dual battery dramas

[Captain Datto]

Got a dual battery set up in the GQ, nothing fancy, bit of cable between them with a manual switch. Everything is powered off the main battery, if I turn the switch off it osolates the second battery. I usually leave it on, just turn it off of I'm parked with the radio on.

Is this a bad set up or something? Had the car 18 months, the second battery died soon after I got it. Left it disconnected, replaced it after a while. Main battery died about 2 months ago. Drove the car on Saturday, started fine. Went to start it Sunday night and it's dead. Alternator is working fine. If i jump it, drive around for a while then turn it off it'll start right away, just doesn't want to hold charge over night.

[chimpboy]

I can't think of anything in the set-up you've described that would be prone to killing batteries.

Obviously you may have a problem, but a cable between the batteries/manual switch set-up would not, in itself, cause it.

[-Scott-]

I know this won't really help, but there is a (small) possibility that you've just had some bad luck - two old batteries died, then your replacement main was a dud? It does happen occasionally.

Presuming you can replace the current dud under warranty, just replace it and see what happens. If you have a multimeter it may be a good idea to monitor battery voltages for a while - check when you get home, just after a run, then again first thing, before you start.

If the morning voltage is below 12.6 I would suspect a problem. If it's always 12.6 or above, I would blame a dud battery.

[Captain Datto]

I think I've actually overlooked something really simple. Turns out my fold up DVD screen had turned itself on, it did this a bit when I first got the car but hadn't played up since. Turned it off yesterday, started up first shot this morning. I've only used it once since I got the car so I'll just rip the stupid thing out. Next time I won't be too lazy to check current draw.