Fix for Connext Battery Voltage Issue - Confirmed

[JDRacing]

So while looking at the sensor wire I noticed a disconnected cord just hanging out...it looks like it comes from the stern of the boat. Should like be connected to the negative of the House battery?

I can't see where that cable goes to from your picture, but there is a single cable that is supposed to connect the two negative terminals of the two batteries together. I think that might be it. It looks from your picture like that cable is attached to one of the negative terminals. I think the other end goes to the negative terninal on the other battery.

 

[JDRacing]

And it looks like my boat is setup just like yours. The Aux Bat cable runs from the Aux battery, towards the house switch then jumps to another loom that goes back into the engine bay. It looks like it skips the house switch all together.

Edit: Maybe it’s not setup like yours if it’s completely skipping the house switch. But if that’s the case, where the heck is it going??

Can't really tell from the pictures, and without a meter. It's been awhile since I did mine and am not certain it ran through the house switch. From what I can see in the picture it looks like the correct wire.

I think you are down to cutting that wire to see if the "SYS" voltage readout goes to zero. That will tell you for sure. Assuming it goes to zero, then splice a new wire onto it and run it to the other battery.

EDIT: In thinking about this a bit more, and for clarity/completeness sake, I believe that cutting the "Aux Bat" at the wire would make the "Aux" readout on the Connext go to zero volts. Once that wire is hooked up to the starter battery, each battery will have its own readout on the Connext, but they will be reversed, unless you swap the wires at the SPU plug as @Mainah described earlier in this thread.

Jeff

 

[Nfinlay1]

Can't really tell from the pictures, and without a meter. It's been awhile since I did mine and am not certain it ran through the house switch. From what I can see in the picture it looks like the correct wire.

I think you are down to cutting that wire to see if the "SYS" voltage readout goes to zero. That will tell you for sure. Assuming it goes to zero, then splice a new wire onto it and run it to the other battery.

Jeff

I’m gonna have to get a buddy who is a bit more experienced with electrical wiring to help me. I am assuming that’s the wire though.

 

[Nfinlay1]

Can't really tell from the pictures, and without a meter. It's been awhile since I did mine and am not certain it ran through the house switch. From what I can see in the picture it looks like the correct wire.

I think you are down to cutting that wire to see if the "SYS" voltage readout goes to zero. That will tell you for sure. Assuming it goes to zero, then splice a new wire onto it and run it to the other battery.

Jeff

I can't see where that cable goes to from your picture, but there is a single cable that is supposed to connect the two negative terminals of the two batteries together. I think that might be it. It looks from your picture like that cable is attached to one of the negative terminals. I think the other end goes to the negative terninal on the other battery.

There were 3 wires connected to the negative post on my start battery. Two with the plastic looms around them and those feed back into the stern of the boat. The wire with the smooth casing connects the two negative terminals. No clue what the two that go back deep into the stern do

 

[Nfinlay1]

Can't really tell from the pictures, and without a meter. It's been awhile since I did mine and am not certain it ran through the house switch. From what I can see in the picture it looks like the correct wire.

I think you are down to cutting that wire to see if the "SYS" voltage readout goes to zero. That will tell you for sure. Assuming it goes to zero, then splice a new wire onto it and run it to the other battery.

Jeff

Well I couldn’t sleep last night, spent all night thinking about batteries and this tiny ass wire. I finally decided to grow some balls and cut the wire...spliced in a small section of new wire and hooked it into the starter battery. I now have two separate battery readings!!!

 

[Cambo]

Are they the correct readings for the system and Auxillery ? I think yamaha messed up the wiring harness but in a previous post I showed how to swap the pins someone else mentioned this but I clarified it . The way to tell is watch the voltage drop when you start the motor . I think you will see the auxiliary drop with the way its set up . The pin swap is easy I clarified it some of the details and that positive wire should have a fuse.

 

[Nfinlay1]

Are they the correct readings for the system and Auxillery ? I think yamaha messed up the wiring harness but in a previous post I showed how to swap the pins someone else mentioned this but I clarified it . The way to tell is watch the voltage drop when you start the motor . I think you will see the auxiliary drop with the way its set up . The pin swap is easy I clarified it some of the details and that positive wire should have a fuse.

I tested everything with a multi meter and it all checked out. Been floating all day and my Start battery is just chilling. Super stoked

edit: I didn’t do the pin swap. I’m ok with understanding that my Aux is my Starter.

