More Alternator questions

Stu Jackson · Jun 3, 2020

The external regulator should be able to "tune down" the alternator output (AO) to avoid belt dust issues.

I'll find some links for you about these things.

Oh, here they are:

Alternator heat, Regulator Controls, Small Engine Mode

Alternator heat, Regulator Controls, Small Engine Mode

Small Engine Mode - discussion with link to the picture of the toggle switch: Alternator heat, Regulator Controls, Small Engine Mode

Small Engine Mode - the picture of the toggle switch Alternator Output Management with External Regulators [Small Engine Mode]

Programming a Balmar Voltage Regulator: (Thanks to Maine Sail)
Programming a Balmar External Voltage Regulator - Marine How To

CarlN · Jun 3, 2020

If your regulator is a Balmar, here’s MaineSail’s exhaustive guide to programming it. I always set the belt load down a bit on mine to reduce load on the engine and belt wear. It doesn’t reduce your charge amps significantly.

But most large alternators create some belt dust. If the belt is lasting over a year it may just be easier to clean the dust up occasionally. I doubt that alternator is big enough to overload the engine.

Programming a Balmar External Voltage Regulator - Marine How To

Preface This article contains three separate videos that show how to physically program Balmar regulators. The videos are meant to be watched in conjunction with reading this article so the misconceptions and misunderstandings I have identified over the years, regarding these regulators, can be...

marinehowto.com

Stu Jackson · Jun 3, 2020

Alignment?

dlochner · Jun 4, 2020

Belt alignment and belt tension may be causing the belt dust.

20 year old hoses? Time to replace not a big job.

What does "high output" mean? How many amps? A ½ inch belt will work up to about 90-100 amps of output. I have a 90 amp CMI alternator driven by a ½" belt, no issue with the belt manager on the the regulator dialed back a bit.

Maine Sail · Jun 4, 2020

We would need to know what external regulator is being used (brand & model) and what the rated Amperage of that alternator is.

With the 1/2" belt on that engine, you should be limiting that alternator to a max of about 65-80A. This is due to the limited belt wrap on the alternator pulley. Balmar external regulators allow you to "de-rate" the alternator via their Belt Load Manager, or in earlier models "Amp Manager", feature.

This article should help:
https://marinehowto.com/marine-alternator-installation-tips-tricks/

Maine Sail · Jun 4, 2020

If it is 125A then you have two options:

#1 Make sure you have a Balmar, Xantrex XAR (The XAR was made by Balmar), or Wakespeed regulator that will allow you to current limit the alternator down to a safe level for the belt. A 125A alternator is far too large for a single 1/2" belt, which already has limited belt wrap.

#2 Order a Balmar/Alt-Mount serpentine kit for your engine.

kloudie1 · Jun 4, 2020

Apex Alternators

Customized High Output Alternators

apexhighoutputalternators.com

Stu Jackson · Jun 4, 2020

Scott T-Bird said:
I was thinking I would need to do #2 if the alternator is 125 amp.

Not neceassarily. I run a 100A alternator off a 3/8" belt on my M25 engine with a Balmar regulator. I discussed all this in the links posted earlier.

dlochner · Jun 4, 2020

Think about how many amps you need to get out of the alternator.

The load issue MS mentions is if the alternator is running at maximum output. If the belt manager on the regulator is used, the output can be lowered to 65-80 amps which the ½" belt will handle.

Scott T-Bird said:
On the topic of batteries, I don't now that I even need over 400 AH. Our current use is satisfactory with just 200 AH. I am considering lightening the load with just one pair of golf carts. If I use a pair of 6-volts at 225 AH each, am I correct that it is roughly 225 AH when paired for 12-volts? Or is there some factor that reduces the amp-hours appreciably?

Correct if you put 2 225 ah GC batteries in series you'll have 12v and 225 ah capacity. However, that may not be enough for your needs. Realistically, there is only about 112 ah available if they are discharged to 50% SOC. That may be fine for weekend overnights or staying at marina with shore power, however, if cruising and staying on anchor it will probably an insufficient capacity because the SOC will seldom go above 80%. As the batteries age, the capacity will decline as they will if discharged below 50% or left in a PSOC. Effectively there will be 67 ah available.

Maine Sail · Jun 4, 2020

Stu Jackson said:
Not neceassarily. I run a 100A alternator off a 3/8" belt on my M25 engine with a Balmar regulator. I discussed all this in the links posted earlier.

