~16 volts ?

[Sven]

We're at the end of what was supposed to have been two weeks of sailing ... ended up being mostly two weeks dockside getting to know the E39-B.

I'll gripe about the weather in another post

When under power I noticed that the voltmeter in the companionway read in the "red" zone which is almost 16 volts. I tried to back off the throttle thinking we might be running too many RPMs (at 2000 we shouldn't be) but even bringing it down to 1000 RPMs still left us in the red.

I know gel cells are prone to die a very early death from overvoltage. My question is if the (stock ?) voltmeter in the companionway is reading the charging voltage or the voltage coming off the alternator before charging regulation ? I have not yet confirmed the reading with a second voltmeter but will do that when we get back down there.


-Sven

 

[newpbs]

Confirm voltage with a multimeter

Sven,

I don't believe that there is such a thing as unregulated voltage. The voltage regulator controls the output from the alternator. The 16 volts you are seeing would be the voltage throughout the system. I would use a multimeter the verify the over voltage. I believe that the correct voltage should be somewhere around 14.5 during charging.

Send some of that warm weather North. We're anxious to get our boats back into action.

Paul

 

[rwthomas1]

It would not be unusual to see that kind of output if the voltage regulator has failed and the alternator is running wide open all the time. I've seen this in vehicles..... Your gauge could be incorrect, etc. but the best way to test is a voltmeter at the batteries. It is also possible that this is a combination of issues. The regulator, either internal or external is in charging mode so the voltage is higher than you would expect, but normal, AND the gauge is faulty. Bottom line, you need to know how your charging/battery system functions. RT

 

[tenders]

I would guess there is a problem with your regulator. Assuming the voltmeter is telling the truth, there is nothing in the system EXCEPT the regulator that could be making this happen. (Low voltage, on the other hand, is another story altogether--could be lots of things.)

If you run it too long the alternator will overheat and will no longer charge. High voltage can also burn out incandescent lights in inconvenient places.

The good news is, if you take the alternator into a shop it will not be very expensive to fix.

I know this because I had this problem this season. The rebuild was $85, at a place called Bronx Ignition near my club in City Island, NY where they do seem to know a great deal about marine alternators.

PS, unless you're already an expert don't bother taking your alternator apart to see if you can figure out what's wrong. You won't have the parts handy anyway; you'll need to take it into a shop. The brushes are put in "just so" and it's pretty difficult to get them like that on the reinstall without breaking them, and the person at the shop will just laugh at you.

 

[Sven]

The joys of a long distance relationship

She is 120 mi or 2.5 hours away and now I know I should have made more measurements and gotten part numbers. Based on the Perkins workshop manual we have either a C.A.V. AC5 or a Lucas 11AC alternator so I think I'll start an on-line search for a rebuilt one and see if that might be the solution.

It seems as if a slip closer to home is becoming available so we might soon be almost within reach but the over-voltage problem will have to be fixed before we make the move so buying a rebuilt alternator might be the most cost effective option despite the short term extravagance.

Thanks for the responses.


-Sven

 

[Sven]

PS, unless you're already an expert don't bother taking your alternator apart to see if you can figure out what's wrong. You won't have the parts handy anyway; you'll need to take it into a shop. The brushes are put in "just so" and it's pretty difficult to get them like that on the reinstall without breaking them, and the person at the shop will just laugh at you.

After some googling it looks as if the regulator is external and could be replaced (if I guess correctly which alternator we have): http://tinyurl.com/7wj7xf

Was it the voltage regulator that was shot or did your alternator actually need rebuilding ?



-Sven

 

[tenders]

> Was it the voltage regulator that was shot or did your alternator actually need rebuilding ?

(My alternator is a 120-amp upgrade for an Atomic Four.)

According to the shop, the regulator was bad and it cooked the windings and both needed to be replaced. But my alternator had an internal regulator -- if you don't have to take the thing apart, for you it may be worth just trying to replace the external regulator. BUT why did it go bad?

Having an extra alternator around as a drop-in spare as you troubleshoot is not the worst thing in the world....

 

[Sven]

BUT why did it go bad?

And how long has it been that way, if it is indeed bad ?

Having an extra alternator around as a drop-in spare as you troubleshoot is not the worst thing in the world....

That was my thinking too. Especially if it is indeed bad as I think that means we'd be dock-locked until it gets fixed.

Thanks,


-Sven

 

[Rocinante33]

Sven,

If you're thinking of replacing your alternator or adding a spare, you should consider a Leece-Neville (Prestolite). I got a 90 amp marine version two years ago for about $170. I think it is a very good value compared to other marine rated alternators.

Search for the old thread about it, if interested.

 

[Sven]

Hi Keith,

If you're thinking of replacing your alternator or adding a spare, you should consider a Leece-Neville (Prestolite).

I'll definitely look up that thread. I don't assume all alternators are the same size and use the same brackets or pulley sizes ? $170 sounds very cheap (compared to what I thought auto-alternators cost, about the same 10 years ago).


-Sven

 

[footrope]

Cautionary tale

> <snip>
According to the shop, the regulator was bad and it cooked the windings and both needed to be replaced. But my alternator had an internal regulator -- if you don't have to take the thing apart, for you it may be worth just trying to replace the external regulator. BUT why did it go bad?

Having an extra alternator around as a drop-in spare as you troubleshoot is not the worst thing in the world....

Exactly, why did it go bad? If a bad component caused another component to blow, you've got about a 50-50 chance of blowing your spare. Real life case - My house bank alternator stopped delivering a charge. I could tell the regulator was bad 'cause the lights on it were all wrong. I tried an identical replacement regulator from my engine charging circuit and promptly blew it also. I bought a new regulator ($275) to get home with, and then got the alternator rebuilt ($200 - the rotor shorted which blew the external regulator) and then I got both old regulators repaired ($120).

So, my DIY troubleshooting expertise cost me around $335. What I should have done was paid to have the alternator tested first ($50). But, we enjoyed the extra night in Anacortes ($20 slip + $3 for power). It is always better to make sure you identify the bad part(s) before plugging in a spare, especially if it's got to do with sparks.

P.S. - All this made me nervous about the dirty old start battery alternator, so I took it in to be overhauled. Turned out that a new Leece-Neville (Prestolite) 51 amp was cheaper than a rebuild ($100). Direct replacement mechanically, but then I had to wire in and adjust the external regulator to match my gel-cell start battery.

20-20 hindsight (priceless!)

Hope things are getting better, Sven.

 

[dwigle]

Check the voltmeter

Before making any assumptions based on the voltmeter, I would make sure that it's accurate. The voltmeter on our 38 pegs just after start-up with any rpms at all. However, the voltmeter on the breaker panel and the Link 10 both read in the 14 volt range. We recently changed to a Balmar alternator and regulator and it still does it, so I just us it as an indicator that the system is charging.

Don Wigle
Wiggle Room
E 38 #8

 

[Sven]

I have not yet confirmed the reading with a second voltmeter but will do that when we get back down there.

It was the gauge ! Yay !!

A new one was about $50 and installed in 20 minutes with spectacular results. The old one was really flaky and erratic. There was no evident calibration screw or any calibration instructions either so now it is a paperweight



-Sven