Ranger z520L battery drain

[Odomsauce]

So i have a 2020 Z520L with Merc 4 stroke v8 and my cranking battery (interstate 31 AGM) is getting drained quickly. I know there must be some sort of constant drain on it even when i am not using the boat because my on board dual pro battery charger constantly kicks on and off charging the cranking battery. The trolling batteries get to full and stay there. I have added a seaclear power harness with a power shutoff switch to all of my electronics on the boat and the drain is still occurring.

I can literally unplug my charger with the cranking battery on green 100% and in the morning plug the charger back in and the battery is on 60%.

Not sure how to locate the issue please help

[hanker71]

are you not turning the power off with the isolation switch?

[Rip Bass]

Lots of add ons will draw current without using a power switch,power poles being one of them.

[C&OcharlieJr]

I know it sounds trivial, but also the battery charge gauge on the outside ( if equipped ) is a constant draw even if the boat power is turned off. It doesn't sound like much, but I've seen it take a hot battery to completely dead in about 2 days.

[Zpilot]

Like mentioned many items draw current. Do you have a point one on your boat that is not switched? What I did is install a perko on/off switch on the positive lead from the cranking battery, shuts everything off.

[rangerjignpig]

I have the exact same problem on a 2020 Z521L. Mine charges full and i unplug it and by the next day the battery is at 12.2 volts and 60%. i think my battery is bad. All the power is turned off by the switch in the back of the boat. I doubt the Battery Fuel gauge would run it down that much.

[wmitch2]

Well, 2 things come to mind. ONE, you should have only the things you WANT to draw current hooked directly to the battery. The big motor, and the Auto Bilge pump is what I run. Then, run a 6 gauge wire from the POS of the Battery to a cut off switch, and then hook the rest of the POS wires to the other side of the switch. Now, with the cut off switch there should be nothing to draw any current from the battery. Second, you can check which accessory is drawing current as you are set up currently with the use of a Test Light. Ground the Test Light to the ground connection of the Starting Battery. You'll probably need a piece of wire to extend this so you can reach the fuse panel with the Light Probe. Now, touch each hot side of the fuse with the Point of the Light Probe. The one/ones that light the probe is drawing current.

[munchie]

Do you have power poles. They can have a small draw of not going to sleep quick enough

[Iowabass3826]

As many have mentioned it’s likely all the accessories, antennas, graphs, etc drawing power. Your best bet is to install a disconnect switch on the positive cable when not in use.

[blkfalc4]

The Merc's 'clean power' connection being disconnected when utilizing the main disconnect?
Only thing that constant power on my rig is the auto bilge when the main is off. Wired my previous 519vx the same way.