Generators needed on boat with solar and lithium.?

[sailingharry]

Originally Posted by sailorboy1

Wow, how many boats have a 300a alternator??????????? Running a main engine to charge batteries is the worst!

I have a 120A and a 150A (I think those are the numbers) at 12V, for a total of 270A on a 4JH2E (55hp or so) Yanmar. Of course, I rarely see 200A total. I can hear the engine bog down when the regulators ramp up the output. But, we rarely sit still long, and so the alternators run as a parasitic load 5-7 days a week, for at least an hour (a bit in and out, if not some on passage). That one hour mostly covers a day's power consumption. That and a bit of solar go a long way to keeping the batteries up. It would be much less useful if we had to run the engine at anchor to charge.

[singlespeed]

Because even in the trade wind zone sunny Eastern Caribbean, you can sometimes have a couple of cloudy wind less days. You refrigeration and water maker don't care, but you will, if the choice is potable water, keeping the beer cold or the anchor light shining.

[HighTemp]

We currently have 1900 aH of LiFePO4 and 2500W of solar, a Fischer Panda 13.5 KW genset, 2X 115A alternators that charge the start batteries and feed the house bank through 2 X 30A Orion DC to DC's on each side.

We just completed a 4 month trip around the Bahamas and in our case, we used the generator maybe 5 or 6 times. Our setup requires it for the washer/dryer, and water heater. If I recall correctly, we used it only once to recharge the batteries due to multiple days with little sun.

We will keep it on board since the only viable replacement in my opinion would be high output alternators, but those come with their own set of issues. As others have said, it comes in really handy when you need it. Of course the down side is the additional weight aft, and the fact that it is a very thirsty little bugger. Consumes almost 1 GPH. Ultimately, I am of the opinion that one can never have too many charging sources.

[noelex 77]

Originally Posted by singlespeed

Because even in the trade wind zone sunny Eastern Caribbean, you can sometimes have a couple of cloudy wind less days. You refrigeration and water maker don't care, but you will, if the choice is potable water, keeping the beer cold or the anchor light shining.

The eastern Caribbean has good solar insolation year round. It is not difficult to set up a system that runs all the devices you mention without a generator or without resorting to using the main engine just for charging.

It is certainly not the only option for producing electricity, but the problem of cloudy and/or windless days is not difficult to overcome with modern solar systems.

[Simi 60]

Originally Posted by The Yacht Rigger

More and more, now that the tech is available. I have 28V 185A alternators on my cat engines.
I much prefer charging at 300A (24v system) running my engines briefly, while I make some hot water, than running and maintaining a generator that can only charge at my on board charging systems capacity (120A).
The rest of the time... silence.

They may be at at what price?

Here in Australia a Balmar 220amp 24v alternator is $6000+
And due to our low rpm motor, not very well suited
https://www.outbackmarine.com.au/j18...-brushless-alt

A Delco Remy 55si will put out 275 amps but is around $5700
And I'll need to modify the mounting being a pad mount vs J180
But at least it puts out more amps at a lower RPM.

Then there's all the extras that are needed to get either of these operational and charge to both house and starts and likely a pro install so close enough to $10,000?

Too hard and too expensive

Seeing as we already have 2500w of solar
And an already installed Genset giving us 180amps @ 24v
A 70 amps dc2dc install for when underway seems a far simpler approach - for us.

[dietmar]

Althoughwe ar eupgrading to 2400 Watts of solar it's (sometimes ) paramount to have a lot of power available . our onan runs on Diesel - and we have plenty in our tanks in case we need it
2) cloudy rainy days - yes it's all good when the sun is shining but not after a storm or the rainy season

3) Stuff always happens at night so if you need ample power at 3 AM - and need to boot up anchor up and are worried about using a lot of power it's a gamechanger - you can focus on the problem at hand not the power usage

4) what I am looking for is a small 15 HP diesel outboard ....

[argonauta1]

Desalinator and refrigeration are the two main power demands of a bluewater cruising vessel. We fitted a second alternator and doubled the stock battery bank. Worked fine and on an ocean passage we perhaps had to run the diesel about an hour every three days. Made water during the engine run of course.
Alternator #1: 300 amp hours and alternator #2, 120 amp hours. House battery bank 800 amp hours. No genset due lack of space plus the extra alternator was much cheaper than a full blown genset. Forget the portable Honda et al. Too noisy, unstable on deck and at anchor annoys the neighbors.

