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02-01-2011, 04:53 AM   #31
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QuoteOriginally posted by raider Quote
freddy - likewise. are u using jpg or raw? is the back LCD screen on?
I shoot just raw, hate jpeg And yes, I've got the LCD screen always on, exposure meter set for 2s. But like I said, the LCD screen eats a lot of power, so if I browse and delete photos etc., I'll definitelly get less than 600 shots. Oh and the power light is turned on lower luminosity, but I don't know if it makes a difference.
Btw. I've got original Sanyo eneloop charger MQR06 with microprocessor and seperate charging chambers. It takes slightly over three hours to charge. Also I strongly recommend not to use faster chargers as it will degrade the battery life significantly, especially when the batteries are not fully discharged. And definitelly get one with microprocessor.

02-01-2011, 05:35 AM   #32
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QuoteOriginally posted by lectrolink Quote
I dont understand how some people are getting over 1000 shots on their rechargeables.
with Sanyo NiMH 2700 I once got 2800 jpeg shots (K-x on a tripod, room temperature, LCD off, no chimping and using remote) in one session - was playing with gifs
It was quite a surprize to me
02-01-2011, 10:23 AM   #33
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QuoteOriginally posted by raider Quote
When I use the Sony charger sometimes the battery gets very hot and I do mean hot not warm. Is this normal? What sort of temp should I be expecting?
Earlier in this thread it was noted that batteries toward the end of charge should be warm-hot - a crude test is to be able to hold one with a tightly closed fist.

If any batteries are too hot (to touch) at the end of charge -
could mean that end of charge was missed leading to over-charge and over-heating
- two of the worst killers of batteries.
I don't know for sure - but could this have been charging 4 at a time on the Sony BCG-34HRMF charger?

As mentioned previously it is hard if not impossible to detect the end of charge -dV with any charge current under 0.5C and charging 4 at a time with the Sony BCG-34HRMF charger means 525mA - which is = 0.26C - less than 0.5C ...

The problem obviously is that tolerance to heat may be different.

Maha rates their cells for a maximum charge temperature of 45 C. Other manufacturers may rate their cells for other temperatures, but 45 C appears to be close to an industry standard maximum for NiMH technology.
from: Performance Measurements of Some NiMH Battery Chargers
Damage Done in Charging

Each charge-discharge cycle damages the batteries somewhat; excessive or improper charging can result in a reduced number of charge cycles over the batteries' lifetime and in reduced energy capacity. Different chargers are said to vary widely in this regard. One of the most commonly cited factors in charger-related battery damage is excessive heat. Charging tends to heat the battery somewhat, due to internal resistance and cell chemistry. Excessive current as the cells become more fully charged, among other factors, tends to generate excessive heat, and a properly designed charger must be careful to back off the current as the cells become increasingly "full." Better chargers use a variety of heuristics to estimate cell state, including the rates of change in temperature and voltage, the aim being fill the cells as close to capacity as possible without overcharging.
There was a very good post (#4) by jtr1962 over at CPF:
Lifetime can be another complex issue. More than anything else it is heat and/or overcharge which destroys rechargeables of all types. For nickel-based chemistries charge rate shouldn't affect lifetime if the cell is kept cool. This obviously means knowing when to stop the high current charge and go to an intermediate charge or a trickle charge. It also means making sure that the trickle charge doesn't continue for more than a set time because overcharge can weaken NiMH cells long term even if there is no overheating. All of these problems can be solved by using the right charger. A good test of how many cycles you can get from a cell is to measure the peak charging temperature in a given charger. If it's 50C or more, you will get at best 300 cycles, and less if temperatures stay above 45C for a prolonged period. If the charger can accurately determine when the cell is full and reduce current before it gets too hot, then the cell should last 500 cycles or more. Tens of thousands of cycles are possible under ideal conditions. Part of the secret besides not overheating is to not fully discharge the cells (except once every month or so to prevent the dreaded "memory" effect), and also to not charge them beyond about 80% to 85% of capacity. That last 15% or so in capacity gain comes at a steep price. You reduce the cell's life from thousands of cycles to perhaps 500 to 1000 (still plenty for consumer devices). In fact, the usual 500 cycle NiMH rating assumes some rough treatment by consumer. Manufacturers would likely have more problems if they rated lifetime rather than capacity optimistically.

Last edited by UnknownVT; 02-01-2011 at 10:38 AM.
02-01-2011, 10:56 AM   #34
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QuoteOriginally posted by lectrolink Quote
I dont understand how some people are getting over 1000 shots on their rechargeables.
Perhaps you didn't mean it that way....

a possibility is they're all lying?

Check out this thread from the early days of the K-x -
there were quite a few who got over 1,000 -
I still get regularly over 1,000 (average 1,200)

K-x owners: NiMH batteries results please ( 1 2 3 ... Last Page)

with probably what was an all time record by OutOfFocus
getting 2,600 shots using 2100mAh NiMH in Post #214
and his modest explanation in Post #246 .....

That is until stanic's report above in Post #32 of 2,800 shots! WoW!

Last edited by UnknownVT; 02-01-2011 at 11:06 AM.
02-01-2011, 03:36 PM   #35
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Thanks UnknownVT again for that explanations.

Okay. the more i think of it the more i do not trust my sony charger now. I recall that more often than not the batteries after charge are so hot, i doubt i can hold the batt in my hand for any extended period of time.

Time to get the maha C9000. I am not ambitious to get 1000 shots per eneloop charge. Even if i can get something like 300ish or 400'ish, I am plenty happy.
02-01-2011, 11:19 PM   #36
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So is it worth getting Eneloops? I had expected a lot more shots, but with only 300-400 it seems like you'd be switching all the time.

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