Measuring the Charge for a Dry Cell Rechargeable Battery

Primary batteries have full power and go down. Rechargable batteries typically get better after a few charges and discharges, and then over time lose their strength. Primary batteries are not rechargeble. You could get a voltmeter to actually measure the potential of your batteries. If you go to Wikepedia and ask about batteries there is a wealth of information. Everything wears out. Just buy good batteries of either the primary or rechargable type and either throw them away when they stop providing enough power for your MP3 radio or flashlight, or recharge them till they don't do it anymore. Unless you are involved in critical industry applications, you probably will be wasting your money buying a meter to test the batteries. Even recharable batteries wear out over time. Sound technicians for concerts buy new batteries for every show.

Just curious; where did you get the term ' primary ' battery ?

GA for a good and correct answer.

You called it as it really is......

GREAT INPUT!!!

i fully agree....

Chemical Reaction (irreversible) is the source in the primary betteries whereas, in the secondary betteries, the betteries acts as a storage element that store energy in the form of chemical changes, when charged...

i love this site.... u always get to knw fascinating things u might have ignored years ago..

To Morepower: A bit long winded but quite helpful along with several of the others that followed. But you raise a point in the early part of answer that I think you might consider. If you have a child (or children) who is (are) 12 or younger you might consider having a "family meeting" (I guess the same as a Town Meeting but you get to be President) and talk about the question of having a "Director of (Household Portable) Energy" i.e. batteries, and the management, purchasing/disposal and recharging of them. For what ever level the kid can function on, (s)he should have responsibility for (portable) Energy within your house. Taught how to schedule, preemptive battery changes and the yearly fire detector battery change, and also keep an inventory for the household finance director. I don't have any kids so I may be just fantasizing the possibility of this. I have been surprised though that there is no where a "club" of battery collectors, keeping a asortment box display of all the different kinds and sizes batteries, that one ends up using in daily life these days, considering that "energy" is along with food, clothing, and shelter a necessity of life. I agree with a later post here that there should be a thorough test, so the ignorant like myself can be healed. Batteries are a high profile concern on the grounds of economics, environment, understanding of technologies and science, and their development which is a big concerns for the future in vehicle. (Maybe Obama can be coaxed to give this "chore" to one of his daughters, and she can then be First Family, Director of White House-hold Portable Energy, providing an example for other families. I have one more pressing angle about this that I want to ask some engineers for some knowledge, which I'll write over the weekend. Thanks again. hn

Good post. My experience has been about the same, although I have yet to find a charger I am really satisfied with (at least for AA NiMH cells -- on the other hand, my power tool chargers have always worked well).

Here in the states, NiCads peaked for power tools in maybe 2004, with NiMH now being more common as original equipment, and with LiIon being the premium standard (as in Dewalt, Milwaukee, etc. tools). I have a couple Craftsman Verspak tools* (which are generally cheap garbage -- but very light, small, and handy at times). The Gold (NiMH) batteries came out in around 2002 or 2003, I'd guess.

* But I have not bothered to replace either my shot Silver batteries or switch to Gold, because the batteries are too expensive to make it worthwile -- when the urge strikes, I'll make up a replacement pack of standard cells -- in the mean time I bought a Ryobi 9.6 V rechargeable which retains the light weight, compact advantage. It was about the same price as a set of Versa Pack batteries, with the drill itself essentially thrown in for free. As it turns out, it's been a great drill, usually the first one I reach for, replacing, for most purposes, my pretty good quality Dewalt corded drill -- which is so old that the cord insulation is crumbling, but is works just as well as it did when brand new.

If Ansmann Chargers are available where you live, I think that you are in for a pleasant surprise.....

Yes they are -- I was just looking into them. I'd love to have the rack mount version -- I much prefer that packaging to the consumer packaging. But alas, I'd have a hard time justifying the cost. Thanks for the suggestion -- I'll no doubt get one of the consumer units.

