For the last year I have been sharing a battery charger with my folks. To avoid the complication I installed a battery charger this afternoon. The best location to provide airflow is on the v-berth bulkhead in place of the large red battery switch.
I removed the switch, covered the hole with a stainless 5" louvered vent (this will help with cooling the battery charger), and then installed the charger.
I purchased a smaller battery switch to save 'bulkhead space'. The new switch is installed to the right of the main power panel. The positive battery lead is just long enough to reach.
(The batt switch is red; the silver cylinder above the switch is the 12V accessory plug; to the right you can see the back of the main power panel switches.)
This is how everything looks 'from the cabin side' -
The project took about 90 minutes. Much more comfortable doing this then when I installed the electrical system on my old M15. It is true that after doing something once future efforts are much easier.
NOTE: the above was first posted in my blog on 30 March, 2010.