aux battery manual override

Excellent system. Not that hard to wire up either.The problem is finding a place for the switch.
Make sure your spark puts a fuseable link on the aux battery aswell (just like the main battery system was designed) and secure the wires as much as possible.
Andrew wheredayathinkwer mike?

You'll probably find that you'll leave the batteries connected all the time. This is good, as it doubles the battery capacity when starting the vehicle, and there is less strain on the batteries. In the ideal world, use identical batteries.

I'd only be separating the batteries if camped more than one night.

Phil

An excellent idea INMHO, and very cost effective. Wire up in parallel using battery cable with a marine type isolating switch.
I've never really been convinced anything more is necessary ... as long as you remember to isolate the second battery when needed.Rosco

another good way , is to use a solinoid or relay swith, and use a ignition wire to activate it . When you turn the ignition all or the vehicle is running , both batteries are connected , when you turn the ignition off , one battery automaticly isolates . That's the way i have set up mine anyway , I used the relay instead of the solinoid due to te fact that it could handle more amps.Venus Bay

For the last 9 yrs. I have used a Bosch Marine isolating solenoid cat. no. 0332 002156-805 This is designed to connect through the alternator field or ign. switch and can be manually overridden. Although very compact it is rated at 75amp. cont. has never given any problem. The box comes with wiring diagram.
Hope this some help
cheers haze

Probably the best system to use, as it can easily be over ridden if the sitch fails
I dont trust electronic voltage sensors, especially travelling in remote areas.
When you camp you can physically isolate your starting battery, run your fridge off the auxillary. Your starting batterey will always be charged, switch over in the morning and when started isolate the starting battery and let the alternator put full charge into the auxillary battery.

heres a thought!... I use a solenoid arrangement and I find that sometimes when the truck isn't running enough per day to fully charge both batteries, eventually the starting battery gets "dragged down" at startup by the second battery.. this is cured by a normally closed momentary push switch on the "control" line... I.E the momentary switch is pushed at startup...holding the solenoid "open" till the engine is running, then released to put the second battery in circuit.