Mercury Pro XS 200 V8 4 Stroke Observed Fault

[1Holeshot]

I went fishing for a few hours and ran two graphs and 1 live well. When I finished and cranked up to leave my Vessel View Mobile displayed a fault:

Critical-Low Voltage

Return to port immediately-Turn off unnecessary loads and check battery connections

I did not think the electronics and live well pumps would pull my AGM cranking battery down to the point of throwing a code.

Have anyone with the new 4.6 V8 Mercs had this problem?

You would think the larger alternator on these engines could keep the battery up since I ran about 30 minutes to my first stop and then another half hour returning to launch.

[EuropeanAM]

Check voltage at the battery with the engine running.

Alternator can only produce so much- excessive loads require the engine run more often, or for longer.

[mdtritn21]

What size battery cranking battery does it have?

[1Holeshot]

Check voltage at the battery with the engine running.

Alternator can only produce so much- excessive loads require the engine run more often, or for longer.

Thank you Don, I have ordered a separate charger to top my battery off after each trip in case I used more juice than alternator replaced.

[1Holeshot]

What size battery cranking battery does it have?

Boat is at marina right now and I can't recall but remember verifying in the past that it is an AGM with recommended capacity and is only four months old.

[DaveTTN]

A separate charger? Did yours not come with a 3 bank?

[TritonTRXV8]

A separate charger? Did yours not come with a 3 bank?

2 bank is standard. I had to order mine with a 3 bank charger. Charging the cranking battery is important the alternator is generally not enough with all the accessories we run today. Most of the time the cranking battery is the last to fully charge on our boat when we plug it in.

[DaveTTN]

Ok mine has a 3 bank. Yeah no way the cranking battery will maintain charge just from the motor.

[1Holeshot]

My 18 TRX was an instock show room model with the standard 2 bank charger. Ordered a 1 bank charger after the fault code just for the cranking battery.

[Shortbus17]

Make sure the wires to cranking battery are tight. If the nuts come loose might cause your problem.

[1Holeshot]

Make sure the wires to cranking battery are tight. If the nuts come loose might cause your problem.

Thank you. Will check Friday when I go to marina.

[1Holeshot]

Update: I charged my cranking battery Friday PM and fished all day Saturday with no issues.

Thanks to Don and others who pointed me in the right direction.