sizzling hot new alternator

[waterdog]

Maine Sail,

I would think that if someone has their nyloc lock-nut melt on an alternator or near the engine somewhere, they have some other issues to contend with. If things are getting hot enough for the nyloc to melt, we have bigger issues... Wouldn't you agree? Having said that, I too use lock washers on most everything around the engine, but then, I guess I am old fashioned and conservative.

Clearly if the nyloc melts there is a bigger issue, but this is not a trivial circuit.   But what if you do have a bigger issue?   If you are running direct to your battery bank with a high output alternator and #2 or bigger cable with 100A or bigger fuse (you must always fuse this) and 4T105s, if that cable falls off your alternator you have a runaway arc welder in your engine room - even with the fuse.    You can burn a hole through your oil pan & sieze your engine before you burn your boat to the waterline .    This is not like a light circuit with #16 wire and two levels of protection (you have fused your main bank right?)  between your fault and all the energy of the battery bank.   It's a beast and demands to be treated with old fashioned conservative respect.   No different than double hose clamps on through hulls below the water line.  

And I have seen the insulation melt on the output post of a high output alternator.  Nylocs don't belong there.   I've also welded a hole through the back of my son's iPod touch, but I would rather not have to explain how I did this with the alternator in a public forum...

[Ron Hill]

Guys : Sorry, that I missed the previous posts.

BTW, there are other types of selflocking nuts that just nylon!!  Look at the inside the hull lock nut holding on the struts of Catalina's.  The nut is a compression with vertical slits.

Another fix is a second nut (jam nut) on top of the first nut.  This is still much better than the old stainless lock washer that doesn't hold its resiliency!  In any case, making a slippage mark will let you see if the nut is backing off.  

I agree with Mah and Lance, if the nylon melts in the self locking nut, you have a Bigger problem than just heat!.  BTW, any nut should be tightened very snug, whether it is self locking or not!   
A few thoughts

[Bobg]

Stu, thanks, I am going up to the boat today, one of my house banks is wired to the 1 position on my Perko switch, the other house bank is wired to the 2 position, the new AO is wired to one of the house banks, I leave the battery selector switch in the All positon.   The starter solenoid is wired to the ALL position in back of the switch,    I only have 3 terminals in back of my Perko battery selector, 1.2.and all.   I don't see anything that remembles a "C",  will check your drawing again.  (Jim Moes  boat is in the marina and hopefully I can get advice there also)

I do have a dedicated start battery with its own isolation switch and a combiner in the system.

I havn't paid much attention to the two ground wires from each bank, (I will now) but I do see they are connected to the engine.

Every thing is set up exactly like it was for the previous 5 years with no issues, except the new wire from the AO going to one of the house banks, (I'm thinking both banks would get a charge with the selector switch in the all position)
Previously the old AO was a number 12 or 10 orange wire that ran all the way up to the switch.  I shortened it and ran  it to the starter solenoid, but the Alt heated up, then I ran the #6 to the house bank, same results. 

Harvey at blue circle told me to run the AO to a test battery just to see what happens, I'll try that too. which would eliminate all the house bank wiring in an attempt to narrow it down

I am agreeing with you it is probably a wiring issue, as it seems worse after a night on the hook. Or it could be a bad new battery, will check with a hydrometer

Thanks to you all, really appreciated  (my batteries are fused with 125 amp for the #4 wire, and 100 amp for the #6 AO wire)

Bob

[Stu Jackson]

1.  The starter solenoid is wired to the ALL position in back of the switch,    

2.   I only have 3 terminals in back of my Perko battery selector, 1.2.and all.   I don't see anything that remembles a "C",  will check your drawing again.  (Jim Moes  boat is in the marina and hopefully I can get advice there also)

3.   I do have a dedicated start battery with its own isolation switch and a combiner in the system.

4.   I shortened it and ran  it to the starter solenoid, but the Alt heated up, then I ran the #6 to the house bank, same results.  

5.   I am agreeing with you it is probably a wiring issue, as it seems worse after a night on the hook. Or it could be a bad new battery, will check with a hydrometer.

1.  Nope, sorry you can't do that, see #2.

2.   As a repeat item, there simply is no ALL post on the 1-2-B switch.  There are three POSTS on the switch, 1, 2 and C (common).  There are four POSITIONS on the switch, Off, 1, Both, 2.  If you look at Dave's wiring diagram on that link, he shows it, so does my IN RED note on my long post.  C is where the power from your position of choice sends the current OUT from the switch.  Get your head around this concept and you'll start to understand.

