Why is my battery running low when isolated

[chkm8]

I have 2 110Ah batteries. The isolator switch is the usual off, 1, both, 2.
The instruments eg: vhf, chart plotter are running from switches connected to the fusebox at the dashboard. On leaving the boat the isolator switch was set to off but the switches at the fuse box for the GPS, wipers and stero were in the on position. Altough all the equipment was turned off using the off or power down buttons both batteries were drained flat when I came back just 2 days later. I thought if the instruments were switched off and the isolator switch was at the off position this couldn't happen. I know I cant turn the instruments on unless the isolator is in the on position but there must be a drain somewhere.

 

[JT!]

Re: Why is my battery running low when isolated

either your switch is faulty or your memory is.

if you turn it off, and your equipment is still powered on, i'd say they are still connected to a powersource.

is the switch the only power tap (draw) on the battery?

 

[chkm8]

Re: Why is my battery running low when isolated

The memory can be faulty but I know I had turned the switch to on then on getting into the seat to start the boat saw 2 switches not in the off position. Thought it would be ok as the isolator switch was definatly without a shadow of a doubt unmistakeably in the off position.
This drain has only occured when a switch at the fuse box was left in the on position and never when all turned off. Yes I know the easy answer is to make sure they are all in the off position but I thought thats what the isolator switch was for.
With the isolator in the off position everything appears dead yet why is there a drain when a switch at the fuse box is left in the on position.

 

[JT!]

Re: Why is my battery running low when isolated

double check that that panel absolutely does get power via the battery bank switch, otherwise it may have its own powerfeed.

 

[chkm8]

Re: Why is my battery running low when isolated

Ok thanks for the help

 

[Silvertip]

Re: Why is my battery running low when isolated

Yup -- you can't turn power off to everything if some of it is still getting power from somewhere else. EVERY device on your boat except for the AUTO bilge pump circuit should be connected to the COM (common) terminal on the switch. Then and only then will everything be turned off with the switch is set to OFF. Your fuse/breaker panel very likely has a separate feed from either or both batteries separate from the COM terminal on the switch.

 

[chkm8]

Re: Why is my battery running low when isolated

Thanks. Pretty new to boats only my 2nd season and only have this one about 2mths. Appreciate the help I have learned so much in the last couple of months but enjoying it all so far though a few weeks completly trouble free with lots of sunshine would be great

 

[triumphrick]

Re: Why is my battery running low when isolated

On my boat I found not only the auto bilge but also my marine radio had a direct feed. With the radio on, but the squelch down, I did not realize it had remained on and after a week or so I found both of my batteries low.

An automotive test lamp/probe with an extended ground wire helped me to track all of that down.