Originally Posted by onehundred80
They are only good as long as the batteries last. 
Can you see if you can take an old one apart and replace the battery in it? We would be in your debt if you succeeded, your reward would be a mention in the Forum Honor Roll, not cash. Sorry.
Electricity is your field so get to it.
You piqued my interest so I stripped one down. It is very heavily potted with a super tough elastic polymer. The battery is a Maxell CR245HR..3 volt putting out 2.99volt at this time. Replacing it not worth the labor cost. Battery diameter 25mm. last a long time. gary