Alternator problems .....continued

[Alan Saunders]

Do not forget that whilst it takes very little current, limited by e.g. a 2W bulb, any poor connection in the 'ignition' circuit (ignition switch, bulb contacts, wiring, terminals etc.) will reduce the current. Fitting a higher wattage bulb may hide an inherent problem. Even if it worked with a previous alternator it may have been marginal

 

e.g. The bulb holder could be corroded to the point that, eventually, the warning light will not light or supply sufficient current to the alternator rotor.

 

Typically, a flat battery at 11.5V o/c should be adequate to excite the alternator. On one occasion my battery was reading 10.5V (the tunnel light had been on for 24 hours). It needed a lot of revs to extinguish the warning light but, as NIckN suggests, the system was then self-sustaining, the increased voltage (12V+) was enough to overcome (I=V/R) any inadequacy in the ignition/warning light circuit.

 

I would first ensure that the ignition/warning lamp circuit is good, ideally by checking for voltage drop or resistance with a DVM. Otherwise, check, clean and secure all connections. Even professionally applied crimp terminals may be inadequate and it is not unknown for multistrand cable to corrode or have a partial break anywhere within the insulation.

 

N.B. Measuring 'voltage drop' means from source to sink, e.g. from battery to alternator.

 

I have not seen an ignition light glowing on tickover since the days of dynamos when it was normal .

 

HTH, Alan

[Loafer]

Do not forget that whilst it takes very little current, limited by e.g. a 2W bulb, any poor connection in the 'ignition' circuit (ignition switch, bulb contacts, wiring, terminals etc.) will reduce the current. Fitting a higher wattage bulb may hide an inherent problem. Even if it worked with a previous alternator it may have been marginal

 

e.g. The bulb holder could be corroded to the point that, eventually, the warning light will not light or supply sufficient current to the alternator rotor.

 

Typically, a flat battery at 11.5V o/c should be adequate to excite the alternator. On one occasion my battery was reading 10.5V (the tunnel light had been on for 24 hours). It needed a lot of revs to extinguish the warning light but, as NIckN suggests, the system was then self-sustaining, the increased voltage (12V+) was enough to overcome (I=V/R) any inadequacy in the ignition/warning light circuit.

 

I would first ensure that the ignition/warning lamp circuit is good, ideally by checking for voltage drop or resistance with a DVM. Otherwise, check, clean and secure all connections. Even professionally applied crimp terminals may be inadequate and it is not unknown for multistrand cable to corrode or have a partial break anywhere within the insulation.

 

N.B. Measuring 'voltage drop' means from source to sink, e.g. from battery to alternator.

 

I have not seen an ignition light glowing on tickover since the days of dynamos when it was normal .

 

HTH, Alan

 

Good words. I'm sure I don't have any other wiring probs, 'cos there has never been any variation, since I bought the boat 5 years ago. Been on board almost the whole time.

 

I always had to blip the throttle, and now I don't.

 

I am now wearing out the starter motor, so that I can keep confirming that replacing the bulbs has done the trick!

 

Stand by for a new thread on how to get me starter motor going agian.

[chubby]

OK

 

This morning i ve tried Petes test & put a test lamp between the cabin bank +ive & the lamp connection at the back of the alternator .

Turned engine on .

Alternator kicked in straightaway & no revs were needed to excite it .

Volts at battery were 14.3 ( cabin ) & 14.5 - engine .

Im going to pull the panel out to check all the connections at the back of the voltmeter lamp .

cheers

[chubby]

ok

 

I ve called Barrus & spoke to a very helpful chap & , they tell me that the original pulley was " around 50 mm " & seemed to belueve that a pulley of 60 mm , as on the new one , would functionin the same way as the old one & ought not make much difference .

 

Im not sure what this means in my situation but thats what they say .

[bizzard]

OK

 

This morning i ve tried Petes test & put a test lamp between the cabin bank +ive & the lamp connection at the back of the alternator .

Turned engine on .

Alternator kicked in straightaway & no revs were needed to excite it .

Volts at battery were 14.3 ( cabin ) & 14.5 - engine .

Im going to pull the panel out to check all the connections at the back of the voltmeter lamp .

cheers

Since I uprated my charge light bulb to 6w my alternator starts charging immediately I turn the start key which means it starts charging almost as soon as the engine begins to turn, something like 30-40 or so rpm!

[smileypete]

OK

 

This morning i ve tried Petes test & put a test lamp between the cabin bank +ive & the lamp connection at the back of the alternator .

Turned engine on .

Alternator kicked in straightaway & no revs were needed to excite it .

Volts at battery were 14.3 ( cabin ) & 14.5 - engine .

Im going to pull the panel out to check all the connections at the back of the voltmeter lamp .

cheers

 

Sounds good, maybe try again tonight when no solar and batts fully charged to see if it stays excited when in idle.

