Charging problem

Wandering Star

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My boats fitted with a Beta 20. The boat hadn’t been used for maybe 10+ years and the alternator fitted to the engine was very rusty. I purchased one of these Pardon our interruption... alternators as a replacement for the original rusty one. Fast forward lots of work and the boat was finally launched a few weeks ago. The engine started immediately but the charging light on the basic Beta control panel glows red which I’m presuming means theres no charge from the alternator?

What can I do to check the alternator is working and the wiring from the alternator to the battery is connected correctly? I’m visiting my boat tomorrow and I’d be grateful four some simple checks to make, I do have a multimeter on board but little experience of using one and although i’m quite handy with most aspects of boat maintenance & repairs including mechanical stuff, but anything to do with electrickery is a dark science to me so please don’t expect me to understand at first go!

This could be something really, really stupid which I’ve done or it could be the alternator is duff, don’t take anything for granted!
 
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Did you rev the engine ? Alternators require a 'starting' voltage to 'excite' the coils ... my alternator on my Perkins needs me to give a good throttle up in neutral for a few secs and then light goes out ... then I can return to neutral and alternator is still outputting ..

If this is not what happens with yours - then I suspect EXCITE lead is not connected ... this is a low amp 12v supply lead that gets the coils energised to start outputting ... it is a lead that initially has 12v flowing - this is RED light ON .... but once alteranator excites and starts to output - it has 12v in opposite direction that makes the excite lead go to zero volts ... RED light goes out..... its usually a LED and will not illuminate the other way.
 
Did you rev the engine ? Alternators require a 'starting' voltage to 'excite' the coils ... my alternator on my Perkins needs me to give a good throttle up in neutral for a few secs and then light goes out ... then I can return to neutral and alternator is still outputting ..

If this is not what happens with yours - then I suspect EXCITE lead is not connected ... this is a low amp 12v supply lead that gets the coils energised to start outputting ... it is a lead that initially has 12v flowing - this is RED light ON .... but once alteranator excites and starts to output - it has 12v in opposite direction that makes the excite lead go to zero volts ... RED light goes out..... its usually a LED and will not illuminate the other way.
You misunderstand why the charge light goes out and an LED will not allow the alternator to charge, it needs to be a fi]lament bulb of around 2.2 watts or a resistor to pass a corresponding current.
 
Is there a key? When you started and took pressure off the key, did you leave it where it "sprang" back to, or did you go one stop further back?

On my ~20 year old Yanmar (~2006) it is possible to start the engine and then effectively turn off the ignition key and the engine will continue to run (there is a separate button to shut it down). The result of this situation is no charge as no excitement.

edit to add in response to this: "This could be something really, really stupid which I’ve done or it could be the alternator is duff, don’t take anything for granted!"

Have you put the belt on and tensioned? (Well you did say ;) ), although the Beta has (I recall) a single belt, where the YM has 2... so if you see cooling water, its probably fitted!
 
Did you rev the engine ? Alternators require a 'starting' voltage to 'excite' the coils ... my alternator on my Perkins needs me to give a good throttle up in neutral for a few secs and then light goes out ... then I can return to neutral and alternator is still outputting ..

If this is not what happens with yours - then I suspect EXCITE lead is not connected ...
If that were the case, the warning lamp would not light up at all.
this is a low amp 12v supply lead that gets the coils energised to start outputting ... it is a lead that initially has 12v flowing - this is RED light ON .... but once alteranator excites and starts to output - it has 12v in opposite direction that makes the excite lead go to zero volts ... RED light goes out..... its usually a LED and will not illuminate the other way.
It's almost never a LED, it's normally incandescent.
 
If that were the case, the warning lamp would not light up at all.

It's almost never a LED, it's normally incandescent.

Anyway - the rev up bit is relevant ... as to red light .. accepted my error of LED or not ... but depending on how OP has his 'charge light' connected - he could have it lit without actually indicating charge or not .. if its lit from the 'start button / key' - which I have seen people do.

To OP - I would get a meter on the batterys and see what happens when engine running vs not running ... the voltage should be higher when engine running than when stopped ... if so - then alternator is charging.
 
The LED yes/no question would be answered if we knew the model of control panel the OP has. Certainly early Beta type A and type AB panels had LEDs but they suffered badly from corrosion where the LEDs were soldered onto the PCB. It appeared that there was no conformal coating applied to the PCB. I have replace all the LEDs in a type A panel on my son's boat due to this corrosion.

Much cheaper than buying a newer replacement panel with incandescent lamps.
 
I’m afraid I’ve unintentionally misled you all although most of you got the “excite” bit correct.

After I serviced the engine ashore and replaced the rusty alternator, the boat was launched and sat on the club pontoon. I only ran the engine for a short period in the water just to ensure it started and that was when I noticed the red charging light was on. I wasn’t too bothered and didn’t investigate as I really don’t understand marine electrickery, I thought I’d post on here for ideas as to why the light was on and then fix it later.

After I moved the boat to my winter swinging mooring, a distance of possibly half a mile, there were a lot of fumes in the main cabin which was worrying (potentially expensive fumes) I had been helming the boat from the cockpit and wasn’t aware of the fumes until I’d tied up and went below to switch off the batteries and get my clobber which I needed to do quickly as the club launch had arrived to take me back.

Today I went back to the boat for the first time to take my first look at the engine, I was dreading what I was expecting to find and on opening up the engine compartment saw immediately the new alternator I’d fitted was hanging down with the belt totally loose which of course meant neither the alternator nor the water pump would have been functioning on my trip to the mooring. Some idiot had forgotten to secure one of the bolts securing the alternator bracket - I’m at a loss to know or identify who the idiot was as I’m the only person who was involved in fitting the new alternator.

So problem solved. Thanks for all the unnecessary advice!
 
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