The charging block for my Oset occasionally makes odd noises when plugged in, almost like there is something mechanical inside it grinding away. I'm pretty sure it's always done this, but not positive. Normal?

If there's a bad connection it could be arcing, check to see if it's hot and for signs of scorching/melting.

Nope, all normal. It's a pulse charge charging block for lead acid batteries fwiw.

Should mention it only does this as a discharged battery is being charged. As of nears full charge it lessens then stops altogether when done charging.

is there a small fan inside, these over time can start to make some very strange noises..