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Mercruiser VesselView4 - Low Voltage Warning

T

tpenfield

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I have twin Mercruiser 6.2 ECT (350 HP) Seacore Bravo 3 (2016) S/N's 2A4585XX SmartCraft & VesselView4

The Starboard engine has been complaining about 'low voltage' when I turn the ignition key to 'on' and let the SmartCraft stuff boot up. I get the warning as the system 'checks' everything (which I then clear). The engines both start easily and run as they should.

I have checked the batteries for each engine with my multi-meter and they are both at 12.8 - 12.9 volts. I have also checked the engine voltages on the VesselView display and they both show the same, yet only the starboard engine is complaining. The only difference I am seeing is that the multi-meter is showing the batteries at 12.8-12.90 volts, while the VesselView shows the engines both at 12.2 volts. I have probed the connections at the engines with the multi-meter, and they were the same as the batteries

I am not sure what to check next ???

Not sure what the threshold for 'low voltage is' or how I should proceed. It is getting really annoying seeing these warnings and beeps every time I start up.

TIA for any guidance.
 
Quick Update . . .

A few more warnings have come up. I isolated the low voltage warning to a bad trim sender. Currently replacing that. Additional warnings that have come up are 'Critical' low voltage warning (different than the initial low voltage warning) and Wheel fault (I believe steering wheel).

I have ordered the Rinda Diacom stuff that I need to get more data from the engines . . . Already have the PC software, but now need the Merc & CAN connectors along with an upgrade for the USB cable.

The continual beeps are annoying to say the least and I have yet to find a setting or other means of turning the buzzer off. There is an alarm/buzzer in the harness behind the instruments, but even unplugged there are loud beeps . . . they must be coming from somewhere else. Maybe inside the VesselView display itself?

Also, FWIW - I have a solar charging system (similar to shore power) and it has the batteries sitting at a nice 13.7 volts . . . Still getting the 'critical' low voltage alarms, vessel view does not give much detail, so I'll have to wait until the Diacom stuff arrives.
 
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Docksidemarineservices said:
You will be checking the 5v reference circuits when you get your scan tool.... (Power1 and Power 2)
Click to expand...

Thanks for the reply. Yes, my understand (so far) is that there are three 5v circuits, 1 and 2 being 'critical' . . . ? I think the trim sender was on a 'non-critical circuit, but there must be something else causing problems on either '1' or '2'.

I'm just hopeful that the PC software (Laptop actually) will have enough information to isolate the problems. Else, it is still a guessing game.

My previous boat had the MEFI-1 controller, so that was pretty basic. I believe that these engines are the PCM-09 controller (and all the digital goodies that go along with it).
 
OK, quick update . . .

The scanning of the PCM (with Rinda Diacom 3.3.2) showed the 5. volt circuits ( 3 of them) are right on spec at 5.0 volts. The 'system voltage' shows 12.8 volts and the 'battery voltage' shows as 11.5 volts. Not physically possible, so it seems that there is some sort of issue that is causing the battery voltage to show as lower than the system voltage. (see attachment)

Stbd-Voltage-Compare.jpg

The port engine has a similar condition, although the voltage difference is 1.0 volts. Starboard engine is 1.3 volts difference. In reality, the 'system' voltage could not be any higher than the battery voltage, since that is where the system gets its power(i.e. voltage)

The batteries themselves are sitting at 13.7 volts on a charger.

I've Googled a few instances where people had the same issue, but no real solution (yet).

FWIW - I did replace a faulty trim sensor, but it made no difference in the voltage error.
 
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The problem/solution seems to be . . .

Weak house battery. It seems that some of the digital 'Smartstuff' is getting voltage from the house (accessory) in addition to the starboard engine battery.

I connected the house battery to the bank of 4 inverter batteries and the warnings have gone away.

The system does not like voltage sources to be different by more than 1.0 volts, and the weaker battery along with some additional connection issue was resulting in more than 1.0 volts difference between the 2 power sources. I could have connected the house battery to the starboard engine battery (which I did for a while) and solve the problem as well. I decided it would be better to have the house battery not depleting the engine battery if lots of power was used during an outing. The inverter has 4 batteries willing to lend a hand to the house battery.
 
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turn off charger and shore power, put a voltmeter on the battery, engine off, what does it read.
Start the engine, what does it read. If you not reading atleast 13.6 your not charging and the battery charger is hiding the real problem
 
With engines running the voltages are 14.1v. For some reason the boat manufacturer is using both the engine battery voltage and the house battery voltage at different points in the system, which causes the Smartcraft to see it as an issue. (which it may be :D )
 
Update . . .

Just following up on the resolution of the issue. I noticed a couple of things . . .
  • The house battery was a bit weaker than the engine batteries.
  • The clean power CB had a slight voltage drop across it.
So, I exercised the CB and joined the house battery to the bank of 4 inverter batteries.

The engines have been happy ever since. There is still a 1.0 voltage difference from what the PCM 'sees' as the system voltage (higher) vs. the battery voltage, which is 'slightly' impossible :oops: I'm still chasing that mystery

I have the CB on my punch list to replace at some point.
 
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