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02-03-2007, 11:01 PM   #16
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trog,

The problem is really not with the batteries, I am pretty sure of that - they perform exceedingly well in many other high-drain devices like flashes (Sunpak 383 & Sunpak PZ 5000AF), Minolta A2, r/c toys and even a battery operated baby swing with a heavy motor that depletes normal alkaline AAs in less than 30 mins.

As I understand it, there is a low-voltage cut-off in the camera to tell when the batteries are low in juice. Apparently, the initial batch of K100Ds expect 6V for full charge and cut-off power if it drops below 5.2V. This works well for Lithiums as they power delivery curve maintains a voltage of 1.5V per cell or close to it, through most of the power cycle and dips to 1.3V only when they are really close to running out of juice.

But the NiMH cells have a nominal voltage of 1.2V, and even when fully charged they do not go above 1.44V. So a set of fully charge NiMHs give about 5.7V, but the voltage fall steadily as power is depleted. So as soon as the cells get close to 1.3V, the K100D senses them as depleted while infact they still have more than 50% juice left in them.

Apparently Pentax noticed this problem and later versions of K100Ds have the low-voltage cut-off reduced to meet the characteristics of NiMHs. There are several user reports about K100D giving more than 600 pics on a single set of rechargeable NiMHs. I don't think mine ever crossed 400 - it was mostly around 250.

Anyway all this is speculation and theories, and until Pentax makes an announcement or issues a fix we will not know for sure.

Teja


QuoteOriginally posted by trog100 Quote
i had to throw a dozen of my newest ones away.. i still go for batteres being the problem.. i would certainly try more before blaming the camera.. i also think the largest capacity ones are the least reliable..

i have some three year old 1800 mah ones that work perfectly.. some 2500 mah six month old ones that dont work at all.. not in my k100 at least..

by not work i mean fail after just few shots or refuse to let the camera turn on at all.. age dosnt seem to play a part..

trog


02-04-2007, 06:34 AM   #17
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i have always thought the initial surface charge disappears quite quickly.. the battery then maintains something close to its nominal 1.2 volts for most of its charge time until it goes flat.. it dosnt fall off gradually..

we are beyond any pentax announcements.. u are correct about the shut off point being too close to the working voltage of the batteries.. so in that sense its the fault of the camera.. but with nimh some batteries perfrom better than others so in that sense its the batteries..

i select sets that do work reasonably well.. but i dont expect all sets to do this.. i am not speculating.. i know there is a large variation between one set of himh batteries and another.. i also know the camera isnt very "poor battery" tolerant..

i dont expect this to change either.. he he.. nicads used to be very reliable and last for years.. nimh i think are all over the place and can fail or suffer from performance loss quite quickly.. in other words some of them are rubbish..

nicad and nimh user for over thirty years.. NiMH in digital cameras for the last five years..

trog
02-04-2007, 06:41 AM   #18
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What you describe is totally normal, every Pentax DSLR model, which can use AA battery, behaves like this.

Just forget to use NiMH and use CR-V3 or Rechargeable CR-V3 (must be voltage regulated one in range of 3 to 3.4V) and problem will be totally solved. THe battery indicator will correctly indicate the battery power status again.

Also, the AF speed will become normal again and there will be less hunting.

In short, the NiMHs should be something that be banned by Pentax, which should not be used in any Pentax DSLR, instead of banning all RCR-V3s just because some of them are not regulated and have excessive (RAW) high voltage.


QuoteOriginally posted by Teja Quote
Hi All,

I've been using the K100D for a few months now with Sanyo 2100 mAh and Tenergy 2300 mAh NiMH rechargeable batteries. I used to get over 400 shots (with mixed flash usage) in a single day shoot, or about 250 shots over a couple of weeks before the battery icons went to empty. Overall I was pretty satisfied with the battery performance.

But since the last couple of weeks, the "low-battery" warning started popping-up frequently. Even when I thought that the batteries were good. So when it happened again a few days back, I decided to test it out.

First, I took out the batteries and tested their voltage - all four measured 1.31V, meaning they still had quite a bit of charge left in them. But to be sure I recharged them again (I use LaCrosse BC-900 chargers) with a 200mA slow charge to ensure that they are properly topped up overnight.

Then I put in the freshly charged batteries in the K100D (battery icon shows full) and shot about 25 pics around the house. Then left the camera in the closet over night.

The next day I took it out it still showed full charge. I took a couple of test shots and the battery icon fell to a half-charge. Took them out and tested the voltage - 1.33V. Put them back in and left the camera in the closet.

