Alternator Help

[holtcl]

Greetings - need some input regarding alternators.

I have a 1971 53 MY. It's a 32 v. system. DD 8v71 naturals. Neither alternator has worked since I got the boat.

Removed STBD alternator and had it tested. It's not working (which I kind of knew). PORT alternator has been missing in action since I've had the boat.

I have a source for new 32v alternators and am ready to buy 2 of them.

Questions:

1. Are the alternators the same for a port and stbd engine?

2. The lower brackets that hold my port and stbd alternators in place are different from each other. One is about 3.25" wide and the other is about 7" wide. Why? Could they have come from the factory that way or might this have due to previous owner work?

3. Presuming I order new alternators, how do I make sure they fit the old brackets? I assume I may have to source replacement lower brackets as well, being that they are different (port and stbd) and not sure they will match the new alternators.

4. On the STBD lower alternator bracket, there appears to be a homemade gasket and some rtv-type material around it - why would this be necessary? What might be behind that bracket that would call for a gasket?

THANKS in advance for any wisdom on this that you can share.

Cheryl
Cinderella
1971 53 MY

 

[MikeP]

Cheryl,

I don't know if our '80 53MY/8V71TIs uses the same alternator as your boat but on our boat, both alternators are identical and they mount exactly the same way on both engines - same brackets, attached in the same place. They are not mirror images, the alternators mount on the same side of each engine (port side)

The alternators should have an identifying/part number on them somewhere - either a tag or stamped into the metal itself. If you can find that, it would tell you if they are the same.

As you know very well, there is NO TELLING what a PO may have done so it's possible they are different alternators/brackets now though they may not have been originally.

Have you considered having the current alternators repaired? That's a fairly common/standard procedure and there are shops in Annapolis than can do that (maybe closer to/on Kent Island as well but I don't know). I don't know what the current price is for that service but I would ASSUME (maybe incorrectly) that it would be much less than new alternators and rebuilt ones would be essentially the same as new - new bearings and necessary electrical parts.

As far as a gasket on the lower bracket, only thing I can think of is that is was placed for spacing/alignment of the bracket but again...who knows what evil lurked in the mind of a PO? One other possibility - and I don't know if it's the case on these engines: on some engines, an external part may be held in place by bolts that penetrate the engine's water jacket. In that case, the bolts must have sealant on them to prevent leaks. Normally though, that is just sealant on the threads, gasket material would not be used or needed. I'm sure other folks here could tell you for sure about those particular bolts. Seems unlikely, especially for a bracket like that, but I have never pulled them so I can't say.

One question for curiosity...you take the boat out quite regularly. If the alternators haven't been working, what has been keeping the batts charged while you are out cruising, do you run the genny/batt charger full time when out?

 

[holtcl]

Mike,

Thanks for that detailed response. My folks were visiting last week and Dad ran the alternators over to Pasco. The folks over there indicated that it would be more cost effective in the long run to get new ones than to rebuild. Something to the effect that with the amount of current going through there, the repair wouldn't hold up over long term and it would be best to get new. ??

I run my generator from the time I leave the dock until I get back, unless hooked up to shore power at another marina.

The alternators on the 44 never worked either. Having had to replace the generators and battery chargers, as well as several battery banks on both of these boats only confirms my suspicion that I must have really irritated a powerful electrical deity up there somewhere

Cheryl
Cinderella
1971 53 MY

 

[Fanfare]

I just wanted to throw in the importance of getting marine quality alternators rather than the more common, readily available and less expensive automotive alternators. The marine ones are spark protected which is absolutely essential for gas boats to prevent explosions, not to mention to pass USCG and insurance requirements. Not so essential for diesel boats but still recommended.

 

[MikeP]

C,

I'm a fan of Pasco so if they say it would better to have new, I wouldn't be one to argue with them though I have to admit I'm not sure why a rebuilt with new bearings/diodes wouldn't be essentially the same as a new one. Could simply be that the old ones are lower in capacity than they should be for "modern" use and they recommend new/different model for that reason. ??

One never knows about the various deities and how they get offended. I have similar issues with on-shore plumbing...

 

[yachtsmanbill]

Youll need to change the block mount on one or the other to match frame models on the alts. That bracket opens the water jacket BTW so youll lose the coolant. Don't forget a new gasket too! ws

 

[holtcl]

Yachtsman Bill,

Thanks very much, that's what I was looking for-- very helpful.

Mike P- also confirming about Pasco. I get my batteries from them and always have been good service.

