Volvo problem

[Osprey]

As I'm a total dunce with (among other things!) boat engines, can any of you clever guys help me with this?

 

Osprey's engine is a Volvo Penta AD41DP and is (touch wood) running well after last season's problems. But....

When I switch on the ignition, the warning lights come on, as they should, I wait a few seconds and the Electrical charging warning light then flashes and the alarm sounds telling me the generator is not charging, (how could it, the engine isn't running yet!)

The voltmeter is showing 12 volts, as it should.

Then I start the engine and the alarm stops, the warning light goes out and the voltmeter reads 14 volts, as it should.

Once or twice the alarm has sounded and light come on when I'm running and using extra electrical power such as raising the tilt.

 

The electrician at the marina has checked it all and can find nothing wrong and suggests a new alternator, but that is going to be expensive and I think he is just guessing.

 

Has anyone got any ideas please?

 

Martyn

p.s. Bloody awful weather still, isn't it?

[mw]

Hi Martyn try try reving the engine when you trim up and see if you still have the problem I had this when I had twin engines but it only did it on tick over

once I had used it for a couple times it went away

mark

[Osprey]

Thanks Mark, I'll try that.

martyn

[Bob F]

The first thing I would do is to make sure the battery(s) are fully charged, especially as over the winter the batteries drain and we don't get to use our boats enough to properly charge them. Even though your volts gauge may be saying you have 12 volts, the battery still may be down on charge. Give the batteries at least a 12 hour charge.

 

Do this first before pointing fingers at the alternator or anything else.

Edited April 5, 2010 by Bob F

[niggle]

Martin if u do end up with getting alternator try C&G marine-Clive he overhauls them for about

[gaffa]

The first thing I would do is to make sure the battery(s) are fully charged, especially as over the winter the batteries drain and we don't get to use our boats enough to properly charge them. Even though your volts gauge may be saying you have 12 volts, the battery still may be down on charge. Give the batteries at least a 12 hour charge.

 

Hi Martyn try try reving the engine when you trim up and see if you still have the problem I had this when I had twin engines but it only did it on tick over

once I had used it for a couple times it went away

mark

 

Hi Martyn,

BobF's recomendation is spot on as is Marks .

 

If the problem is occurring at tickover there is a possibiity of the engine revs falling below the minimum needed for the Alternator to function.i.e the alternator needs to be rotating above a mimimum speed (around 1000-1400 rpm?).

 

This is not the Engine rev speed but the alternator speed as determined by the pulley ratios.

 

Generally this won't be a problem as the alternator pulley ratios have been sized correctly during engine design phase but if batteries are low and starter motor loads them further the engine revs will drop on starting and the alternator speed will drop taking it below the operating point.

 

Extra heavy loads like tilting etc could have a similar effect if the tickover speed was low

 

Try upping the tickover revs before tilting and see if the problem goes away

 

Hope this helps?

 

[Rob]

 

I recently had charging issues on JoJo and thought it was the lighting coil or regulator - everyting was pointing to the regulator after some testing, until I stuck my car's battery in the boat and the charge voltage picked right back up!

 

So if I were you I woudl stick a known good battery in the boat and see if the problems still happen - this is a cheap and easy solution to start with.

 

Rob

[Osprey]

Thank you everyone!

That all sounds like good advice to me.

 

I think the first thing I must do is plug in the shore power to make sure the batteries are fully charged. I never bothered to do this last year as I was expecting to be out a lot more than I actually was. Two trips in the last 6 months can't have helped.

 

Of course, we all know the solution! Get out more!

 

Both batteries are pretty new, so hopefully it's not those breaking down.

 

 

Again, thanks to all who have given advice. It's all very encouraging.

Now, where are my rods?

Martyn