Add second large alternator to charge house batteries

[LooseGoose]

Check out Nigel Calder's newly designed charging solution......

https://youtu.be/0uTNjfb3MNQ

[Matt Johnson]

Haven't read the entire thread, so maybe you've covered this.... But not too many people anchor in the Rio Dulce. Typically you're tied up to a dock in one of the many marinas and can just use shorepower while there.

We made it through summer without AC- and I'm a wimp for heat- but chose our marina and slip based on where we'd get breeze. If you're truely going to anchor, you could adjust locations for the wind too.

Matt

Originally Posted by Augi

My need is for Rio Dulce, Guatemala in summer which is 20 miles inland from the Caribbean Sea. Anywhere anchored in the Caribbean Sea I can get by 12 months year with fans, wind scoop, etc., no air conditioning. It that environment I prefer no air conditioning unless there is no breeze which rarely occurs.

[john manning]

The advice from a64pilot is something you should note. He has highlighted the most commonly forgotten issue relating to belt drives on small engines. ie. There is a mechanical limit for the power you can take from an engine pulley without damaging the engine. The standard 3YM30 alternator is an 850w unit. A 200A alternator is 3 times that.

I have been asked many times to install 150A or 200A alternators on marine diesels. I always advise aginst it. When my customers have insisted I have done the work. The best power output I have seen from a 200A alternator ( on a 75HP engine at 2600rpm) was 110A. So you are paying for something you normally do not get to use.

The other option I have seen used (but also advise against) is to remove the standard alternator ans mount a 220v alternator in its place. Battery charging is then done using a 220v battery charger. Because the smallest 220V alternator available is 1800w it will still overload the pulley drive.

To get power from any alternator the engine needs to be at power. A 150A alternator will need an engine speed above 2500rpm to provide that power. Alternators do not have power with the engine at idle speed.

Also the 3YM30 engine has a significant coking problem when run for extended periods below 2400rpm. This shows up in the wet exhaust gooseneck which can block up so much that the engine will not rev above 2000rpm.

Best option is to add a generator.

[GSwannell]

I ran a Delco Remy 140A alternator for years on my 3GM30 and also replaced it with a Bosch AL9960LH T2 series 150A. Used double belt drive and had a bracket made up picking up the engine mount and the top bolt of the water pump bkt. Will try and post photos here. You can contact me if they do not come out. Even with a smart regulator like a Mastervolt Aplha Pro you will get maybe 90 amps continuous. I would charge while motor sailing or at anchor if needed.

[a64pilot]

Any alternator is not a DC device, they make alternating current, hence the name.
The alternating current is rectified, if I’m using the term correct by passing it through diodes, so the current doesn’t alternate anymore, it does however pulsate, but a battery can accept pulsating DC, and it will act as a Monster capacitor and then you can get real DC.
No alternator is very efficient, they generate a lot of heat, and heat takes a tremendous amount of power, plug a tiny space heater into a Honda generator for instance and that little bit of heat is all the Honda can make.

Alternators are inefficient, most are about 55% efficient on average, some can do much better under ideal conditions, But we don’t operate in ideal conditions very often.
This article really gets deep into the weeds but does explain everything very well.

http://www.delcoremy.com/documents/h...ite-paper.aspx

DC generators may seem at the onset to be the perfect devices, but they aren’t. To start with modern battery chargers are much more efficient than diodes, and they are “smart” with three stage charging and voltages controlled exactly to the .1V or better. Will a DC generator do that? None that I Know of. How about three stage charging, float voltage? Nope they are about as smart as an OEM alternator, and we know how good they are for charging batteries.
Going from AC to DC is now so easy and efficient that there just isn’t any real advantage of generating one over the other. Then because Diesel DC generators are so rare try to find parts, but Onan, Northern Lights etc are as common as Yanmar’s. Parts are available, there is a dealer network, and people know how to fix them.

I would like to know the efficiency of a small single phase AC generator but can’t really find it, but I believe it’s more efficient than an alternator due to the heat loss of an alternator in the diodes.
Anyone have a link?

[skenn_ie]

Many larger vessels have an auxillary pulley shaft/s which can be declutched. These would drive hydrauiic pump, emergency bilge-pump, 240/110V alternator, 24/28V alternator, refrigeration pump ....

Just a caveat on large alternator charging limitied batteries. Don't make a habit of charging above 20% of Ah capacity. DO get a charge controller which facilitates battery temperature monitoring. DO run charger when using high power battery loads, that will substantially extend battery life by mitigating the number of effective charge/discharge cycles

[noelex 77]

Originally Posted by a64pilot

DC generators may seem at the onset to be the perfect devices, but they aren’t. To start with modern battery chargers are much more efficient than diodes, and they are “smart” with three stage charging and voltages controlled exactly to the .1V or better. Will a DC generator do that? None that I Know of. How about three stage charging, float voltage? Nope they are about as smart as an OEM alternator, and we know how good they are for charging batteries.

DC generators are far from perfect, but they do have some advantages over the more common AC marine generators.

The main advantage of a DC generator is that the simple components allow for easier troubleshooting and repair. The other bonus is the variable speed that allows the revs to be tailored for the load and they can produce very large charging currents. The biggest drawback is there are few commercial models available so you may need to design and construct the unit yourself.

The DC generator is essentially a conventional marine engine driving a large alternator, or perhaps better a pair of alternators. There is no problem setting up 3 (or more) stage charging with fine voltage control in the same way as can be done with engine alternators.

[Nibbe]

Without having read all details in this tread... could this e an option? An alternator will never fully charge your batteries. I use it for a 300 Ah bank and its very efficient.
https://smartercharger.com/collectio...ff-road-bundle

[Augi]

Originally Posted by Augi

Is it possible to add a second larger alternators to twin Yanmar 3YM30, 29 HP, dedicated only to charging the house batteries? If yes, what is the largest alternator that is recommended?

