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Rechargeable battery technology has come a long way. Back in my teenage years the choice was either a lead-acid battery or a lead-acid battery… go figure. The first technology to make inroads on this was the NiCd (Nickel Cadmium) battery. It made a lot of new applications possible since it was completely sealed. However good these batteries were, they had one big disadvantage: the maintenance. To prevent a “memory effect” they had to be maintained properly. Which meant that they were simply not maintainable by the average Joe. As a result many of these batteries performed sub par and people became quite frustrated with them. Besides, they are a environmental hazard.

Along came the NiMH (Nickel Metal Hydride), it was way better than the NiCd because it did not suffer from the “memory effect”. But (like the NiCd) they still suffered from the “deep discharge” effect. Which in turn means that storing these rechargeables almost ensures that they will be worthless when you need them. They will often have self destructed by then due to the internal discharge.

In 2005 things got a lot better, Sanyo developed the “Low Self Discharge” variety of the NiMH. This battery type is IMO a heaven-sent rechargeable. They can be charged, put in a drawer and even after a year, or two and even three they will still retain enough charge to be ready-to-use. As a rule of thumb, they will loose about 20% of their charge every year (stored at 20C, 68F). Thus after three years they still have about half their capacity left.

More important than the remaining charge however, this LSD rate means that the battery remains in good shape, even after a couple of years of no use - provided it was charged to full capacity before storage. Pick it out of a drawer after a couple of years, charge it, and its as good as new. An amazing battery imo.

Normally the LSD NiMH can be charged/discharged for something like a thousand times. But that assumes that the battery is not mistreated.

The very worst that can be done to the battery is to overcharge it. That will definitely ruin it. Other things to avoid is to discharge it completely, or to draw too much current. The later is not very likely as the devices they are made for won’t do that. Do make sure however that the battery cannot be accidentally shortened when stored. A complete discharge can be avoided by taking it out of a device when the first signs of a weak charge appear. That should normally not be too difficult.

I find that with all rechargeables it pays to use a good charger. I would recommend to buy a special charger of a good make and to get familiar with it. They are pretty user friendly and will enhance the life of the battery.

I myself have replaced nearly all AA and AAA batteries I use with the NiMH-LSD. I have done so several years ago, and am still very content with that.

The only time when I do not use a NiMH is when it concerns a device that uses very little energy and where the battery will probably never be replaced because the device will be forgotten. Some toys fall in that category, as I am sure you know…

Otherwise I like to top up all batteries once a year. That keeps them in good shape and ready for use when necessary. I can then simply replace an empty battery with a full one, and continue using the device it was in. The empty battery I will charge immediately and put them in storage for later use.

When shopping for the NiMH-LSD, keep in mind that they were build by Sanyo and called Eneloop. However Panasonic now also sells this battery, under the same name: Eneloop. I am not sure if Panasonic bought out Sanyo or not. As far as the battery is concerned, it does not matter as they are exactly the same. Sometimes the Low-Self-Discharge is also sold as “Pre-Charged”. This being made possible by the low self discharge rate of the battery.

I would recommend buying in bulk as that is cheaper, and chances are they will see a lot of use. Prices come down that way to as little as $3 per piece. And it is possible to find them even cheaper than that. Which imo compares favourably to a $1 alkaline battery of a top brand.


Originally posted at: 2016-12-07
Last modified on: 2016-12-07