Cruising Without Alternator (Temporarily)

[Sailmonkey]

Originally Posted by Boatyarddog

So.. You see there are many reasons to have one on board.

Cheers,

SV Cloud Duster

Yes, there are many reasons to have one, but as required equipment? I think not.

For us, a 2000 is too large to store, a 1000 is too small to run our air conditioner (well, marginal at best) and we gain nothing by having it.

[Jim Cate]

It's a nessessary item for any offshore extended cruising.

I'll be damned! I sure wish that you had told me that when we set out cruising in 1986, for it would have kept me from being unfit for offshore extended cruising for all these years! I'm sooo ashamed.

Seriously, a gen set of any size is a convenience, but far from a necessity for offshore cruising of any length.

Jim

[a64pilot]

Originally Posted by Jim Cate

I'll be damned! I sure wish that you had told me that when we set out cruising in 1986, for it would have kept me from being unfit for offshore extended cruising for all these years! I'm sooo ashamed.



Seriously, a gen set of any size is a convenience, but far from a necessity for offshore cruising of any length.



Jim

I’d say that times have changed, to begin with in 1986 there was likely wasn’t a generator worth having, they seemed to all be based on the Briggs and Stratton aluminum bore engines, and would wake the dead and were crap.
That had changed as I took a Honda 1000 with me to Desert Storm 1 in 1990. And it outlasted several of the Briggs and Stratton based ones, but I changed oil like every four days, and that may have been a lot of it.

But we or most of us are far more reliable on electric “stuff” than we used to be with our Engel ice boxes and TV’s and internet etc than used to be.
I could do without a generator, but why would I want to? In 1986, you may not have had a cell phone, and internet, but it’s a different world now.
It’s like refrigeration, of course you don’t need it, but it’s nice to have.

Plus a lot of us have water makers now, and whether DC or AC they do take quite a lot of electricity.
I believe that a generator give us the some of the little luxuries that without them I’d be hard pressed to talk the better half into going, like water and it being hot to.

[Rumpi]

It's actually pretty clear why cruising boats carry generators: the main diesel engine is to big for the installed battery size and type. This will not change until we have batteries that match our ever increasing engines. Lithium is a step in the right direction but most LiFePO4 technology limits safe charging to +/-1C (there are exceptions like A123). Maybe LTO will change this, or A123 will become mainstream. Until then let's consider a good modern cruiser setup of 1000A chinese prismatic LiFePO4. To charge them of the main engine you need 15kW of generator. Now tell me how many boats you know of that actually might carry this much lithium have a main engine of only 30HP? A catamaran would be the most likley option, or a true racer/cruiser. For the same amount in Lead Acid one would only need 4.5kW of generator and even that only for a short time.

The fun fact is that while most of us would not consider switching to a gasoline main engine to the extent that there are no modern fuel injected small gasoline inboards on the market we are happy with our gasoline inverter generators.
Is a generator a must have? Surely not, it's a luxury, but let us be clear, so is the boat.

[theway]

Originally Posted by Rumpi

Let's try to make it dead simple. You need: one positive wire + multimeter (or lamp) + metallic magnetic object. Take a wire long enough to reach from battery positive to the back of the alternator. Measure voltage at battery terminals, write it down.

1. With the wire connected to battey positive post measure between this wire and the negative terminal on the back of the alternator (not the case, the alt is not grounded to the case). You should see the same 12.xx voltage as measured between battery posts. If this is not the case then you have ground problems and you need to keep cleaning contacts until this happens. If all contacts are clean and this still does not happen you have a bad cable. If the voltage is the same as on battery posts you have good ground and can proceed to step 2.
....

Ok, thanks again for your continued help.
I just did test #1 twice and I got 15.98V and 15.73V... again to confirm I connected a wire to one house battery bank Positive and connected to Red on multimeter and touch the Black from multimeter to the Ground post on the back of alternator...

*Note the solar is disconnected, it’s only a 100watt panel anyway.

This number obviously seems high so I tested at the battery red to positive post and black to negative post, I’m getting similar at 15.43V. And a step further I measure only one battery and it gave out 7.44V. (Bank is 2x6V)

On top of all that the volt meter inside the boat for that bank only reads 13V.

