Some domestic appliances come with rechargeable cells that need charging for many hours before their first use.
For example, I have a Panasonic DECT phone with two AAA NiMH cells which needs charging for 7 hours.
But maybe you can't wait that long for some reason and you simply "must" use the appliance!
How much would cell life be reduced if such an appliance is used after, say, only 30 to 60 minutes of charging instead of the 7 hours?
Caspian wrote in news:46a87ac5$0$19518$ snipped-for-privacy@news.shared-secrets.com:
First, take care that NiMH and NiCd are different, Nicads have a 'memory effect' that makes this unwise. You've got Nickel metal hydrides, so you can do it. Most of the charge goes in during the first part of the charge, the increase isn't linear.
That means you can grab a useful charge in the first hour of charge, but to make sure the full charge is properly applied, use up that charge before trying to recharge, then give it the full time. Don't try to guess how much is needed if you charge from empty for an hour, use for half an hour, and such, you'll probably overcharge the batteries.
In short, you can get a lot of capacity from a charge of as little as one third of the time for full charge, but whatever you do, always start the charge on a freshly discharged MiMH battery so you know where you are.
I have done the quick test of a device sometimes without even plugging it in, or after a short charge. I don't try to drain the device, and I never seemed to have a problem. Here is a fairly neat page on battery effects......
greg
snipped-for-privacy@pitt.edu (GregS) wrote in news:f8a5r0$873$ snipped-for-privacy@usenet01.srv.cis.pitt.edu:
NiMH doesn't have memory effects so that's not an issue in my post.
I don't understand what you're saying exactly, but it's undeniable that if you part-charge a NiMH battery during a third of its charge time, then discharge only a little, you can't charge it for the full time unless it IS drained first, for the obvious reason that you'll overcharge it if you try. Some battery chargers might detect the true state of charge, but most assume the battery is really low, and have a very simple timer, if there is any means to prevent overcharge at all.
I have no idea what my chargers know.
I took my camera on vacation after not using it for a couple years and used my older NiMH's. I charged them with two different chargers. One charger would not stop charging. The camera would die very rapidly using these cells. Allthough they are the highest capacity of the dozens I own, I'm wondering if they are permanantely worthless, at least in my camera. I was going to try some brand new cells and check that first. I had to use Lithium backups on vacation for my Minolta. I have a lot to learn about using NiMH cells,even though I have been using them in cheap chargers for many years, but wish there was something better.
I want to make a fixture to discharge my NiMH's down to 1 volt. I was planning on using a diode string to generate a 1 volt zener and using another series current limit resistor. Soon. I'm wondering if that will help my current cells I own.
greg
snipped-for-privacy@pitt.edu (GregS) wrote in news:f8aq9t$cm0$ snipped-for-privacy@usenet01.srv.cis.pitt.edu:
I've recently got a pair of small CR123A lithium rechargeables, 880 mAH. Very nice. The charger cost a bit more than with NiMH types, but only maybe
50% more. Those batteries prefer to be discharged lightly and can be recharged at will and taken off charge at any time for use, and the chargers have to be accurate to sense the battery condition to be safe, so if you can get one that's ok, you might get more out of them that with NiMH. Less weight for a start.The small chargers for 'SureFire' K2 LED torches found on eBay are worth a go. I was nervous about mine at first, the risk of nasty accidents, but it's well behaved and will safely stop charging when it's done. Each cell is handled seperately by the charger. The cell charge voltage should never rise above 4.2V for a 3.6V cell, and I think there are other critical points to watch, but if these things increase in sales without a rise in disaster reports, then all's good. It's dangerous tech, but so are NiMH's, if they get a short circuit.
Top posted just this once...
AT LAST! SOMEONE THAT SCTUALLY KNOW THE PROPER TERMS FOR THE DEVICES HE USES!
Thanks dude... I needed that.
There, english TARDS.
Put that in you enema bag and shove it up your asses!
Wrong.
Single cells have ZERO "memory effect" when charged singularly.
A BATTERY of cells MAY develop a "memory effect".
