nimh batteries died?

Yes, on both counts. If you told it eight cells, it would charge the batt thinking it was an 8S1P. But - I'm guessing about your charger here - the connected voltage would be wrong and it wouldn't charge it that way and give you some kind of error message - at least my Ice would. Connected voltage from the pac has to be within certain range based on number of cells you input. Otherwise, would be a great way to get in trouble.