So I’m hoping all this makes sense, and gives you signs towards a next step It makes me think again that the alternator/regulator is sensing so much voltage that it never kicks on. Another side note is that before when I ran the batteries down a bit to see if the alternator would kick in, after it did not, the solar panels did and that charge was visible on the volt meter inside the boat showing close to 14V

And thanks again, much appreciated.

[Rumpi]

Your digital voltmeter is decalibrated, please refer to it's manual for recalibration. The analog one is correct, 13.2V should be full battery just of the charger (presumably solar was recently connected). For us it does not matter you have sucesfully established good ground. Now proceed to test #2. Test results can be:

A) If magnetism present with outside 12V but not with jumpered blue wire (as per manual) test blue wire for continuity and clean connector (the one that goes on the alternator). If the blue wire is broken (you can not get voltage on the alternator connector) it needs replacement.

B) If no magnetism present with outside 12V on blue wire terminal remove alternator from engine, and replace brushes. (If you have no ideea on how to do that please ask here. We might require a few pictures of your alternator to walk you trough it).

[Dockhead]

Originally Posted by Rumpi

. . . Until then let's consider a good modern cruiser setup of 1000A chinese prismatic LiFePO4. To charge them of the main engine you need 15kW of generator. Now tell me how many boats you know of that actually might carry this much lithium have a main engine of only 30HP? . . .

Why would you be limited to a 30hp main engine for taking off 15kW? That's a healthy load for any main engine I think any of us have.


If you've got a 15kW alternator and batteries which can absorb 15kW, or even 6kW probably, that's a perfectly reasonable use for the main engine of any size put into pleasure boats.


My 100hp Yanmar is only putting out 15hp at 2000 RPM (on the propeller curve, not the maximum possibly output at 2000 RPM), a perfectly healthy regime.




Now it's healthy IF you're not under way at the same time. If you want to generate power and get propulsion at the same time, you need to take care not to overload the engine.

[masonc]

Originally Posted by theway

My alternator recently died and was wondering how long a starter battery can last if only used for cranking the engine? I have the Bluetop D34M. I’m curious about two situations...

1: (Curiosity) If the starter battery was only used for cranking and never charged. How many cranks could it do?

2: (Actual) If the starter battery was charged some from 2 - 100watt solar panels.... I have 2 House banks fed by 2 - 100watt solar panels (one per bank). That power can also be sent to the starter battery when the starter battery switch is on. My general power needs are low and easily met with the solar, my concern is starter battery draw from each crank.

(I’m in Indonesia and would like to make it to Singapore if possible, but that would be about 1,000 miles and about 60 days. A few moments ago I created a separate thread about trying to source a Balmar Alternator in Indonesia. )

Thanks,
austin

If it is your external regulator that died, you can charge the battery by exciting the field with a resistor. 12v will give you 100% output, which you don't want. Try a lightbulb in series. If you get 20 - 30 amps or so, you can charge the batteries. Put a switch in and charge your batteries then turn off. Find a higher resistance and you can trickle charge.

[Rumpi]

Originally Posted by Dockhead

Why would you be limited to a 30hp main engine for taking off 15kW? That's a healthy load for any main engine I think any of us have.


If you've got a 15kW alternator and batteries which can absorb 15kW, or even 6kW probably, that's a perfectly reasonable use for the main engine of any size put into pleasure boats.


My 100hp Yanmar is only putting out 15hp at 2000 RPM (on the propeller curve, not the maximum possibly output at 2000 RPM), a perfectly healthy regime.




Now it's healthy IF you're not under way at the same time. If you want to generate power and get propulsion at the same time, you need to take care not to overload the engine.

Generating 15kW of electricity needs about 23kW (30HP) of engine. I am not limiting anything but operating a diesel engine under 70% load is not healthy or fuel effective. A gasoline engine is different in this respect.

Your 100HP Yanmar is healthy because you got your units mixed up. First at 2000RPM it generates almost 80HP at the crankshaft. Second, on a propeller curve with a 2.5 factor this translates to 30HP. This then translates to around 6l/h fuel consumption. Those are Yanmar literature numbers for the 4JH4-HTE if you are wondering, your engine might be different but not by much.

