It seems curious that the voltage output would be different if they are so compatible.
As far as the specific symptoms of mine, When you to screw in the bat the blue LED DOES dim a little but never changes color and never chargers the battery.
I never said the voltage output was different. Actually, the voltage output should be the same for all models since they all use the same li-on/li-po cells.
Sorry, I guess "charging profile" was a poor choice of words on my part, I think that's what's confusing you. I was just being vague and general because no matter what
should be the case, we just can't guarantee anything about other brands or models, so it's my instinct to go into disclaimer mode and say that anything could be diffferent from what it
should be. Please also remember that I am not an engineer, all my knowledge is working knowledge that I've picked up as I've gone along, so I might misstate things sometimes.
The point is that while we can't guarantee ANYTHING about compatibility with other models, they SHOULD be compatible with other KR8 chargers. Where they aren't the main incompatibility is usually that the indicator lights don't function properly because the charger and batt aren't communicating the batt's charge status properly to each other. But even then they should still charge; and even the indicator lights
shouldn't be a problem with the Fusion chargers, since they are basically the same chargers that the MF batts were designed to work with.
Is that clearer?
If it's not charging at ALL, that's not an incompatability issue per se, it's probably just not making good contact, or is defective. Like I said it might be variations in the threads or in the power pin, preventing good contact. One thing you could try is pulling up the power post on the batt by prying it gently up with a needle or pin to mprove contact.
Or, again, it just might be a bad charger. And you're more than welcome to return it to exchange for another one.