Kind of a dumb question and i have an idea on how i should do it but i just want to get some feed back or ideas fom all you guys to make sure i do it right as some of you seen my 73 c10 is bagged and running into a problem with my battery going dead everytime i fill up my air tanks i know that compressors could draw a lot of current specially when you running multiple compressors .....the battery doesn't completly die but but you can tell it drains it....now i only run the compressor when the truck is running since i added a toggle switch to be able to trun them off any time i want to..... long story short i want to run two batteries with the same altenator and i need to link both batteries together any ideas or pics would be great thanks.......