I have a tjm dual battery management system on my 07 wagon and its chewing up my 2nd battery it must be cooking the crap out of them they only last 12-18 months when the main battery last 4.5yrs , i only use it for my fridge or link up both for the winch (very rare). My question is what do i have to do to preserve the life of my axillary battery do i need to bush this system or do i need a isolation switch to stop over charging i think this system i have is crap any advice would appreciated cheers Eric