Engine failure out on the sea: battery symbol coming on - advice appreciated

[Krumelur]

We’re sailing North of Corsica. The engine alarms of thenD2 55 just came on. It is showing a battery icon.
I noticed that my starter battery has 15.2V according to the panel. Aus battery is at 13V.

Any advice what to check/do is highly appreciated.

Thanks

[SYJetzt]

See explanations on https://bavariayacht.org/forum/index.php/topic,3737.0.html concerning fault issues.

I would not go a longer time with this fault, otherwise you kill your starter battery soon.

First check all battery and alternator/Starter cables, especially the thick ones for proper fit (nothing loose?!?) and traces of corrosion. Follow the path of the cables and try to move every! connector. If this does not show any findings, proceed as follows:

I would see 2 possible faults:
1) Usually you should have a diode splitter (or something more modern) to separate your batteries if engine is not running. There should be a (usually yellow) sensor wire from the aux batt to the alternator, which is telling the alternator to hold charging voltage of the service battery at around 14,2 Volts.
Check if voltage of aux battery is rising up to 14,2 volts when engine is running. If not, remove the yellow wire from aux battery(+) and connect it to the starter battery (+). If alternator/ starterbattery voltage is dropping to 14,2,volts, i would suspect the diode splitter to be blown.
1) Faulty alternator regulator . This happens, if you have (had) contact issues with your cable run, or you switched off your main dc breaker, when engine was running. To fix this, you dont need to replace the whole alternator, just changing the regulator should fix this issue. This could be done without ripping the whole alternator out.

All my hints depend on a standard Bavaria/ Volvo Penta cabling. If you changed the system get advice from the supplier of your equipment
 

[Yngmar]

Starter battery overvoltage at ~15V is usually a faulty alternator regulator. Keeping this up for hours will eventually overcharge the batteries and kill them. Depending on how they're connected, only the starter battery, or the house bank too. If the house bank is low, you can go a long time before damaging it, but keep an eye on the voltages.

Try and minimize motoring until you can replace the regulator (or entire alternator) or swap in your backup alternator if you have one onboard.

Good luck! I'd head for Bastia and order parts ahead

[Krumelur]

After some consultation I ended up with:

- Reconnect D line
- Bridge from starter battery to aix batteries.

Now, the starter is charged and it’s passing it on to aux.
I have an eye on voltage and disconnect manually.

In parallel, I am in contact with VP to organize an technician in Calvi.
I’d work on it myself if it wasn’t a family trip. But in this situation I’m willing to pay premium to get a new alternator and have it installed ASAP.

[Krumelur]

I will meet the technician tomorrow morning. He will install a new alternator and I’m going to pay premium price for it. It will be €1200. The alternative is to go to Bastille and find one there at the Mitsubishi dealer.
I would consider it if this wasn’t a family trip. But like this, we just want to move on with our journey.

[Krumelur]

On our way to meet the technician we ran into a thunder storm. One sail is torn. We have electrical problems. There is a rope in the propeller. There is water everywhere.
I am so glad we survived. I’ve never been so scared in my whole life.
The boat was out of control, we sent MAYDAY, but the Coast Guard was unable to assist due to the Great number of distress calls.After three hours and shooting two red flares, we were rescued by a ferry boat. I had my wife and my two children with me my beloved wife and my two children.
Yesterday, five people died on Corsica. 5000 people were evacuated from campsites.
Ships ran aground or were flipped over. Wind speeds exceeding 200km/h were measured.
I do not know how or if I can make it back to Italy. It’s only 80 NM, but I am so scared.

[Yngmar]

Glad you're okay! So you got rescued off the boat or how did you get rescued and still have the boat?

We heard lots of reports from friends up in Corsica, lost anchors, boats on the rocks, broken moorings, ridiculous wind speeds, shredded sails. We're a bit south in Porto Conte, Sardinia and got very lucky. Saw the huge front heading our way, shat ourselves and prepared as well as possible, but it turned north just before reaching us and we only got some sleep deprivation, crazy wind reversals and a stuck anchor in the morning, which I managed to free by diving. It was caught in a rock crevice - great holding, even though we actually cracked the rock. To my surprise, we didn't even bend the shank on the Rocna

A big FP 47ft catamaran arrived last night without the mast and a lot of damage on deck.

Have a rest and get some sleep, it'll all look better. Then pick a nice calm window and motor down to Italy. In a while it'll all just be a great story to tell 

[Krumelur]

The ferry called a pilot boat which towed Us back.

[Krumelur]

Also, the technician was just here. The issue is not the alternator. It is not the batteries either. And not the splitter box (whatever the correct term is for the The thing is that decides which battery is going to be charged).
The only thing left is the MDI. He will bring a new one this afternoon. Fingers crossed.

[geoff]

Halfway between Machinaggio and the mainland is Capraier with a good sheltered anchorage . Two short hops and back to the mainland. Sorry about the spellings ,but both places offer good shelter. Geoff

[Krumelur]

An update on the motor situation.
It wasn't the MDI box either. In the end, the technician called Volvo and they said the only thing left to try would be a cable going from the starter battery's +12V to the alternator's dynamo connector, even is there is already an existing one.

So we did. We removed the porky-pig-colored cable and connected one at the starter's +12V line. Et voilà! Problem solved! The voltage at the cable increased to about +15V. As expected, charging would switch from the starter battery to the aux batteries as expected.
The existing cable stayed at +12.3V.

The big unknown is now: what happened to the original cable? Why does it deliver an incorrect voltage value? It's not that I changed anything.
Now I have mysterious +12V line ending in my engine compartment which isn't something I like.
To make things more difficult, there's a cable of same color connected behind the 115A fuse of the starter battery. If that is the cable ending at the alternator, it should delliver the correct value.
And then, there's another cable of same color behind the Bavaria control panel. However, this one is disconnected and it has no voltage reading.
It's almost as if somewhere along the way, voltage changes.

[nightowle]

could it have been corrosion within the cable somewhere or at the fittings?