If I had nothing but time and money, I'd have rack mount everything, partly to keep everything where I can find it, partly for the industrial quality level that often goes along with rack-mounted equipment, but just as much for the styling. Stationary components that look like that are designed to move or fly seem silly -- I like the looks of my HP multifunction printer, which is basically a rectangular prism: it doesn't look like it is designed to move, and fortunately, does not.

In a bookstore last night, I casually looked at an IPod dock, it was a fairly large, nicely finished brick-shaped thing, with a single large control knob. It was quite heavy -- I am almost certain it was artificially weighted to give the impression of solidity and quality. It's not something I need or even want all that much, but I certainly fell for the styling.

This is what I use to test my batteries.

It is a cheap battery tester but I have found it to be very useful over the years.

The best batteries for my uses are NIMH for the most part. I do, however, use batteries specifically for high drain electronics in some instances, and, of course, Lithium Ion is best for computer batteries. I don't believe you can get LION in the needed voltage to be used as AA. Someone correct me if I am wrong because I would love to get my hands on some if they exist.

I always use battery chargers that have some intelligence. What I mean is they have to be able to stop charging at a high rate and switch over to trickle charge once the battery is charged up to capacity. These are some of my batteries and chargers:

As far as camera batteries go, I used to work for Event Imaging Solutions at Wild Adventures in Valdosta, GA and they used AA NIMH in all their G4 cameras. So, what does that tell you. Sure, you can get batteries for cameras that might last longer but once they run down they are useless... (like I say, unless you can show me a LIon in an AA that's rechargable... still looking)

I use NiMH for photography too, and would prefer LiIon, but as you may know, the basic voltage of a LiIon cell is too high for direct replacement of an AA cell. For many devices with two AA cells, however, the LiIon voltage (typically 3.6 V, nominal) would work as a replacement for two AAs in series. In fact, some cameras have Li Ion packs, but can also operate on 2 AAs. The camera's battery charge level indicator would have to be modified, of course, and in those cameras which can use both types, I imagine there is a detection method used.

NiMH batteries work far better in cameras that alkaline, with the higher AH rating ones lasting longer, even on a single charge, than the alkalines. However, I've been dissapointed with overall battery life, and have found that some quick (15 minute) chargers (even those equipped with moderately sophisticated electronics, cooling fan, etc.) just destroy the batteries, with the life being only 10 cycles, instead of the advertised 1000 or more -- even when the charger is used with the batteries supplied with it.

Thats similar to my experiences, which is why I recommend Ansmann as being a really good charger manufacturer....in Europe at least!

Thanks for your answer and photos. I have an even simpler smaller (cheaper?) battery tester that I bought from Radio Shack a year ago. But I think I should know more about the batteries status than whether it needs "recharge", (or replacement) is "low" or "good". Aren't there any trackable numbers that go with these things ? E.g. exactly how many volts the battery is putting out (and at what amperage if that's proper electronics) also whether the battery is better for high drain of low drain usage, and most important how many hours, days or months I should expect are left, (on average). It's my general understanding that meters can be built for anything, is one of these functions out of the question ? (Don't the battery manufacturers themselves have all this researched "down to a science"? What I really want is a a battery holder with some circutry built in to it that I can plug into my laptop put a battery in an get a full diagnosis - is this totally out of the question ? hn Also how can my same simple meter, without any "adjustments" measure, totally different kinds of batteries that have a variety of different powers? (US Pat # D297516 and WG (West Germany?)pat #3530148

I am not sure there is a way to scientifically predict the types of things you are looking for. There are too many variables involved to be that precise. I try not to let my batteries get too low before swapping them out. I feel that the more you let them run down, the less life you will get out of the battery. If you completely discharge your batteries every time you may shorten their life regardless of how they appear to be at present. Also, charging too fast will shorten battery life as well, even though some battery makers tout the ability of their batteries to be charged quickly. I wonder if it would not be in their best interest for you to replace your batteries frequently. All in all, I have had good success with my NIMH batteries and long life. I believe this is partly due to just taking good care of my batteries. Also, I would like to mention that I use from 3 to 5 microphones every week with 9 volt NIMH batteries. I don't buy new batteries every time we perform. The cameras I use now use Lithium Ion rechargable batteries but I used NIMH AA for years. I used NICAD before that and they did not do well with repeated charging and discharging only partially because of the memory effect. This not true with NIMH. They seem to get better with repeated use up to a point as was previously mentioned. The battery tester I use introduces a load across the battery and if the battery is weak (not just discharged) it will reflect that. I usually test the battery several times in succession to prove the capacity before sticking it in a device. With repeated use of this tester I can now "read" a battery's condition pretty well. I also try to keep a record of when the battery was purchased. When they start getting 3 or 4 years old I usually relegate them to less hazardous duty (like powering led lights that work even with weak cells).

