Generator won't run with engines on

Any more info on the warning light? Off hand, this sounds like a short or a grounding issue. A short, because your disconnecting the hot-side while still running and not having issues. Is it a floating or grounded system?

Do you have access to the ships wiring diagrams?

What is common between the engines and generator on this boat? Battery, fuel, raw water? Does this happen with only both engines, or only with one of the engines, or either engine? What breaker specifically are you turning off to stop the alarm?

Has any work been done on this boat recently? I assume this is your 53' Navigator you've owned a while.

If this is a new issue, i'd bet somebody has been messing around the batteries. There is a strap off, loose or installed wrong.

Battery charger should be putting out around 14V. Batteries will slowly drop to around 12V without the charger, jump back up to 14V with the charger. If that is what is happening, sounds normal.

Rcrapps is probably right, someone probably did some cleaning and tightening before your journey, and something got bumped or reinstalled incorrectly.

Only happens on one engine? As in, this problem is only affected by a certain engine, or it only occurs when operating on either one out of the two engines are running? Not surprising there's a higher voltage with the generator and charger on.

So the system is operating correctly without the battery charger online? Does your system have any kind of smart regulators for the alternators? If so, that will certainly, and is known to, mess with Penta motormanagement.

As others have said, check your connections.

I don't understand. You titled the thread "gen won't run with engines on"

Then you say "generator still runs"

There could be two issues. First having the charger on confuses the engine electronics and they sense a higher voltage than expected, triggering a warning light. But the generator should still be running. Does it?

What happpens if you start the engines on shorepower with the charger on? Does the warning light comes on?


Other problem, which I have seen in the past is when the generator shares a starting battery with one engines (bad setup). The draw from the engine cranking can be enough to shut down the generator

Is this what happens?

Your gen-set uses the engines battery to start/run. There is a problem in the wires to the battery, alternators from either/both engines to/from the common battery.

Is this a new problem?????????

How are you using the Battery Selector Switch, is it on #1 or #2 or All? Have you tried to isolate each battery? Typically, the Charger is on all of the time.

I would assume the problem may be in the Volvo panel if you are now seeing this for the first time after all these years.

How old are your batteries? To me it sounds like a battery/voltage issue. The charger also could be bad and leaking AC voltage which will play hell with DC electronics.

Have you called Volvo back?

I would change the charger out ASAP or all of your batteries will be fried.

AGMs or Lead Acids? Wrong setting on the charger?

Most likely a bad diode in the charger sending AC voltage through to the batteries.......or just full charge mode and cooking them, but guessing most likely leaking AC voltage into the batteries.

I still think something is missing here.