RE: futaba 12Z battery question
I have found it safer and cheaper to go to online auctions and purchase replacement batteries for Sony Camcorders. Search for Sony NP-F570 and you will come up with both name and generic brands. Some are 7.2v, some are 7.4v but all work the same. You can buy pure name brand Sony if preferred.
Many are shipped from China but I have made purchases that were shipped from the US. Bought two 7.4, 2400mah about 6 months ago for $21.00 shipped from Los Angeles. The hold charge as well as the original Futaba versions. Two can give me a full day of flying although one usually does.
I have been buying these types of replacement packs for several years for my 12Z and 14MZ. No problems at all. They are lithium ion cells.
Your call though.