alternator problem ?

[SEARANGER ANCASTER]

I had an alternator issue last year ( Volvo TAMS75P) in that at 1500 revs , the belt started slipping. Changed belt , changed idler and still the same. Thought maybe it was overcharhing and hence putting too much load on the belt so fitted a new alternator. All was well for a while but now the battery warning light comes on a few minutes after starting the engine. No belt slip or anything obvious and 28v on guage.
Light and alarm goes off after 10 or 15 minutes.
What could be causing this as getting to the end of my tether !

 

[superheat6k]

I had an alternator issue last year ( Volvo TAMS75P) in that at 1500 revs , the belt started slipping. Changed belt , changed idler and still the same. Thought maybe it was overcharhing and hence putting too much load on the belt so fitted a new alternator. All was well for a while but now the battery warning light comes on a few minutes after starting the engine. No belt slip or anything obvious and 28v on guage.
Light and alarm goes off after 10 or 15 minutes.
What could be causing this as getting to the end of my tether !

A few questions

1 Is the electrical load increasing as the problem occurs ?
2 Is there a particular rpm when the problem occurs now.
3 Is the belt flat on the inner surface or toothed.
4 How much of the pulley is in contact with the belt
5 What is slack movement in the centre of a longer section of the belt
6 Is any black dust building up neat the belt.
7 What amp rating is the alternator
8 What size is the belt.

 

[SEARANGER ANCASTER]

no increased load , no particular revs now , no belt slip and belt torqued to 60nm as per manual.

Since posting , I have discovered the boat is fitted with an "Adverc" system so have been warned it may be this that is causing the alarm. It makes sure the engine start batteries are charged first before the leisure batteries I am told so will need to investigate this

 

[superheat6k]

no increased load , no particular revs now , no belt slip and belt torqued to 60nm as per manual.

Since posting , I have discovered the boat is fitted with an "Adverc" system so have been warned it may be this that is causing the alarm. It makes sure the engine start batteries are charged first before the leisure batteries I am told so will need to investigate this

I assume Adverc is an alternator booster similar to the Sterling units. These take over control of the field current / voltage to convert a simple alternator to a battery charger, which remarkably a standard alternator is not ideal for. It might be possible to disconnect the Adverc to see if the alternator works properly in its original mode, but I am not familiar with the Adverc unit.

 

[VicS]

no increased load , no particular revs now , no belt slip and belt torqued to 60nm as per manual.

Since posting , I have discovered the boat is fitted with an "Adverc" system so have been warned it may be this that is causing the alarm. It makes sure the engine start batteries are charged first before the leisure batteries I am told so will need to investigate this

An Adverc does not itself do this. The charging of two battery banks may be controlled manually using a 1,2 both switch or using a diode splitter, or by using a VSR (voltage sensitive relay).

The Adverc is ideally suited to using a diode splitter because it is a "battery sensing" device meaning that its compensates for the voltage drop across a diode splitter. Charging of the two banks takes place simultaneously.

When a VSR is used one battery bank, usually the starter battery, is charged first then when that reaches a certain level the VSR connects the other battery. Both are then charged simultaneously. A VSR is often chosen rather than a diode splitter when an alternator is not "battery sensing" because it does not suffer from any voltage drop.


The Adverc instructions are here: http://www.adverc.co.uk/images/filesmanager/043119_Adverc_installation.pdf.

There is a section on checking the operation of the Adverc using a special wiring harness that allows voltage readings to be made.

Because the Adverc is an add on device I think, like Superheat , that is should be possible to disconnect it to see if the alternator operates normally without it.

I suspect you have a VSR which is why the warning light and alarm go off after 10 to 15 mins ... ie when it cuts in the other battery bank. At the moment though I cannot suggest a reason for it coming on in the first place .... This is the normal ignition warning light rather than the Adverc overcharge warning I assume?

Check the connections of the red and blue wires from the Adverc

 

[SEARANGER ANCASTER]

thanks for that. Will investigate further
Yes its the normal battery light that comes on with alarm. I now silence the alarm and let it flash for a while then it eventually goes out. but obviously want to get to the bottom of it.

 

[VicS]

thanks for that. Will investigate further
Yes its the normal battery light that comes on with alarm. I now silence the alarm and let it flash for a while then it eventually goes out. but obviously want to get to the bottom of it.

If you had not already changed it I might have suspected an alternator problem, even so getting it tested by an auto-electrician might be a good move. The old one too if you still have it. They might be able to identify a fault, esp if they find the same fault in both, that would lead you to a problem elsewhere with the electrics.

 

[SEARANGER ANCASTER]

sent "boat electrician" when first problem appeared and he told me belt was slipping ! I bloody knew belt was slipping but it wasnt slipping due to belt or tensioner or idler .
sent old alternator to repair shop and he said the regulator was faulty and it was overcharging , which proved my point. Fitted new alternator and no belt slip and 28v but this bloody alarm started going off.

 

[aquapower]

sent "boat electrician" when first problem appeared and he told me belt was slipping ! I bloody knew belt was slipping but it wasnt slipping due to belt or tensioner or idler .
sent old alternator to repair shop and he said the regulator was faulty and it was overcharging , which proved my point. Fitted new alternator and no belt slip and 28v but this bloody alarm started going off.

Could be a fault in the Volvo warning light module, these are known to fail, try swapping module with other engine to see if problem moves.