"Critical Voltage" Fault and steady alarm

onislandtime

Received a steady alarm on my Rinker 342 starboard engine. Looking up in mercruiser guide for alarms, Its caused by Battery Voltage being low. Does that mean bad battery or alternator? Any one have insite on this Fault and if Battery why show the fault on the starboard engine? I confirmed its coming from the starboard engine cause when I shut down the engine the alarm goes away. I received the fault through VVM (vessel view moblie). The fault read "return to port immediately critical low voltage. 

Stodge

A bad ground cable can cause all kinds of chaos.

Autodog61

Id check the alternator.  Measure the voltage at rest, should be around 12.7 to 12.9ish.  Start the engine and voltage should go to 13.5ish or higher.  Anything less might be a poorly charging alternator.  Run some accessories too while checking with it running.  A/C, refrig., stereo, blender, etc.  If its not the alternator, are the batteries old?  Have them load tested.  As noted too, a bad ground, ughh.  These can be hard to find. 

onislandtime

Battery 2013 lol. Took it off battery charger, it's at 12.3, I will leave it for a day and see if it holds a charge

Dream_Inn

Well, I will say if I get 5 good years from a battery, it usually comes out after that.  6 years and you are pushing for bad luck.  Not sure what you do in the winter, but at this point it may be worth waiting until spring to put a new one in.  

Spyderweb

@Dream_Inn Regarding battery life, are you guys talking starting batteries, house, or both?

Dream_Inn

@spyderweb really it applies to both batteries, but for me, it's more the house.  For starter batteries, I can switch to emergency and get the engines started and get home.  For house batteries, if I'm out anchored and having issues, it blows my weekend anchored out.  So, for house, I won't go past 5 years even if they look ok.  Starters, I may go longer but change out immediately at first sign of issues.  I am curious this time around because, for the first time, I have all AGM batteries (& tppl for house).  So, maybe they'll last longer?  I also thought for the tppl batteries that they could last longer as well?

Autodog61

I Switched to Optima blue top (AGM-absorbed glass mat for those curious) and I expect to get 7 years or more.  Especially given I have a smart charger through shore power over the winter.  Although the Optima's aren't as good since Johnson Controls took over and moved the operations to Mexico, If I were to buy again, I would buy Odyssey (word is a bunch of Optima guys jumped ship when JC took over and went to Odyssey) for both starting and shore power.  If you stay up on maintenance (trickle charge or shore power charge while on the hook, keep up on fluid top off, keep corrosion away, etc) of lead acids (and they are good quality ones; yes, that means spending coin not cheaping out) I would think 5 years is minimum.