Voltage Leak - 2006 Nautique 226 LE

[Rusty Axle]

I appear to have a mystery voltage leak.

I have been leaving the master switch in the "All Off' position while the boat is on the lift.

However, I had to be towed in recently due to a low battery after maybe 1 hour of bobbing around with the engine off and radio on.

An Optima battery was installed in 2024. The stereo is the factory setup. The alternator puts out 14V at idle.

The first thing I looked for was extra wires attached to the battery that might be bypassing the master switch.

There is a 10 gauge wire on the positive and negative posts.

I disconnected the wire from the positive post and place a voltage meter between it and the battery terminal.

With the master switch in the "All Off" position, 11 volts were passing through the wire.

Thinking that I could identify (by lack of function) what component was on the circuit, I left the wire disconnected, set the master switch to "All On" and attempted to enter the code and bring the electrical system to life.

The code panel had no power. The engine compartment exhaust fan did not power on. The 10 gauge wire apparently supplies current to the entire boat electrical system.

So the mystery is why an 11V drain with the master switch in the "All Off" position. I would assume that there should be no current flow from the battery when the master switch is in the "All Off" position?

There is a circuit breaker panel in the foot well area beneath the instrument cluster. There is another circuit breaker panel in the rear starboard storage compartment next to the engine.

My initial thought is to set the master switch to "All Off", pull the panels and use the wire contacts on back to check for current flow. I would run a ground from the battery and test the connector on the back of each circuit breaker for voltage flow with the voltage meter. Will that work, or is there another method that I should try?

Expertise on how to track this down would be appreciated.

[TechBeer]

I'm assuming you only have 1 battery, and your battery switch is just "on or off"? Do you also have the toggle switch under the dash that has 3 positions (Auto Bilge / OFF / ON)?

When you remove the 10AWG wire and measure the voltage between the battery and the end the wire you read 11V correct? So in reality you have a ~1V drop between the end of the wire and ground (?). A better test would be to put an ammeter (current) between the positive battery terminal and the end of the wire. Be careful though, if there is significant current you might get a spark. But knowing that current level will be a significant clue. With nothing running on the boat I would expect <<100mA.

Let us know.

[Rusty Axle]

Techbeer! The man! My gauges have been working beautifully since your repair.

I have one battery.

I've never found a battery switch.

The 3 -position toggle is beneath the gear/throttle lever, and is the switch referenced in the initial post.



I have a couple meters and results of both are attached. I couldn't get the Craftsman unit to measure amps.

[Rusty Axle]

The first set of pictures is with the 3-position switch in the "All Off" position.

Here's pics with the switch in the "All On" position.

[Rusty Axle]

In both cases the electrical system is off. The code has not been entered into the dash keyboard to turn the electrical system on.

[SilentSeven]

Maybe just a few things that might help....dunno...

At the battery, the 10 gauge positive wire is the main dash power. The dash power is controlled first by the 3 position switch. Once the 3 position set is set to 'on', the keypad and PME are powered. Once the keypad is unlocked with the correct code, buttons on the keypad send a signal to the PME to turn on/off each individual circuit (blower, horn, ballast, lights, etc). Think of the PME as a switching unit controlled by the dash pad. The thick positive cable goes to the starter solenoid. I can't recall how the engine harness is switched on - maybe someone here knows if it's via main positive cable or via the PME unit.

If you believe the battery is draining it's likely one of these items.

1 / bad battery. Won't hold a charge over time. Even new batteries can have issues. Have your battery load tested at an autoparts store.
2 / charging system problem. Not likely your problem if you have over 13.7v when the engine is running.
3 / current leak. Something is consuming power even when the switches are off.

A common source of a current leak is an accessory that's been wired into the positive 10 gauge feed prior to the 3 position switch....typically a stereo item like an aftermarket amp or bluetooth adapter, etc. As TechBeer described, you'll need a connect a meter with amperage measuring ability inline to the positive feed to see if you have a current leak.

Your Craftsman meter is supposed to be able to measure up to 10amps DC current. (Not familiar with the GB meter...looks like it does amps as well). If it's not working, open the back and see if the internal fuse is blown. That's the common problem when a meter won't measure amps. I typically start with the 'amps' setting before going switching down to 'milliamps'. You likely need to set the plugs into specific sockets on the meter; the manual will tell you which.

[Rusty Axle]

Thank you, SilentSeven, very helpful.

The battery load test rules out the battery, it is fine.

I pulled the fuse for the factory stereo receiver, the stereo amp and also the bluetooth receiver. I tested the individual power and ground wires for each. There was no power at any of the devices with the 3-position switch in the "All Off" position.

With all stereo fuses pulled and the 3-position switch in the "All Off" setting, testing from the positive battery pole to the 10 gauge red wire that feeds the control panel, the current draw is still there. So the issue does not appear to be related to the audio system.

There is a small dome for the Sirius satellite radio antenna, but that is wired into the stereo system which has no power.




There is a circuit breaker panel in the footwell under the dash:







The backside shows the red 10 gauge wire incoming and the black 10 gauge ground wire, and also a relay switch above on the right.



With the 3-position switch in the "All Off" position, there is no voltage to the circuit breaker box, based on testing the positive and negative terminals on the box.

With the 3-position switch in the "All On" position, there are 12.4 volts to the circuit breaker box. So everything appears to be in order there.





There is a 2nd circuit breaker box in the rear starboard storage compartment next to the motor.




