Generator Head?

The friendliest place on the web for anyone who enjoys boating.
If you have answers, please help by responding to the unanswered posts.
Yea, my pump runs two units so is a bit bigger than needed by the 6500.
 
Janice-first-glad to hear that Betsy is up and running and that Seaweed not only floats but is mobile! Have you looked either on Amazon or Ebay for portable gennies?

I had a Honda or Yamaha in the 2017 budget plan... just this idea of a generator head and the ability to use diesel instead of gasoline appealed. That the price was low too helped pique my interest.

Aboard Seaweed I have two 35 gallon fuel tanks, so one for gasoline is a possibility. I'd just rather stick with diesel for more flexibility down the waterway.

I think a large DC alternator, maybe additional pulley on Betsy's crank, all running through your batts and inverter could easily run that 500W AC unit, with engine set at maybe 1500rpm.

It's do-able.

When I stayed on my ride in Fla, I could close up the boat an hour before bed and run the gen and AC hard, it would chill and dry out the boat. Then turn it all off. It was good sleeping til the sun came up. That sunshine with no AC on is a very effective alarm clock!!

Thank you Ski.

As for the alternator powering the a/c unit, that's a real possibility. At maximum output my alternator cranks out 55 amps. I should get nearly 30 amps at noonday in the summertime from solar so the deficit would be covered by the alternator when the engine is running. Or the obverse.

I do like this idea a lot: to chill the boat down at bedtime and then wake when it gets warmer. Thus no fuel consumption, quiet, and easy too. Thanks.

Sometimes the obvious is missed when I think.

I appreciate the light bulb moment. :)
 
"I do like this idea a lot: to chill the boat down at bedtime and then wake when it gets warmer."

If the water temperature the boat is floating in is cool enough there are many ways to avoid night air cond.

Use the deck wash pump at sunset to cool the hull's heat away .

Install a small computer fan to lift cool bilge air from below .

Cold air sinks , it takes power to push it up.

Most boats are single skin below the WL and so the bilge is filled with water temp air when the engine is off.

Use it.

With a fitted sun cover and a deck level vent , using cool bilge air works during the heat of daylight too.

With a solar powered vent removing air from the cabin top , you can be at water temperature much of the time.

Plan B is a Honda 2000w, hung from a davit (stops noise and vibration) .
 
I had a Honda or Yamaha in the 2017 budget plan... just this idea of a generator head and the ability to use diesel instead of gasoline appealed. That the price was low too helped pique my interest.

Sounds like if Betsy (and solar) can keep your batteries charged, and if your inverter will run your AC and other stuff... maybe no need for the small portable gen?

In any case and FWIW, you can get propane-converted versions of small Honda and Yamaha gensets. The ones I looked at closest (for home back-up) were Yamaha series, converted by US Carburation. Seems to me that would bypass all the issues with long-term gasoline storage, ethanol, weekly testing during periods of non-use, etc.

-Chris
 
Last edited:
There is a good argument for using the diesel engine, 70 gallon diesel storage and larger alternator that you already have.
 
The hassle with most low priced gen heads is they must also include some sort of engine speed regulation (just like a normal noisemaker) and THAT will control your cruise speed.

Many use similar engines at 1800 to create 60 cps AC current

After you cruise about a bit and decide on your LRC rpm you should be able to belt the gen head with the proper pulley sizes. for the 1800rpm it requires.

OF course you still MUST check with the engine Mfg to see if the engine front end is strong enough to power the unit.
 
Thanks... I'm considering this generator head and still exploring options.

The idea was to only run the generator head when the boat is not in gear. Underway the alternator should do fine. I wondered about using it after I'm done running for the day...

In thinking about it and acknowledging self, it's like this: I have this pathological quirk against running an engine to "charge the batteries" -- whenever I've been in that situation I've raised the anchor and gone somewhere.

Even if I simply run around and return to the same area, I've taken the boat for a ride. Maybe that's why simply sitting at anchor with the engine running to power an alternator seems "wrong" while running Betsy to power a generator head isn't so bad.

It's me. I can see that now as I've been considering the generator head.

A fellow near me advocates "Infrastructure" and I'm almost sold on the whole process. I don't know that I NEED a generator head if I'm only talking about running the engine when it's stinking h-o-t.

