Help Needed with Alternator Wiring

[Sammy Lou]

Hi,

I need some help with alternator wiring for a Bukh DV20 installation in a Southerly 100. Electrics are not my strong point and this is driving me potty.

I've only had the boat a short time and since picking it up we have only managed to use it a handful of times resulting in aprox 4-5 hours engine use.
Something didn't seem right to me as the the battery monitor indicates that the voltage in the starter & domestic batteries is dropping slowly over time.
I volt tested the batteries with a volt meter and the volts at the starter battery are 12.7 with nothing on. Then with the engine on fast idle the voltage remains the same (12.7v as above) at both the battery and at the positive output on the back of the alternator. From this I concluded that the alternator regulator must be shot so I got a new alternator this week from a motor factors. The old alternator was a Paris Rohne A13N1M and the new one is a Paris Rohne A13R222.

I've tried hooking up the new alternator today but I still cannot see a charging voltage at the battery or coming off the alternator.

I need to check that the wiring is right for the new alternator as the connections are different from the old one.

I've put some photo's below the first one is the old alternator wiring & the second is the back of the new one.

On the old alternator the red positive went from the alternator to the starter and then back to the battery, the black negative to the engine block ground and the green wire to the engine control panel loom (for the red 'amp' light).

I assume that for the new alternator the red wire will go to the 'plus' terminal, the black wire to 'w' (not sure what the symbol is?) and the green to '+A'

I've tried all manner of different hook up today, negative on post, negative on frame, positive on +, positive on +A but with no difference in voltage reading.

The green wire confuses me - is this only for lighting the panel? I don't think I had that right today as I think it should be on +A (after some reading) but I put it on to the two flat blade connectors that can be seen at the top of the alternator.

I'd like to have some certainty of the wiring before I return to the boat to try again so I'd be grateful if anyone can advise.

The boat does not have access to shore power so it is important that I sort out the alternator charging before I drain the batteries to far.

The boat is fitted with a VSR but the LED indicator is not lit.


Any help would be very much appreciated.

 

[VicS]

The heavy red wire will almost ceratinly go to the + terminal.

The green wire appears to be the warning light connection "61" on the old old one.

W is usually a connection for a tacho. If there had been one it would have been next to the "61".

I dont see a W terminal on the new one. .. not that it is relevant if you don't have a tacho driven from the alternator

BUT aren't there connections for a plug on the side of the regulator on the new one ( top of your picture) that is where the warning light connection and if fitted the W terminal will be I'd guess.

You did not do enough testing to conclude that the regulator was "shot" ........ just that there was no output!

I would have taken the old alternator to an automobile electrician who would have been able to test it and repair it.

You best bet may still be to return the new one as unsuitable and to take the old one to an electrician for repair. If its not repairable he would be able to supply a replacement and help you with any wiring alterations that are necessary supplying any connectors needed.

 

[pvb]

Agree, I think the OP needs some expert help.

 

[nimbusgb]

W on the new one is top left. There's a bloody great W cutout in the casing!

The two terminals on the top end of the regulator need to be connected to something. They are the brushes to the sliprings that feed the rotor.

Just looked up that regulator and those terminals may be connected to the two flyleads you can see in the casing so ignore that.

 

[ianj99]

If you haven't connected to the terminals on the side of the regulator as Vics mentions, the regulator will not work so no there will be no output.

Also disconnect the green wire (where is the a+ terminal you mention) and measure the voltage on it. Should be 12v when disconnected.

Is the warning light coming on (check the bulb is not blown as the small current through it activates the regulator)?
Ian

 

[Sammy Lou]

Thanks Guys.

Is 'w' on the new alternator, the tacho connection? where should the ground (-) connect to?

 

[Sammy Lou]

If you haven't connected to the terminals on the side of the regulator as Vics mentions, the regulator will not work so no there will be no output.
Ian

connect what to these?

 

[ianj99]

connect what to these?

If there are 2 terminals its possible that this alternator needs a 12v ignition switched supply to one terminal to power the regulator or provide remote voltage sensing, and the other one is for the warning light. (some alternators are not machine sensed and need the remote sensing terminal connected)

It looks like there are a pair of terminals attached to the regulator, at the top in your photo. Try connecting each in turn to the green wire - if the warning light comes on, then start the engine.

 

[nimbusgb]

Thanks Guys.

