Battery Myths

Rechargeable batteries have a lower capacity than disposable alkaline.

It is pretty common for some people to think that a one-time use battery lasts longer than a rechargeable battery. The logical error here is "give and take"-the alkaline battery offers one lengthy charge while the rechargeable battery offers multiple short charges. This is False. Rechargeable batteries are made using the Nickel-Metal Hydride chemistry which is superior to the Zinc and Manganese Oxide chemistry alkaline batteries use. A single charge cycle from a rechargeable battery will last 3-4 times longer than a charge cycle from a disposable alkaline battery. The real "give and take" here is that rechargeable batteries cost a lot more than the disposable alkaline; plus, you need a charger too.

Verdict: False

Misleading battery terms: Super duty batteries last longer than non-super duty batteries.

Do you recognize any of the following phases on the packaging of your batteries? Heavy duty, Super heavy duty, Ultra capacity, Rapid charger, Long life, Max charge, etc.

Since there is no industry standards for the capacity of a battery as of now, many companies use these types of words to market their batteries. The correct way to find the potency of a battery is to look at the amperage and the chemistry it's made from. To make things clear, a "Super Mega Heavy Duty" alkaline battery would not stand a chance against a standard lithium battery.

Verdict: False

Putting batteries in the freezer prolongs their life.

Keeping alkaline batteries stored in "room temperature" only gives them a self discharge rate of 2% per year. Since the self discharge rate is so low, it's not really worth going through the hassle of putting them in the freezer and taking up valuable space that could be used for ice cream. Although the myth is technically true, odds are that you will put your batteries to use in less than a year.

But, if the batteries are stored in higher temperatures around 85 degrees Fahrenheit, the self discharge rises to 5% and at 100 degrees it rises to 25%. So basically, you should not worry about your batteries losing their charge unless the weather is really hot.

Verdict: (Technically ) True

It is best to recharge batteries slowly.

There are some people who believe that overnight chargers are better for batteries than quick chargers because the slow transfer of energy doesn't decrease their capacity. In reality, quick chargers do not negatively affect the capacity of batteries any worse than other chargers out there. The actual cause of capacity loss is overcharging. When a battery continues to charge after it has reached maximum voltage, the capacity will slowly decrease. Make sure your charger is a "smart" charger so that it shuts off automatically when the batteries are fully charged.

Verdict: False

You should use a rechargeable battery until it's fully dead.

This is true for Ni-Cad and Ni-MH batteries. If they are not completely used up of their energy and are charged, they will start developing "memory". Memory decreases the total capacity of a battery. The more memory a battery develops the more capacity it loses. This is not true for Lithium-Ion cells however. Li-Ion cells are not affected by the memory effect and can be recharged at any time.

Verdict: True for Ni-Cad and Ni-MH, False for Li-Ion.

Storing a sealed lead acid battery on concrete floor will gradually discharge it.

Storing, charging or operating batteries on concrete is perfectly OK. The most important things to avoid:

  • Freezing. Avoid locations where freezing temperature is expected. Keeping battery at a high state of charge will also prevent freezing. Freezing results in irreparable damage to battery's plates and container. [Freezing can happen between -19 degrees fahrenheit (40% charge) and -98 degrees (fully charged)]
  • Heat. Avoid direct exposure to heat sources, such as radiators or space heaters. Temperatures above 80 degrees accelerate the battery's self-discharge characteristics.
  • Step by step storage procedure:
    • Completely charge the battery before storing.
    • Store the battery in a cool, dry location, protected from the elements.
    • During storage, monitor the specific gravity (flooded) or voltage. Batteries in storage should be given a boost charge when they show a 70% charge or less. Completely charge the battery before re-activating.

The best place to store an SLA battery is in a cool environment using a battery tender. Battery tenders keep the battery at proper storage voltage so that it does not lose capacity. Some of them also increase their performance.

Verdict: False

Will a higher capacity (mAh) battery ruin my laptop?

A higher capacity (mAh) will not ruin your laptop. Extended batteries are ones that have been made with more capacity (mAh), or amps, in order to power its device for a longer period of time. If your laptop has been powered by a lower capacity (mAh) battery, switching to an extended battery with a higher capacity (mAh) will not harm your laptop. Devices can only be damaged when the voltages don't match up.

Verdict: False