Alternator not Charging

[BabaYaga]

Hi Footsoldier.. I know the very Basics How to Test my Boat Batteries

I am Just wondering does anyone know the mak and Model of this alter ator I cannot see any Make in it, I think there maybe different types also

Regards Graham

The alternator make appears to be CAV (says so on the back side). Maybe something like this?
Alternator 1977-1983 (75 AMP) (UE41719SXR)

 

[William_H]

If there is any doubt re the alternator charging then check the voltage at the battery in use. Use the multimeter on 20v DC range. It should be about 12.6 volts or so. Possibly more if solar is charging. (if so disconnect solar) Or turn lots of load on like lights etc to bring battery volts down a bit. Then start the engine. (it is conceivable that solar and shore power have charged the batteries so much that engine alternator is throttled back not needed so not much charge)
Alternator should charge as indicated by the voltage at the battery rising to 13 .5 volts or more.
If it does not rise then OP has a problem with alternator. If alternator light comes on this usually means current is getting to the alternator field coils via the light. So indicates wiring to that part is OK. When the alternator starts charging the current via the lamp is not needed so lamp goes out.
If light does not come on then it is a wiring problem or as often happens the brushes are worn that carry current to field coils (Which rotate). get alternator tested and repaired.
If light comes on normally then goes out check wiring from alternator (big terminal) to switches etc to battery. If you can get a multimeter probe onto the large terminal at the back of the alternator you should see 12+ volts with engine not running. Then a rise in volts with engine running.

 

[Alex_Blackwood]

Forget all the suggestions on changing/ replacing the alternator. Fact: You have had alterations made to the system. If the alternator was OK before that then that is where the fault lies. Get your contractor back or else find another who knows what they are doing and check the installation.

 

[PaulRainbow]

Perhaps the ammeter broken, or no longer in circuit?
Perhaps no current is flowing because the batteries are already charged ?

The light would still go out if the alternator was working.

If you cover the solar panel to take that out of the circuit, then
Connect voltmeter to engine battery
Select engine battery only
Start engine.

Doesn't matter which battery he selects, it's a 1-2-B switch

Volts should drop to 10 or so while cranking, then recover to 12-ish with no charging, or if the alternator works, the volts will go up to 14-ish.

If your batteries are all fully charged, more than 12.6 'resting' with no load, then you should be fine to motor 25 miles

But it's easier to run the engine afloat and it would be good to sort this before winter.

If the light doesn't go out and the voltmeter doesn't register a charge, that's all pointless.

 

[PaulRainbow]

If there is any doubt re the alternator charging then check the voltage at the battery in use. Use the multimeter on 20v DC range. It should be about 12.6 volts or so. Possibly more if solar is charging. (if so disconnect solar) Or turn lots of load on like lights etc to bring battery volts down a bit. Then start the engine. (it is conceivable that solar and shore power have charged the batteries so much that engine alternator is throttled back not needed so not much charge)
Alternator should charge as indicated by the voltage at the battery rising to 13 .5 volts or more.
If it does not rise then OP has a problem with alternator. If alternator light comes on this usually means current is getting to the alternator field coils via the light. So indicates wiring to that part is OK. When the alternator starts charging the current via the lamp is not needed so lamp goes out.
If light does not come on then it is a wiring problem or as often happens the brushes are worn that carry current to field coils (Which rotate). get alternator tested and repaired.
If light comes on normally then goes out check wiring from alternator (big terminal) to switches etc to battery. If you can get a multimeter probe onto the large terminal at the back of the alternator you should see 12+ volts with engine not running. Then a rise in volts with engine running.

But the OP has said the light comes on, it doesn't go out and the ammeter reads zero.

 

[PaulRainbow]

Forget all the suggestions on changing/ replacing the alternator. Fact: You have had alterations made to the system. If the alternator was OK before that then that is where the fault lies. Get your contractor back or else find another who knows what they are doing and check the installation.

So many replies from posters not reading what the OP has said, as usual.

 

[Refueler]

IMHO opinion - the only solution is to get the Electrician back again and have system checked over fully.

My question is : When he completed the work - did he check all and was all working correctly - Is this a fault that has appeared AFTER he left ?

 

[cherod]

Simple. , if all was working fine before solar instillation then just disconnect it all again and see if the problem is still there , if it is not then the prob is in the installation , if prob is still there then prob is in within orig system , maybe alternator ?? Maybe not

 

[Alex_Blackwood]

Simple. , if all was working fine before solar instillation then just disconnect it all again and see if the problem is still there , if it is not then the prob is in the installation , if prob is still there then prob is in within orig system , maybe alternator ?? Maybe not

Sounds familiar