2008 Range 25SC Batteries discharging

[north25]

We have 3 12vdc battery groups: Starting, House ( 2 12vdc batteries in parallel), and the Thruster Battery. So with the Main DC supply switch in the OFF position, the Staring and House batteries with discharge through some unknown leakage circuit. The Blue Sea DC panel always shows the dc voltage in all 3 DC panel meter positions even with Master Switch OFF. Is this normal? We cannot turn OFF the panel DC meter. I would think the DC panel meter could slowly discharge the batteries if always in the left in the circuit. We are trying to find the DC leakage path. We have replaced the groups of batteries.Help.

 

[knotflying]

I doubt the volt meter is the cause of your discharge. It seems odd that your engine battery and house battery are discharging simultaneously. You need to check your wiring and make sure that they are isolated from one another. Make sure your parallel switch is in the off position. The engine battery should only be powering the starter motor. You have to do a bit of detective work here. Turn everything off including things that are always on, like your CO detector. Hook up an ammeter in series between the positive terminal on the battery and the battery cable and you should have no draw. If you do have a draw start to pull one fuse at a time and see what fuse pulled stops the draw. It is a long tedious process, but eventually you should find the culprit.
The other possibility is bad batteries. This is an easier problem to resolve and I would do this first. Make sure that the batteries are fully charged. Let them rest a few hours and then bring them to an auto store like Napa and have them do a load test.
let us know how you make out.

 

[Andrew Custis]

There are going to be hot powered devices such as bilge pumps, carbon monoxide detectors (if equipped) and whatever else is added direct to the battery with an inline fuse. What I would do is use a clamp meter and go around each positive wire at the battery to start narrowing down what could be the cause. You could also put a ground switch in and kill power to everything leading off the batteries but might take some reconfiguring of your wiring to do this. Not knowing what has been changed or added to the boat over the years you might also think about hiring an electrician to sort out what is going on.

Thank you,

 

[doke01]

Agree with all of the above. Check all of your negative leads are secured properly. I forgot to reconnect one once and was getting really strange leakage issues.