Most modern charging systems incorporated into the devices the cells are placed into themselves, however, have "watchdog circuits" that insure that all cells get "topped off" properly.
You are about five years behind, as are the cell types you attribute this "problem" to.
The "watchdog" circuit protect devices and cells from this problem as well, these days. No overcharging here...
text -
A simple solution might be to use standard disposable AAA batteries until the others are fully charged. There might be a problem if these batteries are left in for a long time but I imagine the risk would be minimal. Most manufacturers have Helplines who could advise. Can anyone tell me what a "Tard" is,let alone an English one? I imagine "Spurious Response" is a Redneck? Curious breed!
Spurious Response wrote in news: snipped-for-privacy@4ax.com:
"Voltage Depression occurs primarily in NiCad batteries. NiMH batteries are almost never affected and Li-Ion batteries are NEVER affected."
I was partially remembering this: "If a cell becomes reverse-charged, or is left flat for a long time, small metal whiskers can grow across the plates."
If the OP had asked questions about memory effect specifically, I'd have checked for current info before posting, but he didn't ask that. It's a side issue, as he asked if his NiMH's can be safely part charged then used. I think my answers to the actual question were right.
Spurious Response wrote in news: snipped-for-privacy@4ax.com:
It would if it had one, perhaps. If all it has is a timer, the obvious thing to do is charge for full time on a freshly discharged cell. If there really IS a non-obvious and different method, I'm not sure it's wise to recommend it to someone asking a very basic question about battery charge. Far better to take the safest course.
Partially true. Only if the cell is abused, especially overcgarging, or perhaps if its been used a lot. I have let cells lie around and they don't go bad. I have had cells practically brand new that shorted after harsh charging. I am referring to NiCad's.
Yes, my Johnson walkie talkies still have German Nicads that still work, and never go dead. I charged them a couple years ago. They are 43 years old.
greg
It's short for "retard", which itself is shorthand for "mentally retarded person".
-- "Liberals used to be the ones who argued that sending U.S. troops abroad was a small price to pay to stop genocide; now they argue that genocide is a small price to pay to bring U.S. troops home." -- Jonah Goldberg
I have often wondered that myself. I see this warning ONLY with consumer appliances. When I buy cells, the data sheet never says anything about needing to charge them fully before the first use in order to avoid some sort of permanent damage or capacity reduction.
I have since ignored the warnings about needing a full charge before first use, with no observed ill effects.
Nope. The term retard can be referring to such a person, but it also means taking a step back.
Take some techno-person, watch him state something utterly ludicrous, and just like the "retarded" timing on an automobile, viola! We have someone that is acting retarded.
They are rampant in Usenet.
Have several sets of batteries with external chargers. While you are gabbing away on your phone, you can be having some batteries on charge. When the batteries in use are running low, you do a battery swap. Calculate the number of sets of batteries and chargers you will need, and then go for it!
By the way it sounds, I would guess you will need three sets of batteries and chargers.
--
Jerry G.
For example, I have a Panasonic DECT phone with two AAA NiMH cells which needs charging for 7 hours.
But maybe you can't wait that long for some reason and you simply "must" use the appliance!
How much would cell life be reduced if such an appliance is used after, say, only 30 to 60 minutes of charging instead of the 7 hours?
No. You have several cell in external charging devices, which been improperly monikered as "battery" chargers.
No. You have some cells on charge.
When the cells run low, you should swap ALL of the CELLS that comprise your device's BATTERY, as swapping only those you perceive as being drained is asking for problems.
Unrelated stupid shit.
Unrelated stupid shit.
Spurious Response wrote in news: snipped-for-privacy@4ax.com:
If it excercises you so much, instead of lambasting someone just because you can, write a letter to the Times or something. Submit an article to a journal. Or at least write to every maker of commercial gear who transgresses. There's more to understanding something than getting the exact words right. Sure it's misleading, but most people know how to avoid the problems. If you really want to evangelise on this point, get a job writing manuals for a major company, as that's the way you'll most likely shape public usage of these terms. You certainly won't reach them this way.
Learn how to attribute your quoting correctly, and/or quote the actual post you are replying to.
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