 

(EDIT:)

 

First try with the built in light to check the problem of alt losing excitation recurs, then stop engine and retry with test lamp powered from domestic batt +ve, and then try again with test lamp powered from engine bat +ve.

 

The results of the second two tests will tell if a relay is needed or will cure the problem of excitation or not.

 

cheers, Pete.

~smpt~

Edited January 7, 2015 by smileypete

[nicknorman]

ok

 

I ve called Barrus & spoke to a very helpful chap & , they tell me that the original pulley was " around 50 mm " & seemed to belueve that a pulley of 60 mm , as on the new one , would functionin the same way as the old one & ought not make much difference .

 

Im not sure what this means in my situation but thats what they say .

If we take the above as "gospel" ie definitely 60mm diameter for the belt (not necessarily to the lip of the pulley) vs 50mm for the old one, that means the engine has to run at 60/50 x the rpm to achieve the same alternator speed. So what was produced at 1000 rpm now needs 1200 rpm to achieve the same thing. That I think is pretty much what you are finding?

[chubby]

Cheers Folks

 

Everydays a schoolday

 

Nick . My measurements are across the diameter of the alternator pulley at its widest points & so i fear my measurements are incorrect as i ve measured at the " lip" , not at the actual " inner or spindle " . I' m sorry

I called the supplier where the auto electricians bought the alternator & asked them , quoting the model number etc printed on my paperwork & was told that on thier " spec sheet " etc that the pulley size was not recorded .

 

Despite having model on the screen in front of him he couldn t tell me the pulley size !

 

When i tried the test lamp it fired up straightaway , no revving at all & i left it running 15 mins & no sign of the problems returned & the voltage at the cabin batts was 14.3 V .

 

So , am i looking at fitting a more powerful red bulb at the voltmeter ?

If yes then i ll have to establish what size / power ( Watts ?) it is & get a suitable one from the auto electrician .

 

cheers again

 

ETA : Thanks Bizzard .

Pete , i tried this test you suggested after trying the engine this morning . I tried the engine twice & on both occasions the lamp came on , buzzer came on . Then i did the test & had the results posted above . I repeated the test & again had the same results - no lamp , no buzzer & 14.3 v at batteries .

 

cheers again

Edited January 7, 2015 by chubby

[bizzard]

Cheers Folks

 

Everydays a schoolday

 

Nick . My measurements are across the diameter of the alternator pulley at its widest points & so i fear my measurements are incorrect as i ve measured at the " lip" , not at the actual " inner or spindle " . I' m sorry

I called the supplier where the auto electricians bought the alternator & asked them , quoting the model number etc printed on my paperwork & was told that on thier " spec sheet " etc that the pulley size was not recorded .

 

Despite having model on the screen in front of him he couldn t tell me the pulley size !

 

When i tried the test lamp it fired up straightaway , no revving at all & i left it running 15 mins & no sign of the problems returned & the voltage at the cabin batts was 14.3 V .

 

So , am i looking at fitting a more powerful red bulb at the voltmeter ?

If yes then i ll have to establish what size / power ( Watts ?) it is & get a suitable one from the auto electrician .

 

cheers again

Did you notice where abouts the alternators belt adjusting bolt was in the adjusting brackets slot. If its more or less in the same position when the belts at the same tension as your old alternator, I'd say its the same size pulley. If the pulley was a different size to your old one the different position in the slot of the adjusting bolt would be very noticeable even with only a small difference in pulley size.

Edited January 7, 2015 by bizzard

[chubby]

Cheers Bizzard .

 

This i did notice . The alternator is in almost the exact same place as the old one . By this i mean that it has to be pushed along the arched tensioning bar to tighten the belt & the new one sits almost exactly where the old one sat .

 

cheers

[bizzard]

Cheers Bizzard .

 

This i did notice . The alternator is in almost the exact same place as the old one . By this i mean that it has to be pushed along the arched tensioning bar to tighten the belt & the new one sits almost exactly where the old one sat .

 

cheers

That's good Chubby. Almost certainly the same size pully then. As I said even a small difference in pulley size will put that adjusting bolt in a totally different place. And I'm talking about inches.

Edited January 7, 2015 by bizzard

[chubby]

The new one is no more than 1 cm max from where the old one was . With hindsight i ought to have marked the arched tensioning bar but thats another lesson learnt .

 

cheers

Edited January 7, 2015 by chubby

[bizzard]

The new one is no more than 1 cm max from where the old one was . With hindsight i ought to have marked the arched tensioning bar but thats another lesson learnt .

 

cheers

Sounds ok. That'll just be the slight differences with your belt tensioning.

[chubby]

Cheers again Bizzard ,

 

So shall i whip out the little bulb & go to the auto electrician & get one of a higher wattage ?

