Marine Sparky - info required

[Dave.S]

Hi all

I am not sure if anyone can give me some ideas on this small problem.

The alternator on my engine squeals when starting the engine, the Tacho does not register until the squeal stops.
I also have a volt meter gauge which does not always show that the batteries are getting a charge i.e. the meter only shows around 12v.
It is supposed to have a split charge system but I have yet to find the relay, I also have a battery selector i.e. Batt 1 or Both or Batt 2. If I select a different battery position it will often charge ok and the gauge showing 13v+

I am wondering if the selector switch is causing the problem?

I have checked the batteries with the engine running and the voltages suggest they are not always charging.
The alternator belt seems tight enough

Anyone any other suggestions to check?

Thanks

Dave

[michael1923]

It might be a long shot, but maybe the alternater is starting to sieze. Check the under side of the belt and see if it shows signs.

If the belt is tight it is the only thing i can think of that would give the symptoms you show.
i.e. loss of charge, squeal is the belt slipping when the alternater siezes.

That is quite rare though.

[scotty-b-]

i am a sparky and work on many comertials generators and military vehicles so i may be able to help.
1 take hold of your fan belt at the longest part between pulleys and try and twist it. if you can turn your belt more than 90 degrees then your belt is slack.

2 if that is not your problem take your belt off and check for oil or grease on the rubber surface of your belt if there is oil or grease wipe it down with a babby wipe to remove traces.

if this all seems fine get a digital volt meter and place the probes onto the poss and neg terminals of your battery. try and start your engine and your voltage should drop to between 10 and 11 voltsish. once tour engine is running you should have around about 13.5v reading on your volt meter and all voltages are dc

4 if you have wet acid batteries by whicjh i mean you are able to take the vent valves off check the levels of acid. Remember to wear gloves and eye sheilds. look and see if your levels are down in simple terms if the fluid levels are below your plates then your levels are down. if they are boil your kettle and let the water cool down completely you can now use this water to top up your batteries so the fluid levels are just above the plates.

5. if all else fails you may need to take your alternator off and check for wear and tear. your brushes have a lengh guide on them and this should not be exceded. it just a simple score along the flat of the brush. also remember you have a rectifier pack on yur alternaror and this can go to.

6 if you have any further problems PM me or you can pay for my flight down and iwill have a look and free days south coast fishing. that was a joke by the way. just pm me mate and i will try and help.

[scotty-b-]

reading it again mate sounds like you have a knackered battery. if your fan belt squeals this means your alternator is being asked to do loads of work and your volt meter is reading the battery voltage but as i said you should be charging at 13.5 volts and your second battery is fine.
what is happening by the sounds of it is your battery is buggered and it is asking the alternator to suppley power to charge it but the battery is not taking the charge because of sulphassion of the plates or plates shorting. this in basic terms means that your battery will not hold its full charge and its SAE/CCA is reduced and the alternator is struggling to charge your system.

do you understand roughly what i am trying to say mate.

just a quick one to try. when your engine is running slacken your battery terminals and remove them quickly of a splict second and check your voltage at your leads. if your battery is buggered them the voltage should raise to 13.5v. remeber you can only remove these leads for a few seconds or you may bugger your alternator.

[Dave.S]

Cheers Scotty

Will do a few more checks when next down on the boat.

Dave