How long does yours hold up?

Talking about batteries, I've been completely amazed at how brilliantly the K10D battery holds its charge.

I've taken very few pics recently, and haven't had to charge the battery at all. So the spare has been sitting about for weeks. I checked it was charged the other day by putting it on the charger - the red light flicked on for about half a second and then out again, so it was still completely full.

How does this compare with other non-Pentax branded batteries?

I guess again it's exactly the same with a different name on it, but the battery for my GX-10 also lasts brilliantly. Although like a lot of Li-Ion things, it does seem to fail very quickly at the end, goes from full to nothing without much warning!

If you end up keeping a Li-Ion battery unused for a long time it's best to keep it cool and about 1/2 charged - that way the capacity loss with time is slowest. (Note that this is a permanent loss of full charge capacity over time, not just a discharge that can be restored). On the other hand being 1/2 charged is less useful if you're wanting it as a spare battery for when the primary one runs flat...

More information than you ever wanted to know about batteries can be found here http://batteryuniversity.com/index.htm

Robin

What an amazing site.

I shall be keeping the spare battery in the fridge henceforth - at least I'll know where to find it, unlike most of my other small bits of gear

In my (limited) experience with the K10D, I've found that long shutter times seem to eat the battery fairly quickly. I've been doing some night sky at 3 minutes or so. (Interestingly, the 'writing to memory' bit takes almost as long as the shutter time - did anyone else notice that?)

That should be true for all lithium ion batteries in good condition. Slow self-discharge is one of the advantages this type has over NiMH, etc.

It's not writing to memory. It's subtracting an equal exposure with the shutter closed, to eliminate noise.

Check the "Noise reduction" entry on the custom menu.

I get superb life out of my genuine K10D battery. even when making very long exposures however when i obtained the camera i also received a second comaptible battery. the second battery however has a very short life even though it has a nominally higher capacity. I suspect that this is due to internal damage (it rattles!).

One question i do have concerning these batteries is: do they contain internal protective circuit modules or are the batteries protected by circuitry in the camera or charger?

Pete.

Do you not think that it's something of a false economy to use a battery that you have good reason to believe is damaged, in a camera worth several hundred pounds?

this is indeed the case

for astro shots, I now disable the onboard noise reduction, take my own dark frame (a shot on the same settings as the others but with the lens cap on) and subtract it inside in the warm. UFRAW allows me to specify a dark frame at the RAW conversion stage and this works very well indeed.