Is 'w' on the new alternator, the tacho connection? where should the ground (-) connect to?

That alternator looks like a negative ground on the frame. Takes its ground through the engine block.

 

[Sammy Lou]

If there are 2 terminals its possible that this alternator needs a 12v ignition switched supply to one terminal to power the regulator or provide remote voltage sensing, and the other one is for the warning light. (some alternators are not machine sensed and need the remote sensing terminal connected)

This sounds plausible, as there are more connections on the new alternator than the old, but I don't know how to go about wiring up this additional supply from the current electrics.

 

[ianj99]

This sounds plausible, as there are more connections on the new alternator than the old, but I don't know how to go about wiring up this additional supply from the current electrics.

Try the suggestion I added to post 8 first.

 

[Sammy Lou]

It looks like there are a pair of terminals attached to the regulator, at the top in your photo. Try connecting each in turn to the green wire - if the warning light comes on, then start the engine.

I tried today to connect the green wire to these terminals. one results in the warning light being lit the other one does not

 

[Billjratt]

The two alternators obviously don't match. Going back to the beginning, you don't seem to have evidence that it ever charged from new(to you) is this correct or do you have an indication that it was originally working?
Were any measurements taken, or did you just go out and buy a new alternator? Do you remember if the ign light came on before the engine started? If so, did it stay on when revs were increased? - any alternator will not start charging if it is not energised either through the ign light or a relay/resistor if there are only 6 diodes inside. (ie a dud bulb can cause your problem...)
The original alternator looks as if it may be isolated - it needs a cable from the negative terminal -> where did it go to, the battery negative or simply to the engine chassis thus defeating the purpose.? Does the starter motor have an isolated ground? If it does, the engine chassis should not be connected to ground and the charging circuit may not be complete. The new alternator looks odd... The "W" actually looks more an M and is unusually large for a tacho connection. The Stud at 11 o'clock may be insulated from the chassis - in which case, I would connect the plus to the starter solenoid, the 11 o'clock stud to neg, and the "M" stud to the ign light and try it out.
I would also consider putting the old one back in and taking some observations : measure the voltages on the three alt terminals with reference to battery neg with ign 'on' and the engine stopped then running, and observe the light.
Finally, does it look as if the regulators are wired the same on both units? Might be worth taking the backs off both and comparing.
We need more info to add sensible value.

 

[pvb]

Agree, I think the OP needs some expert help.

+1...

 

[Sammy Lou]

+1...

thanks for your help - both times - much appreciated

 

[pvb]

thanks for your help - both times - much appreciated

You won't sort your problem by relying on a few random guesses from posters on here.
.

 

[Sammy Lou]

Going back to the beginning, you don't seem to have evidence that it ever charged from new(to you) is this correct or do you have an indication that it was originally working?

no - I have no evidence that charging system was ever working - right from when we collected the boat. The boat was on shore power previously so the batteries were fully charged initially.

Were any measurements taken, or did you just go out and buy a new alternator?

I checked the voltage at the battery, engine off and engine running at load - the voltage was the same - aprox 12.5 volts.
From this I concluded that the alternator was not putting out any charge.

Do you remember if the ign light came on before the engine started? If so, did it stay on when revs were increased? - any alternator will not start charging if it is not energised either through the ign light or a relay/resistor if there are only 6 diodes inside. (ie a dud bulb can cause your problem...)

I'm pretty sure that the light came on when the ignition switch was turned to on but the light did not stay on when the engine was running.

The new alternator looks odd... The "W" actually looks more an M and is unusually large for a tacho connection.

this is part of what I'm asking - I cant understand if this is W or M or some symbol. I thought it was the negative but I agree with your suggestion to try this stud for the green wire.


Unfortunately I do not have the old unit for comparison as the alternator was bought on a exchange basis

 

[Sammy Lou]

You won't sort your problem by relying on a few random guesses from posters on here.
.

I'm only looking for some alternatives before I concede and seek some professional help. I would like to try all options before throwing in the towel though.

 

[pvb]

I'm only looking for some alternatives before I concede and seek some professional help. I would like to try all options before throwing in the towel though.

Fine, but be careful not to damage your new alternator by incorrectly wiring it.

 

[pampas]

I must admit the diode pack looks a bit grotty for a new alt. Sorry but that's how it looks from here. Just goggled A13r222 and that is for external regulator. best thing to do is whip the machine to seller and ask him what goes where.