Greetings,

A long, long time ago (but not very far away at all), I purchased a PCB from the shop. I never used it, because I ended up going with TCSS pre-made packs. Now I'm in a position where I need to build a battery pack and...for the life of me, I cannot remember which PCB I purchased. My question is whether there is any method by which I can visually distinguish the 3.7v PCB from the 7.4v. I looked at the product pages for both, and neither looks like the one I bought.

I include the following pictures for visual reference. There are several markings on the front side, but none that I can decipher.



It sounds like a silly question, but I really can't remember which one I bought. Am I correct in assuming that, if I do wire up two li-ions in series, and this is a 3.7v PCB, it will just limit the voltage to 3.7v? Or will it explode and leave a smoking crater where my workshop was? At this moment, that test seems to be the only way I'll know for sure.

Any ideas?