Here's the backside as best as I could get. The 10 gauge wires are there. I'd like to think that this unit is downstream of the 3-position switch as well. The wiring loom is tight, and I've not tested anything on it as the degree of difficulty associated is going to be high for a 6' 1" 270 pounder. The boat is the "LE" model and there are no ballast pumps.





So the issue remains. With the 3-position switch in the "All Off" position, there is a voltage leak. I can get a visible spark when touching the red 10 gauge wire to the positive battery terminal.

The original owner had new carpet installed by the dealer. But even if the positive wire was damaged during that process, what are the odds that it could it make a ground connection back to the battery? And it seems there would be associated smoke and sparks.

Could the 3-position switch have an issue?

The 10 gauge wire runs under the floor from the battery so there's no visibility beyond the battery area and the circuit breaker boxes.

Not sure where to go from here.

[SilentSeven]

PME = the circuit breaker box in the first picture. https://nautiqueparts.com/breaker-bo...ct-year-model/

Here's a 4 minute video on how to find a current leak - https://www.youtube.com/watch?v=aR4uKca38bk There are lots of others as well.

You want to test current, not voltage.

[Rusty Axle]

Fuse replaced on the meter (it was blown) and the meter configured to measure current with the 10 Amp DC plug and dial setting per the manual.

The meter reads zero when placed between the red 10 gauge wire and the battery positive terminal when the 3 position switch is in "All Off" an also the "All On" position.

With the meter in place I'm unable to enter the dash code and bring the electrical system to life, so no ability to measure current draw on the live system.

The alternator shows 14+ volts at idle via the dash gauge. The Optima battery is one year old and tests fine. The stereo is OEM with no power-robbing subwoofer/amp.

Why I had to be towed in after approximately an hour with the stereo on at low volume remains a mystery, as I've been out for multiple hours before and never had an issue.

Next thing I'll do is try to recreate the issue by leaving the boat on the lift with the electrical system active and the stereo on for a couple hours to see if starting is an issue.

[SilentSeven]

Sounds like progress.

The meter reads zero when placed between the red 10 gauge wire and the battery positive terminal when the 3 position switch is in "All Off" an also the "All On" position.

Did you step down to the milliamp setting after starting at the 10amp setting? You'll want to do this just to see if you have a very small draw. That said, a zero reading suggests no phantom draw on that circuit.

Next thing I'll do is try to recreate the issue by leaving the boat on the lift with the electrical system active and the stereo on for a couple hours to see if starting is an issue.

This seems like a good idea.

Question - when you had to be towed in, did the boat fail to start but the stereo keep operating? In other words, you had power but just not enough to start the boat? If this is true, look at how clean your battery posts and cable ends are. Also check the connection on your postive post on the starter solenoid and where the ground strap bolts to the engine. A poor connection will conduct sufficient current to run small items (stereo) while preventing large current items (a starter) from operating.

[TechBeer]

I'm glad I took a few days off because SilentSeven is all over it. I don't have too much more to add. A few things on DVMs (meters). The "GB" meter has an "unfused" 10A setting which means there is no fuse for that connection. Also meaning that if you push MORE than 10 Amps through the meter you will likely blow up the meter, so be careful. I don't "think" the starter current runs through that wire, but if it does you will blow up your meter if you tried to start the boat. The fuse only applies to the 2A setting, more than 2A and the fuse will blow and you'll have to replace it again. The Craftsman has 2 fuses, one for 10A and another for 200mA. I can't tell from the thread which meter you used for the current measurements. Maybe I missed it.

You should be able to put the current meter in-line with the battery and 10AWG wire. With the toggle switch in the "ON" position you should be able to measure SOME current. Otherwise you don't have a good connection with the meter (or the meter fuse is blown). With nothing on I would think a few mA. You should be able to turn the ignition on via the keypad with the meter in place. If not you have a connection problem again. Once you have this good meter connection you can measure a few things: 1) current with nothing on, 2) current with the ignition on (do NOT start it), 3) current with the radio on, 4) current with other accessories on. This is the key information that SilentSeven and I are looking for.

I have also heard about issues with grounding in these boats. Unlike a car, you are completely reliant on big fat black wires to supply the return ground. A high resistance in the ground return wire might cause weird things.

[Rusty Axle]

Fuses were blown in both meters. I was able to find a 2 amp fuse for the GB meter. The Craftsman requires a 0.2 amp fuse so those will arrive in a few days.

My meters have only probe ends so possibly that's why I can't activate the electrical system? I'll see what I can figure out on that.

Battery and starter cable connections are super clean and tight.

I left the boat on the lift with the electrical system active and the radio on for 3 hours. Boat started without issue.

With the meter in-line between the positive terminal and the 10 gauge wire, and using the 200m DC amp setting I get a 167.4 reading when the 3-position switch is in "All Off" and also when it is the "All On" position.





The front circuit breaker box has no voltage to the 10 gauge connections when the 3-position switch is in the "All Off" position. When the 3-position switch is flipped to "All On" there are 12+ volts to the box.



There is a circuit breaker box in the starboard rear storage compartment next to the motor. Using the positive and ground 10 gauge connections in the box, it shows 12+ volts when the 3-position switch is in the "All Off" (unexpected) and also the "All On" position. The boat is a 226 "LE" model so there are no ballast pumps.




That's what I have for the moment. Boat is going on the trailer this weekend to prep for storage.