Alternator upgrade thoughts for Yanmar

[SycloneDriver]

I've been doing a lot of research trying to find an affordable alternator upgrade for my 3YM20. I've considered modifying the mounting bracket to allow the use of a Delco unit, there are many to choose from. I've worked on many of them 25 years ago when I sold auto parts. The information on the Delco and many other manufactures is readily available, but not so much for the Hitachi. I would prefer not to have to modify the brackets. I really don't need an upgraded alternator, I didn't need a bigger boat either but it happened. As a power guy I just hate seeing the charging rate of less than 5 amps, @ 13.4 volts when the batteries need 20 more AH. After 15 minuets of motoring I was charging @ 3 amps and a few minuets later it was @ 1.5 amps, SOC was 88%. I know this is caused by the internal regulator.

*** I'm fully aware of the limits of the stock Hitachi alternator. ***
I was thinking about purchasing a Hitachi 80 amp unit and modifying it with a better fan from a Delco 12SI, although I'm not sure it would fit or make any real difference. This would be marginally better than the 60 amp unit I have now. I'm sure I could cut/hack and bring the field wire out and use an external regulator. I like a good science project but I'm not sure I want to reinvent the wheel.

I could just spend the money on a Balmar but I really don't need it.

Thoughts?

 

[Ralph Johnstone]

Install an exterior alternator regulator before doing anything else. I suffered the same problem before I installed a Balmar ARS-5.

The first time I fired up the engine after the regulator install, this is what I saw:

Previously, the most I had ever seen was 12A in bulk charge. An increase of 300% in charging.

 

[SycloneDriver]

I thought about modifying the factory alternator for external regulation but I really hate to do that to something that I'm unfamiliar with. I cannot go to the local parts store around here and buy a replacement if I screw it up.

Apparently real Hitachi units are getting hard to find and they are expensive.

 

[garymalmgren]

Listen to Ralph!

gary

 

[dlochner]

There are several good articles on the MarineHowTo.com website.

The Hitachi alternators on Yanmars do you no favors. They are apparently also difficult to convert to external regulation.

The only real solution to better charging from an alternator is an external programmable regulator. Balmar makes the 618 which with the smart shunt and Blue Tooth is far and away an easier regulator to deal with. Wakespeed makes the state of the art regulator that uses current rather voltage to set the charging voltage.

The best option on the market was the Compass Marine alternators, well built external alternators. Unfortunately since MaineSail had his stroke his business is closed, although he continues to contribute here and elsewhere.

Last year I found an old new stock Balmar AT165 for at Hamiton Marine for much less than a new smaller alternator. There are probably still older alternators still kicking around.

 

[SycloneDriver]

I would love to add external regulation but I've never been inside a Hitachi like the one on my boat. I think it may require the use of a saw to access the brush leads. I'm unwilling to destroy a working alternator that would be difficult and expensive to replace.

I had hoped that someone would know of drop in unit. The 2000 Dodge truck looks very close. Several Nissan units look close. I have a Mitsubishi alternator that looks like it might work. I'm afraid that units form cars may not have enough output at low RPM.

I have found many new/rebuilt alternators online. Some of them at prices so low that I really suspect that they are junk. One that holds promise is the Wilson 70-25-12272. I suspect it would still require the use of a saw to modify it.

This would sure be easier if I could use a Delco unit. I could modify the top mount and then use a 12SI, CS130 or AD230. I could build a new mount and keep my original. I just don't think it's worth that much effort.

Maybe a battery to battery charger is a better short term solution. It could be reused if I ever convert to lifepo4 batteries. Even a quality B2B charger isn't that expensive.

Last night I managed to find some alternators that are even more expensive the Balmars and they appear to be modified Delco 12SI units. This makes the Balmar look more attractive.

I should probably stop wasting my time and go sailing!

 

[Davidasailor26]

In case it helps - We added a Smart Shunt to our house bank this winter to start seeing how much we’re actually able to recharge the batteries with our stock Hitachi 80A alternator. Our first interesting test was a few days ago with a short bit of motoring after about 7 hours of sailing.

