Alternator problems .....continued

[chubby]

Dear All

 

I hope it isn t a problem but i m starting a new thread , seeking advice for an alternator problem that just wont go away . After fitting a new alternator , followi g from a thread i started about a fortnight ago i thought it was all sorted but ....

 

The symptoms of my problem is this :

When i turn the ignitionhalf way a buzzer sounds , a red lamp on the voltmeter illuminates .

Ignition on , engine on , rev to 1300 -1400 rpm - buzzer stops , red lamp goes out .

So far , so good ... but

 

When i return the throttle back to idle , after about 5 - 10 seconds the lamp & buzzer come on again & the volts ( on the smartgauge ) drop from 14.4 to 13 .

I expect ( & hope ) its something simple , but my alternator problems just won t go away & my patience is being sorely tested so any help will be greatly appreciated .

In the meantime im going to put the kettle on

 

Thankyou

[MtB]

Is this a new problem or has it always done this?

 

MtB

[bottle]

Previous thread that is still running http://www.canalworld.net/forums/index.php?showtopic=72424&page=12

[chubby]

Cheers Mike ,

 

Brand new alternator fitted last week . My previous thread was " smartgauge stuck at 76 " and theres a reply from Steve ( Eeyore ) , saying this behaviour may be quite normal due to the conditions & starting the engine from cold .

 

Im going to follow the advice given , to maintain slightly higher revs , about 300 above tickover , for a short while , so i shall try this now .

 

cheers

[Tony Brooks]

What is the pulley ratio?

Edited December 31, 2014 by Tony Brooks

[chubby]

Im sorry Tony ,

 

ive no idea of this

 

cheers

 

Barrus shire 1603 , 2 alternators

[chubby]

Problem persists .

 

all connections checked & fine .

Belt tension fine .

 

Smaller alternator for engine battery operating as normal .

 

cheers

[pearley]

I would be inclined to replace the drive belt as a next step.

[chubby]

Cheers

 

Brand new belt fitted last week at same time as the new alternator

[Tony Brooks]

I would be inclined to replace the drive belt as a next step.

 

Agreed but if the OP will not get out a rule and calculate the pulley ratio we can not be sure that the alternator is not being driven too slowly on idle to sustain output.

 

This has gone on long enough so each and every possibility should now be checked. I agree if it is still original spec. the ratio is unlikely to be a problem but its best to check.

 

I also note that a number of years ago Barrus ignored best practice and ran two alternators off one belt. If its one of these engines then it could easily be the lack of belt wrap on the domestic pulley is allowing it to slip. I would also tend to cause excessive belt stretching so require frequent adjustment to maintain tension.

[chubby]

Cheers Tony

 

Im not being lazy , but i dont know HOW to make the calculations .

 

The belt has a number or code : XPA 1157

 

im going to google " calculating pulley ratio " etc as i just dont know whats required .

 

Back soon

 

cheers

[dmr]

I think you really need to answer two of the above questions

 

Is this a new or existing problem?

 

How big (diameter) is alternator pulley, and corresponding pulley on the engine?.

 

and

 

is the new alternator the same model as the old one?, if not what is it?

and does it have the same size pulley as the old one?

 

Do you have anything "big" switched on whilst battery charging?

 

...........Dave

[chubby]

Cheers Tony

 

Im not being lazy , but i dont know HOW to make the calculations .

 

The belt has a number or code : XPA 1157

 

im going to google " calculating pulley ratio " etc as i just dont know whats required .

 

Back soon

 

cheers

[chubby]

Ok

 

Steve ( Eeyore ) suggested a possibilty that the alternatir was perhaps sensing " full " batteries . When this problem arose earlier smartgauge read 100 SOC .

 

To test this i have turned on the invertor , ran my vacuum cleaner for 5 minutes .

SOC dropped to 97 .

Turned engine on . Revved to 1200 to excite

symptoms have gone - no buzzer . no lamp

 

engine battery alternator is charging at 14.4 v

cabin battery bank at 14.15 - 14.20 ( flickering )

Both these reading are from the smartgauge

 

phew !!

Happy new years everyone by the way !

cheers

[chubby]

SOC back at 100 . buzzer & lamp still off .

