Please be patient with me. I have scoured the forum and gleaned quite a bit so far, I think.
I get the fact that a BCR is virtually maintenance free, at around 25 bucks (make that 33 bucks!), for the 9v version.
GunnrunnerJohn helped me identify a 2nd hand K4s, I purchased here, as having a PS1 board in the tender. The current battery, in it, is an MTH 9v Ni–MH. I hope that's what is called for.
I have coming, an alleged PS2 GG1 from a forum member. I have no idea what type of battery will be in it. I'll snap a pic when it arrives for help determining the type of board and proper replacement battery and/or BCR.
1) Can a $24 MTH battery really be better than a $6 Energizer?
Thanks in advance - Ponz