Fix for Connext Battery Voltage Issue - Confirmed

[dalcini]

Can anyone confirm whether model year 2018 boats are affected by this?

 

[JDRacing]

Yes, I can confirm my 2018 212X had both of these issues discussed on page 1 of this thread (1) the two batteries were tied together as noted in post 1, and I separated them per @Mainah's directions. Worked great. At that point my two batteries were finally reading differential voltages, much closer to accurately.

But they were switched around on the Connext readout--the Sys battery read the Aux voltage and vice versa.

So (2) switching the two wires in the SPU block now has them reading correctly.

Somewhere in this thread or another one posted by @Mainah, the specific 2 wire numbers on the SPU block which need to be swapped to get the Connext voltages readings for the actual battery it says it's reading are noted.

Both were an easy fix once you figure out how to do it.

Jeff

 

[dalcini]

Thanks @JDRacing. Adding this to spring to-do list.

 

[Cambo]

The one thing that I noticed is that the reading is slightly off due to voltage drop in the wiring. When I measure the battery terminals with a volt meter they are a few tenths off than the gauge reading something like .2v to .3v only on the aux voltage. When in float mode listening to music the aux batteries look like they are very low around 12.1v or lower depending on the volume. I have a small laminated chart by the throttles showing voltage vs capacity for a flooded lead acid battery at 11.97 it’s in the yellow 40% capacity. But in reality measuring the battery with the .3 v difference it measures 12.29 that is 70% capacity . Sometimes I want to change it back to not have the false sense of the battery bank being lower than it really is. This will also set off the low battery alarm which leads me to believe that yamaha maybe noticed this and figured out a workaround because they have no calibration for the volt meter to compensate for wiring voltage drop. The perfect example of this voltage drop is that if you have not done the fix and you look at the voltage readings they are not the same. The best part of the switch is you can see the VSR, voltage sensing relay switching and combining the batteries or decoupling them when the boat is running.

 

[dalcini]

Thanks @JDRacing - yeah, I've read this thread a few times and have it bookmarked. I may do this fix next summer.

@Cambo, Those are good points. I downloaded a FLA chart from one of the threads here as well. It makes me think that the cheap 12 volt auxiliary with battery meter might be the best "fix" for the voltage reading issue. False low battery alarms would indeed be bothersome and as you state it only takes a few tenths in some instances.