 

i have left engine running ss my understanding is that when smartgauge reads 100 this doesn t mean " ok , stop charging " so even tho smartgauge reads 100 the bank may not be truly " full " .

 

cheers

[chubby]

DMR

 

Engines off now so i ve measured the diameter as best i can .

 

The alternator pulley is 68 mm

The engine pulley ( i think - ive no idea ive never done this before ) is 110 mm

 

The set up , going clickwise is like this : Large alternator , small alternator , large pulley (110mm. ) smaller pulley ( water pump ?? )

 

i am assuming that the 110 mm - the larger of the two pulleys that aren t alternators , is the engine pulley you suggest i measure , but as i say i don t know & looking thru my engine manual doesn t help .

 

This is a new problem i ve not expetienced before . When i last the engine 5 days ago , it did not occur .

 

To my very limited understanding this new alternator is a direct replacement for the old one . The wiring harness & connections matched & it fitted easily with no alterations / modifications etc . it went straight in , but the wiring has been tampered with in the past & it did not function as the old one . The model etc is :

WOOD AUTO . ALT 31085 : MANUFACTURER - MITSUBISHI . ( i believe )

 

I had a heap of problems establishing the wiring requirements & received a good deal of help from several people on another thread .

This alternator appears to require a permanent 12 v + ive connection to the " sense " terminal . When connected & engine is running the alternator delivers 14.15 - 14.4 v .

When this sense terminal is not connected permanently , the alternator delivers 15.4 V . Too high , as i understand it .

 

So therefore there is 2 ft cable between cabin batts +ive & the sense wire ( green ) at the back of the alternator with a fuse inline .

 

Following on from Steve ( Eeyores ) suggested theory that sensing " full " batteries the alternator was shutting itself off & consequently the warning lamp & buzzer activated , i ran my vacuum cleaner to lower the SOC to 97 .

 

When i turn the engine back on , rev to 1200 the alternator kicked in , delivering 14.2 v . This time when i returned the throttle back to tickover the symptoms were not present . I ran the engine till SOC 100 was achieved & for 30 minutes afterwards . The lamp & buzzer remained off .

 

It may be that tho smartgauge is reading 100 , they are infact not entirely " full " & if tomorrow is bright & sunny then solar may push in the last bit of charge to make them truly full again & if i retest tomorrow late afternoon them then if the problem re emerges then it would suggest that Steves theory is correct & the alternator " sensing " that its not required to recharge , turns itself off , or unexcites itself & this results in the buzzer & lamp coming on .

 

If this turns out to be the case , it would at least point towards the problem or reason why this is happening but there would then be a need to fix this persistant buzzing sound & lamp illumination , as its not tolerable & doesn t seem " right " to me . It feels like something is malfunctioning & im out of my depth trying to understand why its happening . The old alternator never behaved this way & the only time the buzzer sounded was when the ignition was turned 1/2 way . Once the engine started & the key sprang back to 1/2 way the buzzer went out . I didn t even have to rev the engine .

 

Hope some of this helps as this problems is wearying me !

 

cheers again

[dmr]

DMR

 

Engines off now so i ve measured the diameter as best i can .

 

The alternator pulley is 68 mm

The engine pulley ( i think - ive no idea ive never done this before ) is 110 mm

 

The set up , going clickwise is like this : Large alternator , small alternator , large pulley (110mm. ) smaller pulley ( water pump ?? )

 

i am assuming that the 110 mm - the larger of the two pulleys that aren t alternators , is the engine pulley you suggest i measure , but as i say i don t know & looking thru my engine manual doesn t help .

 

This is a new problem i ve not expetienced before . When i last the engine 5 days ago , it did not occur .

 

To my very limited understanding this new alternator is a direct replacement for the old one . The wiring harness & connections matched & it fitted easily with no alterations / modifications etc . it went straight in , but the wiring has been tampered with in the past & it did not function as the old one . The model etc is :

WOOD AUTO . ALT 31085 : MANUFACTURER - MITSUBISHI . ( i believe )

 

I had a heap of problems establishing the wiring requirements & received a good deal of help from several people on another thread .

This alternator appears to require a permanent 12 v + ive connection to the " sense " terminal . When connected & engine is running the alternator delivers 14.15 - 14.4 v .

When this sense terminal is not connected permanently , the alternator delivers 15.4 V . Too high , as i understand it .