3.  Maybe now you understand why we suggest you send us a wiring diagram and explain everything up front.  As I recall, you mentioned the separate starter battery in an earlier post.  You may want to stop complicating your life.  Stop separating your house bank(s) with the 1-2-B for separating your house banks, and simply make them one big house bank.  You are shortening the life of them if you keep them separate with the same daily load (draw), but putting them together on ALL with the switch combines anyway them, right?  So why bother with the 1-2-B switch for your house bank?  Either choose to have two separate banks (i.e., house bank and reserve or start bank) with one separate ON/OFF switch and a 1-2-B switch like Jim Moe's diagram (http://www.c34.org/wiki/index.php?title=Catalina_34_Electrical_System_Upgrade), OR drop the other on/off switch to your reserve bank and use ONE simple 1-2-B switch, like my system, and just like Dave's drawing. http://forums.catalina.sailboatowners.com/showthread.php?t=104505 I helped Jim edit that Tech wiki piece of his in 2004, and not much has changed.  Say hi to Jim and Jennie for me.

4.  #6 is still too small.  Just like last week's answer.  And just like your first post:  or maybe I need a bigger wire from the output on the Alt. I'll still bet that's what's causing your problem.  That and it could be the wiring of your separate reserve bank, which may be "on" to the starter solenoid at the same time your house bank is, too, which could be "combining" your house and reserve banks.  You wrote: If I run a Alt output wire directly to the house batteries, do I come off the output post on the Alt with a #4 wire, and snake it to the house bank under the floor sole and connect it one of the house  batteries? And do I run a new #4 wire from the C Post on the battery selector switch to the starter solenoid as per your Fig 3 drawing Answer: yes and no.  A new AO to the house bank.  You can use #4 with your 50A alternator, but I recommend a #2 just in case you want a larger output alternator inthe future.  You do NOT need to run a new wire from the 1-2-B switch to the starter solenoid because that wire should already be there.

5.   See #4 above, but not a bad idea to check your batteries with the hydrometer.

You, and we to help you, need a wiring diagram, because otherwise we're just guessing.

Your discussion of #12 or #10 wiring between the alternator and starter solenoid and, as you said, "to the switch" appears to be something related to the engine wiring harness, http://www.c34.org/wiki/index.php?title=Engine_Harness_Upgrade.  That small wiring did also go to the 1-2-B switch, and was the old small, inadequate AO wiring to the old ammeters in the cockpit panel and back to the batteries. That may be what you were referring to.

As I suggested earlier, drawing a wiring diagram first before you do anything, and then a final one, will go a long way to understanding what you have, for both you and for us to help you out.

This long link may help, too.  http://c34.org/bbs/index.php/topic,5159.0.html

[Bobg]

Hi, am attempting to send a crude wiring diagram, I drew it out and took a picture of it, hope you can understand it.  tried to scan, but came out horrible, I am going to change the ALT output wire to a #2 when I get to the boat,  this alternator heats up sizzling hot so quickly, (30-60 seconds) and stays hot for an hour or so.
The arrangement you see in the picture has worked for years, trouble started when I lost continuity on the AO wire, due to the melted wiring harness plug at the cockpit instrument panel.  I cut the connecting plug out and hard wired the connections to their prospective terminals.  I did not redo the plug at the engine as it looked fine, is it possible there is still a problem with the harness to make the alt heat up so fast?  with all connections off the alt, it does not heat up while running.  I also  checked the new batteries with a expensive battery checker, and I did the SP check, everything fine.  I tried dropping the DP ground off the battery to eliminate shorts at the DP. 
All Ground connections have been removed and cleaned, actually the one on the bell housing was in terrible shape, the ring terminal came off in my hand, I thought "Eureka" thats it, crimped and soldered a new one on, cleaned the connection, to no avail.

I tried a spare Alt and that heats up too. 

[Ken Juul]

If one end of the wiring harness was bad, chances are the other end is also bad.  Plugs themselve may look clean, but no way to see corrosion inside the rubber.  Before I went any farther, I would change the other plug.

Without re reading the whole thread, it appears from your wiring diagram that the only way to charge the second house bank is to have the battery switch in both.  Since you have the banks split for a reason, would it not be easier to add a automatic charge relay/echo charger to automatically charge the other house bank?

[Ron Volk]

I have a couple of questions regarding my batteries & alternator.  I have Prestolite 51 amp alt. ( Not sure what the internal regulator is set at). I have a 310 AH house system and a separate start battery.  What would be the consequences if I added a smart 3 stage reg. to the alternator without upgrading to a larger output alternator.  If I'm looking at say being 60-70 amps down on my batteries when I initially start the engine is there any difference in the operation of the alternator whether it has just an internal reg. compared to a external one.  Also, Mainsail discussed the mod. of an older Alt. to upgrade it to raise the reg. set point to 14.4V, how much difference will that make?  Thanks for any help.