Mostly in the past I've been able to get comfortable by doing nothing at mid-day and rearranging my "schedule" to take advantage of the cooler temperatures.

As for the water temperatures down here, we are looking at 80+ degrees. It's not cool by any means and the top two feet is hotter. I do have a fan-tastic fan (wonderful thing incidentally, albeit noisy -- it seems to make less noise when it's hot though)

The solar panels are over where I sit in the galley and that should make a big difference. I'll have to get out my infrared temperature gun and check... it feels cooler when I put my hand to the overhead where the solar has shaded it.

Anyway, I thank you for your input. I'd wondered if anyone here had used a starter generator and had any guidance. I need to learn more about how they work when loads come on and cycle off. BUt not today.

Tomorrow is fine.

J, recovering from a dentist visit. (And she looked so young and sweet too...)
 
The idea was to only run the generator head when the boat is not in gear. Underway the alternator should do fine. I wondered about using it after I'm done running for the day...

In thinking about it and acknowledging self, it's like this: I have this pathological quirk against running an engine to "charge the batteries" -- whenever I've been in that situation I've raised the anchor and gone somewhere.

Even if I simply run around and return to the same area, I've taken the boat for a ride. Maybe that's why simply sitting at anchor with the engine running to power an alternator seems "wrong" while running Betsy to power a generator head isn't so bad.

It's me. I can see that now as I've been considering the generator head.


Hello, my name is Janice, and I have a problem...

:)

Not much difference between running a small diesel engine with a 40-amp alternator to charge batteries -- versus running a small diesel (same engine) to power a generator to make AC to run a 40-amp battery charger to charge batteries…

In fact, I think the latter is less efficient anyway, given that in the first you put DC directly into the batteries, but in the second you have to create AC and then convert if to DC in order to put DC into the batteries.

Running AC stuff from an inverter (including perhaps a small aircon?) connected to those batteries won’t really depend on where you get your DC from.

I just happened to notice my own genset specs yesterday: it’s running off a 14-hp Yanmar (at 1800 RPM<s). Same approximate size as Betsy, yes?


Did you learn whether your existing inverter will start and run your small aircon?

-Chris
 
Last edited:
Using a DC alt with a large enough inverter would be preferred to an AC gen head.

THe gen head will require a constant regulated engine speed , the DC alt just needs to be spun fast enough to provide enough power to operate the system.

Auto alts are not robust and have a very poor rating after they become hot.

Perhaps a truck 130A alt (about $130) could be fitted with dual belts for longevity.

Yes , the first test will be to operate the engine at a modest speed and see if your existing inverter will start the air cond , and weather it does operate at full power.

Usually full air cond power only comes from a Sine Wave style inverter, expensive.
 
Buy a Honda, do not do as I often do by trying to reinvent the wheel. My bill fold has more than a quiver full of arrows sticking out of it from riding across that Indian country.
 
Janice, your idea has merit, and has been done lots of times. Just build the bracket to mount the gen head so it can be belted off the front of the engine. No need to run the engine at 3600 rpm, just get your pulley ratio correct so the engine can deliver enough power at the lowest rpm needed to spin the gen at 3600. And no, you dont need any rpm regulation, you Kubota diesel engine has it built in, they were used in millions of gensets without added rpm regulation, the pump just does it. If you want to run the gen while cruising you will still need to set your rpm to keep the gen at 60Hz. It would take some calculating to get a good cruise/power the boat/generator setting, but experimenting would be fun. Pulleys are not that expensive. I think it would work great. An inverter/charger would make it even better. After all, a generator is nothing but a big alternator.
 
I just happened to notice my own genset specs yesterday: it’s running off a 14-hp Yanmar (at 1800 RPM<s). Same approximate size as Betsy, yes?


Did you learn whether your existing inverter will start and run your small aircon?

Hi Chris. This identical engine (18hp Kubota) in a tractor uses .5 liter per hour at 1700 rpm. That's in the sticks clearing brush and such. My friend Harold is gung ho on the engine and it's fuel sipping capabilities. I'll admit that certainly piqued my interest.

