NIMH battery charging.

Hi Lenny...

Respectfully suggest that that's because you aren't charging them, you're just teasing them a little :)

Unless 50 mills is a mis-type, that is.

If you really have to charge them manually, then read the capacity (current "normal" is 2500 mah) and charge them 10 percent (250 mils in this case) for 14 hours.

Or better, buy yourself a nimh charger. If the budget is a concern, then Walmart has an Eveready "dumb" charger that comes with two AA's, all for only a little under 10 dollars (cdn).

If the budget isn't of concern, then there are "smart" chargers available that will on an individual cell basis pre-determine the state of charge, charge them to 100% quickly, and then leave them on trickle (about your 50 mil rate) until you remove them.

Take care.

Ken

I kinda wish someone would write up the best ideas that work about various batterys and charging methods, and methods to test each for quality. In working with NIMH, I have yet to gather enough information to really evaluate them properly. I have some that seem to shut down prematurly powering a digital camera. I think its just one cell acting up or something like that sometimes. I always wanted to build a charger, like one charging position for each cell. I never liked charging them in series or parallel. Each one should be individually handled.

greg

The Ansmann Energy 16 will handle up to 12 AA cells treating each individually. It has a function that will automatically renew old cells that seem to be failing. It will do that by its refresh mode. Any cell that needs this will not effect the state of charge or the charge time of any other cell.

always wanted to build

charging them

So far it seems Maha makes chargers that do a pretty good job. They have a couple that are said to rejuvenate cells - - the MH-C204F and the MH-401FS. I bought the more expensive MH-401FS because it charges and monitors each cell individually, and can be set for either 2 hr or 5 hr rate. So far, my NiMH AA cells are performing well in regular use in a 3-watt Luxeon flashlight that pulls about an amp out of a pair of Energizer 2300 mAh cells

Chuck.

I agree. When a set of four is brand new they usually all charge in the same time, but as they age it seems that one or two cells in the set will become different from the others and will take much longer to charge. When that happens I don't see how two different cells can be charged properly if they're on the same circuit. That's why I like the Maha C401FS chargers that have individual circuits for each cell. I also have a couple of the older Maha C204Fs which reviewers all raved about, but because they charge cells in pairs I now use them only occasionally for the conditioning feature.

N.

Well, the C204F can condition cells by automatically deep-cycling them. The C401FS does not have this feature.

Yes, the C401FS is my favorite charger too. While it's not cheap, I doubt it's possible to get as good a charger at a better price. Absolutely, having a separate circuit for each cell is a good idea, and I appreciate the fast/slow charge switch too. Normally I use the slow rate because the cells stay cooler, but it's often handy to have the faster rate available when I need 'em in a hurry.

N.

Yeah, I've got several devices which take *three* AA's...makes it kind of difficult to charge them, when my charger only does two at a time....

jak

Yes, I'll bet. I don't think I've ever had anything that took three AA cells.

N.

All four of my FRS radios take three AA cells each. I've seen (but wouldn't own) flashlights that take three AAs.

At least half a dozen Motorola FRS radios and an LED flashlight, for starters....

jak

Then you're missing out on a good thing. I have a small light that uses a high intensity Luxeon LED powered by 3 AAA cells. It's noticably brighter than 2D cell flashlights using krypton bulbs. The light pattern is better too, although as with most LED lights, there's no focusing.

My good LED flashlights take either two or four AA's. One of the "fours" has seven white LEDs, a decent if not pinpoint pattern, and turned out to be intrinsically safe in the bargain. (At least it's marked so; I haven't turned on the gas to experiment. :)

Not having seen the Luxeon or any other LED lights with three cells, I was referring to some old-style krypton-bulb three-AA flashlights that just weren't worth the effort of carrying.

I believe I stated specifically an LED flashlight. It was one of the first ones available, from C. Crane. There are much better ones sold nowadays; but until this one dies, I'm keepin' it. I get 50 hours from a fresh set of alkaline AA's, and it will stay lit for an additional

jak

On 25 Sep 2005 13:42:18 -0700, Too_Many_Tools wrote:

Several years ago when there were very few smart chargers available from any sources, their "timer" chargers were fair to good. They had one large smart charger that handled AAA through D cells, but it was a dud. I found that when it finished charging, the cells were only about 1/3 charged. I attempted to exchange it but found that that model had been pulled from all of the stores. As of early this year the only smart charger I've seen in any of the local stores is a tiny little thing, probably not high on too many lists because it's a fairly slow charger. But it has some nice features. It appears to have 4 independent charging circuits (but there's no easy way for me to verify this because it has only a single LED indicator). It charges up to 4 AA or AAA cells, NiCad or NiMH. Its best feature is that unlike my other finicky smart chargers that too readily refuse to charge what they consider to be marginal batteries, this one hasn't given up on any yet. And the batteries that the other chargers refuse to charge still have most of their original capacity and perform very well in everything I've put them in, except for the other "smart" chargers. This little charger, BTW, is the only one that isn't on the shelves with all of the other chargers. It's stored with the battery powered toy racing cars, with an Xmods logo. It sells for about $24, but comes with 8 of Radio Shack's standard AAA NiMH cells. Even though I have more AAA batteries than I can use, I might get another of these chargers because what they do, they do well, and if RS stops selling them I doubt that I'll be able to find any other similar chargers.

Their NiMH batteries are green, and have been for far too long. They're good batteries, but unless they were recently changed, still have the same modest 1800 or 850 mah capacity that they've had for several years. If you are considering getting their NiCads, watch out, as they have two types. One is OK, but the other has a capacity and weight that's only about 1/2 of the better type.

When it comes to rechargeable batteries and chargers, I've found that this site offers a good selection, and decent prices.

Note: I am in no way connected to this site, its owner, or anything; just thought it might be helpful to any who are looking for rechargeables or chargers.

Theoretically speaking, slow charging will give more recharge cycles before the cell is worn out. However, with a decent delta-v charger doing fast charging, it's less of an issue these days. In the past, fast charging cells using the timer method was brutal and could often result in overheating and overcharging.

Dave

Here's a very good place to get the latest on chargers and batteries

Chuck

Theoretically, yes. In practice, it's possible for them to deteriorate.

Dave