testing NiMH's

is it possible to test NiMH's to tell if my 1850's are actualy holding 1850?

i have a craftsman brand digital volt-meter that seems to have as many settings as the D~7Hi!!
it has no MaH setting but does have a "Ma" setting.

i have heard of chargers with a built in meter for this but all i have is the standard maha-c204f.

how does one go about testing these batteries.

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Dimage~7Hi
&
Olympus~D490z

For a starter you can read the excellent Battery Shootout article by Dave over at imaging-resource: http://www.imaging-resource.com/ACCS/BATTS/BATTS.HTM

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Cheers,

Thordur Arnason
All about DiMAGE - http://www.alldimage.com/

You won't find a mAh reading on a meter. You can read volts or milliamps because those are instantaneous things, like miles per hour or kilometers per hour. But the mAh rating depends on time. It's like asking the question, "how long did you travel at 60 miles per hour?" mAh is the number of mA times the number of hours. To test a battery for its mAh rating, you have to be able to discharge it at a given mA rate and time how long it lasts. It's not very easy to check it against its rating, though, because you have to make some assumptions. An example of this is what voltage you assume constitutes a fully-discharged state. Or to be more accurate, what the manufacturer assumed. And there's the catch. Even if you can do this type of measurement, you have to know the numbers the manufacturer assumed in the first place when he gave the battery that rating.

The best you can do is to compare one battery to another, or read some of the web sites where they do that. The other thing you can do is to search the forum and learn what other people are experiencing. Then you can see if you're getting similar results. How long a battery lasts depends on a lot of things. If your mileage varies a lot from what most people are getting, and one particular set seems to not be doing so well, then I'd try replacing that set.

trauma-hawk said:

is it possible to test NiMH's to tell if my 1850's are actualy
holding 1850?

Click to expand...

I have an interest in photography as well as radio controlled airplanes, the electic ones. Well, in this hobby, battery chargers are amazing! They can charge a full battery in only 15 minutes by showing in juice at the rate of 5 amps!

Anyway, my point is that my new charger, a Piranha charger made by DuraTraxx, has amazing features. You can control the rate of the charge, tell it how sensitive you want it to be for the cut off, and of most importance, how much juice it put in the battery in terms of mAh. If you have 1600 mAh batteries, you can see how much was actually put into them. To charge them in one hour, you set a charge rate of 1.6 A and wait for it to finish. Anyway, I can't say enough about this charger. I ordered it from a hobby store here in Canada for $90 canadian, so I'm sure its much lower in the US. I don't know why people bother with all those maha chargers and all. These are superior in every way!

Kiran

I suggest you go to the Duratrax web site before using this charger on any AA's. Especially if you want to condition them, seems it's not recommended for batteries smaller than sub C's. Also while you can certainly charge a battery this quickly it will wreck havoc on the ultimate life of the battery. User be aware!

Thanks for the suggestion. I would definately never charge them at faster than 1C... which would be the amperage of the mAh rating.... (ie. 1600 mAh batteriers at the rate of 1.6 amps) This would charge them in 1 hour, which many fast chargers for our digicams claim to do. As for the sub C, I don't think there is a problem. I have tiny battery packs, a 6 cell one that only hold 150mAh and is obviously much smaller than a C cell, even small than a AAA, so I don't think there will be a problem. THe specs on the charger are 50 to 5000 mAh battery packs. I had two AAA Ni-HM batteries that I bought but had never been able to charge yet cause I didn't have the adapter and managed to put 364 mAh into them, even though they are rated for 700. I think this makes sense cause Ni-MH batteires take a few charges to get going up to full speed so slightly over half is pretty good. I'm still waiting to drain my first set of 4 AA's and see how much charge they take. (i haven't been taking very many pics lately

The best part is that you have control over how sensitive your want the end point to be. I know that maha and similar chargers are easy and automatic, but just like with cameras... i want to have all the control!!!

Kiran

Bob Grenfell said:

I suggest you go to the Duratrax web site before using this charger
on any AA's. Especially if you want to condition them, seems it's
not recommended for batteries smaller than sub C's. Also while you
can certainly charge a battery this quickly it will wreck havoc on
the ultimate life of the battery. User be aware!

Click to expand...