Fact is small loads kill big diesel engines and gasoline engines are not wanted. OTOH the price of installing enough lithium and retrofitting the engine with enough generator capacity can buy the genset and keep it fueled for it's lifetime.

[a64pilot]

Where does this it’s not healthy to operate a Diesel under 70% load come from?
Which “expert” is spouting this? I ask as almost all Diesels are operated well under 70% load, and the longest lasting ones are operated well below that number.
Dockhead’s engine being a 100 HP makes the Math easy, at 2000 RPM, an RPM many of us operate at, its at 15% load.
You need enough load to fully warm it up is all, and an occasional blowing it out isn’t bad for it, but running the snot out of it continuously is.

Aircraft Piston engines are the only ones I know of that are operated at 75% power often and usually don’t last 2000 hours, and they aren’t junk motors made from inferior parts, they wear out so fast because they are run so hard.

Engines like DD’s run very conservatively can last, well almost forever, run them hard and they don’t, they have been around forever, that has been known forever.

[theway]

Originally Posted by Rumpi

Let's try to make it dead simple. You need: one positive wire + multimeter (or lamp) + metallic magnetic object. Take a wire long enough to reach from battery positive to the back of the alternator. Measure voltage at battery terminals, write it down.

1. With the wire connected to battey positive post measure between this wire and the negative terminal on the back of the alternator (not the case, the alt is not grounded to the case). You should see the same 12.xx voltage as measured between battery posts. If this is not the case then you have ground problems and you need to keep cleaning contacts until this happens. If all contacts are clean and this still does not happen you have a bad cable. If the voltage is the same as on battery posts you have good ground and can proceed to step 2.

2. Identify the blue cable coming from the regulator. It connects to the alternator either by a ring terminal or trough a plastic connector combining two wires one blue one white (series 9 alt should have a rectangular grey plastic connector). Disconnect blue wire and connect in place 12V positive from battery (if plastic connector is used you need to put a female spade terminal on the wire first and identify the correct spade). Check with multimeter to see if you still got 12.xxV between this wire and alt ground post (jumper cable may have disconnected). Now you should have strong magnetism on the bolt holding the pulley. Check with metallic object. If no magnetism present it means the brushes are not contacting and you need to take the alt out and at least clean if not replace them.

Test 2 was done and still no magnetism. I didn’t have a spade terminal but used a small alligator clamp, and tested the voltage many time to make sure it was 12V. I’m guessing nothing needed to be done with the white side terminal during the test.

My plan is to get to Singapore and take it off completely. I’ll take it to a shop and see what they think and then decide on a repair or replacement.

Thanks a lot for the help, if any other ideas come along please feel free to share.

[Dockhead]

Originally Posted by Rumpi

Generating 15kW of electricity needs about 23kW (30HP) of engine. I am not limiting anything but operating a diesel engine under 70% load is not healthy or fuel effective. A gasoline engine is different in this respect.

This is really not true -- an old wives' tale. To keep a diesel engine healthy, you only need enough load to keep the cylinders warm, and provided the cylinders are warm enough, the less load, the longer the life, like any machinery.



And the minimum healthy load is not indeed a percentage of maximum power, which is really irrelevant if you don't at least consider what RPM you're running. The true measure is a certain power output per volume of air flowed by the engine. So smaller displacement turbocharged engines can run happily at smaller percentages of their maximum power, than large displacement naturally aspirated engines.


No cruising boat runs its main engine at 70% of maximum power. That would be achieved on my boat, and this would be typical, at only just below redline, and that is clearly a less healthy regime.

Originally Posted by Rumpi

Your 100HP Yanmar is healthy because you got your units mixed up. First at 2000RPM it generates almost 80HP at the crankshaft. Second, on a propeller curve with a 2.5 factor this translates to 30HP.

No, it does not. Maximum possible power of my 4JH3 HTE at 2000 RPM is 42 HP. The power on the propeller curve is 15hp, as I wrote:





That's 15% of maximum, and a perfectly healthy load. It would be 30% of the maximum power of the naturally aspirated version of this engine, showing again the irrelevance of % of maximum power, in judging the health of any given load on a diesel engine.