 

So therefore there is 2 ft cable between cabin batts +ive & the sense wire ( green ) at the back of the alternator with a fuse inline .

 

Following on from Steve ( Eeyores ) suggested theory that sensing " full " batteries the alternator was shutting itself off & consequently the warning lamp & buzzer activated , i ran my vacuum cleaner to lower the SOC to 97 .

 

When i turn the engine back on , rev to 1200 the alternator kicked in , delivering 14.2 v . This time when i returned the throttle back to tickover the symptoms were not present . I ran the engine till SOC 100 was achieved & for 30 minutes afterwards . The lamp & buzzer remained off .

 

It may be that tho smartgauge is reading 100 , they are infact not entirely " full " & if tomorrow is bright & sunny then solar may push in the last bit of charge to make them truly full again & if i retest tomorrow late afternoon them then if the problem re emerges then it would suggest that Steves theory is correct & the alternator " sensing " that its not required to recharge , turns itself off , or unexcites itself & this results in the buzzer & lamp coming on .

 

If this turns out to be the case , it would at least point towards the problem or reason why this is happening but there would then be a need to fix this persistant buzzing sound & lamp illumination , as its not tolerable & doesn t seem " right " to me . It feels like something is malfunctioning & im out of my depth trying to understand why its happening . The old alternator never behaved this way & the only time the buzzer sounded was when the ignition was turned 1/2 way . Once the engine started & the key sprang back to 1/2 way the buzzer went out . I didn t even have to rev the engine .

 

Hope some of this helps as this problems is wearying me !

 

cheers again

 

I am getting out of my depth here as I have general knowledge but no Barrus specific knowledge. We need input from Tony as he has hands-on experience of a wide range of engines.

A 110mm engine pulley driving a 68mm alternator gives a ratio of 110/68 or about 1.6. This is a bit low. If your engine tickover is (say) 800rpm then the alternator spped is 1280rpm. Most alternators need about 2000 rpm to work.

I am not aware of any alternators that actually shut down on a fully charged battery (but could be wrong) but if they did then I would expect them to go into "float" rather than shutting right down so would not activate the light/buzzer. I would be very surprised if Barrus would fit an alternator that did a full shut down. The buzzer should really only sound when something is seriously wrong.

 

My best guess is that your alternator is turning too slowly but I do not know why this problem has just started. Your voltage readings would support this.

If you are right "on the edge" then the problem may well appear to come and go

 

...........Dave

[nicknorman]

I am getting out of my depth here as I have general knowledge but no Barrus specific knowledge. We need input from Tony as he has hands-on experience of a wide range of engines.

A 110mm engine pulley driving a 68mm alternator gives a ratio of 110/68 or about 1.6. This is a bit low. If your engine tickover is (say) 800rpm then the alternator spped is 1280rpm. Most alternators need about 2000 rpm to work.

I am not aware of any alternators that actually shut down on a fully charged battery (but could be wrong) but if they did then I would expect them to go into "float" rather than shutting right down so would not activate the light/buzzer. I would be very surprised if Barrus would fit an alternator that did a full shut down. The buzzer should really only sound when something is seriously wrong.

 

My best guess is that your alternator is turning too slowly but I do not know why this problem has just started. Your voltage readings would support this.

If you are right "on the edge" then the problem may well appear to come and go

 

...........Dave

I am talking right out of my arse here but present this for your contemplation:

 

The alternator warning light / buzzer is extinguished when the alternator's auxiliary field diodes rectify a small proportion of the stator's output in order to supply the field current, bringing the field supply voltage up to circa 12v and hence extinguishing the warning light and buzzer. The field current is (maybe) further restricted by the regulator, in order to regulate the stator output voltage. Output voltage is in fact regulated by controlling the current according to the relationship between the output voltage and the load which, according to ohm's law, when the load is zero, requires the current to be zero. To get the stator current to zero requires the regulator to remove all the field current. So with no field current, there is no stator output and therefore no stator output to be rectified by the field diodes to get the D+ terminal up to circa 12v in order to extinguish the light and buzzer.

 

All typed after 2 Pegu Clubs, 1/2 bottle of Cava and a Hendricks & tonic so E&OE

[Eeyore]

No sensible response possible; blame it on the single malt!