The top plot is house bank voltage and State of Charge while the engine was running at cruise speed for about 25 minutes. Bottom plot is the house loads (yellow) and net current going into the bank (green).

So as the bank charged from 75% SOC to 82% SOC the alternator was pushing over 30A (plus up to 10A more for the loads). The way that the net current stays pretty constant while the loads vary makes me think the batteries are the limiting factor at this SOC, not the alternator.

Our house bank is 2x Group 31 AGM’s. It’s still early in the year so the air is pretty cool, and I haven’t had a chance to run the engine from a lower SOC for a longer period. I’m curious to see how the alternator output responds once it’s more challenged.

 

[SycloneDriver]

David,

Tell more about your Smart Shunt. It appears that you might have 2 shunts. All that data is very interesting!

I have a Victron Smart Shut but I don't have nearly that much data available.

My house bank is just 2 flooded group 24s. I do have a good 30 amp shore charger. The boat lives on shore power 99.8% of the time. I don't need a better alternator I just want one. Some day I hope to take the boat down the ICW from Oklahoma to the Gulf and on to Florida, I'll need a better alternator then.

 

[Davidasailor26]

David,

Tell more about your Smart Shunt. It appears that you might have 2 shunts. All that data is very interesting!

I have a Victron Smart Shut but I don't have nearly that much data available.

My house bank is just 2 flooded group 24s. I do have a good 30 amp shore charger. The boat lives on shore power 99.8% of the time. I don't need a better alternator I just want one. Some day I hope to take the boat down the ICW from Oklahoma to the Gulf and on to Florida, I'll need a better alternator then.

I do have 2 shunts - the load amount is from the original shunt that came with the boat, located on the ground for the regular house loads. That one doesn’t see the changing circuit or a couple loads like the windlass or bilge pump. I added the Smart Shunt directly to the battery so it measures the net charge/discharge. I have a Raspberry Pi setup to read the data from the shunts and some other sensors, and that’s what helps with the graphing. I plan on documenting the whole architecture and code at some point and I’ll be sure to post a link when I do.

 

[Maine Sail]

If you're on a budget a Balmar 6-series(YANMAR 3.15" saddle-mount). is your best option..

https://marinehowto.com/automotive-alternators-vs-deep-cycle-batteries/

 

[Ralph Johnstone]

I thought about modifying the factory alternator for external regulation but I really hate to do that to something that I'm unfamiliar with.

I was of the same mind when I decided I had to do something about the lack of charging.
I took it to an automotive alternator repair place who I had recently dealt with on a car issue and he charged me $50.00 to, as he put it "swap out a wire" and that was it. Sounds like a very simple job.

Fitting an external regulator to alternator

I've a Yanmar 2GM20F with stock alternator. I would like to fit an external regulator so that I get better charging when on engine. Appreciate advise on where can I find modification to alternator and ext. regulator installation instructions? Thanks.

forums.sailboatowners.com

See post #9.

 

[Stu Jackson]

1. As a power guy I just hate seeing the charging rate of less than 5 amps, @ 13.4 volts when the batteries need 20 more AH. After 15 minuets of motoring I was charging @ 3 amps and a few minuets later it was @ 1.5 amps, SOC was 88%. I know this is caused by the internal regulator.

2. *** I'm fully aware of the limits of the stock Hitachi alternator. ***

3. I was thinking about purchasing a Hitachi 80 amp unit and modifying it with a better fan from a Delco 12SI, although I'm not sure it would fit or make any real difference. This would be marginally better than the 60 amp unit I have now. I'm sure I could cut/hack and bring the field wire out and use an external regulator. I like a good science project but I'm not sure I want to reinvent the wheel.

I could just spend the money on a Balmar but I really don't need it.

Thoughts?

1. The REASON is your batteries are almost full because you've been plugged in. Battery acceptance reduces the amount of input they can take. Of course, it is exacerbated by your internal regulator on the Hitachi which is also temperature compensated, and of a fixed voltage below what an external regulator would provide in bulk phase. You already know this, see #2! Maine Sail's link, in addition to #2, means you should know that bulk with an internal regulator is pretty much the same except for the voltage, messed up by the Hitachi.

