Overnight Cooling Without Shore Power

[witzgall]

Concerning PTO - one of the interesting things is that generally as you move up in voltage in alternator design two things happen. The turn-on speed increases, and the efficiency increases as well. For the 96 series we wanted an alternator that had a very low turn-on speed compared to what else is out in the marketplace.

The PTO for these units is impressive for the power they produce. I am working on a graph that illustrates this in comparison to one of our 12v units. In the meantime, the graph below might be of interest to some of you. The turn-on speeds are in the green box upper-left (the start of the PTO graphs are when we start recording, not when they turn-on.) For the 60a unit, the PTO is ~2.2hp at 2500 alternator RPM, which might be 1000 engine rpm. Ramp up to 3500 and you are at 6hp.

A creative sailor should be able to use these alternators to generate some serious power in a very efficient manner. The 100a unit can produce 5kw of power!

Chris

[witzgall]

Yanmar publishes their MAX PTO specifications for their engines. as an example, on the common rail 80 and 100hp engines, it is 6HP when the pulley is 30 degrees from the crankshaft. If you move it around, that number changes.

A 12v 200a alternator most likely does not, or shall I say does not grossly exceed that value, especially when the alternator is hot, and we are talking max rpm usually here. Who revs up their engine to max rpm right from cold?

Thr Balmar technical support staff is always willing to talk about these issue with our customers.

Originally Posted by a64pilot

I m not pointing you out, but the industry if you will, I believe when someone sells a 200 amp or other above 100 amp alternator at 12V, meant to fit a Yanmar, half that at 24 of course, there ought to be a warning to check that your not exceeding your engines limit.

[a64pilot]

Originally Posted by RaymondR

There is a lot of difference in the loading imposed between a hydraulic pump with an inline installation on the front of the engine and an alternator where the extra loading is lateral.

I don’t believe there is, torque is the issue, however how far in front of the harmonic balancer apparently does matter, amounts to leverage I believe.
The Yanmar installation manual that someone posted details different installations, but for my 44 HP engine it’s 8 HP at max RPM with a straight line deviation for RPM, so at my normal cruise speed which is half full Rated RPM I can pull 4 HP max, and that’s 100 amps plus or minus very little.

I agree I also used to think it was side load, but the Yanmar installation manual cleared that up.

[a64pilot]

Originally Posted by witzgall

Yanmar publishes their MAX PTO specifications for their engines. as an example, on the common rail 80 and 100hp engines, it is 6HP when the pulley is 30 degrees from the crankshaft. If you move it around, that number changes.

A 12v 200a alternator most likely does not, or shall I say does not grossly exceed that value, especially when the alternator is hot, and we are talking max rpm usually here. Who revs up their engine to max rpm right from cold?

Thr Balmar technical support staff is always willing to talk about these issue with our customers.

Balmar says that an alternator pulls 1 hp per 25 amps, that number is also pretty widely quoted other places, so it’s likely valid.
So a 200 amp alternator will need 8 HP to pull it, many engines can only drive a 200 amp alternator if the engine is at red line RPM and stay barely within limits, now tell me how many people run their motor at redline to charge batteries?
At 50% or 1800 RPM my motor and I think my 4JHE is pretty typical, the max torque that can be extracted is 4 HP, or 100 amps, for lower RPM the amps are lower of course.
So if you want to charge your batteries at anchor and say run your motor at 1200 RPM the max amps you can pull from a 4JHE is I believe 66 amps, but I suck at math, so verify please.
Now these numbers are valid for my ancient 4JHE, so of course find out what yours are.

[a64pilot]

Chris the available PTO limit is RPM derived, it’s not 6 HP except at one RPM.
As it’s actually a torque limit it’s a function of RPM, double the RPM and you double the power you can pull.

BTW, It should take about 14 HP to make 5,000W, that is using Balmar’s 25 amps per HP, assuming a 14V output then 1 HP will generate 350W which makes it 50% efficient, which is about right for an alternator.
So divide 5000 by 350 and you end up with a little more than 14 HP.

