Charging question

Mr Googler

Mr Googler

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Whilst on anchor for 4 hours, my port engine wouldn't start. No issue as 10 mins of genny and off we went.

I have however started to look at the charging arrangements.

2 isolators port and starboard and a 3rd domestic isolator. The domestic will only work with port side isolator on. 4 batteries paired with 2 going to each port and starboard isolator.

I've have a 0.1amp drain with nothing on and went through each domestic feed at the board. Nothing jumped out as drawing beyond what you would expect. Nothing unusual so far. . ...Now it gets strange.

I checked the charging side and port engine charges the port side battery pair, starboard engine charges all 4 batteries! Does that seem strange?

The starboard engine also appears to be permanently connected to port side pair as with all isolators off and starboard batts disconnected, it will power up gauges/stop solenoid and start solenoid but won't fire up. I assume this is because starter motor is powered from starboard pair.

It's all very weird. Any advice greatly received especially on the starboard charging all batts
 
Do you normally keep your boat moored and connected to shore power and charger ?

If so I would first look at the batteries as possibly failing. Fine when the shore power is just turned off, but losing it rapidly once no trickle charge is available.

What is the terminal voltage just before and just after you operate the starter ?

Although your charging set up sounds strange, I would regard issues here as likely secondary to the problem you have just explained.
 
I do keep it plugged in. The 2 port batteries where new 10 months ago. Voltage after an hour off charge was 12.7v after 5 mins running 13 point something I think.

Is it ok to effectively have 2 different alternators charging the same batteries?

I do have an electric sea toilet (jabsco conversion thing) which draws the voltage to 11.2 when running and dips the light so I think that needs to go. I tried to measure the amp draw of that but my meter only goes to 10 amp. The display flashed 18 amp!! Probably needs to go :)

Thanks Trevor
 
Sorry I meant the battery voltage to the port starter just before and just after operating the starter assuming the engine is not running / hasn't started (nor starboard running).

With two DC supplies the current will favour that with the higher voltage, but having two alternators would not cause harm as each will regulate to provide the current flow required to maintain the charge voltage.

Do you have a wiring diagram for the boat or can you draw one out from the cabling - not the whole boat, just the major cables from the batteries and alternators and any other substantial parts along the cabling.

I am assuming this is a new problem on a set up that, although bizarre, has been working perfectly well. For this reason I would not be distracted by something that might be OK. No one ever said fault finding would be straight forward.
 
I found the issue....the generator has its own battery in the lazerette. It turns out this is also connected to the main bank! Had it tested and it's completely fubar. I didn't notice as obviously the genny started up no problem from the main bank. I will replace and make it independent from the main batteries.

I am still looking at connections in the main panel to separate port and starboard completely but at least I have found the drain issue.
 
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