But Stu you also say use small engine mode, a 50% cut in field potential, and also claim you never see anywhere near full output from your alternator. With minimal belt wrap, as many marine engines have due to water pumps, the 80A for 3/8" and 100A for 1/2" are not always realistic, especially if you have a large bank or a high acceptance bank.

We have a customer who used GC2's for years with a 100A alternator on a 1/2" belt. He had a tolerable level of belt dust and a perfect alignment. The minute he switched to Firefly AGM batteries, no other changes, he burned out two Gates belts in 30 engine hours and also melted the front bearing seal right out of the drive end bearing of the alt...

Unless you have 180 degrees of belt wrap the 80A & 100A guidance is a bit off. This is where small engine mode, belt load manager or amp manager come into play..

Stu Jackson · Jun 4, 2020

Maine Sail said:
1. Unless you have 180 degrees of belt wrap the 80A & 100A guidance is a bit off.
2.This is where small engine mode, belt load manager or amp manager come into play..

1. That's not what I said, nor what my links discuss
2. I agree, which is what my links describe

And, of course, if some dummy puts in Fireflys and wonders why he burns stuff up, he needed to read your material first.

And sometimes when I read Scott's posts, I wonder why he hasn't been "keeping up" with material you and I have written for the past 2 decades on boat electrical systems. It then occurred to me that the boat he has had and his cruising just hasn't warranted the level of detail he's now getting into.

He should be thankful for all the information he now has at his fingertips - stuff we never had when we got started. Remeber "The Good Old Days?"

jviss · Jun 4, 2020

Scott T-Bird said:
Echo charger is something I am not familiar with.

The Echo Charger is to charge a starter or other auxiliary battery from your main bank when there is a charging source connected to the main bank. I have one now, and have had one before, and have had one of them fail. I like the idea of an echo charger, but would probably use an ACR next time.

Stu Jackson · Jun 4, 2020

Scott T-Bird said:
It seems to me that it doesn't make sense to get a higher output alternator only to regulate it down for belt management. The Powermax seems to advertise "highest output at idle speeds". Maybe it makes sense when there is no access to shore power, but that's not my situation. Surveyor recommended that I add a battery charger. On board right now is just a Xantrex echo charger. I suppose that is used to charge the auxiliary battery from the charging source that would be either the solar panels or the alternator? Echo charger is something I am not familiar with. I'm only familiar with the Sterling Pro Charge Ultra.

Glad you found out what you have. Which is, actually, pretty superb. Good alternator, the best regulator.
Often, the "it doesn't make sense" eventually does when you dig deeper. The concept is to have a larger alternator work less hard to supply the given demand from the batteries when charging. It is a tried and true approach.
1. A reasonably sized battery bank of 400 ah, when empty (50% discharged) can take anywhere from 50-70A. The idea is to have the alternator work less hard, since a 70A alternator would be running full out and get hot.
2. One derates the AO either with belt manager or SEM as discussed in my links.

Scott, MS and I have been writing about these things for years and we have both shared as much as we know. He has his own website. This is my contribution:

Electrical Systems 101 Electrical Systems 101

Happy learning, we're here to help.

dlochner · Jun 4, 2020

Scott T-Bird said:
It seems to me that it doesn't make sense to get a higher output alternator only to regulate it down for belt management. The Powermax seems to advertise "highest output at idle speeds". Maybe it makes sense when there is no access to shore power, but that's not my situation. Surveyor recommended that I add a battery charger. On board right now is just a Xantrex echo charger. I suppose that is used to charge the auxiliary battery from the charging source that would be either the solar panels or the alternator? Echo charger is something I am not familiar with. I'm only familiar with the Sterling Pro Charge Ultra.

I'll just add to what @Stu Jackson said. Running the alternator below its full on rated capacity prolongs the life of the alternator. Heat is the enemy, an alternator running below its capacity generates less heat and becomes more efficient, especially if the regulator has temperature compensation. Temp compensation for the alternator and the batteries will reduce the alternators output.

Benny17441 · Jun 4, 2020

From what you are saying about your needs you could consider replacing that alternator with a 55A with internal regulator and avoid having to change pulleys or regulator to detune that thing. The Battery Bank at 225Ah is not that big to require more than a 55A alternator and you say you do not run the engine that much anyways. Put your money on a good inboard charger.