Can such alternators be engaged and un-engaged at the helm station or electrical panel or navigation station.

Does having the large, second alternators partially or fully alleviate potential issues from idling the engine daily at a high enough RPM for the alternator to provide 50% of it's rated output due to the increased load of running the second laternator?

What are the pros and cons of this sort of set up as opposed to having a generator on a Cat that has two engines as described above to charge a large bank of lithium batteries. The boat has 1200 watts of solar and 800AH of lithium batteries at 12 volts.

As described above and with the size alternators you recommended how long would both engines need be idled to maintain output from both alternators of 50% of their rated value? is there a way to keep the alternators cool enough so that they don't lose output or at least don't lose significant output from getting hot or is it all about selecting the best possible alternator for the job?

For those interested just came across this provider of solutions for electrical power on a yacht without a separate generator.

https://integrelsolutions.com/#howdoesitwork

Thanks for everyone's input. Quite excellent!!

[skenn_ie]

I have a similarly sized auxillary engine which belt drives a HD alternator. I sized the pullies so that the alternator can produce about 70% of it's capability while the engine is doing about 50% of it's speed range. The latest one, a 3-cylinder Kubota, has a decent governor. The previous one, didn't. I had bought an electronic governor, but never fitted it. In the future, I will probably eliminate the 24/28V alternator for a 230AC generator, then charge batteries through a good charger.

[Augi]

Originally Posted by Augi

For those interested just came across this provider of solutions for electrical power on a yacht without a separate generator.

https://integrelsolutions.com/#howdoesitwork

Thanks for everyone's input. Quite excellent!!

Below is the link for data sheet for the system mentioned above. Fasten your seat belt. It ain't cheap! There is a place(see link) to put in basic specs of a specific boat, your location, etc. If nothing else the data sheet and estimator illustrates what is involved and the key variables.

For most the system is going to be too expensive for the advantage of not having a separate generator. It starts to make more sense if you were designing a boat from scratch and did not have to replace existing equipment.


https://integrelsolutions.com/wp-con...019-Master.pdf


https://integrelsolutions.com/estimator/

[sailingharry]

The system is more hype than real function.


It loads your engine with an 8KW (10HP) generator -- meaning, most of us will see the engine running at under 25% load -- surely better than a 100A alternator, but not long term desirable.


If you are going to run a steady load (where a generator shines) of say 2KW (an A/C for instance), then no matter how big your batteries are, you'll need to run the engine 25% of the time, or on average 6 hours per day.


This has serious potential for folks that motor a lot, and rarely sit still. A nice big Lithium battery will run your A/C all night long. Then the 8KW generator will recharge as you motor along the next day. And for true sailors or anchor out types, charging at the equivalent of 800A is, well, nirvana -- but the cost is impossible to justify for us. My daily usage of around 300Ah would be taken care of in 20 minutes (if it puts out 8KW continuous). But I'm not a candidate for a generator either.

[Augi]

Originally Posted by sailingharry

The system is more hype than real function.


It loads your engine with an 8KW (10HP) generator -- meaning, most of us will see the engine running at under 25% load -- surely better than a 100A alternator, but not long term desirable.


If you are going to run a steady load (where a generator shines) of say 2KW (an A/C for instance), then no matter how big your batteries are, you'll need to run the engine 25% of the time, or on average 6 hours per day.


This has serious potential for folks that motor a lot, and rarely sit still. A nice big Lithium battery will run your A/C all night long. Then the 8KW generator will recharge as you motor along the next day. And for true sailors or anchor out types, charging at the equivalent of 800A is, well, nirvana -- but the cost is impossible to justify for us. My daily usage of around 300Ah would be taken care of in 20 minutes (if it puts out 8KW continuous). But I'm not a candidate for a generator either.

As mentioned the cost does not seem to make sense for most people compared to buying a stand alone generator especially in my case. What I was hoping to determine(and have), is what it takes to be able to run the air conditioner each night for 8 hours with out a generator or engine running and without running a generator or engine(s) daily more than a very little. The answer is a lot of solar panels and lithium batteries. What the Integral System seems to offers(if their claims are true), for a lot of extra $$ you can charge lithium batteries very rapidly so in comparison a user does not have to run the engine(s) much or have a huge generator(that can charge lithium rapidly), saving a lot of weight or need for the space.

In the end, for the Integral System you would be paying a lot of extra $$ to not have a large stand alone generator and have silence more hours per day in order to have air conditioning that runs all night.

In my case the difference in price is approx. $10K-15K upfront to have the Integral System versus a stand alone generator(that would run more time per day), with lithium batteries that will run the air cond. all night. Or a difference of 25K if I skip the lithium batteries and go with small Next Gen or similar stand alone generator that runs most of the night to power the conditioner.

Since I am not a full time live-a-board, if I am tired of being hot and tired of listening to the generator(or don't want to bother my neighbors out courtesy), an option is go to a marina and plug into shore power. I prefer too anchor out but in my case the $$ involved point to going to a marina now and then.

[CarlF]

I recently read about two new 12v and 24v air conditioners that could deliver 16k BTU with much greater efficiency than 110v AC. I can't remember the publication but I expect Google can help.

I have a Balmar Alt-Mount kit driving a 200AH off the crank on my 4JH4. Works great and it's comforting to have Balmar standing behind it. The 2nd alternator Alt-mount doesn't seem to be available for the OP's engine but the serpentine belt kit is. I'd call Balmar and ask if it could be used with one of their excellent AT170 alternators.

AltMount Pulley Kit: 48-YSP-3YM-B