Originally Posted by Rumpi

. . .Fact is small loads kill big diesel engines . . .

Certainly this is true, but to be harmful, the load needs to be so small that the cylinders don't warm up. This is a lot less than 70% in all cases, and for most diesels it's less than 15%, and it also depends on RPM (again -- the point at which the load becomes harmful can't be expressed as a percentage of maximum power; some percentage of maximum power AT THAT RPM would be somewhat more relevant, but power produced per quantum of air flowed is the real measure of the health of the load).



The biggest underloading problems are with constant speed generators, because they don't modulate power output with RPM. That means that a lot of air can be pumped through with very little fuel burned, at that is what causes wet stacking and other damage.


My own 6.5kW generator, for example, has a 1500 RPM Yanmar 1000cc 3TNE74. In other forms, this engine produces 24 horsepower. The constant speed version is identical to this engine just with the governor set at 1500RPM. So even at full electrical load, this engine is at something like 40% of maximum power, and at 25% -- a specifically allowed regime -- it's 10%. But unlike my main engine, the RPM does not vary, so the amount of fuel injected per quantum of air falls much more sharply, so if you get much below 25% electrical load, you risk wet stacking and other damage, and Kohler forbid this. So with this kind of setup you have to be really careful -- running these all night for air conditioning while the a/c is mostly cycled off, notoriously kills them.

[theway]

And since the talk of generators has come up prominently here I feel I should share my story....

I was entering Pago Pago, American Samoa. It was night and I felt ok about it. There were many lights and I could navigate it quite easily. However, since there were a few boats moving around in the bay entrance and the wind was dying, I decided to drop the mainsail and roll up the genoa. I rolled the genoa, started the engine, and set the tiller pilot. I looked around and then freed the main halyard. I stepped up on deck to the mast and began pulling down the mainsail. While I was up there the engine died. I didn’t think much of it, but realized that my batteries were dead too. I turn on all my lights to be more visible and my nav lights are not LED, but usually no big deal while the engine is running.

I left California a year and a half earlier with no generator. I definitely wanted one then, but couldn’t justify the space, the weight, and the cost. I made it pretty far with out one. But that night, with all my batteries dead in the middle of Pago Pago harbor I damn sure had some justification. So, luckily a nice gentle breeze from the east blew in and filled my reopened genoa down toward the anchorage past the huge cargo ships. All were docked with bright lights and loud moaning engines . I could see boats shapes ahead deeper into the bay but many did not have anchor lights. I knew where I wanted to anchor from prior analysis and I knew I would only have one chance to set the hook. I turned south and slowly wound up the genoa as I came into the wind, cleated the furling line and hastily walked to the bow. I dropped the delta and drifted back. To my delight, the drifting was soon halted. I was anchored in Pago Pago. When I left two weeks later towards Tonga, I had a new starter battery and... a generator.

But maybe the funny part is that now two years later I’ve only used the generator ~5 times to charge my computer and drone batteries out of curiosity when I had extra gas/petrol. Go figure.


austin

[valhalla360]

Originally Posted by theway

The one I have actually has little battery charger outlet and cables.

Wait a sec...you have a generator?

Just charge up the battery bank with it occasionally...being careful of exhaust fumes.

[wingssail]

Originally Posted by theway

(I’m in Indonesia and would like to make it to Singapore if possible, but that would be about 1,000 miles and about 60 days. A few moments ago I created a separate thread about trying to source a Balmar Alternator in Indonesia. )

Get the alternator fixed, or replaced with an automotive type. There will be someone in the nearest moderate sized Indo town who repairs alternators including diodes, bearings, and rewinding. We had our Balmar rewired in Padang in a dirt floor workshop for about $20, over night.

Even if you can make it to Singapore without an alternator (you probably can, especially if you rewire your solar to continuously charge your starting battery), why do it? Without an alternator you only need one more thing to go wrong and you soon have a cascading series of problems which can put you in a bad spot without an engine. Have you considered navigating through Singapore waters without an engine? And by the way, Singapore does not allow sailing except in certain areas.

Finally, in Indo you will probably be motoring a lot. Even a small capacity alternator with internal regulator will keep your batteries up if you motor for a few hours.

Get it fixed or replaced.