I just posted in reply to someone else, it tells you that what you have been doing is excellent, but now you can see why it is excellent!

Thanks for both your answers 18 and 19. Yes, I would like to see the manual if it's in English, (or even if only in German if it has many diagrams and illustrations). Maybe the Patent number also if available.(Patents usually have some good illustrations. I'm glad this hits a good enough chord that some one has already done it, including the hook up to computer. Now who do you think is using it, either by industry, function, or something else? Is it being sold on EBay? Or how to describe it and I'll make myself an Ebay Alert. Is it "a battery (cell) diagnostic machine ?" But the greater question, is can it be made much cheaper ? i.e. what's in it circuit-wise ? And if not the whole thing, than just some useful functions ? xxxx I didn't know that about the weakest cell, and that pretty useful info. Thanks. I look forward to more details. Also, what's/where's the post you refer to in your shorter 2nd message ? hn

I have looked at the manual, it won't be easy to understand without being able to read German. There appears to be no English version as far as I can tell.

The company is called ELV, see if they have an outlet in the USA on the internet in the USA.....

Their products are seldom seen on ebay....except 2nd hand maybe, they do not sell there as far as I am aware....

Of course, anything is possible, here is just what you wanted (sorry its in German) it does all what you wanted too, it can even be connected to a PC, can have ID tags on each battery pack etc etc, but it costs €299 or the best part of $400!! Do you want to pay that much?

If yes, I can check for you to see if there is an English manual, just let me know please.

I personally would rather invest (far) less money in a good charger and good batteries. It has stood me in very good stead up to now.

By the way, an important criteria is to know the point at which a battery should be regarded as being "empty" even though voltage may be still available. For rechargeable cells it is usually around 1 volt per cell, sometimes 1.1 volts......

Do not forget that in a Battery (a collection of single cells), what always happens is that one cell is always "weaker" than the rest and is therefore "empty" first, then the current passing through it from the other cells, reverse polarize and damage it further, eventually (sometimes instantly) this cell does not take a charge anymore and the battery can be put into the the correct place to get rid of useless batteries (not the trash please!).

This problem is true of all the normal cell types in a battery, Lead Acid, Nicad, NiMH, Li Po etc etc....

I tend to not run a "Battery" (a collection of cells, not a single cell) down to the minimum for that reason. Its not quite so bad if you have another cell of the same type, from the same manufacturer of the same age to replace it, but anything else is just asking for problems........Car batteries cannot be quite so easily split up either! and since the cell connections get covered up nowadays, most people don't even notice that only one cell is bad!!.....For lead acid batteries, those cheap chargers are often the reason that the batteries die before there time.....but here is not the place to discuss Lead Acid batteries....

Any further questions, just ask!!!

BTW, after rambling on about other issues:

I use a digital VOM (measuring repeatably, but not necessarily accurately, to .01 volt) to monitor batteries. I keep mental track of (no load) fully charged voltages for good batteries (and having no functional memory, I have to retest a known good battery to occasionally recalibrate my thinking). I mark suspect batteries and watch them more closely, to avoid getting stuck with a failing battery in the camera, and to avoid having a good battery mixed with a bad one. Purely subjectively, I'd say that if the fully charged voltage is .1V lower than for a good battery, the battery is on its way out, and is getting pretty close to the knee in the life curve where things are going to hell in a handbasket.

You might get a better feel for actual condition with a standard load on the battery while testing, but that seems a little extreme, from my perspective, for AA cells.