Still, after five hours I know I've not yet burned a gallon of fuel -- but that's at fast idle or in gear at near idle speed. I'll have real world numbers this coming week.

Next is the new fuel line (turning that second tank back into fuel) and routing for fuel return line too for the second tank. For some reason I was not recirculating the fuel (no return lines) for the BOB engine.

Have not yet wired in the new pure sine wave inverter. It's 1200 continuous and 2400 peak which is well within the specs for the 455 watt Haier 5000btu wall-banger. Where I might have an issue is if the a/c is on I might have to shut it down to run the 700 watt microwave

My Killowatt meter shows 1000 watts though label reads 700 for the microwave. Turning the a/c temp up would keep it from cycling on (cooling) while my popcorn was popping.

I am addicted (two bowls, sometimes three!) to my single serving popcorn. There's something about fresh hot popcorn cooked in coconut oil that is simply amazing.

You know, this life of decadence is very wonderful. I'm there too Chris. And truth to tell, I do not need an air conditioner. Of course it's easy to say that when the temperature is 80 degrees and the wind is blowing. At 90-plus I'll probably be changing my tune.

That is one reason why I'm buying into the Infrastructure bit. The thing is, I'm set now exactly as Seaweed is. This tweaking is icing on the cake.

I'll be leaving this dock in a few days to give it all a whirl. Time simply flew this month! I still need to get the anchor chain ready to go. Tested the anchor light last night -- works fine. Final filling of canning jars is nearly finished. I'll cook down the turkey bones and make turkey soup starter too.

Canning allows me to make fresh soup with good ingredients at will. And the stock, with lots of bits of turkey means I can make stuffing on the stovetop in fifteen minutes with a few fresh ingredients.

Life is wonderful afloat. Thanks for the information.

Although I'm leaning toward using my alternator (free!) I'll still give a call to the generator head company and see what they say. For those of us with small engines (or even wing engines?) this might be an additional source of power.

We shall see. Thank you again.
 
"It's 1200 continuous and 2400 peak which is well within the specs for the 455 watt Haier 5000btu wall-banger."

The usual LRC (starting current) is 300% of the normal running load , so 1500W will do fine for the start with under 500w the normal run current .

You may need to keep an eye on the DC voltage while operating as the usual 55A car alt , does very poorly when warm, maybe 40A output after 15 -20 min.

You would like to see 14+ volts , so the house batt set is charging as you operate.
 
.5ltrs =.13US gallons per hour.

or to put it another way at full load 18 hp should take about 1 gal per hour.

I am skeptical about the fuel use claims. .5 liters will only produce about 3 HP.
 
Last edited:
.5ltrs =.13US gallons per hour.

or to put it another way at full load 18 hp should take about 1 gal per hour.

I am skeptical about the fuel use claims. .5 liters will only produce about 3 HP.

I admit to being curious too.

According to the prop book guy to move at hull speed requires 8hp. She's 18hp, so would that work out to 1/2 gallon per hour using your figures?

I'd like to get some numbers on my tachometer gun too. The tach meter at the helm does not work. At a certain point I'll be able to listen and know how many rpm I'm turning. That will come with miles under her keel.

Real world numbers are upcoming. It was a mad house here in St. Pete this weekend. Every person and their dog was on the water. That is not the time I want to be out testing fuel consumption.

And thanks too for your numbers. I'm interested in learning about my Kubota.

(Still writing the articles about taking a tractor motor and turning it into a boat propulsion system... it's a biggie and I want it correct so that's been taking a lot of time. I'll post it here too, in my Tractor thread. But not yet. It's at least a week away from being ready to proof-read.)

Thank you for the additional information regarding powering a small wall-banger room air-conditioner for Seaweed. There's a lot to learn.
 
EZ to find the sweet spot for cruising.

Borrow a GPS and on a nice flat day create a paper graph of RPM/ Speed , say every 200 rpm.

This will take a while as 200RPM is slow to effect a displacement hull, give it 2 min at each setting.

Your boat will go faster with every RPM increase BUT at a certain boat speed , the increases will get smaller and smaller.

Cruise where the living is easy and 1/2 GPH should be the norm.
 