In the evening the same day, I turned on the camera again, The camera didn't turn on and got the blinking empty battery icon. Tried off and on a few times and suddenly the battery icon shows a FULL battery and the camera starts working normally. Took a dozen or so pics with flash and the battery icon still shows FULL. So I turn off the camera for a few mins and turn it back on now the battery indicator is half-full.

One thing for sure is I am not getting more than a 100 shots per set of NiMH over 3 or 4 days, whereas till last month I was getting at least 250 easy over a couple of weeks. I know it is not the batteries, I tested them in other gadgets and I also used a new set of NiMHs in the K100D and it still has the erratic battery indicator.

So anyone know what is happening with my K100D? I wouldn't mind it so much if the camera didn't shut down whenever the battery indicator turned empty. I tried to search on these symptoms and found a couple of posts over at DPReview. Possible suggested causes:

- The cold temp effects the K100D battery usage significantly (well, it has been really cold here in Illinois for the past couple of weeks).

- The new 1.02 firmware somehow messed up the battery sensor and made it erratic. (But I was facing this problem with my K100D even before I upgraded to the 1.02 firmware).

- A few early batches of K100D have a bad battery calibration circuit and have to be sent in for servicing. (But mine was working fine with no problems till last month.)

I am leaving for a month long trip to India next week - was really looking forward to it. But this battery problem has me worried My backup is a Minolta DiMAGE A2. I will call-up Pentax on Monday and see if the problem is known and they have a fix. But I don't think they will fix it in time for my trip.

If anyone one has had this problem, then please post your experiences here - especially if you talked to Pentax about it.

Thanks
Teja
02-04-2007, 08:50 AM   #19
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I' m watching this thread with interest. My trusty set of NiMH that have performed flawlessly (and continue to do so) in my A70 gave me less than 75 shots in my K100. A fresh set of 1900 mAH NiMH gave me 20 flash pictures before the camera packed it in! I switched to Eneloops, and am approaching 300 shots on the initial (out of the package) charge. I have shot many long-exposure and flash shots in the 300 to date, and the battery indicator is still full (with the odd drop to half after using the flash). I expect that with a fresh set, I will be able to get 500+ outdoor shots without flash. Still, if Pentax can / will fix the performance with standard NiMH batteries, it would be nice, so I am watching to see what they say to the OP.

Chris

02-04-2007, 09:14 AM   #20
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I got two sets of Sanyo eneloop AA batteries for my K100D, put in the first set right after I got the camera even without charging it. The camera took over 1.1k photos before the batteries ran out of juice.

Put in a set of Sanyo 2500mA NiMH rechargeable after that. Three days later w/ about 250 shots, the battery indicate indicates empty battery just now ...


I'm w/ some others above: go and get a couple sets of Sanyo eneloop rechargeable batteries for normaly daily use, and several sets of CRV3 or Lithium AA batteries for travel
02-04-2007, 09:50 AM   #21
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My energizer 2500 batteries consistently give me 600-700 shots per charge. After about 250 shots the battery meter reads half full and after 500-600 it reads as empty but will still shoot for another 50-100 pics. When it shows as empty I just get the other set ready.

On the other hand I have a set of 2300 London Drugs batteries that give anywhere between 200-400 shots per charge.
02-04-2007, 12:21 PM   #22
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one of the first reviews i read on the k100 started off with.. "none of the NiMH batteries we had kicking about the office would power up the camera we had to go out and buy a new set of energizers".. he he

the only thing i would add here is.. its not the capacity that matters.. its the ability of each sell in the pack to tolerate a high current draw without its voltage dropping below the cameras cut-off point.. some can some cant..

trog
02-04-2007, 04:45 PM   #23
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Yeah, my Powerex 2300s have only been getting me around 100-200 shots per charge. The truth is, they don't do much better in my Panasonic FZ20 so I'm not surprised.

I just now put a new set of Eneloops in so it'll be interesting to see how they do over the next several days.

I got three sets from Thomas Distributing last Friday so we'll see. I'll be happy to toss the old ones if these perform as promised. By the way, I used a good Maha mh-c401fs charger so that's not my problem. Got to be the batteries.

02-04-2007, 06:45 PM   #24
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I have 2 sets of Eneloops and I've recharged them a total of three times since October (close to 2000 shots with occasional flash). Just my experience.

