View Full Version : The Care and Feeding of NiMH

09-24-2005, 03:11 PM
If you just ordered your brand new digital camera, you should probably order a quality battery charger and a set of high capacity rechargeable batteries now before the camera arrives. The charger and batteries that come inside your camera box will more than likely be equivalent to the cables and no-name batteries that came inside your new stereo equipment [Need I say more?]

The answer to that burning question is Yes, you can use a higher capacity battery in your camera even though the OEM that came with it was only, say, 2000 mAh. The number only denotes capacity, not voltage. The voltage for all AA and AAA batteries is 1.2V. The capacity is how much power a battery holds once it is fully charged. And the more capacity, the longer a battery will last in any given application.

By getting new batteries all charged up before your camera arrives, youíll be able to use it as soon as you open the box. And you can charge those no name batteries as recommended Ė overnight.

Donít be surprised if your new batteries donít deliver top performance out-of-the-box. New NiMH batteries may need several so-called ďcyclesĒ to condition them before performing as well as they should. This is normal until the batteries are actually worn in. Whatís a cycle?

First, charge the batteries fully
Then allow them to cool off before putting them in your equipment
Finally, use your equipment normally, and when itís time to recharge the batteriesÖ
Thatís a complete cycle: fully charge, cool off, then discharge

The importance of a quality charger canít be overstated. There is an ongoing debate about the advantages of slow charging over fast charging and vice-versa. Many quality chargers will give you a choice of charging methods. The most complete process involves discharging the battery, then charging it and topping it off. Typical charging modes are Charge, Discharge, Refresh and Test. But the key is to find a charger that wonít overcharge your batteries, because that will shorten the life of the batteries.

And speaking of shortened battery lifeÖ Avoid dropping your batteries on hard surfaces, such as countertops or the floor. Also avoid carrying those AA and AAA batteries in your pockets. Get yourself a plastic battery holder. Coins or other metal items in your pocket can cause batteries to short out and may even cause injury by burning or exploding in your pocket. Be safe, purchase a plastic battery holder. Many battery dealers will throw them in for free with the purchase of batteries.

You should try to charge your stored batteries at least once every 30 days. If left longer than 60 days, the batteries may not accept a charge at all. So itís not a bad idea to store them in a slow charger to keep them in peak condition. By the way, NiMH batteries begin to lose power when stored for only a few days at room temperature. The good news is that they will retain 90% charge if you store them in your freezer after they are charged and have cooled down. Be sure to keep them in a tightly sealed plastic bag to keep them dry. And let them return to room temperature before inserting them in your equipment.

NiMH, like all rechargeable batteries, will lose some capacity in time, but it is normally very gradual. However, cheaper no-name brands of NiMH have a higher rate of loss. Newer brands of NiMH rechargeable batteries are designed to have a much longer cycle life than older generation NiMH batteries. Normally after 300 - 400 cycles, battery capacity will decrease 10 to 15%.

Iíve used a lot of battery chargers over the past few years. The one Iím currently using is the best of the best. The La Crosse BC-900U is a state-of-the-art battery charger that does it all: Tests, Refreshes, Charges and Discharges. And you get to choose the charging current (200, 500, 700 or 1000 mA). It also keeps you informed of its progress with an individual LCD readout for each charging battery in a set of four.

This battery charger does it all, and the LCD readout allows you to keep track of the charging. Most battery chargers plug directly into the wall outlet, but the La Crosse has its own transformer. It allows you to place the charger on a flat surface, which makes it more convenient to monitor. Those numbers indicate the current by which the batteries are being charged. You may charge the batteries at a slower rate (200) which would be ideal for overnight charging. There are other chargers available on the market that tout quick charging. However, the best strategy, the practice that will ensure longer battery life is to have several spare batteries so that you won't need to quick charge your batteries. The default charging rate for this charger is the ideal 200mA, which is a trickle charge.

09-24-2005, 05:41 PM
but what about the Rats of NIMH? :D

Seriously, though, useful article. :) What do you think of the Maha chargers? heard a lot of good things about 'em...

09-24-2005, 07:23 PM
I like the Maha brand, which was my favorite before La Crosse came out. The new Maha, Model #MH-C801D, that recharges 8 batteries at a time, is set to be released next week. It, too, has an LCD readout, but I haven't found any info on how flexible it is with regard to charging. I think the new Maha and the LaCrosse will be fairly equal, with the edge going to Maha for its 8-battery capacity. These two chargers are head and shoulders above those standard chargers with the one red diode... making them, by comparison, mickey-mouse :D

09-26-2005, 03:40 PM
That was great. I'm finally changing from film to digital and had no idea about chargers. That really cleared up a lot.
Thank you.

09-27-2005, 03:44 AM
Glad I could help. The capacity of AA batteries seems to be growing rapidly. I expect they will break the 3000mAh level by January.

09-27-2005, 07:29 AM
Speaking of batteries, are there any that you would recommend? i.e. are all 2500mAh batteries created equal, or are there differences between brands?

09-27-2005, 08:06 AM
Speaking of batteries, are there any that you would recommend? i.e. are all 2500mAh batteries created equal, or are there differences between brands?

I would highly recommend Powerex and Energizer brands, with Sanyo pulling up a close third. There is a large middle-of-the-field, and there are a few I would stay away from. The iPowerUS brand is usually given away by dealers as a bonus. The brand is troublesome. They seem to lose capacity with each cycle. When I ordered my LaCrosse charger, the dealer included a set of four iPowerUS AA's. They were sealed and brand new, but one of them was a dud. I notified the dealer, who was quick to send me another one. :( And some reviews call the brand "delicate," meaning that it doesn't take much to drain them. I won't use that brand in my equipment. I'd put them in non-demanding applications like remote controls.

You will find several "battery shootouts" on the Internet, comparing various brands. The problem is that the industry is bringing out new, more powerful versions so rapidly that the shootout results are dated. For example, 2600mAh rechargeables are the latest, but most reviews I've seen lately haven't caught up. They're comparing 2300's! The Powerex and Engergizers are about neck 'n neck, trading top power honors with each new model. If you stick with those, you can't go wrong.

One way to save cash is to order batteries that aren't the top power capacity when a new level comes out. For example, you can get great deals on 2300s now because 2600s have come out. When the 2700s hit the scene, that's a good time to buy 2400s... and so on. :)