 

[Pullen724]

I tested everything with a multi meter and it all checked out. Been floating all day and my Start battery is just chilling. Super stoked

edit: I didn’t do the pin swap. I’m ok with understanding that my Aux is my Starter.

I was super nervous (and put off for a while) doing the pin swap but my OCD had to have this fixed the right way. It is extremely easy and just takes a few minutes to swap them once you identify the two wires which is pretty easy too.

 

[Nfinlay1]

I was super nervous (and put off for a while) doing the pin swap but my OCD had to have this fixed the right way. It is extremely easy and just takes a few minutes to swap them once you identify the two wires which is pretty easy too.

Guess Im not sleeping tonight either...I need to stop reading the boards before bed

 

[JDRacing]

If it helps you sleep better, I can attest to the fact that you've already successfully completed the hard part of this project.

Jeff

 

[props2you]

Due to some electrical gremlins, I went ahead and did this battery voltage mod.

Took me a bit to wrap my head around what exactly was happening with this but, once understood it's a simple mod and took under 10 minutes, now I'll be able to actually see the voltage of the System (start batt) and Aux (house batts) accurately. Previously the batts were reading the same and not truly separate.


Pre battery mod

Clipped aux wire near power switches:

Aux wired to starting battery: Depending on your preferences you can leave it this way or flip the wires at the SPU. I prefer house batts as AUX and starting batt as SYS.

Switched wires at the SPU and now AUX are the house batts and the SYS is the starting batt.

 

[Cambo]

Great job mine is done as well in your last picture it shows SYS at 12.8V and aux at 12.5V . What I noticed there is some type of voltage drop or off calibration in the reading, most likely off calibration in the AUX voltage not huge but about .3 volts low . Are you seeing the same thing I wonder if there is some type of calibration available. This is with all items off I have two meters one on an eq and one by the amps and they read a higher voltage all wired to the aux line and probed with a meter . Some members have been saying they get some issues with low battery alarms , maybe the Aux does not throw the alarm if it gets low and the bad calibration paired with a battery that is lower but still viable throws the alarm on the system if the pins are not swapped you can see in your second to last picture , so this is another reason to swap the pins

 

[props2you]

Great job mine is done as well in your last picture it shows SYS at 12.8V and aux at 12.5V . What I noticed there is some type of voltage drop or off calibration in the reading, most likely off calibration in the AUX voltage not huge but about .3 volts low . Are you seeing the same thing I wonder if there is some type of calibration available. This is with all items off I have two meters one on an eq and one by the amps and they read a higher voltage all wired to the aux line and probed with a meter . Some members have been saying they get some issues with low battery alarms , maybe the Aux does not throw the alarm if it gets low and the bad calibration paired with a battery that is lower but still viable throws the alarm on the system if the pins are not swapped you can see in your second to last picture , so this is another reason to swap the pins

During the pic I actually had the volume up to see, in fact that it was drawing from the correct source. I believe the OEM set up was designed to be the SYS as the start and the AUX as the house, so if there is other programming based on that, I could see that being an issue if you left them swapped.

I was previously having issues with this and decided this mod needed to be done to help clarify a potential issue. Here is the thread to my issue https://jetboaters.net/threads/👀-redundant-port-engine-issue-limited-rpm.27069/#post-450293

 

[Brian McIver]

This is a long and interesting thread. However my question just to clarify is this. By design the DVSM parallels (connects in parallel) the starting and house batteries when it detects charging voltage (engines running) after a 5 second delay which will show nearly identical voltage readouts on the connext for both batteries. When the DVSM detects the batteries aren’t being charged (engines off and I’m assuming float mode) after a 20 second delay it will uncouple the batteries. So, by design shouldn’t the connext readings be accurate with the engines off or in float mode? Or is the contention after all the experimentation that the way the DVSM is wired into the system or the SPU’s own internal circuitry the root of all the false voltage readouts?

 

[Neutron]

This is a long and interesting thread. However my question just to clarify is this. By design the DVSM parallels (connects in parallel) the starting and house batteries when it detects charging voltage (engines running) after a 5 second delay which will show nearly identical voltage readouts on the connext for both batteries. When the DVSM detects the batteries aren’t being charged (engines off and I’m assuming float mode) after a 20 second delay it will uncouple the batteries. So, by design shouldn’t the connext readings be accurate with the engines off or in float mode? Or is the contention after all the experimentation that the way the DVSM is wired into the system or the SPU’s own internal circuitry the root of all the false voltage readouts?

