OBC or Batteries AHHHH!

[PuttPutt]

After doing a bunch of searches and reading, I think we have a bad OBC. But I am afraid to pull the trigger and buy a new one. Here is what I have so far:

Battery light on dash does not come on at all. Pull the power plug during the charge cycle no light to indicate an interruption.

Charger is staying on way over 16 hours. Not shutting off.

Charger is not doing the normal test cycle when plugged in, comes on in about 6 sec. But stays on
doesn't turn off and come back on.

Reset OBC. No Change.

Pack reaches 60.5 volts on the charger doesn't climb past that. Charger indicate 4.5 amps.

After 8 hours rest pack is at 50.4 volts 8.5 to 8.4 across the pack

On a slight hill when I mash the peddle volts drop to 43 then quickly go to 47 at 16 MPH.

The cart is performing well on the golf course.

Took each cable off and cleaned eyelets and battery terminals.

I tried a second charger and it was still going at 60.5 volts. Pack was at 50.x when plugged in left it on for about 3 hours never past 60.3volts at 4.5 to 5 amps. did not shut down automatically. Had to return the charger so couldn't leave it on.

So seems to point to the OBC

One last piece of the puzzle, the pack is 4 years old, which makes me question is it batteries or OBC.

Thanks
Afraid to pull the trigger, cha ching $$$$$$