[ytterbium]

For energy not to be lost in additional voltage downconverters, both voltages might be used, All in series 6V, and 3V from center tap (2 in series).

[madphys]

That only means that you should use Bipolar power supply. From what you said one can conclude that K200D eats +/- 2,4V.
The jumper between 2 & 4 is zerro potential - and 1 respectively is positive terminal and 3 is negative terminal - easy.
Or might be as mentioned above

[rpriedhorsky]

Agreed - but in his thread -
NiMh Battery Shoot Out (follow up NiMh Battery Shoot Out Part II )
would reveal some of his methodolgy. I believe he normally uses sets of 4 and checks their consistency and rejects or doesn't even test unless they are consistent

I'd still call that a single sample, since it's a closely related group of four cells -- if they came in the same package, they probably came off the assembly line at about the same time and aren't really independent.

since the threads are long running SilverFox is often notified of any differences from other people's testing

That's encouraging.

I am not being "defensive" about SilverFox's work

Defensive is different than defending, and the latter is important. I don't read your comments as the former.

but these are long running threads over at CandlePowerForums (for flashlight enthusiasts) where there would be a great deal of interest and knowledge about batteries - although there might be a "sacred cow" or even "emperor's new clothes" syndrome -
I don't really think this is the case, considering how many true experts and electrical/electronics engineers are over there. I believe the threads contain some really good information and has stood the test of time and scrutiny of others better than me.

I agree that there's lots of good information to be had in threads like this one and like the ones you describe. I didn't intend to imply otherwise, though I won't insist that I accomplished that well.

One just has to keep in mind that most of the information is anecdotal (which is different than "without value"), and that the experiments often have shaky methodology (again, different than "without value") -- it's hard to put together a really solid experiment.

The batteries appear not be in a single, straight series only configuration, here is what I found.

The way I interpret your explanation is four cells connected in series, 1 -> 2 -> 4 -> 3, though I'm having a little bit of a hard time visualizing without the device in front of me.

Then using a regulated power supply I connected a range of 4.8 to 6 volts positive to #1 in down in the battery compartment and the negative to #3.

The camera would not turn on.

I can think of a couple of alternate explanations for the camera not turning on.

1. There are physical detectors which prevent the camera from turning on without cell-sized objects being inserted into the bays.

2. The camera samples the voltages between each cell and refuses to turn on if things seem funny.

I think #2 is fairly likely, actually, because this kind of circuit would be useful for protecting against weak cells' having reverse voltage applied (which causes nasty things), and I seem to recall reading that the K200d has such protection.

This might indicate that there actually is a simple voltage trigger which turns off the camera if a single cell falls below some threshold. However, I'd expect it to be much closer to 0 volts than 1.19 for this purpose.

[UnknownVT]

Laying the K200D upside down with the lens pointed away from me, I numbered the battery compartments in the following manner. Most foward was #1, going CCW, #2, then #3, then #4. Using an ohmmeter I found #2 and #4 are a direct short (a jumper internal inside the camera).

Then using the same numbers for the battery cover, it is plain to see a jumper between #1 and #2 and a jumper between #3 and #4.

Drawing that out, #1 down in the camera is the most positive voltage source of battery pack and #3 is the most negative source.

Then using a regulated power supply I connected a range of 4.8 to 6 volts positive to #1 in down in the battery compartment and the negative to #3.

The camera would not turn on.

I think you may have made a mistake on the battery series.....
but I only have a Pentax K100D

Let's make sure of what we are talking about first -
K200D battery compartment....

This is WRONG!

EDIT - Sorry my Mistake on battery numbering

I must be dyslexic in my reading the battery numbering that dmessing posted -
he wrote "CCW"
which for some unknown reason I kept interpreting as "ClockWise"

Sorry for my mistake -
here hopfully is the correct numbering -

K200D


K100D


I hope I now have numbering convention the right way round .

So using the "correct" numbering this is what I found on my Pentax K100D - as you say -ve of 1 shorts to + of 2, and +ve of 3 shorts to -ve of 4 pretty obviously seen on the compartment cover.

