universal m18 alternator recomendations

[adamv]

any recomendations for alternators for an m18? (i have 3 batteries + solar panel, autopilot. no fridge). ideally one with tach signal

backstory: the boat came with what im told is, incorrectly for this boat, a delco. certainly its preventing me installing the bracket upgtade as it fouls the tension arm... and the unattached purple wire always concerned me! What is this wire? Had assumed it was the tach sender (as the boat has no tach) but could it be intended to go to the ignition?

 

[SycloneDriver]

I'm happy with my Balmar but that seems like overkill for your boat. Hopefully someone else will chime in.

 

[adamv]

thanks, yeah balmar would be awesome but the pennies would be best spent elsewhere on my boat i think!

 

[SycloneDriver]

I'm really surprised that no one has offered a suggestion. Bump.

 

[adamv]

Looks like this is the most 'official' replacement: ARCO NEW Original Equipment Quality Replacement Alternator - 60104 - its relatively expensive for its unexciting output but i guess it is expected to work. If there is a better one for less of course i'd rather go that route

 

[SycloneDriver]

I think that alternator should work fine, you don't have a lot load and you have solar. How much solar do you have?

 

[jssailem]

Take the alternator out of the boat and into town to an Automotive Electrical shop. They are likely to have one that will work in your boat. Describe the space issue and identify the type of bolt connectors used to fit the engine ( diameter, number of feet, how you need to tension the alternator). They should be able to help you. I did that with my first alternator. Easy action. The shop had three different ones to select from they tested output right in front of me.

Cost (5 years ago) $75 for a 70amp alternator that was spark arrested for use in a boat. Fit right in to my boat like a glove.

 

[adamv]

thanks both - actually looking more closely I think my current alternator is not a Delco as someone had suggested on another page but looks more like an Arco - just not the model recommended.

The problem is @jssailem is that the alternator that is in my boat isnt correct- at least i cant use the upgraded bracket. I could certainly ask for a 'smaller alt than this one' but its kind of hard to quantify. Its not like buying a washing machine for a tight space where the dimensions are everything

 

[jssailem]

Pictures will help the shop help you. Use a tape to help the image. Configure the new bracket upgrade then show the image. They may or may not have what you need.

I have often heard that it is the technician who manages the install. The manufacturer just makes products. The shop I visited the guy was helpful. The images I provided gave the shop what they needed.

 

[Stu Jackson]

1. The problem is @jssailem is that the alternator that is in my boat isnt correct- at least i cant use the upgraded bracket.

23. I could certainly ask for a 'smaller alt than this one' but its kind of hard to quantify. Its not like buying a washing machine for a tight space where the dimensions are everything

1. The upgraded bracket should be your HIGHEST PRIORITY. Why? What is your ENTIRE engine worth to you? If that old bracket lets go, your engine is KILLED because the gear case gets rapped and they don't make those cases anymore. Believe me, buddy, my old bracket let go in 1999 and I was lucky: the oil filter saved the day but it got dented and leaked all over. I was running at slow bell when it happened. Do NOT minimize this risk.

2. Then go learn about different alternator sizes, go measure what you have, put a ruler down in where you took your picture and take pictures of the measurements, draw a diagram, take a video, and find the right alternator(s). Denial is not helping you here. ASE Supply has tons of alternators and they know your engine. Maine Sail's www.marinehowto.com discusses Universal alternators and describes their feet and sizes. A little Googling will "learn you" all about alternator sizes and descriptions. Really, don't tell me you can't do that?!?

You NEED to replace that alternator and mount the new bracket. NOW, before you go use your boat again.

Many of us have been beating this dead horse about Universal brackets of a quarter of a century. We don't do it for our health. I actually had an Ericson owner once ask: "I have the bracket, should I put it in?" I told him to take it on a date...idiot. And I HAD the bracket, had just bought it, but went to visit a friend in a closeby slip. Boom, oil leak, f-ing mess. Please: don't be THAT guy!!!

Here's my story:

Alternator mount/bracket upgrade Important safety upgrade for M25 (not XP) owners by Stu Jackson

 

[Stu Jackson]

and the unattached purple wire always concerned me! What is this wire? Had assumed it was the tach sender (as the boat has no tach) but could it be intended to go to the ignition?

Back again: this link shows the wiring colors in a wiring diagram. Make one for your boat and do some research to see if your colors are the same.

Engine harness upgrade: A comprehensive overview by Gerry Douglas

Newports and Catalinas are very similar in construction about these issues.

