I used to think the batteries were too expensive, but eventually I bit the bullet and bought a batch of 3 new ones from eBay. I'm glad I did as the machines are now much more reliable than they were with my homemade 3.6V batteries! However they cost me more than I would have liked, but the seller was selling them cheaper than Maplins and Radioshack do (in the UK at least).

It is always good when you liberate a Mac and find that the battery still works, although with most 68K's that is a very rare occurance.