BUT inside the compartment can be a bit tricky as the contacts are the raised part of the spring (and not the fastened part at the bottom) using the raised part it is the +ve of 4 that contacts the -ve of 2.

So the series connection is +1,2,4,3-
to spell it out kind of "graphically":

+1- +2- +4- +3-

So the most +ve is at 1 and the most -ve is at 3 - both (obviously) inside the compartment -
it's the raised part of the spring that's the actual contact.

This is in agreement with what you found.....

Sorry to kick up a fuss for nothing!

I wrote PM to dmessing who pointed out his numbering system - that's why I corrected mine above. He also mentioned a "sensor/switch" of some kind when closing the battery cover - I also found that.

Using a 4AA battery holder and confirming I had 5+V I attempted to power on my K100D keeping the sensor/switch depressed - much to my chagrin and dismay it would not power on either.

So I cannot figure out what will power the camera on without the batteries physically in their compartment either.

Please see follow up post below for a possible alternative.

---

Last edited by UnknownVT; 01-05-2009 at 04:53 PM. Reason: typo + corrected battery numbering

[UnknownVT]

I wrote PM to dmessing who pointed out his numbering system - that's why I corrected mine above. He also mentioned a "sensor/switch" of some kind when closing the battery cover - I also found that.

Using a 4AA battery holder and confirming I had 5+V I attempted to power on my K100D keeping the sensor/switch depressed - much to my chagrin and dismay it would not power on either.

So I cannot figure out what will power the camera on without the batteries physically in their compartment.

Please see follow up post below for a possible alternative.

Then I remembered that the K100D (and K200D can be powered by AC adapter - the socket/receptacle is marked 6.5V



Although it might not be as valid -
perhaps varying the voltage carefully via the AC adapter socket may show us what the battery meter readings and the cutoff threshold voltage are for the K200D?
- I am hoping that the camera will operate just via the AC adapter socket and withOUT batteries in the compartment?

[madbrain]

- I am hoping that the camera will operate just via the AC adapter socket and withOUT batteries in the compartment?

Yes, I just tested this, and the K200D works fine with the AC adapter (from radio shack) and no batteries.

[rpriedhorsky]

A few notes based on my experience with my K200d which arrived yesterday:

1. There's definitely a switch activated by closing the battery door.

2. The connections between cells 1/2 and 3/4 are on the battery door and not available for voltage sampling by the camera.

3. I encountered the same behavior as the OP. A relatively fresh (charged ~2 weeks ago) set of LaCrosse 2600 mAh yielded on a few dozen shots; however, removing and reinserting the same cells put the battery meter back up to 100% and it has remained there for about 100 more. I suspect a power-cycle would have done the same thing.

Reid

[dmessing]

I wanted to learn the following about my K200D, the cutoff battery voltage/monitor reading, and current drawn during different functions.

The batteries in the camera are in series. The battery toward the lens side of the camea is the plus, the battery 3rd from the lens side is the minus. There is a small switch activated when the battery door closes, that must be pushed in to power up the camera.

Here is what I observed:

Batteries were out of my camera for several days I placed fully charged batteries in the camera, camera wouldn’t turn on. Put those in the Maha charger and noticed they were full. Put in the second set and camera still didn’t turn on. Within a minute, tried the camera again and it came on with no problem. It was like there was a large capacitor that had to charge first???

I was able to connect directly to the battery clips, pushing in the little switch, the camera came on. I had a 25 amp adjustable supply allowing voltages down to 1 volt. I started with at 5.2 volts and zeroed in on 4.8 volts. I watched the voltage with two digital meters at the supply output both were exactly the same. The Beckman 223 reading is the left value/Fluke 87 is the right reading

4.59 Volts NO Turn On
4.60/4.596 Turns ON, Shutter trips every time, Flash charges and works
4.65 volts Camera Came On, Bat Monitor Empty
4.69 volts Camera Came On, Bat Monitor Empty
4.73 volts Camera Came On, Bat Monitor Full
4.76 volts Camera Came On, Bat Monitor Full
4.78 volts Camera Came On, Bat Monitor Full
4.79 volts Camera Came On, Bat Monitor Full
4.8 volts Camera Came On, Bat Monitor Full

Here is what is very interesting. If I very slowly started turning down the voltage, the battery monitor didn’t change from full, even if the power supply was down to 2.6 volts. It was like a charged capacitor was maintaining the operation. In order to catch the threshold, the supply voltage was adjusted a small fraction, the bottom switch was depressed and it then would show the difference after camera came on.

