Attaching a 5KW generator to the main 45 HP boat engine

[a64pilot]

Originally Posted by Sailor Doug

Most Harley's use a tooth belt but I still would worry engine would not take side load


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Back to the PTO then, that is what they were made for.
But now we are talking more money than a purpose built stand alone generator?


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[Dockhead]

Originally Posted by a64pilot

Back to the PTO then, that is what they were made for.
But now we are talking more money than a purpose built stand alone generator?


Sent from my iPad Pro using Cruisers Sailing Forum

Neither toothed belt nor serpentine belt impart such high side loads as v-belts. That should work fine.

However, a real engineer should be consulted. A lot of things can go wrong if you just cobble it up in your basement.

[Lepke]

There was a hydraulic generator run by a hydraulic pump on the engine. That way engine speed isn't an issue. The generators fishermen put on their main engines are usually used when running to save running a generator. Commercial fishing boat engines are usually heavy duty or at least medium duty. Recreational diesels are light duty. Heavy duty diesels are designed to drive several auxiliaries, pumps, etc. They have big journals and bearings so side thrust isn't an issue. Not so with light duty.

[HappyMdRSailor]

Originally Posted by Dockhead

There are different solutions, the cheapest of which is to use a single school bus alternator with appropriate double belt or serpentine pulleys and a proper bracket. I get 2.5kW out of mine (Leece Neville 24v, 110 amp).

Boy oh boy DH...

I see you write on your bus alt all the time... but I FINALLY just looked on ebay, and saw what was available... Found a NEW 24V/160A and got so light headed I had to sit down... This sir... goes on the definite "to do someday" list!

[Dockhead]

Originally Posted by HappyMdRSailor

Boy oh boy DH...

I see you write on your bus alt all the time... but I FINALLY just looked on ebay, and saw what was available... Found a NEW 24V/160A and got so light headed I had to sit down... This sir... goes on the definite "to do someday" list!

True Secrets of Cruising being unlocked at last, eh?


This is a very common solution already on cruising boats, at least larger ones.

For a typical pattern of cruising where you up anchor/leave harbor, sail for a day, come in, stay for a couple of days, move, etc. -- and you're motoring for at least some part of the time, you make most of your electrical power essentially free this way. I reckon having this inexpensive and reliable school bus alternator saves 50% of my generator run time. Plus it's an effective backup to the generator in case of any problems (knocking on wood).

One of the most useful items of gear on board. And the usefulness vs. cost ratio is just off the scale. Compare it to my generator which if I had to install a new one from scratch would cost about 10 000 pounds here ($15k).

Heavy duty alternator is worth its weight in gold for cruisers.


For my next boat I consider having a small propulsion engine attached to two of these, instead of a normal generator. Totally simple and bulletproof -- a true KISS generator. Keep an entire spare alternator and there's practically nothing which can go wrong which you can't field repair.

[HappyMdRSailor]

Originally Posted by Dockhead

True secrets of cruising being unlocked at last, eh?


This is a very common solution already on cruising boats, at least larger ones.

For a typical pattern of cruising where you up anchor/leave harbor, sail for a day, come in, stay for a couple of days, move, etc. -- and you're motoring for at least some part of the time, you make most of your electrical power essentially free this way. I reckon having this inexpensive and reliable school bus alternator saves 50% of my generator run time. Plus it's an effective backup to the generator in case of any problems (knocking on wood).

One of the most useful items of gear on board. And the usefulness vs. cost ratio is just off the scale. Compare it to my generator which if I had to install a new one from scratch would cost about 10 000 pounds here ($15k).

Heavy duty alternator is worth its weight in gold for cruisers.

Indeed!

I have a double setup now with a 12V??A for the 3 start batts, and a Balmar 12/160 for house... BUT... I swooned a little at the "double VA" of the 24/160 for $250US new... I have room... a cogged cam belt, AC clutch and a bit of simple machining are sure to replace my going to sleep thoughts for a while...

[Dockhead]

Originally Posted by HappyMdRSailor

Indeed!

I have a double setup now with a 12V??A for the 3 start batts, and a Balmar 12/160 for house... BUT... I swooned a little at the "double VA" of the 24/160 for $250US new... I have room... a cogged cam belt, AC clutch and a bit of simple machining are sure to replace my going to sleep thoughts for a while...

Well, but 12/160 is like 24/80. If it's branded "Balmar" it's just a Leece Neville stencil branded. Sounds like you're already in very good shape. That's already nearly 2kW, and depending on how the pulleys are set up, you're probably getting 1.5kW at low cruising RPMs.

[HappyMdRSailor]

Originally Posted by Dockhead

Well, but 12/160 is like 24/80. If it's branded "Balmar" it's just a Leece Neville stencil branded. Sounds like you're already in very good shape. That's already nearly 2kW, and depending on how the pulleys are set up, you're probably getting 1.5kW at low cruising RPMs.

The LN=Balmar was unknown to me... Thanks!

I guess I'm a little eager having the experience that my house takes more time to come up than I'd like... Probably more a function of aged batts than of charging capacity...

