow. It’s very tricky. Under most circumstances you won’t even see capacity ratings marked on alkaline batteries. Why? High drain electronic devices like computer peripherals, portable music players, and digital cameras burn through alkaline batteries in no time. Alkaline batteries deliver only a small fraction of the battery’s rated capacity. So, just because an alkaline battery has a rated capacity of 2800 mAh doesn’t mean it will outperform a NiMH battery with a rated capacity of 1800 mAh. NiMH and NiCD batteries are more likely to deliver closer to their rated capacity when using high drain devices.
There may be some truth to some of the sayings about rechargeable batteries and their basic capacity ratings. However, most of it is a stretch. The next time you hear someone claiming these myths as truths direct them to this article.
LaptopsForLess.com has a huge selection of rechargeable batteries in stock, at very reasonable prices [often a fraction of the cost of manufacturers’ own brand replacements]. We stock; Laptop Batteries, Power Tool Batteries, PDA Batteries, Camera/Camcorder Batteries, Cell Phone Batteries and much more. If an electronic device contains a battery, we’ll stock that battery!