[Stu Jackson]

Bob,

Very good job on the wiring diagram.  It is very helpful both to us & to you!

From this distance, and from your notes and the diagram itself, here's what I can offer so far:

1.   Wiring harness--- I agree completely with Ken.  If one end is shot, the other end MUST be redone, too.  I have never heard of anyone who only did one end, 'cuz it's hotter and nastier in the engine room than it is up at the cockpit panel.  Another possibility is that when you did the cockpit end something got misplaced or wired incorrectly.  We don't know, and maybe even now you don't, so you might consider yourself back to square one because the ONLY thing you claimed you changed was the cockpit end of the wiring harness.  I hate to be the bearer of bad news, but if it was my boat, I'd check them very carefully – again.

2.   The overall wiring setup appears that it will work. 

3.   The alternator has four wires leaving it:  #6 to the house bank, red, switch and tach.  What switch?  Where does the red go?  If you haven't yet, please see the "back of the old alternator wiring" diagram I posted, here:  http://c34.org/bbs/index.php/topic,4548.0.html  You need to be absolutely sure you have these correct at both end of the harness.  Those diagrams are a bit different than yours would be since I was installing a new alternator with an internal regulator, and removing an old AutoMac which dealt with the field wire somewhat differently, but the concepts remain the same.

4.   The alternator is grounded to the engine via the alternator bracket.  You have an M25XP engine.  That engine came with the "new improved" bracket already installed.  Are you VERY sure that that ground is solid?  You may want to consider checking the continuity of that ground and make sure there's nothing isolating the alternator from that bracket and the bracket from the engine – no fiber washers, the studs are tight on the bracket, the bracket's tight to the engine.  You may also want to consider simply adding a ground wire from the alternator ground to the engine ground bolt.

5.   You already know about the #6 wire, won't beat a dead horse.  Your note #3 says: "Alt stays cool when all wires are disconnected."  You may want to consider dealing with a wire at a time so you can play detective yourself and find out which wire is the culprit.  That'll narrow down your search.

Did you see Jim Moe?  Any input from him?  I'd start on the harness. 

Ken's also right about the combiner location and your unusual arrangement of your house bank, but why not wait for another day until you get this sorted out.  It's only an operational / switch issue that can be addressed with a simple wiring change, but let's not complicate "this" situation with other changes until you get this one corrected.

[Ron Hill]

Ron : WOW ! there have been numerous posts on this very topic and volumes written on it - just on this web site.
First you can add&do need a 3 stage external Voltage regulator to your present 51 amp Prestolite, but first you need to (have someone) disconnect the persent internal V-regulator and wire the new one into it's place.

I'll let Stu give you a dissertation on "how to and why you need to" get a better charging system - if you usually don't live off of shore power.  

[Stu Jackson]

I have a couple of questions regarding my batteries & alternator.  I have Prestolite 51 amp alt. ( Not sure what the internal regulator is set at). I have a 310 AH house system and a separate start battery.  What would be the consequences if I added a smart 3 stage reg. to the alternator without upgrading to a larger output alternator.  If I'm looking at say being 60-70 amps down on my batteries when I initially start the engine is there any difference in the operation of the alternator whether it has just an internal reg. compared to a external one.  Also, Mainsail discussed the mod. of an older Alt. to upgrade it to raise the reg. set point to 14.4V, how much difference will that make?  Thanks for any help.

Ron V,

Great question.

I'll save the dissertation, 'cuz Ron's right, as usual, it's all here.

What I can provide are a few links and directions, some or most of which you may have already employed.  You can measure your existing alternator output voltage very easily at the house bank when depleted with the engine running, no shorepower.  Let us know what it is, then we can better respond to setpoints or Maine Sail can let you know.

Perhaps the "Momma of All Write-ups" is this one by Maine Sail.  I got there by doing a search on "Leece" and this one was the second one down.

That said, Maine Sail and I diverge slightly on using an existing OEM alternator with the newer three stage charging from external regulators.  I think if an OEM alternator is ready for reconsideration, OR if all you want to do is improve your charging from the engine, then you know it's time for a full upgrade, not just part of it, and leaving the part of it that works the hardest and you're now demanding even more from it.  The two parts are the alternator and the regulator.  And I think that an old alternator may not take the demands of running full time on bigger house banks.  Ya gotta change the AO anyway to deal with the bigger alternator to bank current.  MS figures they can handle it I believe.  Hence, the Leece discussions and his excellent Leece write-ups and this one in particular.  I'll let him chime in here, too.  I've been known to misquote him all too frequently, and this probably won't be the last!

http://c34.org/bbs/index.php/topic,4879.0.html

The first topic in the search results is a good one, too.  This one summarizes this topic, too:  http://c34.org/bbs/index.php/topic,5686.0.html

Read 'em all.  If you have already, then my advice is up above.

