400: Does My Generator Charge Stating Batteries?

[AZ_Zoner]

I'm away from my boat and just received a msg that my starting batteries are running a low voltage and will not crank the engines. Will starting the generator charge the starting batteries?

We've only owned the boat a few months so not up on everything yet.

thanks,

Craig

[TurninTurtle]

Depends on how the electrical system is set up...
So many ways to do it and it depends on who made the boat, how old the boat is and what changes have been done over the years.

The way to check is to voltage test the starting battery with everything off, then start the generator and test voltage at the starting battery. If the results are the same, you aren't charging.

If not, you can get the wiring change made for it. It will probably mean buying a "battery isolater" or a charger.

If it is trying to charge then you should have the battery checked and probably replaced.

[AZ_Zoner]

I wish I were at the boat to try these options out but I'm not. In general on newer Lagoons, mines a 2011, does the generator charge the starting batteries. No modification to any of the electrical has been done. It's stock.


I'd like to be able to tell the boat sitter to just start the generator and bring the batteries back up, and when I return I'll investigate what is wrong.


thanks,


Craig

[a64pilot]

Nothing to lose by trying.
I'm assuming no shore power? Most likely there will be a circuit breaker I assume marked battery charger, if that is on most likely when the generator comes online and supplies AC power, the batteries will be charged.
So tell them to check that circuit breaker, I know nothing about Lagoons, but doubt the generator if it has an alternator is wired to charge the main engine starting batteries, but bet the house battery charger might.


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[feebs]

I have a 2010 L400 and no it doesn't on mine - you may be able to try the crossover battery switch located next to starboard engine battery switch.


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[AZ_Zoner]

Originally Posted by feebs

I have a 2010 L400 and no it doesn't on mine - you may be able to try the crossover battery switch located next to starboard engine battery switch.


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feebs,
thanks for the info. This is a challenging debug problem from 3000 miles away and the person that is checking on the boat is not real familiar with it. Neither am I since I've only owned a few months.

A question for you is on your electrical control panel, What are the top two breakers on the left side? do you think one of those breakers would control a charger that would keep the starting batteries charged?

thanks

Craig

[feebs]

I agree & a similar distance from my boat today....



Switch 6 connects port & starboard engine start batteries - this may provide extra bit of grunt to start an engine - haven't had to use mine as yet....




When you talk about circuit breaker, are you referring to 230/115 volt switches on top LHS of this panel for AC charger?


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[AZ_Zoner]

Originally Posted by feebs

I agree & a similar distance from my boat today....

Attachment 128622

Switch 6 connects port & starboard engine start batteries - this may provide extra bit of grunt to start an engine - haven't had to use mine as yet....


Attachment 128623

When you talk about circuit breaker, are you referring to 230/115 volt switches on top LHS of this panel for AC charger?


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Yes on the breakers I shut those off when we left the boat. We've never had starter battery problems till now. I'll suggest to the boat sitter to turn those two back on. and see if the voltage comes back up. Neither engine will fire up right now.

I'm sure we could switch to the house batteries to start but then the starter batteries would just slowly drop back down.

hope this makes sense. Thanks.

Craig

[TurninTurtle]

Could have the boat sitter call a local boat service and see what they want to check out and charge the battery.

They might even accidentally show the boat sitter how to set it up to charge from the generator.

[feebs]

OK, I think I am following now.

Have him check & record both engine voltages + domestic voltage on display (top RHS of panel, by pressing LHS of selector below this read out) - if this doesn't display both engine battery voltages, then engine batteries are not turned on correctly.

Next have him turn AC charger switch on LHS of panel ( 2nd switch down) & recheck voltages - provided shore power is connected, domestic bank should have increased & read up to 14ish Volts. Now if your boat is wired to charge engine batteries from chargers, engine batteries will show an increase in voltage up to 14ish. If domestic voltage doesn't show an increase in voltage, either shore power isn't connected correctly, or your chargers are faulty..

Hope this helps.


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[AZ_Zoner]

I'm on a mooring. My house batteries are at 13.6 and just being charged by the solar. I've been gone a week. Starters are down to 10.6.
I'll see if they can flip the 2nd breaker down and start the generator and see if the inverter/charger will increase the starter voltage.

thanks for the help.

Craig

[feebs]

Doesn't sound great....

Are your engine batteries original & same as these? (Tudor brand)



I have had my boat 12 months & I think mine are originals - so must be getting near end of life....they go down to about 12.5 volts after engines not being run for about 10 days, otherwise they sit about 12.6 - 12.7 volts




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[feebs]

Also, I have my boat on a mooring & solar keeps house bank topped up too. My generator doesn't charge engine batteries via chargers.


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[TOT]

Craig l had issues with my Port engine battery showing low voltage but the battery was fine it turned out that the cable further away from the battery terminal just need cleaning with a wire brush, look at the leads that run under your bed.


SV TOT
Wayne 😃

[Redpcx]

Generators on a boat often do not charge the starting battery. Usually, it is a sign of a bad starting battery, because the engine and battery do not supply house loads, and the battery stays charged by the alternator on the engine. Time for jumper cables, and a new starting battery.