380: Battery Charging: One or Two Engines ?

[Jerry Woodward]

Do both engines contribute to charging the house bank and the starting batteies on a Lagoon 380, or does one charge the house and the other one charge the start batteries? If the former, does running both engines double the charging rate? I will be chartering a 380 in Nov. and I began to think about this question.

[DRS]

I can't speak for all but on mine port engine charges its starting and the house batteries. Starboard engine charges its own starting battery. I suspect that is the case with most

[careka]

Has anyone done changes, on the normal setup ?
And what have you done ?

[colemj]

Why wouldn't both alternators run to the house banks and let the starting batteries charge by combiners or echo chargers? To have one alternator charge just a start battery is a waste of alternator. I'm surprised Lagoon set them up this way, and can't think of any logical reason other than to save a few bucks in wire and relays.

And yes, during bulk charging, you do get double the charging rate when they are set up correctly.

Mark

[SvLetitgo]

Both engine go to a central point and get redistributed to all battery banks, 3 in total.

So when you start the second engine the second alternator doesn't switch itself off seen that the first one is offering all the load.

Have a look at that post should answer all your question

Totally wired | Lagoon Inside

Don't hesitate to ask, one of us may have the answer.

[colemj]

That is a bit of a complicated system and I don't know what the box is that the second alternator feeds that is also connected to the B switch. However, if both alternators feed all banks, then both alternators will contribute to the charging and you will get the combined output during the bulk phase. During absorption, one alternator will predominate because the regulators will not see equal voltages. But this is OK, because the current will be less than any single alternator's output, so it doesn't matter if one shuts down.

Mark

[careka]

Very nice info, on how to look after your battbank,
Offshore Sailboat Battery Test, 18 Month Report

[roetter]

Originally Posted by SvLetitgo

Both engine go to a central point and get redistributed to all battery banks, 3 in total.

So when you start the second engine the second alternator doesn't switch itself off seen that the first one is offering all the load.

Have a look at that post should answer all your question

Totally wired | Lagoon Inside

Don't hesitate to ask, one of us may have the answer.

I don't see anything about the alternators in the Lagoon wiring diagram. It only shows the consumer side (i.e. starter motor on the engine). The only charging in this diagram is from the shore power charger.

We still do not know how the alternators are wired with regards to controller and the three batteries.

[SvLetitgo]

The Hitachi are directly link to the studer isolator via the B+ at the back of them.

They are internally regulated, and have a diode and a ptc back to B+ from the ignition plug.

And are grounded

No other connection from them

Detail here

Electromaax install. · SV Letitgo

Tomorrow will have post about the new one we just put on.

[gspeak]

On my 2004 L380, as far as I can tell my starboard motor only charges its starter battery. The voltmeter only shows charging when the port motor is running. This is crazy

There is two solenoids in the battery compartment under the the port aft berth that get very hot when the motors are running. These obviously switch charging to different banks but I have yet to work how these work and I'm sure that the starboard motor doesn't add to the house batteries.

Would love to correct this. Any ideas?

L380 #241