Happy new year to you all.

Steve (Eeyore)

[MtB]

All typed after 2 Pegu Clubs, 1/2 bottle of Cava and a Hendricks & tonic so E&OE

 

 

And not a single spilling mistake. I'm very impressed!

 

 

MtB

[Tony Brooks]

I have heard of other cases warning lamps glowing after a prolonged period of good solar charging and also over-voltage warnings going off on associated equipment. Particularly with PWM controllers that as far as I know pulse the solar panel voltage to provide an "average" voltage suitable for charging. I can only conclude that the solar input is rapidly pulsing between zero and 17 volts, maybe higher on domestic panels.

 

I agree that pulley ratio seems is horribly low but now I think the OP has confirmed it is a single belt installation and that was always going to produce problems of one sort or another. It is no accident that the other marinisers and now Barrus have moved to separate belts for a second alternator. Its years since I looked at one of these single belt - twin alternator installations but from hazy memory I think it may be difficult to retrofit idler pulleys to increase the bely wrap on not only the alternator pulleys but also the water pump one as well. I suspect the long term cure and maybe to also prevent overheating (belt slipping on water pump pulley) it may be best for the OP to convert his engine to a twin belt installation and at the same time get a larger engine pulley and/or a smaller alternator one.

 

If in all other respects the charging is sufficient for the OP's use then I see no reason to rush to do anything as long as this glowing lamp is only evident after or during periods of higher solar input. One way to tets it is to wait until it does it again and then throw a blanket over the panel. If the bulb ten goes out you know what caused it.

[Sir Nibble]

I have looked at the alternator and refreshed my memory by looking at the correct rectifier and regulator. This is indeed a 9 diode machine and therefore self exciting. Perhaps the OP would be so good as to measure the voltage at the alternator output terminals when this occurs?

[chubby]

Good Morning

 

Thankyou again for all your help . So far this morning i haven t yet turned on the engine to see if this problem arises again , now that SOC has returned to 100 .

 

Yesterday evening i dug out the original engine manuals & found an engine 12 v wiring diagram .

The marinisers , Barrus Shire labelled this duagram as " issue 10 " & i supposed that there policy was to update thier diagrams from time to time as they alteredd ( improved ... unlikely !) thier system .

On this diagram is a relay - very clearly present .

In the top right corner of this diagram is a small box , inside of which are written the dates when Barrus made these changes .

On 25/05/2001 - issue 10 of thier wiring diagram took effect .

My boat dates from December 2001 on its documentation .

The change made to the system was this :

" Relay added to seperately excite 80A alt . Provide terminal for second battery bank "

So , i think , it clearly did use a relay as part of the set up .

 

The diagram shows the relay with 4 terminals & 4 coloured wires as such

 

30 red

85 black

86 grey

87 green

 

there is no grey wire present . There is a white & black wire tho .

 

Is this info useful in determining which type of fuse to install , if i need to . I went back thru the older posts on this thread , to try & determine which type of fuse i needed from the Durite website link that Steve ( Eeyore ) provided . But , i just cannot work which one i need .

I feel like im going round in circles a bit as i thought it was fixed . I was advised by the alternator dealer that the sense terminal must have a permanent 12 v connection & this i ve done & so im stumped & it seems that

once it senses " full " batteries , it unexcites & the alarm & lamp operate , which to me sounds a bit rubbish if this is indeed how its meant to function .

 

Im going to try the engine & see what happens

 

cheers again

 

ETA : Thanks Sir Nibble ( thats gotta be the best name on this forum !) .

You say it " self excites. " , but at present it doesn t , not until i rev from. idle (950 or so ) up to 1200 . At 1200 the volts shoot up to 14+ .

 

cheers

Edited January 1, 2015 by chubby

[Sir Nibble]

Those relay terminations tell me that... Red (30) is a supply from the domestic battery. Green (87) is the alternator sense wire. White (86) is an ignition supply (from engine battery) and black (85) is negative. The supply 86 runs through the relay coil to negative at 85 and the resulting magnetism closes contacts from domestic pos at 30 to give the alternator it's sensing.

Does the relay click when ignition is turned on?

[bottle]

I can answer that, there is no relay, the socket is there but relay removed, not been there since Chubby bought the boat.