Janice, very unlikely you could externally regulate the 55A alternator and expect it to last, particularly with a large battery bank. External regulation should only be used on alternators designed for continuous high output operation. Most stock alternators are designed to charge start batteries and not much more, when pressed into continuous high output, by external regulators, they tend to overheat and give up pretty quickly. If you wanted more output you'd almost certainly have to go with a dedicated HO alternator and external regulator.

A final thought, if you go the gas Honda route, be sure to install a carbon monoxide detector in your cabin. CO-related deaths, while not common thankfully, do occur both ashore and aboard boats, several just occurred, ashore, last week.
 
yes, .5 GPH


if you are in S. pete I can lend you a photo tachometer to calibrate your ears. What FF said above will find a reasonably economical speed.
 
Janice- I am putting in a serious plug for upgrading your alternator and avoiding the AC generator option. A high output alt is likely a good bit lighter and therefore easier to mount. The AC gen will require engine to run at a single rpm regardless of load. It will also require you to switch between running the engine or running the inverter. Going inverter will be seamless. And even with the gen mounted, you will still need a dc alt. Put a big dc alt on, and that is all that is needed on front of engine. But would still need belt to run water pump, that may need a little fiddling, or keep the old alt as an idler pulley.

Try running the aircon on the inverter, see how it handles it. Then decide how much battery and alternator you need.

I agree with Steve, the little alt is not designed for continuous high output and may burn up if put to that task.

Post a photo of the alt and front of engine, that will help figure what may fit.
 
A truck alt is usually 130A or so and about $130 at a big truck supply.

Many are Leece Neville , which are great units.

IT is BIGGER than the car alt and will need a bracket made to mount it. .

These are heavy duty and have the electrical setup to install an external regulator.

AS your battery bank is tiny , only the voltage to keep your inverter happy is required and the stock V regulatior might work fine.

I would check with your engine folks and see if a dual or triple belt pulley is available.

More belts , more time between belt adjustment or replacement.
 
Janice- I am putting in a serious plug for upgrading your alternator and avoiding the AC generator option. A high output alt is likely a good bit lighter and therefore easier to mount. The AC gen will require engine to run at a single rpm regardless of load. It will also require you to switch between running the engine or running the inverter. Going inverter will be seamless. And even with the gen mounted, you will still need a dc alt. Put a big dc alt on, and that is all that is needed on front of engine. But would still need belt to run water pump, that may need a little fiddling, or keep the old alt as an idler pulley.

Try running the aircon on the inverter, see how it handles it. Then decide how much battery and alternator you need.

I agree with Steve, the little alt is not designed for continuous high output and may burn up if put to that task.

Post a photo of the alt and front of engine, that will help figure what may fit.

I've been exploring the generator head and it takes 25 to 29 amps DC to power. That is half the rating of my alternator and well, it's a lot.

Ski, your idea (and others) has merit re the larger alternator. What concerns me regarding that route is this:

Over 100 amps as I understand it requires two belts. Ratings and actual amperage delivered differ, sometimes substantially.

Front end of Betsy:
BetsyFrontEnd.jpg


Belt is off. We need to get a smaller belt.

Will run the a/c tomorrow from the 1000 watt square wave inverter. I still have not yet hooked up the pure sine wave one.

I can plug it in and give it a go -- jut haven't done it yet. It's on The List. The weather is absolutely perfect, except for the rain at night.

And thanks to all for your input.

One of my flaws is a tendency to complicate things wanting them better/etc. I can see where a generator head adds another layer of potential problems. An alternator does not.

The one I have was wired nicely. I start the engine, then turn on the alternator. Mechanic Edwin was concerned that if I ever was in a situation where I needed every bit of engine output, the alternator would take some hp away from me. So I have a switch.

Start engine. Then turn on alternator. I anticipate no issues but having the switch is insurance.

Oh, and Seaweed does have a pretty decent battery bank. She's got five Group 27's (500 amp hours total) along with a couple of Group 29's (200 more amp hours) ... I always run on Both.

With multiple sources of power regeneration there's no reason not to combine everything. The wind will blow, the sun will shine and even if I take the batts down, they will recover.

The alternator will/should (in theory) power the a/c unit without a problem. Solar and wind will take care of the rest of the boat with ease.

Okay, off to my bunk. It's been a long day. And I still didn't bail out Algae. It rained. One more thing on the To-Do list.