2. Good, no need to republish that.

3. You ARE reinventing the wheel. Read the other posts, especially Maine Sail's and Ralph's.

If you are not yet going to be "out there" for a long time, then you do not need to make any changes now.

Thoughts? Do your homework with the info provided here and make the smart choice(s).

 

[dlochner]

1. The REASON is your batteries are almost full because you've been plugged in. Battery acceptance reduces the amount of input they can take. Of course, it is exacerbated by your internal regulator on the Hitachi which is also temperature compensated, and of a fixed voltage below what an external regulator would provide in bulk phase. You already know this, see #2! Maine Sail's link, in addition to #2, means you should know that bulk with an internal regulator is pretty much the same except for the voltage, messed up by the Hitachi.

2. Good, no need to republish that.

3. You ARE reinventing the wheel. Read the other posts, especially Maine Sail's and Ralph's.

If you are not yet going to be "out there" for a long time, then you do not need to make any changes now.

Thoughts? Do your homework with the info provided here and make the smart choice(s).

To expand a bit on @Stu Jackson's post, there are 2 factors that determine how much current a battery can absorb:

1) the maximum of current the charging source can provide up to the absorption voltage;

2) the battery's SOC and its capacity to absorb the current.

Ideally at all stages these factors are matched, i.e., the current the charging source provides equals the current a moderately to deeply discharged battery can absorb.

 

[SycloneDriver]

I do understand how batteries and power systems work, it's my job. I work on the power crew for a large communication company. That said I really do appreciate all the input.

I will probably just replace the small ground wire from the alternator and check for poor connections. I'll live with the poor charging until its time to do something about it.

Looking at the cost of an external regulator vs a kit that includes the alternator & regulator. The kit looks like a much better deal. When it's time I'll probably just do both at the same time.

Thanks again.

 

[dlochner]

I do understand how batteries and power systems work, it's my job. I work on the power crew for a large communication company. That said I really do appreciate all the input.

One thing I've learned over the years being on SBO and elsewhere is there are a lot of lurkers. People who are interested in the topic but don't ask questions or post. Some of the posts guys like @Stu Jackson make may seem a little off topic or below the OPs pay grade however there are others reading. We post for them too.

A few weeks ago in a marina on a small island in the Abacos, I met a fellow a guy when I introduced myself he asked if I was the Dave Lochner on SBO and that he read a lot of what I had posted and found it helpful. It was humbling and a reminder that there is a large silent group of lurkers who benefit from the questions and discussions here. So at times we digress a bit, however it is often helpful to others.

 

[SycloneDriver]

I'm not offended at all. I completely expected post exactly like a few of them. I know they are trying to help and I did ask for input.

Thanks Dave.

 

[Stu Jackson]

Some of the posts guys like @Stu Jackson make may seem a little off topic or below the OPs pay grade however there are others reading. We post for them too.

I'm not offended at all.

Glad to be able to help, thank you both.

 

[nramsey]

For an external regulator take a look at the WS100. I think it is a better buy than Balmar.
I bought a 200 amp brushless alternator that fit, with a little work, for $320 CAD a few years ago and a local machine shop made the serpentine pulleys for $250 CAD. I know those are better prices than any Balmar or the like.

 

[Maine Sail]

For an external regulator take a look at the WS100. I think it is a better buy than Balmar.
I bought a 200 amp brushless alternator that fit, with a little work, for $320 CAD a few years ago and a local machine shop made the serpentine pulleys for $250 CAD. I know those are better prices than any Balmar or the like.

The WS100 has been discontinued and the Balmar ARS-5 took a significant price drop last year. We may see a WS 1XX out within the next year or so too..For now the best bang for the buck is the Balmar ARS-5 and it is far more configurable than the WS100 was...

 

[dLj]

The WS100 has been discontinued and the Balmar ARS-5 took a significant price drop last year. We may see a WS 1XX out within the next year or so too..For now the best bang for the buck is the Balmar ARS-5 and it is far more configurable than the WS100 was...

@Maine Sail What's your opinion on the WakeSpeed 500?

dj