I don't know of any test other than what IBM may post at thier support website, so check there. Further, just clean the contacts on both battery and laptop as best as possible. Even if you didn't use the system on batteries very much, it seems batteries tend to degenerate after 18mo. used or not, in other words expect problems around then. If proper care is used it *may* extend battery life, but still not 100%. Understand, after every recharge the battery tends to keep dropping from delivering its time limit bit by bit. Also, buy from a good source just to try getting the freshest battery possible, one sitting on a shelf for awhile maynot be a best buy if you run across real low low prices, that maybe why.
good luck -----Willy
I have an IBM laptop 2621 - 548 thinkpad. The item will not operate on its battery. Its confirmed that the battery is totally flat. The laptop runs on mains ok .
Before I invest in a new battery I want to confirm that the charging circuit is functioning. Does anyone have information on how to do this?