Battery Error message on S90

Increasingly, and now about half of the time, when I power up my S90, I get an error message that says "check battery" even though my battery is 90 to 100% charged. I can get the camera to operate if I power off, eject the battery, reinsert, and repower. I will mention that I never had this problem until I started using a micro sd card and adapter as my storage medium. The battery is only as old as the camera, about a year and a half.

Has anyone else had this problem ,and how did you solve it? I would hate to buy a $45-60 battery to find out it was a camera problem. I would prefer to keep using the micro sd card as it is 16G and more than I would ever need to carry, as my next size down is only 4G.

Thanks.

Can you just just the 4GB regular SD card for a while to see if the problem goes away? 4GB is still a few hundred images on the S90. If it doesn't, you know it is the battery or a camera problem. If it does, then you know your camera doesn't like the adapter.

Sadly, it also happens with the 4G card. I was hoping maybe it was a problem with the microSD and adpapter, that the camera was getting a bad read, but it seems time to replace the battery. BTW, is $15 for "genuine canon" battery TGTBT? I think so, as I recall paying more like $60 last time I replaced a canon battery with the real thing.

The exact error message is "change battery pack" yet with the workaround I get it working (often after I missed a shot :mad.

Any similar experiences?