Optimax, Smartcraft battery warning question

[phayward]

My Port motor shows a battery warning about a minute after I start planing. Comes up every 30 seconds or so. Engines start fine and run at low rpm with no warning. I have replaced both batteries. Guages showed 10.8 - 11.8 volts before and after the batteries were replaced and the warning was coming up. Same warning only on port motor regardles if it is running off battery one or two. Does this mean I have a bad alternator on the port motor? Possible wiring problem or short? I'll take any sugestions. I live in the caribbean so I have limited options for getting work done.

[Glen E]

not sure what's doing it but your batts are way too low - and opti's don't like that:

State of Charge 12 Volt battery Volts per Cell
100% --- 12.7 2.12
90% --- 12.5 2.08
80% --- 12.42 2.07
70% --- 12.32 2.05
60% --- 12.20 2.03
50% --- 12.06 2.01
40%--- 11.9 1.98

[fishcop]

Hey Glen would bigger batteries be better? I think I had a friend with optie's have a similar problem, I think he added another battery to the mix and went up in group size. Does this sound right? I can call him tomorrow and check.

[Glen E]

it realy does not matter how many batts you have, if they are bad, as his are....I ran two sets of twin optis with two std flooded 1000 MCA starting batts with no problems for 5 years but they were always at least 90% charged....

[Snowwolfe]

Does using two batteries smaller than 1000 MCA, say, two with 750 MCA make up for not having one with at least 1000 MCA?

[MakoMyDay]

What's the voltage read when the engine is running? If it's under 13V then the alternator is on the fritz