 

cheers

[bizzard]

Cheers again Bizzard ,

 

So shall i whip out the little bulb & go to the auto electrician & get one of a higher wattage ?

 

cheers

Well, I'd certainly try one. Looks like your wiring is ok now. Be careful though if the bulb holder is plastic, a higher wattage bulb will be hotter. Having said that the bulb shouldn't be alight for very long unless you inadvertently leave the ignition switch turned on.

Edited January 7, 2015 by bizzard

[OldGoat]

Chubby,

Just for my innate curtiosity - please would you explain why running the engine just a little bit faster is a nono for you?

Is it because you're bothered about the additional noise, or perhaps you're bothered about fuel consumption, or something else?

 

Running the engine a tad faster solves the problem with no extra fiddling about...

 

On the subject of belt wrap - I found that using a cogged belt :-

http://www.bearingboys.co.uk/AX_Cogged_Belts__13mm_x_8mm_-1519-c

 

solved my problem of rapid belt wear, reducing from two per year to none in 4 years.

Not that slipping belts are really your problem.

It's about gearing as you have found. Increasing the bulb wattage is not the best solution - IMO.

 

 

[bizzard]

Chubby,

Just for my innate curtiosity - please would you explain why running the engine just a little bit faster is a nono for you?

Is it because you're bothered about the additional noise, or perhaps you're bothered about fuel consumption, or something else?

 

Running the engine a tad faster solves the problem with no extra fiddling about...

 

On the subject of belt wrap - I found that using a cogged belt :-

http://www.bearingboys.co.uk/AX_Cogged_Belts__13mm_x_8mm_-1519-c

 

solved my problem of rapid belt wear, reducing from two per year to none in 4 years.

Not that slipping belts are really your problem.

It's about gearing as you have found. Increasing the bulb wattage is not the best solution - IMO.

 

 

Chubby says he cruises along frequently on tick over and doesn't want it to keep stopping charging and the light and buzzer coming on because he has to keep revving up to correct it.

[bottle]

Yes it is when Chubby passes moored boats at tick-over, that the buzzer annoys him and it would me.

[chubby]

Cheers again

 

Thanks for that link OldGoat . The belt ive fitted is " new " . At least it came out of a bag & was amongst spares on the boat when i bought it almost 2 years ago . How old is it actually ? Who can say .

What i shall do , is heed your advice re the belt & order one like you use as i like personal recommendations & if youve seen a benefit then i shall fit one too & keep the one got as a spare ( or just order 2 of the better ones )

 

To answer your curiosity , the reason i want the alternator to function at idle is simple for me : Because it should !

I wouldn t. go so far as to say im a control freak or im OCD but i just cannot bear it when things don t just " work " & i don t like bodging stuff & cruising at say 1100 revs " because i have to " feels like a bodge . Unfortunately this mentality runs alongside my inexperience with engines , electrics etc & just about everything else remotely technical on my boat . Its the worst of both worlds .

I cant stand things being " not right " but don t know how to fix it !!!

 

When i go cruising the throttle lever seems to like only two positions or speeds . Idle & just above maybe upto 1100 revs which is just pootling along . Or 1800 revs which is a white knuckle ride for me ! If i put the lever anywhere in the middle , it just drops back to lower speed .

I used to have a Raleigh Chopper back in the 70 s as a kid & even that had 3 speeds .

So i need the alternator to function at idle or just above because thats my cruising speed preference . When i go past moored boats it do so at tickover & when the boats in a lock etc .

 

The whole idea of changing pulleys etc is pretty demoralising to be honest . I will get it done if i have to but if theres a way out of it then i ll look to that first .The main reason if im honest is cost . I am way out of my depth if it came to that & i very much expect it to be an expensive job to get done at a boatyard .

Its not to save diesel or anything like that etc , its i just would like the engine to run as quietly as i can - im never in a hurry when i untie my boat & the slower the better for me . Theres a couple of beautiful old boats on my moorings with old fashioned engines & when i go past them i think to myself that it must a total joy to listen to when cruising & one day i ll day i ll have one myself . But not yet & so as quiet as poss is my need . Not easy when your engine comes out of a Japanese digger !

 

I don t really run my engine for charging either . Since fitting 400w of solar panels in March i haven t run my engine for charging even once . Even during this episode the bright sunshine down south has topped up my batteries & because im a low user of power just the usual pumps for several mins each day , telly - once a week ... if that .... maybe champions league football & charging a phone . No laptops , no gadgets etc .

 

So really i just like things to function as they should & my last alternator seemed ok on idle . I thought it d be a straight swap & it was in the physical sense . The new one went straight in where the old one went , the connections all married up , but fir some reason this new alternator has different " needs " and it does seem as if a larger bulb will do the trick . When i tried it earlier the alternator started working immediately & remained working & it looked & felt .... right .

