I have the Odyessy PC925LMJT in mine [boot mount std]. I have it hooked up to a Braille remote control that isolates the battery for all except the alarm - so I have to reset the clock and climate control when I use the car. The alarm has its own power source.
I also wired in a small 2 pin plug above the number plate. I use this to plug in a solar panel lead when the Skyline is not being used. The solar panel is mounted on the carport roof and runs through a Sunergy PR1210L solar regulator. My battery is over 4 years old and still going strong. I think this is not so important in the summer cos warmer temperatures help with the chemical reaction. But in the winter it is essential.
BTW, I fabbed up my own battery holder and brackets for this. I also had to change my live lead and the lead from the Braille switch [one in, one out] to the harness etc.