Is there any good advice either pro or con about using re-chargable batteries in timing equipment (tags, photocells, Summit wireless, etc). Each ski season our organization goes through a huge amount of AA batteries -- most only half used. Nobody ever trusts the last users notes re: the batteries condition, when they were changed, etc.

Are there re-chargable systems that can be trusted?. what are other using if any?

I tend to use fresh alkalines on jobs. It is cheap insurance. I can certainly understand the issues with an active race dept. I guess the only answer is testing. A decent multi tester can be purchased at Sears Craftsman or Radio Shack for $25.00. Putting a meter on any battery will tell you it's value. Get a few bins and label them. That way you can toss the batteries in either: Decent, Marginal, or Recycle.

Fred is right..

Other thing you can do is to test the voltage when they are cold (not warm). If they are sitting about 1.3 V when frozen, then you good to go for a few more days. Don't just use a voltmeter, use a Battery tester that actually puts a load on the battery for testing.

They aren't drained that fast. Rechargeables are. Cold will kill NiCads and others in a hart beat.

from http://www.greenbatteries.com/batterymyths.html#Freezer

Alkaline batteries stored at "room temperature" self discharge at a rate of less than two percent per year. So normally refrigerating or freezing them will only help maintain their charge by a tiny amount. Hardly worth the effort of chilling them. However, if alkaline batteries are stored at higher temperatures they will start to lose capacity much quicker. At 85 degrees F they only lose about 5% per year, but at 100 degrees they lose 25% per year. So if you live in a very hot climate or are storing your batteries in a very hot location, it may be worthwhile for you to store your alkaline batteries in a refrigerator instead.

NiMH and NiCd batteries self discharge at a MUCH faster rate than alkaline batteries. In fact, at "room temperature" (about 70 degrees F) NiMH and NiCD batteries will self discharge a few percent PER DAY. Storing them at lower temperatures will slow their self discharge rate dramatically. NiMH batteries stored at freezing will retain over 90% of their charge for full month. So it might make sense to store them in a freezer. If you do, it's best to bring them back to room temperature before using them. Even if you don't freeze your NiMH batteries after charging them, you should store them in a cool place to minimize their self discharge.