Cane Pole,
Nice work on the battery. I have two onboard chargers (dual bank and single bank) mounted back in the battery compartment. The dual bank is mounted vertically on the wall next to the aft minnow bucket. The single bank is mounted on the floor aft of the starting battery. I used rivnuts and stainless steel machine screws to mount them. One of these places may work for you as well.
Keith
2008 NWR Bash Crappie Champion
2010 NWR Bash Yellow Perch Champion
2010 Buggs Bash Smallest Crappie Award