[Dockhead]

Originally Posted by HappyMdRSailor

The LN=Balmar was unknown to me... Thanks!

I guess I'm a little eager having the experience that my house takes more time to come up than I'd like... Probably more a function of aged batts than of charging capacity...

Sometimes Balmar upgrades stuff they sell, but sometimes not. For example, the Merlin Smart Gauge is just renamed and cost doubled (great device by the way, the best battery monitor).

What's your battery capacity?

Have you measured the current output of the alternator with the batteries down?

160 amps max should give you 130 or 140 or so at slow cruising speeds, if the pulleys are set up right, which is about what you want for a bank of 600 or 700 amp/hours of lead acid batts. Unless you have AGM, you really don't want to charge much faster than 20% of C -- will shorten battery life.

It sounds to me like you already have an excellent setup.

[mikecambrai]

I don't think that we established just why a 4KW alternator was necessary in the first place.
An angine alternator is designed to charge engine batteries from 70% charge to 90% charge and support any loads in place such as lights etc. If you are trying to charge service batteries, which will go down to much lower levels of charge, you really need a smart charger.
Old fashioned chargers and alternators will take the voltage up to around 14/28V.
A smart charger takes into account the different voltage levels that a battery needs dependant on the level of charge that it has come from.
To be really efficient, batteries should be charged using a mains smart charger OR a DC smart charger such as STERLING make, which will go through the 4 different stages of levels of charge. My smart AC charger has in fact 7 levels of different charging cycles. These new chargers are so compact as well.
So it may pay to charge batteries the smart way rather than the old way. You will notice that when you start your engine you will charge at a high level but this quickly falls away. So a 70A alternator might start at 70A but soon falls to 10/15 amps thus prolonging the charge time. A smart STERLING type system will keep the alternator at a high charge level and monitor the alternators temperature as well to ensure that it is not over heating.
Battery charging is a really complex science.

[Dockhead]

Originally Posted by mikecambrai

I don't think that we established just why a 4KW alternator was necessary in the first place.
An angine alternator is designed to charge engine batteries from 70% charge to 90% charge and support any loads in place such as lights etc. If you are trying to charge service batteries, which will go down to much lower levels of charge, you really need a smart charger.
Old fashioned chargers and alternators will take the voltage up to around 14/28V.
A smart charger takes into account the different voltage levels that a battery needs dependant on the level of charge that it has come from.
To be really efficient, batteries should be charged using a mains smart charger OR a DC smart charger such as STERLING make, which will go through the 4 different stages of levels of charge. My smart AC charger has in fact 7 levels of different charging cycles. These new chargers are so compact as well.
So it may pay to charge batteries the smart way rather than the old way. You will notice that when you start your engine you will charge at a high level but this quickly falls away. So a 70A alternator might start at 70A but soon falls to 10/15 amps thus prolonging the charge time. A smart STERLING type system will keep the alternator at a high charge level and monitor the alternators temperature as well to ensure that it is not over heating.
Battery charging is a really complex science.

A good external regulator will do the same job with an alternator. And to boot will protect the alternator from being overloaded when charging a deeply discharged bank.

[HappyMdRSailor]

Originally Posted by Dockhead

Sometimes Balmar upgrades stuff they sell, but sometimes not. For example, the Merlin Smart Gauge is just renamed and cost doubled (great device by the way, the best battery monitor).

What's your battery capacity?

Have you measured the current output of the alternator with the batteries down?

160 amps max should give you 130 or 140 or so at slow cruising speeds, if the pulleys are set up right, which is about what you want for a bank of 600 or 700 amp/hours of lead acid batts. Unless you have AGM, you really don't want to charge much faster than 20% of C -- will shorten battery life.

It sounds to me like you already have an excellent setup.

Have Mastervolt "kindasmart" going to add a Balmar supersmart... Way too cool of a kit...

Cap=Smidge over 1kah AGM... and I "have not" tossed the DC amprobe on the alt out... For some stupid reason, I guess my alt output is not run through the shunt... On my list... (edit... looooong list)

I will perform my due diligence before impulse engineering!
Thanks for your input DH!

[Dockhead]

Originally Posted by HappyMdRSailor

. . . Cap=Smidge over 1kah AGM... and I "have not" tossed the DC amprobe on the alt out... For some stupid reason, I guess my alt output is not run through the shunt... On my list... (edit... looooong list)

I will perform my due diligence before impulse engineering!
Thanks for your input DH!

Another tip: forget shunts, and try a SmartGauge. You'll never go back.

Order from the maker in the UK, and skip Balmar who mark up the price about 100%.

[TheThunderbird]

1. Power Alternator
2. Solar
3. DC generator
4. Hydraulics (transmission included )

[RaymondR]

In the days before high powered inverters there was an AC system where the alternator fitted between the flywheel and the gearbox and the excitation to provide cycle frequency was carried out electronically so that the cycles were constant no matter the engine speed. Only ever saw one on a cat a friend had bought.