Well, last time i checked, I am not colorblind, and know the difference
between black and red! I assure you polarity was correct.

Jerry G. wrote:

I have seen users change their own batteries and put them in reverse
polarity. This blows the main board every time!

This type of procedure makes for the repairs to be very expensive. APC does
not sell the parts, or service manuals to non-APC servicers. You will have
to send back the UPS for an estimate. In the end, you will most likely find
that it may be cheaper to buy a new one! I have no idea if they will take
back the batteries. Usually, batteries are a non returnable item.