Thank you again for the words of wisdom. It is appreciated.
 
A generator head does not take any DC amps to power, it makes that its own self to run the rotor. Your alternator switch is a joke foisted upon you by yet another ignorant would be mechanic, just regulate it, unless you dont have any alternator regulation, then the switch just puts the alternator into full on, another really bad idea. Janice dear, as much as I love reading your posts I do think you need some good help. As we say down here, bless yur hart.
 
"and even if I take the batts down, they will recover."

That depends on how far you take them down, too far and they will have a very short life ,

A SOC meter would be a good investment. SOON!!!!!

"A generator head does not take any DC amps to power, it makes that its own self to run the rotor"

It takes engine power from its drive belt to function.

"Your alternator switch is a joke foisted upon you by yet another ignorant would be mechanic, just regulate it, unless you dont have any alternator regulation, then the switch just puts the alternator into full on, another really bad idea. "

Not at all, the of on switch would simply be wired onto the V regulator power supply.

When off, the 2-4 HP of a large alt would be usefull as power.

When on the V reg will simply charge the batts as it normally would.

Switching off the V reg is how the better rotary power switches save the alt from dummies.

An aftermarket boat , not a car or truck V reg is desired as it can cut the numbers of hours to charge any batt set.
 
Last edited:
A generator head does not take any DC amps to power, it makes that its own self to run the rotor. Your alternator switch is a joke foisted upon you by yet another ignorant would be mechanic, just regulate it, unless you dont have any alternator regulation, then the switch just puts the alternator into full on, another really bad idea. Janice dear, as much as I love reading your posts I do think you need some good help. As we say down here, bless yur hart.

I spoke with Bob Fury at Fabco and maybe I misunderstood regarding the DC amperage part.
Website: Manufacturers of Belt Driven Generators | Hydraulic Generators | DC Welders | Fire Truck Generators | Fabco Power ... It is likely that I do not clearly understand the system Mr. Fury invented back in 1958. I've got a lot to learn no doubt.

And he (Mr. Fury) is a fascinating gent. I wish I could be a fly on the wall when he is chatting power with someone who knows the subject well. What an education that would be!

For the time being I'm going to give the current alternator/inverter set-up a go. If it works, I'm good. Exploring an option (the generator head) does not mean it is the Best and Only solution to power production for an air-conditioner.

Mostly there are only two months when it's not too great at anchor in the summertime. That's when those afternoon naps play such an important role. If I can run the air conditioner, great. If not, I've lived without a/c most of my life. Heck, I grew up with oil lanterns. DC power was $$ and out of our range until the late 60's.

A cool glass of iced tea (with ice!) will certainly be refreshing, especially now that I do not have to haul ice to the boat. I love my refrigerator and it runs a-okay off the inverter with the solar panels I have. I've been running the microwave off shore power. The rest of the boat is strictly off-the-grid.

That sounds like a lot -- it is not. The computer (15 watts) runs off 12-volts. The DVD player (24 watts) does too. And a couple of LED (.01 watts eac), plus the VHF and depth sounder and sometimes the radio.

The refrigerator in 80 degree ambient used 60 amp hours in 24 hours.

And no, I still have not wired the new inverter. For that I need both time and no distractions. Y'all experts can do it in a jiffy without much thought no doubt. I will be reading and double-checking everything to make sure I get it right.

I installed the old one in 2010. It was not hard. Yes, I did have an ABYC certified fellow confirm I had it correct, and will do so again with this one. It's a bit more complicated though the instructions were clear.

Next kulas, I am confused.
I fail to understand why an on off switch for the alternator is a "really bad idea" -- ??

The alternator that came with Betsy was a 5 amp toy. I wanted more and thus the 55 amp Hurth.

The mounted alternator does have an internal regulator.


And FF, the furthest the batts ever went down was once in 2014 to 12.1 ... I had ten days of no wind and overcast skies. To make matters more "interesting" the doggone pine trees were dropping pollen the size of dimes. Twice a day I was cleaning the solar panels. Otherwise "low" is 12.4 or 12.3

I have voltage meters scattered throughout the boat so wherever I am I can see the voltage.