The dvsm is completely out of the picture when the the voltage drops below the threshold that activates it.
The connext will always show identical voltage all of the time before this mod is performed. The connext voltage issue is a completely different system.
The dvsm is only activated when voltage goes above the activation threshold(forget what it is) even with the engines running, both batteries will most likely have seperate voltages depending on battery drain prior to running.

There is a seperate mod to isolate each battery to charge separately on a seperate bank charger. That mod will only activate the dvsr when there is ignition voltage.

 

[Brian McIver]

The dvsm is completely out of the picture when the the voltage drops below the threshold that activates it.

Not exactly. It’s still connected to the hot side of each battery switch and it grounded. It draws (without the cut loop mod) about 2 mA at all times. I was curious if the system got battery voltages through it or the SPU.

The connext will always show identical voltage all of the time before this mod is performed. The connext voltage issue is a completely different system.

Well, my connext in float mode will show battery voltage on the house battery lower than system/start battery. This is what has me confused.

The dvsm is only activated when voltage goes above the activation threshold(forget what it is) even with the engines running, both batteries will most likely have seperate voltages depending on battery drain prior to running.

Agreed.

There is a seperate mod to isolate each battery to charge separately on a seperate bank charger. That mod will only activate the dvsr when there is ignition voltage.

This is what I’m getting at. Does each engine stator output go separately to the individual batteries (which doesn't make sense because it would make having a DVSM pointless. I assume they parallel out of both engines then to the DVSM to the STARTING battery, and then after the 5 second delay also the House battery through the DVSM. You say there’s a mod completely removing the DVSM to isolate charging from each engine? Boy a system schematic of the charging system would clear a lot up. Haven’t found more than a basic diagram.

 

[Brian McIver]

And that didn’t copy like I thought. Sorry everyone, you’ll have to do a literal reading between the lines

 

[Brian McIver]

I

View attachment 48747 There is a black box with two large wire packs under the starboard rear seat known as a gateway. This is the device that allows the Connext screen to control the bilge, lights, etc by communicating with Connext screen over the N2k network. The wire pack on the left contains the two voltage sensing wires. The are both red and one is labeled SYS BATT and the other is labeled AUX BATT. The issue is that they have continuity courtesy of the SPU. So if you clip the SYS BATT wire and run a direct wire from the start battery switch to the SYS BATT wire on the gateway (cover the end coming from the SPU) and do the same for the AUX BATT to the house battery this should kind of fix the issue ... read on for more before doing this.

In the stock set up you will almost always read nearly the same voltage because of the DVSR. The DVSR keeps the batteries connected in the stock configuration even after the motors are off for quite some time. If you have done the cut the DVSR red loop mod and are triggering the DVSR only when the engines are running with the engine on wire then the voltage fix will be a bit more worthwhile. Even then once the DVSR engages you will be getting nearly the same voltage for both. The next issue is latent surface charge voltage. Unless you have something to draw just a bit of power off the batteries after they have been charging they will continue to show the surface charge voltage. The stereo takes care of this for the house battery but there is nothing to take care of this for the start battery. Just reading the voltage through Connext draws so little amperage (milli amps) that the surface charge remains for some time.

All of that said this mod would help anyone to diagnose a low voltage condition it just won't be the most accurate after charging.

Update - @swatski has done this mod and posted proof on page 2 of this thread.

Update 2 - Added quick graphic how to due to questions that I have received.

understand this 100%. I get how the DVSR works and when and how it ties the batteries for charging, and when and how it disconnects them after engine shutdown. I get how the connext would show similar and different voltages when the DVSR is doing it’s thing. Now, does anyone know what is going on in the SPU to give readings different from a direct line to each battery? Has only one measured voltage into the SPU and found if there is a difference between that and the battery voltage? Does the SPU output voltage match the Connext display? Has anyone considered line loss of voltage through all the wiring, SPU and Gateway?

 

[Brian McIver]

This TOTALLY doesn’t surprise me. There have been so many manufacturing blunders with my boat, it’s completely clear that Pot smokers are being gainfully employed at Yamaha. I’m certainly going to check this out.

So everyone I went and looked and the lead coming out of my switch for the house battery had a second wire with it. I took apart the battery switch and swapped the leads for the house and start batteries. Sadly this is how it was labeled so it looks like it was installed wrong. Hooked everything back up and poof I now have two different readings. Did not have to cut, splice or change anything else at all. Hope others have the same luck.

 

[Five Faces]

What gauge wire is everyone using to extend the sensing wire?