Inexpensive High Capacity Alternators

[Ray & Sandy Erps]

A few years back, Jim Moe gave C-34 owners some great advice on a source for a high output alternator.  I installed one on the C-34 we had and it worked great. 

I just recently did a major boo-boo on our current boat and damaged one of the alternators.  It was a 105 amp Lestek alternator.  When I started looking for repair parts for it I found that Lestek, Balmar, Ample Power, Powerline and others each have high capacity alternators based on a cheap old Delco Alternator that was popular in the 60's and 70's.  I just re-read Jim's post, and it appears that the Blue Circle alternator is also based on the same Delco, although that still needs to be confirmed.  The Delco is model 10-DN, called a three wire alternator, because it was externally regulated.  If you google Delco 10dn, you'll find quite a bit of information about them.

You can buy a used Delco at an junk yard for around $25.  You can buy a 105 amp rebuild kit that includes diodes, stator, brushes and bearings for just under $40.  These Delcos come apart and go together pretty easy compared to other alternators I've been into.  So for under $80, you can build your own high capacity alternator, or if you already installed the blue circle alternator, you can have a repair kit that replaces diodes, brushes and a few other parts for around $20.

My current boat has two alternators on it.  After doing this little bit of research, it turns out that they're both Delco's and the one repair kit will probably work in either if I screw up again (sometimes it takes me a couple of times to learn from my mistakes).  Unfortunately, I learned all this a little too late, because the Lestek is already in the shop and I'll probably end up paying a large fee for a kit that costs $20.  Nutz.

[Stu Jackson]

Ray wrote: " I just re-read Jim's post, and it appears that the Blue Circle alternator is also based on the same Delco, although that still needs to be confirmed."

Consider it confirmed, we have one.

[johan]

Ray,

thanks for the info. I have the Blue Circle alternator (thanks Jim Moe)
Five minutes after reading your post, I'd ordered the repair kit on Ebay ($30, incl shipping)
Hope I never need it!

Tony Dolk

[Lance Jones]

Where can I obtain said alternator (Blue Circle)?

[Stu Jackson]

Where can I obtain said alternator (Blue Circle)?

In the tech wiki, this article.  This thread is seven years old, so Blue Circle may not be in business anymore.

Electrical system upgrade: A comprehensive electrical system upgrade by Jim Moe

http://www.c34.org/wiki/index.php?title=Catalina_34_Electrical_System_Upgrade

In that case, either a series 6 Balmar, go here: 

http://www.ase-supply.com/Leece_Neville_110_603_12V_90_amp_ALTERNATOR_p/mo-110-603.htm

This is NOT a specific alternator choice, but a link to the website.  Call them and talk to Bob.  IIRC, my notes say if I was going to do it, I'd do this:

future--Leece Neville  ASE 110-602 plus Kit 1070 #114-307    The kit's for the external regulator we have.

[Lance Jones]

Thanks Stu!

[Noah]

I got my 90 amp Leece-Neville 8MR Series alternator (and external regulator adaptor kit) from Spyder Marine. Was about $275 including shipping I believe. Maine Sail has some info on this alternator and kit on his website

[mainesail]

There is actually a lot of difference between a heavy duty high output 10DN and an eBay parts 10DN. All our marine alternators are "based on" any one of 15 or so well utilized cases. Hitachi mount, CS130D, 10DN, J180, Motorola etc. etc.. eBay parts can get you through in a pinch but won't hold up to the abuses of AGM, GEL or large flooded banks for the long haul. Low RPM output performance will also be lacking...

I used to offer my customers a 10DN cased alternator & I used the same exact USA builder Ample Power does only I beefed my specs beyond theirs. Today I build my high performance alts based on the Delco CS130D case or a Denso based case as the dual internal fans simply cool better than the older 10DN case does. Same specs apply...

Most recently I have been trying to develop a Hitachi case 80-105A externally regulated inexpensive alternator. So far every single one I have built and tested has failed the testing in 25-40 minutes when driven to full field.. Inexpensive and severe duty do not mutually go hand in hand. Problem is if I spend any more than where I am now I am into one of my actual high performance alternators.....

Here are just some of the differences in what makes these true heavy duty alts and not just "high output for a few minutes". This is also why they are more expensive. My cost on parts alone is at least 4 - 6X what I can buy eBay level parts for...

*Hand wound stators, wound specifically for low RPM performance (these are wound here in the USA not on a machine in China).

*14GA magnet wire.

*The best quality magnet wire with higher heat tolerance than standard run of the mill magnet wire.

*Precision machined rotor and slip rings for greater contact at all RPM.

*Stainless steel fan

*1", 2" and 3.15" Foot Mounts

*Tighter tolerance stator/rotor gap for better performance. A feature not found in standard alternators. This is 3X the tolerance of standard alternators.

*Precision milled stators utilizing a special dacron/mylar insulator. The industry norm is paper.

*Stainless draw bolts, pivot bolts and adjustment bolts

*Hot run tested to ensure performance is met

*Stator Tap

*Rotor is precision balanced to .015 ounce inches. Industry norm is .050 - .090 eBay norm is over 0.100. This means SMOOTH operation and less harmonics...

*Motorola 50A X 100V press fit diodes. Industry standards are no-name Chinese button diodes and 25-30A rated. These diodes carry a performance rating to 300F.

*Internal wire leads are ultra high temperature acrylic coated fiberglass insulation sleeves not cheap rubber sleeving.

*Brushes are high copper content composite not run of the mill carbon brushes. This yields superior conductivity and considerably longer life.

*Isolated ground option which means the neg terminal is 100% isolated from the case. This is a significant cost upgrade over case ground alternators. Both the positive and negative studs are 5/16" not wimpy 1/4" or #10 studs. These studs are bolted directly to the rectifier bridge for the best possible connection. Industry standard is a compression fit.

*High quality USA made bearings with a 350F performance rating.

*On my new CS-130 based alts there is an internal regulator as a fall back safety net.


For the average boater with a small bank of flooded batteries even an auto based alt will be fine. As you move to larger banks or AGM, GEL or TPPL AGM then consideration should be given to an alt designed to handle that type of abuse and even then they need proper set up...