Broken Wires and... "Entropy"

[Loren Beach]

Broken Alternator Wire = "Entropy"

The constant decay of everything to a lower level of order... in the universe... or something like that.

So we were motoring home for 5 wind-less hours, one day last week. 'Twas the finish of a nice little vacation trip down the river to the sea and back.

I soon note that the E-meter shows only battery voltage, and not the usual 14 volts. Hmm. After a night at a down river city guest dock w/o shorepower, it should show some charge for a half hour or so. Hmm...

Engine runs fine, and the belt goes round 'n' round. We slow down the revs and I gingerly touch each wire on the alternator. Sparks fly from the + output.
Since the engine will run fine as long as the belt goes 'round to keep the raw water pump happy, we continue home.
Yesterday I got the alternator off, and the wire crimp on the #10 orange wire broke off. I drive over to Bill's shop, PMX inc, that does the bulk of the marine alternator/starter work in our fair city. He confirms that when the wire, breaking strands over the years, lost its continuity for a second, diodes were either fried or will fail soon. For under $200, the Motorola 55 amp alternator will be rebuilt and handed back to me, the clueless owner, in about a week.
Lesson (re-) learned: constant vibration, over time, will work-harden wires and they *will* fail. This will then lead to other expense and inconvenience.
Well, Duh!

Anyhoo... it is really past time to start to address some of the rats' nest of old wire splices around the starboard side of the Universal.

That is the one of the last remaining problem areas inherited from the prior owner of this boat, because that side the engine is really hard to get at on our model boat. (That's my only sorry-a__ excuse and I'm sticking to it!)

Upon request, Bill rebuilds these alternators for external regulation, but unless you are really going cruising and spending weeks on passage-making, he sees no reason to do this. "If it met your needs from 1988 to 2007, why change now?"


Cheers,
Loren in PDX
O-34, Universal M25XP

 

[rwthomas1]

I must disagree on the point that a simple single stage regulator is "enough" for the average boat. Once the house capacity exceeds 200 amp hours then there is no way the built in regulator will keep up if the bank is only moderately discharged. While everything may see fine it is quite likely that the battery bank is chronically undercharged. This will lead in time to premature battery death. Batteries are expensive. So is a decent 3 stage regulator however in theory this should be a one-time expense. My new alt/reg package made a believer out of me. The recharge times have dropped very significantly and the house bank shows more capacity at all times. Even if the just the regulator was upgraded and the alternator current limited to keep the alternator alive it would take better care of the batteries simply because of the multiple stage protocol.

Obviously, if you are on shore power frequently and have a good AC charger then this is a non-issue. I am on a mooring and so a top notch self contained charge setup is important.

RT

 

[Loren Beach]

Obviously, if you are on shore power frequently and have a good AC charger then this is a non-issue. I am on a mooring and so a top notch self contained charge setup is important.
RT

Right you are. And around here, I would guess that 98% of all boats are tied to docks and have shore power available. Always been that way for us.
OTOH, I have seen some boats in slips that use only solar panels to maintain their batteries.
The "2%" that are on moorings would be a few in protected bays up in Puget Sound, BTW.

Loren in PDX

 

[Rocinante33]

For less than $200, the Motorola 55 amp alternator will be rebuilt and handed back to me, the clueless owner, in about a week.

Loren,

For about $167 you can have a brand new, 90 amp marine alternator. I installed a Prestolite (Leece-Neville) for that much. Are you sure you want to spend $200 to rebuild 55 amps?

Also, of you haven't done the alt bracket upgrade, this sounds like a good time.

 

[Captron]

Entropy

Entropy as it relates to boats goes like this...

The day you first put a boat in the water, it begins to sink. From then on, one can only delay the inevitable, usually with massive infusions of cash.

 

[Loren Beach]

Loren,
For about $167 you can have a brand new, 90 amp marine alternator. I installed a Prestolite (Leece-Neville) for that much. Are you sure you want to spend $200 to rebuild 55 amps?
Also, of you haven't done the alt bracket upgrade, this sounds like a good time.