I also keep a set of lithiums in my bag just in case.
02-04-2007, 08:51 PM   #25
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funny, my wife's k100 will get over 250-300 shots with Sanyo's NI-MH 2500 model HR-3U with occational use of the pop up flash. previewing a lot of photos on the digital display cuts the battery life in half, or more.
they were 27 canadian dollars for 4 plus the charger and another 15 dollars for 4 AA and 2 AAA at costco.

really happy with them, no problems so far.

cheers
02-04-2007, 09:23 PM   #26
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my local aldis super market had some cheap special offer medion branded ones.. 2 for 4 AAs.. i bought 10 worth which gave me twenty batteries.. only opened a couple of packets so far but they seem to work as well as any i have tried in the k100..

i wouldnt have been surprized if they hadnt thow.. he he..

trog
02-05-2007, 09:57 PM   #27
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Tonight I experienced 'proof' of a low-battery voltage sensitivity problem. While shooting indoors with flash, the battery meter dropped to half. After less than 10 shots, I received a 'battery depleted' message, and the camera shut down. I left the camera off for about 3 minutes, and then started it back up. Amazingly, my 'depleted batteries' continued on for 65 more flash photos, and currently show a full battery. Obviously there is something to this issue.

"Use stupidly expensive CR-V3's, or buy rechargable CR-V3's that void your warranty" is not a solution (but thanks for the suggestion). Pentax needs to acknowledge this issue and correct it.

Chris
02-06-2007, 12:56 AM   #28
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Got a set of Rayovac Hybrids from my local Walmart ($4 after $5 off coupon). Showed full in the camera straight from the pack - no charging. Took about 20 pics yesterday, shut off for the night. Showed full charge in the morning. Took some more pics. Shut off. Still shows full charge after dinner. Looks promising I must say. If this performance continues for another two days, I am gonna pick-up a few more sets of the Hybrids. Must say the price is right - $1 per battery.... can't beat that

In case someone is wondering, the $5 Off promotional coupon is valid on both Rayovac Hybrid batteries & charger sets, and valid till 03/31/07. You may look for these coupons in your local sunday paper or coupon book. Also selling on eBay for about $1 for two coupons.

I got mine from couponclippers.com. But had to order 30 as they have a minimum order requirement, so I have a bunch to spare. Giving some to my friends but I expect I will still have some left. If someone here is interested, then send me a PM. $1 for first 3 coupons with first class mail, and 20 cents per each additional coupon. First come first serve.

Cheers
Teja

Last edited by Teja; 02-06-2007 at 02:36 PM.
02-06-2007, 04:20 AM   #29
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QuoteOriginally posted by silverbullet Quote
Tonight I experienced 'proof' of a low-battery voltage sensitivity problem. While shooting indoors with flash, the battery meter dropped to half. After less than 10 shots, I received a 'battery depleted' message, and the camera shut down. I left the camera off for about 3 minutes, and then started it back up. Amazingly, my 'depleted batteries' continued on for 65 more flash photos, and currently show a full battery. Obviously there is something to this issue.

"Use stupidly expensive CR-V3's, or buy rechargable CR-V3's that void your warranty" is not a solution (but thanks for the suggestion). Pentax needs to acknowledge this issue and correct it.

Chris
I bet Pentax have never acknowledged and will never acknowledge this problem but they have already corrected it in their K10D, that is, they use no more AA batteries.

I reported this problem more than 3 years ago with my *ist D and still reported this problem for my *ist DS 2 years ago. If Pentax had ever acknowledged the problem and listened to us, they would have already corrected it with the K100D, but unfortunately, not.

I have never particularly reported this battery problem again with my K100D (in my reviews and OTs) as I have faced the fact that every Pentax DSLR uses AA batteries behave like this! (well, but some Pentaxians of those DSLRs called me a "Pentax basher" forever :-))
02-06-2007, 07:01 AM   #30
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the first thing.. u cannot tell how much charge is in NiMH batteries by looking at the battery life indicator.. the batteries do not slowly lose voltage as the charge drops.. the meter is simply a volt meter.. its impossible for it to know how much charge is left in a set of NiMH batteries..

it knows when they have some charge in them and it knows when they are flat.. thats all it knows.. fact..

with batteries that slowy lose voltage as the charge drops it works..

with batteries that maintain a nominal voltage until they suddenly go flat it dosnt work..

a heavy voltage drop after high current drain and then recovering afterwards is perfecty normal..

as R/H says lithium only with the K10 solves all these probems of what batteries to use..

i like useing NiMH batteries but i do know how to use them.. it seems many do not.. there is no fault here.. its just the way NiMH batteries behave.. if u dont like it use another type..

make sure u have a good set.. always charge before use.. carry a spare set of fully charged ones.. allow for the fact they self discharge.. allow for the fact u only know they are fully charged when fresh off charge..

follow a few simple rules and they work okay.. dont follow those rules and they wont work okay..

trog

ps.. fact.. the battery life indicator is of no real use at all with NiMH batteries..

Last edited by trog100; 02-06-2007 at 07:09 AM.
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