[gbillman]

Originally Posted by UYA

They don't. At least we don't:
We moved to lithium (7.5kwh) and solar 1600W. We ditched our 40year old 3.5kw generator and never looked back.
Today we power everything with electricity except propulsion: cooking, water maker, dish washer, washing machine, toilet.
We are a family of 4 on a 42 foot monohull cruising full time in the tropics and subtropics being 100% at anchor. We dont charge the lithium batteries with our engine.
If there are a few days without sun (solar also works without sun but just not as good) we hold off on cloth washing, water making etc. This happens very rarely. Worse case you can use your engine to resupply some energy.
I think the magic sauce is the combo of enough solar (as much as you can) and lithium batteries.

Concur with all. But I'd add that a large-enough inverter is also required. I can only run 1 of our 2 air conditioners with ours, which isn't a problem when we don't have guests over in the guest cabin on the other side of the cat.

[SV__Grace]

Living on the hook here in PNW our solar and wind keeps up with our power use and we almost never run the generator from April to October.

November through March the days are too short and the cloud cover too dense to keep our batteries charged and we typically need to run the generator every 3-4 days or so. Having lithium batteries allows us to halve the time/fuel it takes to charge the batteries and it is a blessing that lithium batteries love partial state of charge (PSoC) so we stop the generator when the voltage is high enough that the charging current starts dropping, about 90%.

Thought a lot about adding solar panels but in the months that we need that extra power generation I can't see us keeping up with our daily use even with tripling the number of panels even if I figured out how to mount them.

[Talbot]

A few years bac I saw someone who had added an additional generator to their engine, using an AC clutch from a car, and getting 240v from the generator. In the same way you can set up an alternator as a welder.
Beyond my capabilities, so I will soldier on with my diesel gennie as I cook with a microwave/convection oven, and don't have the space for batteries and panels needed for that.

[CaptainRivet]

Originally Posted by Chotu

Air conditioning

Only if you have factory 230V aircon, efficent 12/24V aircon and enough solar/LFP capacity no gen is needed

[CaptainRivet]

Originally Posted by SV__Grace

Living on the hook here in PNW our solar and wind keeps up with our power use and we almost never run the generator from April to October.

November through March the days are too short and the cloud cover too dense to keep our batteries charged and we typically need to run the generator every 3-4 days or so. Having lithium batteries allows us to halve the time/fuel it takes to charge the batteries and it is a blessing that lithium batteries love partial state of charge (PSoC) so we stop the generator when the voltage is high enough that the charging current starts dropping, about 90%.

Thought a lot about adding solar panels but in the months that we need that extra power generation I can't see us keeping up with our daily use even with tripling the number of panels even if I figured out how to mount them.

That when you really need a gen.
Alternative big alternotors on the engines can avoid to have a 2nd or 3rd (if cat) engine aka genny in this situation. Yes its less efficent but less maintenace/cost and if you move october till march the engine already fill up the bank.

[CaptainRivet]

Originally Posted by gbillman

Concur with all. But I'd add that a large-enough inverter is also required. I can only run 1 of our 2 air conditioners with ours, which isn't a problem when we don't have guests over in the guest cabin on the other side of the cat.

Switch them to 12/24V aircon and you don't need inverter and gen as enough solar and a big alternator for the really bad weather weeks or winter.
These 110V/230V are power honks...

[CaptainRivet]

Originally Posted by dietmar

Althoughwe ar eupgrading to 2400 Watts of solar it's (sometimes ) paramount to have a lot of power available . our onan runs on Diesel - and we have plenty in our tanks in case we need it
2) cloudy rainy days - yes it's all good when the sun is shining but not after a storm or the rainy season

3) Stuff always happens at night so if you need ample power at 3 AM - and need to boot up anchor up and are worried about using a lot of power it's a gamechanger - you can focus on the problem at hand not the power usage

4) what I am looking for is a small 15 HP diesel outboard ....

4 is the dream of us all, best replacement is the 26kg 1 cylinder Tohastu MB 9.8hp 2 Stroke, 2,7 Billion fisherman cannot be wrong....
Even starts if you drain it...

[toddster8]

Winter.

Even in summer, with refrigeration, freezer, and starlink, there is often a deficit at the end of the day that requires an hour or so of running the generator. Yeah, get more solar panels. Somehow. But then, winter.