Go Back   Steve's Digicams Forums > Digicam Help > Batteries or Power Packs

Reply
 
Thread Tools Search this Thread
Old May 15, 2006, 12:44 PM   #1
Senior Member
 
Join Date: Mar 2006
Posts: 163
Default

I use NiMH AA of different mah and manufacturers. I do not mix brands nor mah;

however, I find it _extremely_ difficult to keep 2 used batteries together.

It is a hassle, and adds time when replacing the batteries thereby causing me

to miss shots. What I mean is, if I have 6 AA of same brand and mah, which I dont want

to mix up. Unless you mark them, eventually you will mix them up.

I heard this will harm the camera.

Thus, what is the solution? To use disposables such as Alkaline, Lithium, or to use AA packs? Perhaps completely discharging all batteries will do?

Also, if you use disposables and you take with you 10 batteries, you will go home

lighter with no need to carry a charger.
romphotog is offline   Reply With Quote
Sponsored Links
Old May 15, 2006, 2:10 PM   #2
E.T
Senior Member
 
E.T's Avatar
 
Join Date: Jul 2003
Posts: 921
Default

romphotog wrote:
Quote:
Also, if you use disposables and you take with you 10 batteries, you will go home lighter with no need to carry a charger.
Definitely much lighter... with much lighter walla because digicams empty alkalines as fast as alcoholic full pints. But those 10 disposables might even give you as many shots as couple NiMHs.

Mixing them doesn't do anything to camera but it shortens lifetime of batteries.

And now what is so hard in marking them?
E.T is offline   Reply With Quote
Old May 15, 2006, 10:38 PM   #3
Senior Member
 
Join Date: Mar 2006
Posts: 163
Default

E.T wrote:
Quote:
romphotog wrote:
Quote:
Also, if you use disposables and you take with you 10 batteries, you will go home lighter with no need to carry a charger.
Definitely much lighter... with much lighter walla because digicams empty alkalines as fast as alcoholic full pints. But those 10 disposables might even give you as many shots as couple NiMHs.

Mixing them doesn't do anything to camera but it shortens lifetime of batteries.

And now what is so hard in marking them?
you mean it's ok to mix brands and mah?


romphotog is offline   Reply With Quote
Old May 16, 2006, 2:43 AM   #4
E.T
Senior Member
 
E.T's Avatar
 
Join Date: Jul 2003
Posts: 921
Default

If one battery in serial connection gets empty faster than others it will seriously limit current those others can deliver.


Just mark them and store them in battery cases, I crafted cheap cases from packages in which batteries came.
When changing batteries I just put empty ones into case other end first so seeing how many are empty and which ones are full is easy.

And if you don't have cases for them definitely get one now. If you store them loosely there's risk of shortcut and in that situation NiMHs can output more power than what is necessary for fire hazard.
E.T is offline   Reply With Quote
Old May 16, 2006, 6:12 AM   #5
Senior Member
 
Join Date: Jan 2006
Posts: 111
Default

I used labels from old VHS tapes to identify different sets of batteries. Most tapes come with a set of labels that include numbers and letters. Each set of four batteries has a differentnumber or letter so it's easy to keep them separate. E.T.'s suggestion about keeping them in cases is a good one. It allows you to keep different sets together and prevents accidental contact between battery poles.
Wolverine@MSU is offline   Reply With Quote
Old May 16, 2006, 10:16 AM   #6
Senior Member
 
Join Date: Jul 2005
Posts: 358
Default

Hello Romphotog,

The reason you are warned not to mix brands of batteries is because the batteries from different brands behave a bit differently. When two or more batteries are used together, and one battery empties before the other ones, the batteries that have more capacity try to reverse charge the empty one. This results in damaged to the battery that was reversed charged, and poor performance because one of the cells is not carrying its load. When you have cells that are matched in a battery pack, each one will be in balance and you will get better performance.

As batteries age, their performance drops off and they become unbalanced. If you have a charger that charges each cell independently you can get extra life from your batteries because everything is balanced during the charge. You can also balance the cells if they are charged in series and left on the charger for a few hours after the charge is completed. When a cell dies, you end up with very poor performance. You get 2-5 shots from your camera and the low battery indicator comes on.

I use batteries in batches. When I buy 4 cells, I will keep those 4 together and use pairs of them without concern. I happen to mark my cells, but that is mostly for testing purposes. When I get a new batch, I try to keep them together.

The camera manufacturers have some safeguards in place. The shut down the power when the voltage drops to around 1.0 volts per cell. This gives some leeway if a cell not matched and will protect against reverse charging in the camera.

The battery manufacturers have realized that we can not keep track of the amount of cycles we put on our batteries, and that more advertised capacity sells. As a result we have high capacity cells. The trade off is that you get fewer cycles with these high capacity cells.

2000 mAh seems to be the dividing line. If your cells are around 2000 mAh, you can expect extended cycle life from them. If your cells are over that, the cycle life is reduced. I ran a test on some 2500 mAh cells and was surprised to see the performance drop in as little as 125 cycles. At 150 cycles they still showed decent capacity, but the voltage was so low that they would not power up my camera.

In a device, like a camera, that has a low voltage limit, it is probably OK to be less concerned about keeping track of exact pairs of cells. In other applications you can ruin your batteries and/or the device you are using the batteries in. I still do not recommend mixing brands or capacity, but in an emergency you could do that if you remembered not to run the batteries completely out.

You will get the best performance if you mark the cells, use them in pairs, charge them individually, and replace them at the first signs of reduced performance.

Tom
SilverFoxCPF is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 10:18 PM.