The stock Cessna battery box lid has a protrusion which interferes with installation of a Concorde battery. Watch as I modify my battery box lid to allow room for the Concorde.
Mostly I get very tired of seeing battery lids which were cut apart during my pre-purchase inspections. I tell them about doing it this way, and thought it would be good to have an example available. Concorde makes a more robust sealed battery than Gill's offering and folks have been reporting very good results with them. Although I can't complain about the longevity of my current Gill. I'll have the option when the time comes.