Genset cost per KW hour

[BandB]

For us it's pretty simple with all the things we need "electricity" for. For cruising, when we disconnect the shore power cords, we start up a generator.

 

[Aquabelle]

BandB: I assume you do not have an inverter & that is why you run the generator while cruising?

 

[BandB]

BandB: I assume you do not have an inverter & that is why you run the generator while cruising?

Do have an inverter. Just have a lot of things to power. We do have times we do run on inverter only but that's rare. Depends somewhat on which boat. On one of our boats we will run regularly without the generator. But as you add more and more things it becomes less practical. At the moment we're on a charter boat and when we pull away from the dock will have AC, refrigerator, two freezers, washer and dryer using electricity. Perhaps stove or microwave or electric grill as well. The boat we're on at the moment has a 4800 watt inverter and 33 kw and 28 kw generators. Also the gens have PTO's for the thrusters. Now recognize this is a larger boat we're on at the moment.

 

[BandB]

BandB: I assume you do not have an inverter & that is why you run the generator while cruising?

Curious as to what you find you're able to run on your inverter?

 

[Aquabelle]

B&B: I have a 300W inverter...240v here in Australia. I don't ever run air-con while underway. I have 160A and 120A alternators on my propulsion engines (both de-rated by 20% via smart regulators) and the Stbd engine also runs a hydraulic pump for stabilizers. I have no other hydraulics (well the auto-pilot/steering system, but that's 12v). Underway and/or anchored out, we use microwave, d/washer, elec convection oven, 240v fridge, washer, dryer, coffee maker, hair dryers (spouse & teenage daughter)...and can do all that with the inverter off our 970Ah house bank. Sure, we don't turn everything on at the same time...but we don't need to think about it much, as we wouldn't normally be wanting to do that anyway. BUT even if we did, the inverter is a Victron and this, like MasterVolt, can be parallel’d to genset or to a 2nd (or 3rd) inverter if need be: haven't found it necessary.

Apart from running air-con while underway in very hot/humid conditions (which would be found only in northern Australia & in summer by and large), I don't get the concept of operating the genny while cruising. Seems to me a correctly sized house bank, alternator/regulator charging system and inverter should be able to cope with everything pretty easily while underway. As for hydraulics, I would have thought running stabilizers off the propulsion engine made the most sense for that application (you don't use stabilizers unless underway....note exception for newer stabilization-at-anchor options). So that would leave turning on the genny for hydraulic davit/winch/thruster...just when docking/anchoring/launching the tender, not during the cruise itself.

We use the genset very, very rarely. Occasional very hot summer night at anchor for air-con (maybe once a year in Sydney region); or to top up batteries if we've been anchored out in one spot for 3 days without re-locating and House bank is at 60%.

Interesting how different people use and set up their boats differently, isn't it?

 

[markpierce]

My inverter (making 110-volt power) is used to run the boat's air compressor, small electrical devices, the occasional power tool, the water heater (also uses engine heat), and a small electric heater. Don't have A/C, TV, microwave, electric stove (use propane), or coffee maker. And don't have a genset (declined the $7,500 option for a 3.5KW genset). Power comes from shore, the engine's 140-amp alternator, or the house batteries. The boat's dual 24-volt 200 AH AGM house batteries last two days/nights at anchor if not making heat and still have over 60% capacity left. The engine's alternator provides plenty of power while underway.

 

[BandB]

B&B: I have a 300W inverter...240v here in Australia. I don't ever run air-con while underway. I have 160A and 120A alternators on my propulsion engines (both de-rated by 20% via smart regulators) and the Stbd engine also runs a hydraulic pump for stabilizers. I have no other hydraulics (well the auto-pilot/steering system, but that's 12v). Underway and/or anchored out, we use microwave, d/washer, elec convection oven, 240v fridge, washer, dryer, coffee maker, hair dryers (spouse & teenage daughter)...and can do all that with the inverter off our 970Ah house bank. Sure, we don't turn everything on at the same time...but we don't need to think about it much, as we wouldn't normally be wanting to do that anyway. BUT even if we did, the inverter is a Victron and this, like MasterVolt, can be parallel’d to genset or to a 2nd (or 3rd) inverter if need be: haven't found it necessary.

Apart from running air-con while underway in very hot/humid conditions (which would be found only in northern Australia & in summer by and large), I don't get the concept of operating the genny while cruising. Seems to me a correctly sized house bank, alternator/regulator charging system and inverter should be able to cope with everything pretty easily while underway. As for hydraulics, I would have thought running stabilizers off the propulsion engine made the most sense for that application (you don't use stabilizers unless underway....note exception for newer stabilization-at-anchor options). So that would leave turning on the genny for hydraulic davit/winch/thruster...just when docking/anchoring/launching the tender, not during the cruise itself.

We use the genset very, very rarely. Occasional very hot summer night at anchor for air-con (maybe once a year in Sydney region); or to top up batteries if we've been anchored out in one spot for 3 days without re-locating and House bank is at 60%.