I did look at those nifty SOC units a while back. It's in the "would be nice to have" list though it is unlikely I'd cough up the $$ for one. An extra battery (or two) evens out the price and according to Calder, more is better.

That is why I run "Both" to power Seaweed. Right now, wind genny off, I'm at 12.8. By morning I'll be teetering about 12.5.

Such is life at five knots.
 
I have voltage meters scattered throughout the boat so wherever I am I can see the voltage.

Aint much but V meters eat a bit of power.

Best is a push button , so its only ON when you are looking.
 
A truck alt is usually 130A or so and about $130 at a big truck supply.

Many are Leece Neville , which are great units.

Janice,

I think FF is right on here. Another option is your local auto electric shop. They can build anything you want. Usually for a very reasonable price. External regulation as noted above is key for optimal output.

Rob
 
I meant that it was a really bad idea only if the alternator was not being regulated. JMO, the switch is not neccessary. Generally the key switch sends power to turn on the alternator, which works fine. I dont think you would ever be in a situation to need that extra little bit of power that the alternator uses. If so, just turn off the A.C.
 
Today I did run the a/c off my old 1000 watt inverter -- no problems. It comes on (even if on cold cycle versus fan) without an issue. It cools too.

That's one less thing on my mind. Now I know what I have will work so any generator head is a thing of the future.

A local is big on Infrastructure and I admit I'm becoming convinced. Still I don't want to be so busy improving Seaweed that I don't use her. I've seen that happen all too frequently.

Anyway, tomorrow if all goes well the a/c will be mounted on the overhead in my galley. I've got the hood well-insulated. It's a pretty slick set-up. To have the a/c off my head will be a real good thing. I'm right tired of moving it.

In the meantime I think that's the last of the chores to do.

Unless I can talk my friend into making me a 1/2 height tuna door that is. ;)

Since my a/c will work off the inverter the generator head is now shelved for the near term. I cannot see any reason to spend perfectly good money for it at this point. And even in the future I've been sold on the alternator route.

It's easy. It's been done. And it's lots less expensive.

That's not to say that if a Fabco generator head arrived in my mailbox I would not have that puppy installed in a heartbeat. However it is not necessary --- not at this point. Life is good just as it is.

Happy happy happy with my Betsy.
Article(s) on turning a tractor engine into a boat propulsion system is still in progress.

Thanks to you all, especially as I explored the Generator Head technology/application thereof as it concerns Seaweed.

J.
 
Oh, and another view of the alternator and label:

55-AlternatorLabel.jpg
 
Final Update: Ski (and others) I did take your advice. I've upgraded to a 120A alternator -- same size as my 55A. It works. The a/c works a-okay from it.

Took my girl out for a three hour cruise a couple days back. Got back happy, tired and joyous after seven-plus hours. Trip included fuel (65 gallons) and visiting a guy at anchor and McDonald's for chicken nuggets, then around another bay...

Met a fellow (Pete) in a marshmallow who lead me into a safe anchorage -- one canal south of where I am docked. He and his Linda (lost their website address -- it's here somewhere!) used to own a couple of Californian's. He's nice.

Anyway, Seaweed got her fair share of attention -- everybody waves. :)

The alternator is the permanent solution to my power problem. It was $180 from a local outfit (Will's Starter and Alternator)

Will's is the type of place where you know they know their stuff. The walls in the back were lined with alternators. These guys have been there forever and treat their people right. Prices are good too.

I am happy.

He changed the belt to a V-belt from serpentine. At some point I might go serpentine but not now. Use what I have, right?!?

Seaweed handles wakes nicely. She is practically perfect in every way.

I wanted to say thank you and note that I listened/learned. Though a generator head may be right for some, for Seaweed the best solution is the least complicated.

My alternator is internally regulated. I won't be using the alternator at any place near top rating -- 60 amps or so would be about max output so hopefully this unit will last me for a long time. Life is wonderful afloat.

Have I mentioned how happy happy happy I am?!?!? Seriously, finally I have a boat that moves. Fueled up and am ready to go. A front was to come through here. All around had weather but so far right here has been quite pleasant.

Anyway, that's life from the slow lane. Thanks again for the input on the power. You were right. Simple is best.
 
Back
Top Bottom