 

again my brains aching , time for a cuppa

Edited January 7, 2015 by chubby

[bottle]

When i go cruising the throttle lever seems to like only two positions or speeds . Idle & just above maybe upto 1100 revs which is just pootling along . Or 1800 revs which is a white knuckle ride for me ! If i put the lever anywhere in the middle , it just drops back to lower speed .

 

That can be fixed, depends on you lever make, how it is achieved.

 

Sometime just a bolt at the back

 

Something else that is not right, better have two cups of tea ..

Edited January 7, 2015 by bottle

[smileypete]

Pete , i tried this test you suggested after trying the engine this morning . I tried the engine twice & on both occasions the lamp came on , buzzer came on . Then i did the test & had the results posted above . I repeated the test & again had the same results - no lamp , no buzzer & 14.3 v at batteries .

 

OK from this I take it that a more powerful warning lamp, powered from domestic batt positive (eg via a relay) would cure both the need to rev to get excitation, plus the problem of it dropping out of excitation at tickover.

 

Not clear if running a more powerful lamp from *engine batt* instead positive will give the same results, but at least both problems look to be fixable, and the next step looks to be to source a more powerful bulb for the existing holder if poss.

 

It could be that the new alt supplies enough charge current at tickover/normal cruising speed for chubbys needs.

 

cheers, Pete.

~smpt~

Edited January 7, 2015 by smileypete

[chubby]

Thanks again Pete ,

 

The type of bulb , following a bit of googlage is R286 & it seems like the bog standard for dashboard bulbs from what i can gather . They all seem to be 1.2 W though which is ( i think ) the same as i already have .

The biggest wattage i could find for the same size bulb is 2.3W which is type 284 . It looks the same as what i have , so i 'll fit it tomorrow & try it .

 

cheers

 

Bottle : Thanks again - good to hear i can get that throttle lever sorted . Maybe that can my next job / headache / nightmare , cheers

 

ETA : To follow up onyour last point Pete. When i ran the engine this morning on a bigger test bulb . The problems did not occur & even at idle the alternator delivered 14.3 V . I ran it 15 mins at idle & all seemed ok

cheers

Edited January 7, 2015 by chubby

[smileypete]

ETA : To follow up onyour last point Pete. When i ran the engine this morning on a bigger test bulb . The problems did not occur & even at idle the alternator delivered 14.3 V . I ran it 15 mins at idle & all seemed ok

cheers

 

If it works equally well connected to engine batt then no need for a relay too.

 

If it only works 100% connected to domestic batt then it'll probably need a relay to switch the feed from domestic batt when the ignition is on.

 

cheers, Pete.

~smpt~

[chubby]

Cheers again Pete ,

 

Ok , i ll try this tomorrow afternoon using the engine battery . Its sounding like it might all get complicated again if it involves relays . Ive got a relay holder wired up but it seems redundant & the old alternator seems not to have used or needed it .

On 01/01 , post 25 i think Sir Nibble gives info about my current relay wiring ( theres a relay on the engine wiring diagrams) set up .

The alternator isn t using it now & the sense terminal is permanently connected to the domestic +ive .

Would it be worthwhile reconfiguring the wiring , meaning reconnecting the green sense connection at the back of the alternator to the green wire at the relay holder & putting in a relay which i bought a day or two ago ?

Worth a try ? Or may it cause damage ? Or , if it doesn t appear needed just continue to leave it out altogether . Confusing stuff this electrics !

 

I ll retest again from the engine batt tomorrow

 

Thanks again

[Alan Saunders]

Cheers again Pete ,

 

Ok , i ll try this tomorrow afternoon using the engine battery . Its sounding like it might all get complicated again if it involves relays . Ive got a relay holder wired up but it seems redundant & the old alternator seems not to have used or needed it .

On 01/01 , post 25 i think Sir Nibble gives info about my current relay wiring ( theres a relay on the engine wiring diagrams) set up .

The alternator isn t using it now & the sense terminal is permanently connected to the domestic +ive .

Would it be worthwhile reconfiguring the wiring , meaning reconnecting the green sense connection at the back of the alternator to the green wire at the relay holder & putting in a relay which i bought a day or two ago ?

Worth a try ? Or may it cause damage ? Or , if it doesn t appear needed just continue to leave it out altogether . Confusing stuff this electrics !

 

I ll retest again from the engine batt tomorrow

 

Thanks again

If the original manufacturer of the engine found it necessary to add a relay I would reinstate it. However, simply plugging in a new relay probaly will not work as whoever removed the relay most likely also made some wiring changes.

 

Yes, your alternator should charge at tickover. Ideally, attain 80% of maximum at cruising rpm and not disintegrate at max. rpm.