(ET) battery problem/question???

["Chapin, Tim" <tchapin umich edu>]

I picked up 2 12v 18 ah sealed batteries on ebay (uses but like new the add
read) for my dead ryobi push.  I stuck them on the 24v scooter charger that
I use with my weekly ryobi mower.  The other day the charger showed that 
the
batterys were charged (green light).  Stuck them in the ryobi, pulled the
handle and the battery meter pegged on empty and the motor turned
backwards...  That strange!!  I hooked them up just like the old pack..
Pulled out the multi meter and stuck it on the battery and it read -25.8
volts.  Eather the pools have reversed on the 2 batteries or the batteries
were manufactured wrong..   Pos. terminal (marked in read and +) is showing
neg. The design is just like the other 2 sets I have and the post are in 
the
same positions.  I hooked the pack in backwards, the meter showed nearly
full, the motor turned correctly and the mower mowed.  It didn't have the
power of the other ryobi (stalled it in grass that wasn't real tall).
drained one bat to nothing and stuck it on the car charger and the charger
pegged and the override kicked in so the bat is backwards.  Is there a way
to reverse the poles or should I worry about it or is the batteries junk???


Just strange..