Alternator -- New or Rebuild?

[Stu Jackson]

DH, a not unreasonable conclusion. Except....

I had two alternators rebuilt last year. Slapped one in and went cruising. After about 30 hours, the alternator started sparking!!! The isolator between the +V post and the case had slipped off and melted!!! I disconnected the regulator and alternator output and managed for get home by spending a night plugged in at a marina (I don't have a generator).

I did have another alternator ready to slap right in, but it was in my garage at home - did me no damn good since I was on the boat and it wasn't!!!

I was two days sailing away from home, but only a two hour drive from my house. The car was also in the garage!

I put the spare alternator in when I returned, had the busted one repaired and it now lives on the boat. Seems a lot easier, and my boat's only 34 feet. I think you can find the room.

Yes, in retrospect I probably could have cobbled together a fix for the isolator.

Your boat, your choice.

[Dockhead]

Originally Posted by Udacha

If you have it rebuilt you can ask them to increase the amps output. I recently had the one on my motorhome rebuilt and increased the output to 200 amps and could have went up to 500 amps.

Or, they are not too difficult to rebuild yourself and buy a few of everything so you can make repairs anywhere

Good luck with it

Thanks. I would be tempted to do it myself -- always really useful to have had something apart, in case you need to fix it in the field -- but just too busy and too many other things to fix.

I think this is one of those things which is reliable enough that you don't need to spend a lot of time worrying about it.

[Cadence]

Originally Posted by Dockhead

Well, I am pretty fanatic about spare parts on board. For example, I have a repair kit for every single pump on board, and a couple of spare entire pumps for critical things.

But you have to be rational about carrying spares, because it would be too costly, too bulky, and too heavy to carry spares for everything.

So I look at it from these points of view:

1. How likely is it to fail?
2. How difficult is it to repair or source out in the wild?
3. Is it mission critical, or backed up by something?
4. How bulky and/or expensive is it?

So I come out wrong for this particular item on all points -- very reliable, quite easy to fix even in third world countries (it's a common school bus alternator), it's not mission critical (I can use my generator), and it's fairly bulky and expensive.

Therefore, I have decided not to carry a spare.

I found a guy recommended by other cruisers, who is local to me and who specializes in alternator rebuilds. He replaces all wear parts (including bearings, etc.) and anything which is broken or sub-standard, and gives a year warranty.

Seems good enough to me.

I hope you are right. I have a friend that rebuilt them long a ago, as a summer job. Most brightening up the housing and replacing diodes. I have had good luck with auto alternations rebuilt, but the tow truck is close

[GrahamHO]

Originally Posted by svseawitch

Over the course of a 10 year circumnavigation, we did not have great results on a number of rebuilds. We had rebuilds done in Mexico, Costa Rica and spain. Each of the three repairshops had differing opinions regarding rewinding methods, wire thickness and wire coating. None of the rebuilds were done to original specs. And none of the 3 rebuilds lasted more than a year. The original alternator went about 5 years before the first failure

All my alternators were the Balmar single belt models with an external smart regulator that was dialed back a bit to improve belt life. Dual belt setup is just not practical in our engine room.

When we got home from cruising, I bought a couple new Balmars and got rid of the failed ones.

Note: none of the repair shops did the work to make the alternator "like new" The cost to: rewind everything, replace all the diodes and replace bearings was not really a savings over a new alternator.

Sounds like a lot of experience. But for others if you don't have room for a double belt on your alternator drive you can make the alternator pulley a larger diameter than original. I made mine 10 mm larger diameter than standard. That both increases belt wrap and decreases the load, like a bigger cog on a bike wheel. It made no noticeable decrease in the charging rate. Probably a little less only on idle. The pulley was machined and fitted by an engineer. The original Hitachi pulley was two segments of pressed steel with poor contact area.

Motorcar alternators can spend a lot of time idling in traffic which is one of the several reasons cars changed from generators to alternators maybe in the 1940s. But boat motors can spend a lot of time at 2/3000 rpm where a 10 mm larger pulley does not decrease the charge in practical terms.

This resulted in greatly decreased belt wear using a smart regulator.

[Kenomac]

I'd buy a new alternator, then have the old one rebuilt to have as a spare. I just did exactly that with a generator water pump. I do the same with all our pumps onboard. Will also buy a spare engine starter motor for next season, after having one fail last season.

Don't be cheap, it'll always end up biting you in the ass... just like your used sail experience last season.

BTW: did you end up getting a new set of sails?

[dannc]

DockHead,

Dear Sir,

I will be sending you a bill for the new alternator I had to buy today for my truck. The alternator was just fine until I read your discussion about your boat alternator and I think said discussion jinxed my perfectly fine alternator. The fact that the alternator is 14 years old and has 205,000 miles on it is not important.



The new alternator is 110 amps and was 202 USD. A rebuild was only $38 cheaper. After this thread's discussion of rebuild vs new, as well as my own dislike to buy used, I went with the new alternator. Should be here Friday to install. The alternator started acting up this morning on the drive to work and it worked just enough to get me home without leaving me on the side of the road.

