Continue to read updates on battery for KX.
Some good feedback from this gentleman in dpreview:
http://forums.dpreview.com/forums/read.asp?forum=1036&message=33659044
Cut and paste below for other users/potential users of the KX.
Posted by Owen Marshall [PROFILE]
Date/Time 00:25:01, 11 November 2009 (GMT)
I bought a K-x yesterday (serial no. starting 344...) , and after testing it briefly with the supplied Lithiums at work (the indicator was first orange, but eventually turned green and everything worked fine) I was rather anxious (considering this thread) to try it out with my Ni-MH batteries. The results were rather interesting, and, ultimately, surprising: the short version is that the camera initially didn't work with Ni-MHs, but now works fine. Read on for the blow-by-blow details ...
First, I tried some newly charged Varta 2500mAh batteries I've been using in a Canon P&S (without issues) for about a year. Waited five seconds, turned on the power switch: nothing.
Waited another ten seconds, turned it on: orange indicator, which quickly became red and then "batteries depleted" after taking three shots. During this time, I changed the battery setting from auto to NiMH and tried using LV, neither of which prevented the camera dying.
Left the camera another ten seconds before switching on again, with the same result. And then randomly after further lots of five-ten seconds either the camera would not turn on or would show in quick succession a red battery indicator, "batteries depleted" and then switch off.
I was thinking at this point that I've got a lemon, and grabbed another set of rechargables (older Energizer 2500mAh). These wouldn't even switch the camera on.
In desperation I put the Vartas back in and tried switching the order of the batteries, trying all combinations. No luck, the same behaviour as before.
So I was cursing my luck and working out when I could take the camera back to the shop in the morning. But I decided that I might as well play around with the camera using Lithiums a bit more in the meantime, and took about fifty shots with these. I turned the battery setting back to "Auto" during this time, and left it there.
Then I figured I'd give the Vartas one more try, remembering some previous posts on this thread. This time, I left the camera a full five minutes between inserting the batteries and turning it on, making myself a drink while I waited ...
... and when I turned it on this time, the indicator was orange, quickly changed to green, and has sat on green happily through about a hundred shots, much menu fooling around, one movie test and some extensive use of live view. Turning the camera off and then on again still keeps the indicator on green (so once the batteries are correctly detected, you don't need to go through the five minute wait again). In fact, I haven't been able to shift it off green since, irrespective of LV usage, processing of HDR shots or anything else I can throw at it.
Therefore, I'm thinking that the time period for the camera to detect and adapt to new batteries is fairly critical for Ni-MHs. Setting the battery type to "NIMH" does nothing to change this, as far as I can tell (perhaps this is a f/w bug?) -- the camera needs to work the battery type out on its own, and once it's done this things are fine. At least, this is the case with my unit, and it seems to fit with the recent experiences of a few others in this forum. I'm going to perform a few more tests tonight with my other rechargables, to see if they'll work after the five minute rule, and also see if I can reproduce this behaviour after putting the Lithiums back in the camera to reset the battery type. I'll also test if setting the battery type to "Lithium" prevents my Ni-MHs from working.
But at this stage I think (or rather, hope!) that the ultimate message is that yes, there is a major problem here that will hopefully be addressed in firmware (you shouldn't have to wait five minutes after inserting a new lot of batteries!), but it may not be as catastrophic as it seems at first (since my camera did, ultimately, work with some basic, cheap NiMHs).
Curiously, the manual makes no mention of needing to wait a substantial amount of time before using NIMHs, and even seems to recommend their usage over Lithiums and Alkalines. No mention is made of eneloop-type technology in the manual, and the quoted shot numbers with NiMH batteries are based on using 1900mAh-rated cells (so Pentax clearly thought you didn't need anything particularly flash to get this camera to work!)
(and sorry for the rather long first post in this forum! The K-x is an awesome little camera ... it's such a pity it's got this silly battery bug)
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I hope Pentax can improve on this in the next firmware update.
The advantage of AA batteries is it's easy availability but if not all types of AAs can be used then may become a disadvantage.
cheers