If you are depending on your alternator for longer cruises, get a bigger alternator and it can be either internally or externally regulated.  You'd get more bang for the bucks that way, and Maine Sail should agree, since his boat had an internally regulated alternator and the POs spent five years cruising keeping the house bank between 50 and 80%.  If you have shorepower and are a marina hopper, either leave it all alone until you HAVE to replace the alternator, or if ya just wanna spend unnecessary $$ slap an external regulator on what you have, 'cuz it won't see much load on the old alternator anyway.

And this even yet another opportunity to suggest that "It All Depnds on How You Use Your Boat."  ...and how it's wired.

Thanks for listening, and, as always:

Your boat, your choice

[Ron Volk]

Stu,

Thanks for your reply, I have read the 'Catalina Electrical System Upgrade' by Jim Moe, the Ample Power Technical Docs., and a variety of the web site information, but had not seen much about using the std. Alt. with a smart Reg.  Thanks for your 2 web site references and your thoughts, this has helped me.

Thanks Again,

[Bobg]

Thanks stu and all, will go up to the boat today and do a little troubleshooting, will have company the weekend, and work next week, so won't be able to do the other end of the harness upgrade for about 10 days

Stu the switch you asked about is the ignition switch at the cockpit panel, the purple wire gets power when the switch is turned on, I have verifyed it works.  not sure where the red wire comes from, but I do believe it is from the switch as well, I will run that down.  the only other two wires are the tach and output wire.

I agree that I must reexamine the cockpit instrument cluster and make sure all is well there.

I will try starting the engine with one wire off at a time and see if I can narrow it down,  trouble with that, alt heats up so fast (30-60 sec) and stays hot for a couple of hours, but I can deal with that, lots of other things to do on the boat while the alt is cooling back down.

I can see now why the PO told me to leave the battery selector switch in the all position,

I have cleaned all grounds and ran a seperate ground from the alt case to the block, didn't make a differnce though,

Thanks for the help and hopfully I can get back with good news,   Bob

[Stu Jackson]

not sure where the red wire comes from, but I do believe it is from the switch as well, I will run that down.  the only other two wires are the tach and output wire.

Bob, the red wire has to be for the power to the instrument cluster and has to come from the inside panel because it doesn't go on unless you turn the 1-2-B switch or perhaps your secondary reserve bank switch.  Trace it out.

Good luck.

[Bobg]

OK guys, after a 2 day boat working holiday, I have come to the conclusion that my 55 amp Mando Alternator just can't charge my new 6 volt T105 golf cart batteries with out burning up.  Batteries have all been tested with a very expensive tester and also the specific gravity of individual cells have determined all batteries are good.

I did the wiring harness upgrade on both ends before starting my Alt testing, the plug at the engine was also burned up, now it has been replaced with a nice terminal strip.

OK, I first took all house boat loads  off the system, (ie) I removed the #4 wire that goes to the dist panel and the ground, I disconnected the combiner,  I then made up a #2 ga wire for the AO and used that on all tests.

If I connect only my reserve (start) battery to the alternator, I get 14.40 volts off the Alt, same reading at batt terminals, and a cool alternator.

If I do the same as above with a spare battery I brought with, I get the same results.

If I attempt to charge any two of a combination of 4 6 volt batterys, the alt puts out 13.65 volts, slowly climbs to around 14, but the alt heats up so fast I have to shut it down or it will lock on me.

All these tests were taken with all boat house systems disconnected.   new #4 ground from the neg on the battery to the engine, a #4 wire from the + on the battery to the starter solenoid..and the #2 from the AO to the + on the battery. Pretty simple and forward. 

The marina mechanic has seen this before where a alt just will not work on a bigger amp battery without getting impossibly hot, couple minutes you can light matches off it.

The mechanic suggested I only wire it to the reserve (start) battery located behind the engine, and charge the 4 6 volts with shore power and when (out there) recharge with my Honda generator.

Or as he was doing to another boat with the same problem, install another external adjustable regulator that is a extension of my internal regulator that will limit the AO  up to 5 amps.  Or as he suggested get a nice Balmor AO with external 3 stage reg.

Course it is still possible my new Alt just ain't a good one, I don't recall ever having a problem like this with my old 55 amp Motorola.  Bottom line, it won't charge 2 6 volt golf cart battery's with clean connections and new cables.  using the same scenario it will work perfectly on smaller 12 volt batteries.  Thank you all and escpecially Stu, I am going on to other boat projects that are more fun, like bright work and cockpit shower installation   Bob

[prh77]

If you did not have this problem with your original Motorola, it sure sounds like an alternator problem.