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You see, it's not about the 'power' in the battery - it's about the very high cut off votage of my camera. As someone said, it should be ~1.3 V; not 1.6 V. We are not making use of the 'power' in the battery.

jharris9

Forum: Pentax DSLR Discussion 09-23-2012, 08:20 PM

Intolerable problem with batteries in K200
Posted By jharris9

Replies: 22
Views: 5,311

Cleaning the contacks is a good idea I have not done. Thanks.

As for the other replys - the ponit is the nominl voltage of the reccommended battery is 1.5 V and the camera stops working at 1.6 V - my K200D anyway.

And, as I said the Ultimate Lithiums are working for a few hundres shots, so that workable, but they should last a lot longer and we are not using the batteries efectively. Since other are not having this problem, is may be my cameras problem.

jharris9

Thanks

Jim

Forum: Pentax DSLR Discussion 09-22-2012, 12:40 PM

Intolerable problem with batteries in K200
Posted By jharris9

Replies: 22
Views: 5,311

In my K200 DSLR battery life is erratic and sometimes is pretty short – a few hundred shots. I’m using Energizer Ultimate Lithium AA cells. The listed ‘nominal’ voltage of a lithium AA cell is 1.5 volts. Its actual voltage output on a new cell is from 1.79 to 1.89 volts DC, even after one year of storage at room temperature.

These are all primary cells – not rechargeable. I have tried rechargeable and they did not work at all for me.

I measured some “failed’ batteries from my camera. First with no load and then with a ~3.5 ma resistor load:

The four batteries measured 1.608, 1.586, 1.606, 1.605 Volts.
With the resistor load they were 1.607,1.578, 1.604, 1.604 Volts.

Then I took out the batteries I had been using for just a few weeks and very few shots they measured (with the same resistor load):
1.776, 1,776, 1.776, 1.778 Volts

Since the nominal battery voltage is 1.5 the “failed” batteries should not have failed and Pentax has a design flaw in that the under voltage detect circuit is set too high or the circuit design is such that it requires a higher than nominal battery voltage. This is why NiCad batteries hardly work at all in this camera.

This means that we are not taking any where near all the available energy out of these batteries and why some folks use the batteries in their radio or flash light after the camera says they are bad. For my camera I'm probably using only 10 - 20 % of the battery energy before they "fail".

Energizer makes it hard to find good specifications, but I did find some discharge curves of a sort. Unfortunately I could not paste the cures in here but you can find it at http://data.energizer.com/PDFs/l91.pdf.

The curve for Ultimate Lithium indicates 1.6 v is the starting voltage with a 50 ma load. Since my “failed” battery set averaged 1.598 volts, this type of battery should not work at all in this camera – at least not with a 50 ma load.

The Advanced Lithium type battery is a bit worse for this application. http://data.energizer.com/PDFs/ea91.PDF

This is a design flaw in the K200 camera (or at least in my K200) and Pentax should fix it for free. There is a slight chance of this being a software fix, if the trip point is settable in software.

The cameras manual says it will run on plain alkaline batteries for 200 (non-flash) images and on lithium for 1100 images - and this is certainly not true for my camera.

Forum: Pentax SLR Lens Discussion 05-29-2012, 09:04 PM

Wide zoom or prime lens
Posted By jharris9

Replies: 15
Views: 2,265

I am looking for a wide lens for my K200. Tempted by Sigma 10-20 in either F3.5 or F 4.5-5.6, but both have some significant problems. A 10 or 12 mm prime (not fish eye) would be good - but alas I don't find any. Pentax should do this.

The Q is should I wait for a really good solution or buy a Sigma, and if the latter, the F3.5 or the cheaper 4.5-5.6? Anyone know what might be available in the next 6 months?

Thanks

Jim

Forum: Site Suggestions and Help 07-03-2010, 03:23 PM

B&H Contest theme nominations
Posted By jharris9

Replies: 360
Views: 24,233

I'd go for People & Emotions

Forum: Product Suggestions and Feedback 06-06-2010, 04:03 PM

Sticky: Dear Pentax
Posted By jharris9

Replies: 1,346
Views: 413,853

I'd like to see a 10 or 12 mm fast prime lense for my K200D.

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