Turn ON is 4.60 volts. I tripped the shutter 4 times, popped up the flash tripped shutter two, it worked every time with no flicker on the 4.60 volts supply. ON MY CAMERA 4.60/4.596 VOLTS IS THE LIMIT LOW, STILL WORKS AT THAT VOLTAGE! Readings shown are a Beckman reading on the left and Fluke on the right.

Never saw half a battery monitor, ever. Above 4.72/4.715 Battery Monitor was full. The above voltages were straight from the power supply, no measuring resistance in series.

The Current Draw Measurements were made at about 5.2 volts, with a lab type HP 0.1 ohm shunt for converting mA to mV for the Scope meter and double checking that with the Fluke 87 in series. The Fluke 87 was set for Record in Min Max with 100 mS capture. The HP 0.1 ohm shunt fed a Fluke Scopemeter for comparison of accuracy, both the same readings.

Functions of the K200D:

Turn camera on: Quick short spike of 1296 mA ( within a second)
First Stage, Camera On, LCD Screen On, 260 mA
Second Stage, Camera On, LCD Screen Off 149 mA for about 10 seconds
Third Stage, Camera On in standby 87 mA
Fourth Stage Sutter Tripped 1.484 mA for less than a second
Flipped up the Flash and Charge, for a brief moment 1.480 mA
I used two digital meters, the Beckman 223 and Fluke 87B. Where the above voltage reading are shown, i.e. 4.60/4.596 those are from the Beckman and the Fluke at the output of a 25 amp voltage regulated/adjustable dc power supply.

I didn't write it down, but it seems during a 30 sec time expose, after the initial quick 1484 mA spike, the current draw was 400 mA with shutter open.

I wish to thank UnknownVT who collaborated with me all week and corrected my typos and gave me additional ideas. The part that was confusing at first is getting past a point where the camera needs a short time after power has been removed to establish a point where it will turn on.

Not a part of these measurements shown above, but FYI only. Regarding the connector for an external power supply, I was surprised how many styles and sizes are listed in Wikipedia. Those in the US, Germany, Din, Japan all are different. A 5mm OD 2mm ID easily goes into the camera, but the I.D. is too big creating an intermittent connection . Closest to what I could purchase locally from Radio Shack was the Adaptaplug “C” part # 273-1706. Its size is listed as 4.7 mm O.D. 1.7 mm I.D. These are made plug on their power supplies. I soldered two wires onto the plug and tested with an external power supply and it had no signs of being intermittent.

Dave

[rpriedhorsky]

dmessing, I'm concerned that you are still assuming that the battery meter is based on voltage only, which as I've mentioned above I believe to be unfounded. Or did I misread your comments?

[dmessing]

From what I see, the voltage level does have a major result on the battery monitor. The Turn On current draw each time the camera comes on is exactly the same. By changing the voltage output upward or downward and cycing the camera back on, the level at which the battery monitor shows full to empty repeats with the same results. Below a certain voltage the battery monitor is empty the camera operates until it sees the cutoff voltage and shuts off.

I believe 4.7 Volts total, (1.175/Cell) and above the monitor is Full.
4.6 to 4.7 volts (1.15 to 1.175/Cell) camera still works monitor is Empty
4.6 Volts and less (1.15 Volts/Cell) camera is off line

I think what is a little deceiving it appears the camera has a large value capacator that holds the voltage level at a certain level and the voltage monitor doesn't quickly track it.

I hadn't given this as much emphasis as to what voltage the camera fails to operate. My main concern does the camera operate at less than 1.2 volts per cell, 4.8 volts total, and yes it does. With any supply be it AC powered or battery supply a certain voltage is needed , if the capacity is low then the voltage quickly sags under load.