Good points. Actually the estimate was from $120 to about $180. I was just rounding up to a couple of B.U.C.'s.
This shop is known for honesty, and perhaps I should have been more precise. As to a change in brand, I am not against it, but starting over would perhaps involve research on pully size and also the issue of the # of poles to keep the tach readings ok...
My present alternator output is about 25% of the house bank size, and that's what most of the books advise, so there is no particular reason to go larger. Also, it takes XX amount of hp to drive XXX amount of amp output, and my little diesel has only 23 hp total on a good day, as it is.

I have thought of upsizing the alternator a little bit and going with an external regulator, and may yet do so someday... When I do I will still want this one for a back-up.

So, I would not disagree with your logic, but this seems to be my best decision for the present.

As to the bracket, I am not sure what that entails.The M25XP model may have the improved bracket.


Best,
Loren

 

[Rocinante33]

As to a change in brand, I am not against it, but starting over would perhaps involve research on pully size and also the issue of the # of poles to keep the tach readings ok...
Also, it takes XX amount of hp to drive XXX amount of amp output, and my little diesel has only 23 hp total on a good day, as it is.

I have thought of upsizing the alternator a little bit and going with an external regulator, and may yet do so someday...

As to the bracket, I am not sure what that entails.The M25XP model may have the improved bracket.

Loren,
1. If you have the stock 55 amp Motorola, the Leece-Neville has the same # of poles = same tach reading.
2. My even smaller 21 HP M-25 drives it OK, though I have not tested it with low battery banks.
3. An optional bypass plate is appaently available for the Leece Neville which allows use of an external regulator (I do not know part #s, but Prestolite may help).
4. As far as the bracket upgrade, refer to Geoff's thread from 2003 (referenced in my thread on Alt Upgrade). He has a picture, plus description of what could happen if you don't upgrade. Also see my picture. If the tensioner/adjustment bracket is below the alt, and the main bracket bolts to the exhaust manifold, you have the new modification. If it is above, and bolts to the front cover, you may have the old type, prone to breaking the front cover.

 

[footrope]

I replaced the 55 amp Motorola with a 51 amp Leece-Neville, after finding out the re-build of the Motorola was almost as much as new. It's a dusty, crusty old thing and it now awaits my labor to rebuild it into a spare (brushes, bearings, cleaning). The Leece-Neville works fine, although since the 2007 Rendezvous my tach readings are going goofy - about 200-500 RPM high on my Motorola tachometer. Cleaning the tach terminals did not help.

I was given the optional back cover that replaces the built-in regulator and permits use of an external regulator, so they are available. I have a gel cell for a starter battery and an Alpha regulator all set up for it. (recall I have a second alternator for the house bank)

I think you did fine keeping the Motorola. I had to spend quite a bit of time adapting the wiring to the new alternator and trying to keep it backward compatible to the Motorola.

 

[Glyn Judson]

Alternator replacement..

All, After sharint the 30 amp vs. the 55 amp story and how it potentially saps power from the prop, I failed to tell you that when my little 30 amp went south, I simply took it to a local starter motor/alternator repair shop to be rebuilt. One day and $90.00 later it was as good as new and back on the engine. They even gave it a Yanmar gray paint job that matched almost perfectly. Curious, I asked the guy to tell me if the innards were different from any other automotive alternator. The answer was that it ws identical to ones he works on every day. I wondered if there might have been spark arrestors or other such thing in it to cause the replacement cost of something like $400+ I'd been quoted a few days before. Regards, Glyn Judson, E31 hull #55, Marina del Rey, CA

 

[footrope]

What Glyn said!

I had my large (190 amp) alternator rebuilt at a shop that does work on auto and industrial electrics, for about $275. That included a new rotor to replace the shorted one. New alternator that size would have been around $1000. When I returned for preventive maintenance on the 55 amp, I ended up with the L-N for about $110. I'll go back there and get the new parts and the bearings pressed in when I get around to the rebuild of the Motorola.

The trick is to get the alternator to adapt to an external regulator if you don't have lead-acid batteries.

 

[Loren Beach]

Motorola alternator is back on and charging again. Total rebuild cost was $155.
On to other chores, for now...
Loren