Later,
Dan

[model 10]

Not all new alternators are so great. I don't know about bus alternators but a Balmar is a good alternator. A rebuilt Balmar is a much better alternator than many other new alternators. It would be a waste to not rebuild it.
I carry as a spare brand a new Delco 100 amp 1 wire "marine" alternator. They cost under a $100 on EBAY. It looks good but I bet it's made in China. I used one 2 years ago to get home .It was a direct bolt on for the Balmar and probably took 20 minutes to install. It was complete toast after about 1000 miles. It always ran super hot. I've bought another one for a spare. I really can't afford another Balmar and another smart regulator as spares.

[hellosailor]

Dan-
If you are in the US, take a very good look at the box which your "new" alternator comes in. Dollars to donuts it will say "remanufactured by" or some other term. No one in this country manufactures actual new alternators at that price, unless it is "new" by BillyBob's Beaudacious Alternator Company. Go to Toyota, Honda, GM...order a new alternator for a ten year old car, and it inevitably comes in an OEM branded box, but says something about being reborn.


That's why there is always a "core charge" for the dead one. The frame from the dead one gets stripped down and cleaned up, and it becomes the not-really-new one that you buy for $600 or more. Remanufactured, just by the authorized remanufacturer, not BillyBob.

[Stu Jackson]

Originally Posted by hellosailor

......not BillyBob.

Billy Bob here, just though I'd chime in. They ain't been makin' anything new here in this country since 1999. Heck, I don't mind, it keeps me in business rebuilding alternators. And labelin' them new!

[Dockhead]

Originally Posted by Guy

Not all new alternators are so great. I don't know about bus alternators but a Balmar is a good alternator. A rebuilt Balmar is a much better alternator than many other new alternators. It would be a waste to not rebuild it.
I carry as a spare brand a new Delco 100 amp 1 wire "marine" alternator. They cost under a $100 on EBAY. It looks good but I bet it's made in China. I used one 2 years ago to get home .It was a direct bolt on for the Balmar and probably took 20 minutes to install. It was complete toast after about 1000 miles. It always ran super hot. I've bought another one for a spare. I really can't afford another Balmar and another smart regulator as spares.

Keep in mind that Balmar don't make alternators either. I believe they are relabelled Prestolite alternators (which is also what my Leece Neville is if I am not mistaken).

Balmar also sell the British made Smartgauge battery monitor -- relabeled and at double the price, but precisely the same device.

[a64pilot]

Paint on anything that you want to radiate heat and cool itself is a no-no as well

[transmitterdan]

Originally Posted by a64pilot

Paint on anything that you want to radiate heat and cool itself is a no-no as well

There are many paints that promote cooling by radiation. The emissivity of many black paints is significantly higher than bare steel or aluminum. Paint of the right type and color is not a no-no. It can be very helpful.

[a64pilot]

Originally Posted by transmitterdan

There are many paints that promote cooling by radiation. The emissivity of many black paints is significantly higher than bare steel or aluminum. Paint of the right type and color is not a no-no. It can be very helpful.

Did a little searching, and you appear to be correct, although I don't understand tape?
Methods of Increasing Emissivity in the Infrared Spectrum
Continued looking and found that apparently surface texture is more important to emissivity than color, flat paints are much better than gloss at radiating in the infrared

[dannc]

Originally Posted by hellosailor

Dan-
If you are in the US, take a very good look at the box which your "new" alternator comes in. Dollars to donuts it will say "remanufactured by" or some other term. No one in this country manufactures actual new alternators at that price, unless it is "new" by BillyBob's Beaudacious Alternator Company. Go to Toyota, Honda, GM...order a new alternator for a ten year old car, and it inevitably comes in an OEM branded box, but says something about being reborn.

...

The box says 100% new and the alternator looks new as well. I was looking at the screen when the parts guy and I were looking at alternators and he selected the new one. Not much difference between new and old. It is new and fresh from China.

There is a core charge but it is only $12 US. I suspect the regulator is fried and I might try to fix it since I don't know how long this new alternator will work. Reports on the truck website are not encouraging about the alternator lasting.

Later,
Dan

[becrux]

My Balmar alternator is toast, but the regulator is fine. My alternator guy tore the alt apart and did a little research on it. Said it was built in Argentina and marinized just up the road a piece by Balmar who painted it white and sold it as theirs. He said he couldn't get the parts to fix it.
I could probably find another shop to do it. I might just try it myself. As someone else said, it isn't a lung transplant. Balmar's replacements are just too damn expensive and Mark Grasser's are about half that- still too damn expensive. For that kind of money i could buy 6 or 12 Chinese alternators and toss'em when they fry.
I still want to use the excellent Balmar regulator, though. It isn't rocket science to bypass the internal regulator on the cheapo and add a wire for the external regulator (requires soldering a wire to a brush.) Think I'll get two cheapos, and slap one in as is while i tinker with the other one. When i get the other one set up, i'll swap 'em. Then i'll have a go at the fried Balmar.
The cheapos aren't fully insulated, but that's overrated. For the money... $78 includes shipping, compared to $449 or $1000+
If nothing else, it's a cheap spare.