Toronto Photography Meetup Group

I haven't been using Digital Cameras for long enough to know from experience, but a Pro who runs a studio in Barrie once told me that the capacity drops off very slowly, and then at the end takes a nose dive. I am asking the Pros here, whether or not if this is you experience?

conditions? how much do you keep your camera on, what do you use with it (flash etc.) what sort of battery do you mean... there's a lot more details that have a play in battery life

If your referring to overall battery life. Yep.

They are great when you first get them and eventually begin to loose a little (after many, many uses). When they are at retirement they will loose their charge rapidly.

The Pro was referring to Lithium-Ion Camera Batteries, and as a Pro I would assume be used his batteries to a very low level before recharging, and after recharging they would get used right away again. I would think this is the ideal way to get the most shots out of a battery of this type.

disclaimer: I am not a 'Pro' (whatever that means)

battery capacity across its useful life or discharge voltage across one discharge?

And, what kind of batteries? Li-ion Camera/NiMH flash/SLA for portable power packs?

For discharge voltage, sure thing, but the 'gradual drop' depends on chemistry, see: http://www.mpoweruk.com/performance.htm

As for capacity across life, I'm inclined to say that it's probably very similar. In most cases though, it is not as if there are a plethora of choices for batteries; I can't power my camera with an SLA, neither can I run alkalines with the big strobes.

Actually, I'm curious, why ask this question?

Mike

Looks like you were posting at about the same time I was posting to provide more info and narrow thw scope of the type of battery I was refering to.

As to why as the question, guess I am trying to justify to my self why I am not comfortable unless I have at least 3 batteries for each of my digital cameras. One of them might suddenly die unexpectantly, if what I have heard is true.

insecurities if you charge it and provided you have common sense, one will last throughout the day most of the time. The only times I have experienced somebody's battery die unexpectedly were when they hadn't charged them fully before coming out

or in the case of the person, who asked the Pro at the Barrie Photo Club meeting, after his battery died suddenly after being fully charged. Further more the battery on the previous charge lasted a resonable period of time. The Pros answer to the question was that this is normal at the end of a batteries life. I prefer to be as close to 100% secure as I can get in this particular situation.

As to common sense, I have plenty of that, sometimes I may be absent minded, but that I have some control over and if I fk up I have only my self to blame. I have no control over the physical and chemical behavior of a Li-Ion battery at the end of its useful life.

Batteries will die (or drop off to a certain level when it is not usable anymore). It is just a matter of when. If you have an 3-4 years old laptop, you probably already have experience on how Li-Ion battery wear out thru out its useful life. One thing I noticed is to not keep toping up the battery everyday.

Having said that, Nikon cameras from D80 onwards have built in battery life meter, it's a basic 0 to 4 rating. If it get to 4, the battery is close to its end of its useful life.

Hope it helps.

Higher End Canons seem to have it too nowadays

I am sure batteries also have life expectancy cycle, but just like shutter actuation count I wouldn't trust it to be black/white

Are you implying that this life expectancy rating indicator built into the battery is based on time alone rather than some internal analysis of the physical or chemical state of the battery. I would expect it to be the latter, and thus more accurate, but then what do I know.

No, I meant the number the manufacturer usually gives you, not the level in-camera. On the other hand, talking about the levels, I've found that you can't exactly trust the battery indicator when it's on. E.G. in winter when shooting in cold weather the indicator drops to 1/3 of the full capacity shortly after a lot of shooting and then keeps holding up forever until the battery is drained, i.e. not gradually decreasing from full to 2/3 and then 1/3. Weird, or what?

I usually carry a couple spare batteries with me but rarely need them. I agree with Ken Rockwells' take on batteries:

Charging Li-ion batteries is like lunch: do it early and often.

http://www.kenrockwell.com/tech/battery-life.htm

Yes, this has pretty much been my experience with batteries -- when they are at the end of their lives, they don't last long.

Read

http://batteryuniversity.com/learn/arti ... _batteries

or

http://www.tech-no-media.com/2009/07/ho ... aptop.html

Potatoeye

We are talking about the life of the battery as in the end of its life when it is of no further use, and not life or capacity of a single charge, as you seem to be refering to in the last couple of posts you have made.

Thank you Metrix. It would seem that an internal battery life detecter (as opposed to an internal charge detecter) would need to measure the voltage and current of the battery and given that voltage measured while current i been drawn and using the no load voltage it can come up with the batteroes internal reistance, at the time the camera is turned on. This along with a measurement of the temperature should give an indication of where the battery is in its life time. An approx anyway thus life values of 0 to 4 as opposed to a finer scale of 1 to 100.

In short, internal resistance, temperature, table lookup (that is based on what is known ) -> battery life index.

Perhaps the detecter gets it right 80% of the time.

Actually the detecter only has to do this when it determines that the battery is fully charged, it does not have to do this every second of the batteries use. Alternatively the detecter can do somethin similar to what was described in a previous post, but when the battery is charging.

well, once again, in my limited experience, I get the same battery capacity over life performance as the others report.

practically, what this means is that for less than 1-2 year old battery (depending on usage, of course) i don't bother with too many spares. Nearer the end of life, I would buy fresh batteries, which would have a better capacity. In other words, yes, don't take the risk with old batteries; always have 'young' batteries on hand.

I haven't owned a camera/battery long enough to ever know !

but, it's like a car. You can drive home one night after work just fine. The next morning, the car doesn't start. battery is dead. Just like that. Very fast very sudden. Of course , those are sealed lead acid batteries.

Now for lithium batteries, well , please read the link above someone posted for Battery University. Very good link.

Basically, Li Ion batteries have 'built' in life cycles at a given temperature. Each cylce depends on how deep the battery was discharged.

Some Li Ion batteries will not recharge, if the have been used only a little bit, and still have more than 80% internal charge left. It's preset by the manufacturer. Topping up slightly used batteries , reduces the number of life cycles left that i mentioned above. So it's best to run the battery down. But not until it's dead empty.