Could be the camera has two circuits providing the battery monitor operation. It would amount to both a voltage value and a current value.

For the camera circuits to measure a current value, the current flow would have to be converted to a voltage for the circuit to measure it. A current measurement is accomplished by a drop across a very low impedance such as .1 ohm. Ohms law for a value of current drawn is voltage divided by resistance.

There is really no need for both to be measured. If the capacaity of the supply is weak, the voltage will immediately be weak under that load.

[UnknownVT]

First, a BIG THANK YOU to dmessing for doing this sterling work.

dmessing, I'm concerned that you are still assuming that the battery meter is based on voltage only, which as I've mentioned above I believe to be unfounded. Or did I misread your comments?

This may help us with a clue.

Since dmessing did not see a half battery signal ever in his tests - and although I only have the K100D - I see the half battery meter signal often.



So perhaps voltage alone may not be the whole story, although it is obviously important - as seen by the cutoff threshold and the full and empty battery signals -
but perhaps lower current measurements/sensing may also contribute to the overall battery meter signal?

As with all batteries - it's the overall power delivery (watts) that's important - most batteries are within a certain voltage range have varying ability to deliver current at those voltages -
or said another way - to deliver a certain amount of current the batteries can only maintain a certain voltage level depending on its state of charge -
all this sounds unnecessarily complicated - it basically boils down to what power the battery can deliver at any point in time/state of charge.
Which is the same as saying a battery's state is dependent on both the voltage it is maintaining and the current it is able to deliver at that voltage.

So measuring voltage alone may not be a good enough indicator of battery state - it should be both voltage and the current it can deliver.

dmessing's sterling effort was with a power supply that could be regarded for his tests on the K200D as one with infinite current delivery - at least far in excess of the current demand which seems to top out at about 1.484 Amps for a short duration (his power supply is rated at 25 Amps).

For batteries realistically at a constant discharge current one can see the voltage gradually drop during discharge - so at each point in time the ability to deliver power (watts) is gradually diminishing.

So to cut this long strory short - if it is possible to set the voltage level at each threshold check point then gradually limit the current - perhaps one would then see the half battery signal - and perhaps the cutoff threshold may be revealed to be also dependent on current limit/delivery
(an obvious check, if a supply is able to maintain say 4.78 V which on an infinite current supply shows full battery meter - I would hazard a guess that if the current was limited to below the lowest standby current (87mA) the camera would no longer be on.....)

[dmessing]

Thank you Vincent for the kind words.

With the adjustment on my power supply, I was able to hit all voltages, but there was a spot on the Voltage Adjust Control that would not let me hit exactly 4.7 volts. You will see that is missing on my list. I could have made an external voltage divider circuit, but didn't take that extra time.

The camera monitor circuit has a dampening feature. That monitor circuit has to be the one that drives the monitor up to the point it also trips off the camera. Without an average of the value, the would be tripping off all the time. Once the camera trips off it stays off until power is recycled. Between functions such as shutter and flash spikes, the result needs to be smooth. I think this is where it is hard to track with a quick result.

As capacity drops, voltage sags.

If a power supply that has a current limit feature, when the current limit is reached, the voltage begins to drop.

[UnknownVT]

As capacity drops, voltage sags.
If a power supply that has a current limit feature, when the current limit is reached, the voltage begins to drop.

This is how batteries work -
so if your power supply can limit the current -
then the test would actually be pretty realistic for battery usage?

Here are the animated current discharge curves comparing 3 LSD batteries, and the one comparing eneloops with well known higher capacity NiMH -
this time I put the red-line at 1.15V - the tested cutoff voltage for the K200D -



(NOTE: to be fair - the horizontal scale in the second animated comparison are not the same for the higher capacity NiMH, their ranges are wider (better) )

Since the max current demand seemed to be tested at about 1.484Amps the critical curve would be somewhere between the 2Amp curve (dark green) and the 1Amp (purple).