I have no idea how many Yanmar sailboat motors can supply 14 HP at cruise speed, but bet it’s not many.

Other motors I have no idea, but it’s not logical to assume that Yanmar is exceptionally weak.

[a64pilot]

I would actually love to be proven wrong, that would be good news.

[witzgall]

You are correct, I was omitting that was at max rpm. The 1hp per 25 amps (@12v) is a guideline, and it does differ depending on the alternator. As you can see from the graph - the 100a 96-series is taking 11.x HP at max RPM, lower than the 14HP the straight-line formula would suggest.

Nobody is going to simply slap one of these on their engine and call it a day, at least not on most of the engines that the members here are using. I am simply showing what is possible. This tread may not be the best place to do this.

I think in the future we will see more high power solutions. Bruce earlier mentioned that the Intgrel system is being approved on some Beta engines - at 8KW! It is pretty smart of Beta to do this, leading the way. I think we will see more of this sort of thing in the future - MFG embracing higher output generation.

Originally Posted by a64pilot

Chris the available PTO limit is RPM derived, it’s not 6 HP except at one RPM.
As it’s actually a torque limit it’s a function of RPM, double the RPM and you double the power you can pull.

BTW, It should take about 14 HP to make 5,000W, that is using Balmar’s 25 amps per HP, assuming a 14V output then 1 HP will generate 350W which makes it 50% efficient, which is about right for an alternator.
So divide 5000 by 350 and you end up with a little more than 14 HP.

I have no idea how many Yanmar sailboat motors can supply 14 HP at cruise speed, but bet it’s not many.

Other motors I have no idea, but it’s not logical to assume that Yanmar is exceptionally weak.

[valhalla360]

Fun conversation but so far we have no clue it if has any relevance to the OP's question...since the OP has failed to provide any additional details regarding his solution.

[Dockhead]

Originally Posted by witzgall

You are correct, I was omitting that was at max rpm. The 1hp per 25 amps (@12v) is a guideline, and it does differ depending on the alternator. As you can see from the graph - the 100a 96-series is taking 11.x HP at max RPM, lower than the 14HP the straight-line formula would suggest.

Nobody is going to simply slap one of these on their engine and call it a day, at least not on most of the engines that the members here are using. I am simply showing what is possible. This tread may not be the best place to do this.

I think in the future we will see more high power solutions. Bruce earlier mentioned that the Intgrel system is being approved on some Beta engines - at 8KW! It is pretty smart of Beta to do this, leading the way. I think we will see more of this sort of thing in the future - MFG embracing higher output generation.

It's encouraging to see the engine makers (or marinizers) embracing this. I do agree that generating more electrical power from the main engine has got to become a trend. So it behooves the engine makers (or marinizers) to get ahead of that trend and test and possibly adapt their engines to work better with (or confirm that they already work ok) higher power alternators.


Whether Yanmars are exceptionally weak for PTO, as A64 asks -- I don't know, but it might actually be the case, as many Yanmar engines are specifically designed as marine engines so we could imagine that they might have lighter front main bearings and/or lighter built crankshafts than general purpose industrial engines like those used by Volvo, Perkins, Beta, Nanni etc.



Concerning the problem of overloading the main engine, touched on by A64, this is surely also solvable if we look at all of this as an integrated system and prop the boat in a way which gives enough headroom for whatever amount of power generation we intend to do, and maybe regulate the alternator not to overload the engine at specific RPMs if that is happening (Balmar, you listening on that last point?).


Once you have a big enough alternator, you might also consider using it to generate power when you are not driving the boat with the prop -- so turning the main engine into a generator. You could have two regimes -- one for when the shaft is turning and one when not, and turn down the alternator when the shaft is turning in order not to overload the engine. This would require some solution to the PTO problem obviously.





