How to analyze a battery?

[pedalinbob]

I have a Vanson charger (BC1HU, or something like that), and it does not have an analyze function.

Due to shorter runtimes, I believe some of my batteries may be pooping out. How can I determine their health? Their voltages appear normal, but I know that voltage is only part of the story...

 

[SilverFox]

Hello Pedalinbob,

Without an analyzer it will be difficult to determine what is going on, but there are a few things you can do.

The Vanson should have a discharge function. You can charge the cells up, then remove them, then put them back in and select the discharge function. Now you need to set a timer and frequently check the discharge progress.

You are looking for all the cells to end up empty at roughly the same time. In a multicell application the most common failure is for one cell to crap out bringing the total run time down.

I don't recall the discharge rate on the Vanson, but let's say it discharges at 350 mA. If the discharge time goes for 6 hours, your cells would have around 2100 mAh of capacity.

While these numbers won't be exact, they should give you a good idea of the comparison from cell to cell. In addition, you can compare your capacities with what is labeled on the cells. When NiMh cells drop below 80% of the initial capacity they are ready to be recycled, if you are using them in critical applications.

Tom

 

[pedalinbob]

Duh! Why didn't I think of that?

Thanks, Silverfox. I did that by accident...sorta.
I had 4 of my older 2500 bats, which should have been in the same state of discharge. I noticed two were fully charged much faster, and this was my initial indication that maybe my battery fleet is tiring.

Didn't really think about it again until my wife indicated that the camera wasn't operating as long as it used to. This is frustrating because we have a 6 month-old, so keeping the camera rolling is important!

I will do the charge/discharge cycle to see what happens.
I really want to get some Eneloops (or Duraloops) because I believe my camera may perform better with them, but I hate to waste perfectly good batteries...hence my desire to confirm impending weakness.
Funny...though I am far from poor, I still cannot justify wastefulness.

Currently, I have Rayovac Hybrids and some Kodak 2500s, so I worry that my wife or someone else will mix them up, though I do keep them apart and instruct everyone to only use bats together with the same label.
This is another reason to get the Eneloops--no possibility of mix-up!

LOL! I just noticed your siglines!!!

Edited to add: This could be my imagination, but lately I think the bats have been coming off the charger much hotter than in the past. Could that be an indication of the bats having problems?

Take care,
Bob

 

[SilverFox]

Hello Bob,

As batteries age it becomes harder to detect the end of charge signal. As a result, the cells will end up being overcharged, and heat up.

If a few charge/discharge cycles on the Vanson don't show improvement, it is probably time to recycle those cells and move on.

Tom

 

[pedalinbob]

Thanks again for the info, Silverfox.

LOL! Your siglines crack me up every time.