The story does not change much - the eneloop shows more curves above the 1.15V red-line than the other 2 LSD batteries and the 2 well known higher capacity NiMH, and if one cares to look at the curves in NiMh Battery Shoot Out - the eneloop maintains noticably higher voltages than any other NiMH battery LSD or otherwise.

[dmessing]

Vincent and all Others,

I appreciate the graph updates. Knowing what I know now, they make a huge amount of sense. I am also glad to know Pentax was not to conservative on the battery monitoring and actual cutoff. In fact, I think they took it to beyond what I would have personally designed.

It was just due the poor performance of my Engerizer 2550 mAHr batteries with nearly 1.5 amp draws.

I am looking forward to the new Sanyo Eneloop batteries from Amazon, scheduled to arrive tomorrow.

I really wish to thank each and every person that lead me to the correct battery source. Obviously through many hours of trial and error, it comes down to what works.

I was curious if any company manufactured a Li-ion like used in my Nikon and in laptop computers built in a rechargeable AA package. So far none have turned up my searches. That seems to be some of the best capacity in a given physical size.

I saw a posting under another heading about someone wanting to build their own external power supply. I have built many power supplies, but when it comes to powering something as expensive as this camera, one would need to consider extra circuit design in the power supply to protect from over voltage with a crowbar circuit and a current limit circuit. Good sources for already built regulated supplies are Allied Electronics and Mouser Electronics.

Another gotcha I had with an expensive 900 mHz Ethernet modem at work was connecting and disconnecting the power plug with the power supply powered on. A small arc is created at time of connect and disconnect creating spike that fried an internal voltage regulator. I never connect or disconnect to a device with the voltage on, especially after that. Some companies do a good job in protecting internal circuitry form such action, others don't. During this past week when I tested the camera current using the external connector, the 5 mm OD x 2 mm ID plug was intermittent. I quickly stopped and found a plug that was tight.

For whats it worth.

[UnknownVT]

I was curious if any company manufactured a Li-ion like used in my Nikon and in laptop computers built in a rechargeable AA package. So far none have turned up my searches. That seems to be some of the best capacity in a given physical size.

I think you have contributed way more here -
so thanks right back at ya!

There are rechargeable Li-Ion CR-V3 batteries -
hmmmm... I just noticed there's a difference -
my K100D manual says one of the battery types is CR-V3,
BUT the K200D does not list them......



Anyway CR-V3 batteries are supposed to be able to replace a pair of AA batteries in series -
since the battery compartment layout of the K200D is similar to the K100D
then may be the CR-V3 batteries may work in the Pentax K200D (caveat*)

Caveat* - this is the BIG one - see
RiceHigh's Pentax Blog: Pentax Forbade Use of CR-V3 Batteries in the K200D

It links to Post #4 that shows a photo why CR-V3 cannot fit at all in the K200D battery compartment.

So the option for CR-V3 is out for the K200D

For the K200D one could try the newly announced NiZn batteries
(now available as Quantaray - from Ritz and Wolf cameras) may be useful -

Nickel-Zinc (NiZn - Wikipedia)

CPF thread - Nickel-Zinc to hit the streets end of April

enGadget link , and the manufacturer - PowerGenix link

according to the NiZn AA pdf spec sheet - the nominal voltage is 1.65V.

This is good news as the discharge curve -

shows that the battery remains above 1.15V (Pentax dSLR cutoff threshold) for the tested currents up to 1C = 1.5A - until it's truly depleted - so it may be capable of delivering almost all of its rated capacity before the Pentax dSLR shuts down

The not quite as good news, is the capacity - typical 1500mAh with a minimum of 1350mAh (compared to 2000mAh typical and 1900mAh min for eneloops)


in a kind of mitigation - because it maintains higher voltage it appears that the batteries may be able to deliver its full capacity before Pentax dSLRs shuts down.

Some have said that the self-discharge rate is supposed to be about the same as typical (non LSD) NiMH.......

The other problem is that because of the higher nominal voltage chargers have to be different - one cannot use existing NiMH chargers.

Personally although that sounds good - eneloops are working so well for my usage of the K100D -
I don't see any reason for change until a lot more information/test results are available for the NiZn batteries -
(ie: I don't like being an early adpater)