I am very happy with my own quite modest setup, consisting of a 110 amp * 24v bog standard cheap Leece Neville school bus alternator and 100hp Yanmar. I generate a ton of power with this; probably more power cumulatively than I have with my generator (heavy duty low speed Kohler 6.5kW). When motoring somewhere it's almost like having shore power -- I do laundry, do electric cooking, whatever. And I typically arrive in the anchorage with full batteries.


No complaints about Yanmar in my case -- my second alternator is mounted with factory brackets and pulleys -- the engine (4JH3 HTE) was designed to have a heavy duty alternator on it besides the regular one.





As lithium batteries become more widespread, powerful alternators will become even more relevant. Kudos to Balmar for pushing in this direction, which I think is an interesting one.

[RaymondR]

Design reversion to some of the earliest auto generators which had V shaped permanent magnets bolted to the flywheel and there is an AC mains voltage system which sandwiches between the flywheel and the output shaft. You could probably get rid of the starter motor also.

I don't particularly like the idea of computer controlled, common rail fuel systems in boats but since they are computer controlled it would appear readily achievable to have a power sharing control algorithm included in the software so that when you placed the engine in gear it limited the amount of power draw from the alternator.

Having mounted some pretty hefty in line, direct driven hydraulic pumps on the front of engines without any problems from the engine manufacturer I am a little baffled as to why Yanmar appears to have placed what appears to be a very low torque limit on this type of installation. I can readily perceive that they might express the limit as torque on a lateral drive installation as the lateral force on the crankshaft varies as the pulley diameter.

[malbert73]

I think the answer is there. Kabota diesels are used in a ton of different industrial applications so likely front bearings are heavy duty in anticipation of different use cases in industrial settings. So probably safer for Beta engines. Yanmar diesel are used in tractor or boat engines mainly to my knowledge. So maybe not a whole lot of front bearing take off applications.

Regardless, I am a huge proponent now of installing an exhaust gas temperature gauge to monitor actual load on the engine. Using an oversized alternator, or over propping to some degree, can help you use the otherwise unused mid RPM horsepower and torque at cruising (not max RPM) speeds. But you have to monitor that you’re not overloading the engine and an EGT helps you do that

[a64pilot]

With the application of enough money, most anything can be solved. You don’t have to have the engine computer controlled, you can do that with the alternator, I believe the Integral is.

Often times what drives a supplier to determine if something can be done, is whether or not the item will last though the warranty period, not if it will reduce the life limit or if so by how much.
I’ve seen a few Companies that try to educate the purchasers though, we built an aircraft for Military applications, it had Pratt & Whitney Canada biggest turboprop, and first me, and then PWC tried our best to explain to the client that running the aircraft at max continuous power, continuously will seriously shorten the life limit of the engine. To no avail of course as they were selling the aircraft and it would sell better if it posted better “numbers” than another similar aircraft, with the same engine.

[Lepke]

A decent inverter and battery bank can run AC overnight. Then you recharge the next day running a generator on main. You can have more than one alternator on an engine, etc. It's not rocket science, just numbers.
My whole boat is AC except for some 12v nav instruments and running lights. I can run a large reefer, 2 freezers, computer, tv, lights, water pump, Incinolet toilets for several days with the inverter. Sometimes the water heater. While I avoid hot weather, I could easily run a couple AC all night. Buy a decent inverter and make room for batteries.

[malbert73]

Originally Posted by Lepke

A decent inverter and battery bank can run AC overnight. Then you recharge the next day running a generator on main. You can have more than one alternator on an engine, etc. It's not rocket science, just numbers.
My whole boat is AC except for some 12v nav instruments and running lights. I can run a large reefer, 2 freezers, computer, tv, lights, water pump, Incinolet toilets for several days with the inverter. Sometimes the water heater. While I avoid hot weather, I could easily run a couple AC all night. Buy a decent inverter and make room for batteries.

I will note your boat is listed as 83 feet long.

Me thinks your idea of “decent” battery bank is different that those of us with paltry sailboats especially who don’t run our main all day