If I can't get hold of manufacturer supplied batteries can I safely replace rechargeable Lithium-ion 40mAh 3.7 V DC with 3.7V 40mAh,12C Li-Polymer? Thanks! -edit- LMAO! I carried on searching for this problem and finally found a forum thread on Google that looked exactly like what I was looking for. I was like, sweet, somebody is asking the same question. It turned out to be this thread, ranked and indexed within a few minutes.