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External batteries

I have read reports who says more than 1000 shots on one charge... No further details.

That sounds awfully high, and with no further details, I would be quite skeptical.

I am also aware that Li-Ion chemistry should not require discharge-charge cycles, but never the less, most users get improved battery life after a few recycles. As I wrote, I suspect it could be something with cell alignment.

I don't know what you mean about 'cell alignment.' A discharge cycle simply recalibrates the battery level indicator in the camera (or laptop or whatever) to match what's actually being reported by the battery, instead of shutting down prematurely.
 
Well, I have some non-scientific data to share with my charge/discharge cycles of the five batteries that I use.

Unfortunately I don't have a multi-meter, so couldn't use any baseline voltages for comparison.

However, here is some useful information, or at least I think it is. :z02_deal:

1. Batteries: 4 Minolta NP-400, and 1 Sigma BP-21 (All the same of course).
2. Test: Discharge and charge batteries 3 times.
3. Log the discharge time of fully charged battery on Sigma SD-14 "looping slideshow", with 2-second intervals, mode.

Oldest battery Minolta NP-400 about 4 years old, and approximately 35 discharge/charge cycles over lifetime:
Discharge time on slideshow: 12 minutes

Battery Minolta NP-400 about 4 years old, and approximately 30 discharge/charge cycles over lifetime:
Discharge time on slideshow: 28 minutes

Battery Minolta NP-400 about 18 months old, and approximately 15 discharge/charge cycles over lifetime:
Discharge time on slideshow: 2 hours, 40 minutes

Battery Minolta NP-400 about 18 months old, and approximately 10 discharge/charge cycles over lifetime:
Discharge time on slideshow: 3 hours, 10 minutes

Battery Sigma BP-21 about 2 months old, and approximately 10 discharge/charge cycles over lifetime:
Discharge time on slideshow: 4 hours, 36 minutes

Conclusion: Obviously pretty much what I would suspect -
1. As the battery ages, the ability to hold a full charge decreases.
2. The higher numbers of charge/recharge cycles possibly reduces ability to hold a full charge.
3. Surprised with the high degree of degradation of the older batteries that have about 30-35 cycles. I thought they
would do better, since they are advertised as capable of "hundreds of cycles".

What I will do:
1. I will retire the two oldest batteries to the recycle bin.
2. I will continue to keep track of the remaining three batteries, so that I know when to retire batteries and purchase new.
 
That sounds awfully high, and with no further details, I would be quite skeptical.

http://forums.dpreview.com/forums/read.asp?forum=1027&message=23418832&q=battery+1000+dominic&qf=m

I don't know what you mean about 'cell alignment.' A discharge cycle simply recalibrates the battery level indicator in the camera (or laptop or whatever) to match what's actually being reported by the battery, instead of shutting down prematurely.

A recalibration of the battery level indicator? Possibly, but why is several recycles needed then?
I have read about cell alignment somewhere...

kind regards
Øyvind Strøm
 
Hi All,

1) Li ION Batteries do not have any memory-effect-problems! Therefore you do not have to recharge them from time to time to "format" all the cells, wired in line.
2) Li ION Batteries develop their full capacity not until several recharging cycles.
3) After their "peak performance" they constantly decrease in their capacity.
4) After around 300 complete recharging cycles their capacity will have run down to ca. 40% .... time to replace them!

However ... I think the SD14 is quite well powerd with a quality NP-400 battery. When out of power, It takes just a few seconds having it reloaded again.:) I do not see any real problems coming up with power supply.

See you with nice pictures

Klaus
 
Hello Klaus. Thank you for the information. In my case, it seems it only took about 35 cycles for the older ones to become weak. However, they are pretty old as well -- does just "sitting" over time weaken these batteries? I understand that they will discharge over those longer times, but I am surprised that mine are only taking a weak charge.
 

That says he gets 300-400 most of the time (which in my experience is on the high side as it is), with the 1000 apparently a bit of a fluke.

A recalibration of the battery level indicator? Possibly, but why is several recycles needed then?

Maybe the new battery has no calibration data at all or it's way off because the battery has been sitting in a box for a while not being used, and it needs more than just one cycle to fully calibrate it?

I have read about cell alignment somewhere...

I'd be curious to see what that is, since I've never heard of it.
 
does just "sitting" over time weaken these batteries? I understand that they will discharge over those longer times, but I am surprised that mine are only taking a weak charge.

Lithium Ion batteries degrade whether you use them or not. 2-3 years is typical until the reduced capacity becomes a problem, sometimes maybe a little longer.
 
Well yes ... decay starts with having them charged the first time.

Never used, they can grow really old. Do not ask me why (I am no chemist) .... I just read it.

See you with nice pictures

Klaus
 
kakou and Klaus, thank you. Of course I also assumed that they degrade over time...I was just surprised at how much the older ones degraded, with the combination of a couple of years time, but only about 35 cycles.

So it appears that I will more than likely look at exchanging batteries out at least every couple years or so.

So at least something came out of it.
icon12.gif


Looks like we can pretty much toss this thread now. THANK YOU, all of you, for helping me to clarify why my own batteries degraded so heavily.
 
To the rumors of 1000 shots from a single BP-21, I have a comparable example.

I have two BP-21s, the first came with my SD14, purchased in October 2008 and the second in January 2009. I did not specifically perform a break in and simply gave each an initial full charge before putting them to use. I also purchased my Power Grip at the same time as the second BP-21 and since they have been used together and charged when the SD14 shows that their power is not at peak.

This past Easter, I set up my SD14 to run a time lapse shoot and I decided to stop when the SD14 was flashing the battery level indicator. After the SD14 settled from it's marathon, no more than 10 seconds after pressing the stop button on the intervalometer, the battery indicator stopped flashing, so it was not actually as low as it indicated.

Now, the numbers: 2,147 exposures, one every 5 seconds for 179 minutes. The focus was set to manual and no flash was needed or used.

I have a link to the time lapse video here in my original thread:

Easter Sky Time Lapse

Anyone can watch the video to see every exposure, this was no fluke and it's not a myth or rumor. At the time, I had no idea that my SD14 was running so well and I was actually disappointed to have to cut my time lapse shoot short.
 
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