 

[adamv]

Thanks @Stu Jackson and yes I have been following your recomendations and thats why i find myself staring at an alternator that is now evidently wrong for the boat, and am looking for the right one so i can finish the job. I got as far as bolting the bracket and alt in before realising there's no way it will fit without further action; perhaps fabricating a new, longer tension arm (a friend has offered, for free) but my preference is to get the correct alt so i dont have to mess around with non-standard belt lengths, hence my question as to any advice on an average alt for an average M18 boat

 

[adamv]

Take the alternator out of the boat and into town to an Automotive Electrical shop. They are likely to have one that will work in your boat. Describe the space issue and identify the type of bolt connectors used to fit the engine ( diameter, number of feet, how you need to tension the alternator). They should be able to help you. I did that with my first alternator. Easy action. The shop had three different ones to select from they tested output right in front of me.

Cost (5 years ago) $75 for a 70amp alternator that was spark arrested for use in a boat. Fit right in to my boat like a glove.

Thanks do you think a 70amp is about right for a boat with 3 x 100ah batteries, chartplotter, autopilot, depth, a CD radio, a solar panel (guessing 150W?), LED lighting and possibly an ipad & AIS in future? The stock seems to be 55A. I have no idea what the current one is rated to.

 

[Stu Jackson]

but my preference is to get the correct alt so i dont have to mess around with non-standard belt lengths, hence my question as to any advice on an average alt for an average M18 boat

That's good news. Don't sweat the alt belt length. Whatever they give you with the new bracket kits probably won't fit anyway! I found the ONLY way to assure the right fit is to TRY THEM OUT and use a belt tensioner. I tried 7390 and 7400, one too short one too long. I found a 7395 fit perfectly on MY engine in MY boat. I bought all three, returned two and bought four more 7395 belts. It takes work to do this, but know that the chances are very high that what the supply may not work - reread my article, I covered it in 1999 and remains valid ever since.

"...an average alt for an average M18 boat..." makes no sense and you should already know that. Are you a marina hopper or an anchor out kinda guy? Do you want or need a higher output alternator or can you live with a 35A or 55A? Do you want or need external regulation? Do you have solar? Are you in a slip or a mooring field.? See what I'm getting at? First figure out what you need, then what you want, see if they're different and then start making decisions.

 

[Stu Jackson]

do you think a 70amp is about right for a boat with 3 x 100ah batteries, chartplotter, autopilot, depth, a CD radio, a solar panel (guessing 150W?), LED lighting and possibly an ipad & AIS in future? The stock seems to be 55A. I have no idea what the current one is rated to.

Find out how big your solar panel really is, first.
How much do you motor?

 

[SycloneDriver]

I new this thread had potential.

 

[adamv]

"...an average alt for an average M18 boat..." makes no sense and you should already know that. Are you a marina hopper or an anchor out kinda guy? Do you want or need a higher output alternator or can you live with a 35A or 55A? Do you want or need external regulation? Do you have solar? Are you in a slip or a mooring field.? See what I'm getting at? First figure out what you need, then what you want, see if they're different and then start making decisions.

I honestly have no idea. This is my first year of sailboat ownership. The boat is moored but as mentioned a couple of times i have a smallish (2 x 3ft) solar panel and basic electronics and house requirements so assuming a small to medium size current will be fine, but im not sure what that would be hence my questions

 

[jssailem]

Adamv
300 amp hrs of batteries. You only want to consume half of that ... 150hrs to optimize your battery life. If you have a 70 AMP alternartor and use the engine to charge your batteries, as the engine gets warm the alternator starts to produce less power. Alternators hate heat. Conservatively you can count on 35 amps per hour being output by the alternator. In about 4.5 hours of running your engine you will have recharged your batteries.

150 AMP charger would be over kill. Likely the 18 HP engine would not be able to power an alternator that big and still the push the boat through the water as hull speed.

With the other sources of charge power you mention (solar and marina shore power) a 70 or 90 amp alternator should provide the charge power you need. You might want to confirm it with your electrical sources.

Your boat your choice.

 

[Stu Jackson]

I honestly have no idea. This is my first year of sailboat ownership. The boat is moored but as mentioned a couple of times i have a smallish (2 x 3ft) solar panel and basic electronics and house requirements so assuming a small to medium size current will be fine, but im not sure what that would be hence my questions

Then I suggest you do some research and homework.
None of us was born a boat electrical systems expert.
We all spent time learning, via books, magazines, articles and, for those of you these days, the internet.
Many of us learned about this stuff before the internet! How medieval... And yet, it could be and was done.
So look Adam,spend a day reading at least the topics (i.e., headlines) at these two 'sites, and go out and buy Charlie Wing's boat electric book (I'll even send you a copy I got on the internet for free and legally a few years ago if you pm me and ask).

Electrical Systems 101 Electrical Systems 101

www.marinehowto.com

 

[Maine Sail]

A Leece Neville 110-547 is the same alt frame that came on your engine. Be very careful however to buy only a genuine Leece- Neville.The market is flooded with cheap knock-offs that use the LN part# and they are pure junk! The one in the link is an actual Leece-Neville.Keep in mind these alts do not come with a pulley 5/8" shaft or the 1" to 2" fit-kit.