Cheryl
Cinderella
1971 53 MY

 

[rsmith]

just my 2 cents but I had a lot of issues over the years with the external regulators. But in the quest for more speed I started thinking "if im running the genny anyhow why to I need to sap HP off the mains to charge starting batts" So I pulled the belts with the Idea if I ever needed the alts. I could pop the belts on and go. Some 20 years went by operating with out the need to use the alts. At the time we were fishing some of the far reaches of the Bahamas down by San Salvador and i started thinking maybe it would be a good idea if I checked the alts to see if they were still good to go. Well they were'nt so I went the same route your going. Same deal cheaper to buy a new self contained one than fix the old. At the time I think they were $550 each for new. I started thinking "why do I need 2?" Im only looking for back up and I have 2 generators anyhow. So I just put one on the STB engine which makes it convienent to pop the belts on if nessasary.

 

[jim rosenthal]

I'm sure you're not looking for ways to spend additional money, but think about having them built without regulators and using external (like Balmar) regulators. The alternators work a lot more efficiently with smart regulators than they do with the built-in ones.

 

[holtcl]

Jim- thanks for bringing up the issue of regulators as I'd overlooked that. I seem to recall having issues with at least one of them on the 44. Can someone educate me on what the regulator does (e.g., 'regulators 101'?) I have a few spare ones in my storage unit but no idea if any of them work.

Cheryl
Cinderella
1971 53 MY

 

[davidwigler]

I could be wrong but don't think Balmar offers 32 volt alternators or regulators.

Cheryl, I recommend Nigel Calder's book on this topic and more:

http://www.amazon.com/Boatowners-Me...&sr=8-1&keywords=marine+mechanical+electrical

 

[q240z]

holtcl, voltage regulators keep tabs on the battery voltage and regulate the output of the alternator based on need. When the battery voltage is low, they ramp up the alternator output to put more juice in the battery. As the battery reaches full charge, the regulators taper off the alternator output so the batteries don't overcharge.

Large case alternators used to be able to be rebuilt for far less than $550. I had the 32v one on my Connie rebuilt for about $200, and it was still working great when I sold the boat. I did upgrade to Balmar regulators. They don't advertise a 32v unit, but they sell them. It's a modified 24v unit, as I understand it. They're not cheap in 12v or 32, though. Still, well worth the money...especially when compared to new batteries!

ymmv
Q

 

[rsmith]

I could be wrong but don't think Balmar offers 32 volt alternators or regulators.

Cheryl, I recommend Nigel Calder's book on this topic and more:

http://www.amazon.com/Boatowners-Me...&sr=8-1&keywords=marine+mechanical+electrical

I don't worship at the alter of Nigel like most on here do. I

 

[rsmith]

I don't worship at the alter of Nigel like most on here do. I

Read some of the reviews on it and you'll see what I mean.

 

[jim rosenthal]

David, you may be right. I'd forgotten that the 53 has a 32vdc system. Sorry. You may be stuck with the single-stage regulator that comes in each alternator.

What do regulators do? They vary the output of the alternator (how many amperes charge it's putting out) based on what they sense that the battery needs. Multi-stage regulators are able to match the curve of the alternator output to the battery's ability to accept charging current from the alternator. Since the dc systems are also powering all the boat's accessories while the engine is running and the alternator is turning, the regulator also reckons that current demand into its charging curve. I think the regulator accomplishes all this by varying the field coil strength in the alternator, but I may be wrong on that.

Multi-stage or smart regulators are able to vary the charge current going to the battery bank and better fit the acceptance of the battery bank- kind of like a smart charger does. (some of the same circuits may be in there for all I know) A sixty-amp alternator with a smart regulator won't put out any more than it would with a single-stage regulator, but it will do it in a charge curve that charges the batteries faster and more completely.

Converting my alternators to smart regulators was done years ago in the process of an electrical system refit on Blue Note. They are Balmar regulators, and so far, so good, after about seven years, although they now have updated models. But they seem to work fine and keep all the banks charged up nicely.

 

[holtcl]

Thanks everyone for this helpful information. Sounds like I need to address not only the alternators but potentially also the regulators. I'm not sure their status (e.g., are they operational; do they need to be replaced or rebuilt).

Cheryl
Cinderella
1971 53 MY

 

[Boatnut]

I don't worship at the alter of Nigel like most on here do. I

Neither do I. IMO, his book on electrical systems is not worth the paper it's printed on.