Do rechargeable batteries wear out? How many times can I recharge them? How do I know when they are worn out? Open


All rechargeable batteries wear out. Your car battery is a well known example. Every time a rechargeable battery is used, it loses a small amount of capacity. Whether that becomes a problem or not depends on how much capacity you need. Here's an example: let's say you have an SM transmitter and the NiMh AA rechargeable batteries that we provide, currently 4 each 2200mAh Eveready batteries. These batteries happen to run your SM transmitter for 4 hours and 5 minutes (4:05) and that is just fine with you because you only have to operate the transmitter for exactly four hours every day. In few weeks, you are going to be very disappointed, because after 20 charges, the battery will only power the transmitter for 3:59. The reason is that every time you charge the batteries you will lose a tiny amount of capacity and you don't have any spare capacity to lose. In fact after a year of use, the batteries will probably only run the transmitter for 3 hours. There is nothing wrong with the batteries or the transmitter. Rechargeable batteries just slowly wear out.

The solution is to start out with a higher capacity NiMh AA battery such as an Eveready 2500 mAh cell or a Sanyo 2700 mAh cell. You will now get almost 5 hours of battery life initially and you won't be down to 4 hours of life until 200 recharges or 6 months later. This is even after assuming that the higher capacity batteries wear out twice as fast. (Eveready quotes the 2200 mAh battery as being rechargeable 1000 times and the 2500 mAh being rechargeable 500 times.)

This is an extreme example caused by your run time requirements being so close to the limits of the smaller capacity battery. If you only needed 2 hours of battery operating time, the smaller battery would be fine and would actually operate for many years before falling below your requirements. If you look at the economics of the battery for the SM, the rechargeable batteries really make sense. Top quality alkaline batteries will only run the SM transmitter for less than two hours and cost about 40 cents apiece. Two hours is rarely long enough. Lithium AA batteries will run the SM for 6 hours but they are $2.00 each. High capacity NiMh AA batteries are $3.00 each but the cost per use is a tiny 1.5 cents. Compared to a lithium AA battery, just two uses of a rechargeable AA pays for the battery.

This discussion is also applicable to the iPower 9 Volt lithium ion polymer rechargeable battery. Exactly the same arguments can be made about both saving money and gradual wear out of the battery with recharging. (See FAQ#089-WIRELESS)

Q: So do rechargeable batteries wear out? 
A: Yes

Q: How many times can I recharge them? 
A: It depends on your run time requirements.

Q: How do i know when they are worn out? 
A: When they no longer meet your requirements.

Posted 3 years agoby LectroAdmin

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