Interesting how different people use and set up their boats differently, isn't it?

It is interesting to find differences. And in this case some of the huge differences are both location and type and size boat combined with just personal preferences. When we're in an open boat or coupe type then very little load as we're not running air conditioning or really doing much in the galley. Now when we're in a larger boat like the one we're chartering right now, and in South Florida or the gulf, then we run the air conditioning the vast majority of time. And since we are on an 85', there is an 8 ton and a 2 ton unit.

 

[rwidman]

A beautiful anchorage beats a dock any day, whatever the costs!

Without a genset chugging away! Yours or someone else's.

 

[ronlord]

Thanks for input Ron!

Sounds interesting... You have it permanently affixed some location aboard with gasoline exhaust safely routed? And, if so, is it hotwired into your main elect panel’s applicable breakers?

Nope. It sits on the swim platform when we are using it, plugged right into the regular shore power cord with a 30 to 15 amp adapter.

 

[Art]

Nope. It sits on the swim platform when we are using it, plugged right into the regular shore power cord with a 30 to 15 amp adapter.

Simple and Cool!

 

[Ski in NC]

A friend had his Honda on the swim platform, and a freak wake washed it off into the water. It was tied up, so he recovered it. Rinsed it off and let it dry in the sun and it worked another year!!!

Nice little machines, hard to beat the cost equation. I still prefer my little diesel gennie, though.

And getting back to the original post, it is ludicrous to use cost/kwH or similar metrics on gennies, or for that matter the whole boat, fish caught, or even cars.

Buy a fishing boat and catch a fish. Divide cost of boat by weight of fish. Pretty expensive fish.

If you apply financial metrics to all parts of your life, and make decisions based purely on the financials, you are going to live a very boring life.

 

[Art]

A friend had his Honda on the swim platform, and a freak wake washed it off into the water. It was tied up, so he recovered it. Rinsed it off and let it dry in the sun and it worked another year!!!

Nice little machines, hard to beat the cost equation. I still prefer my little diesel gennie, though.

And getting back to the original post, it is ludicrous to use cost/kwH or similar metrics on gennies, or for that matter the whole boat, fish caught, or even cars.

Buy a fishing boat and catch a fish. Divide cost of boat by weight of fish. Pretty expensive fish.

If you apply financial metrics to all parts of your life, and make decisions based purely on the financials, you are going to live a very boring life.

Yo Ski - But a very full bank account - maybe??

 

[superdiver]

I am relatively new to boats and I have learned int hat short time that figuring the cost of something is purely for arguments sake...

if it REALLY mattered, why would anyone EVER own a boat???

 

[Art]

I am relatively new to boats and I have learned int hat short time that figuring the cost of something is purely for arguments sake...

if it REALLY mattered, why would anyone EVER own a boat???

Bingo - On most levels...

In that: IMO, the most important time to actually be counting on all fingers and toes (regarding boat costs) is when reviewing a boat to purchase. Once you own her, you're basically wed to her, and - she owns you too! Before purchase you can still get away pretty clean before a full-on marriage to any boat... after paying and signing on the dotted line... you had better counted on all your digits correctly!

Happy Boat Costing Daze! - Art

 

[FlyWright]

I am relatively new to boats and I have learned int hat short time that figuring the cost of something is purely for arguments sake...

if it REALLY mattered, why would anyone EVER own a boat???

SD! Long time, no read!! Glad to see you wading in these treacherous waters again!

I like to call it rationalization.

It seems like an exercise in futility like using a cheap camera to photograph a quickly moving target. The results are vague and blurry and never the same twice, but you feel better trying to capture the moment in time.

 

[rwidman]

Nigel Calder has an excellent article in this months PBB working out the cost per KW of AC power and battery charging.

www.proboat.com/

The numbers are frightening the high side is $19.00 per KW.

Most boat yards will have a copy or two , sit down before reading the true costs of your noisemaker.

I would copy and post it , but dont know the copyright laws .

Yea, Mr. Calder is also involved in some sort of study of electric or hybrid propulsion for boats as opposed to conventional diesel. It's in some magazine I read lately.

I don't doubt his intelligence or his work but some of this stuff doesn't really have a practical use for us mere boat owners. If you believe you need a genset to boat you're going to buy a genset regardless of the cost per KWH. The fact that electricity on a boat costs more than electricity at home is irrelevant.

 

[sunchaser]

Ron

My take on Calder's writings are he is still trying to come up with positive financials for diesel electric on boats we use. He is as stumped as you and many of us are, but he is a busy writer so some arcane paragraph or two may come from his pen suggesting a likely seemingly positive outcome. Then the next day arrives. --------

 

[Moonfish]

Nope. It sits on the swim platform when we are using it, plugged right into the regular shore power cord with a 30 to 15 amp adapter.

We picked up the same adapter for our Honda gen. Makes it super easy to use when needed. We bought it last August as our NextGen suffered a loss of raw water (plugged intake) and the local repair companies were booking in October/November! As we were "out" for another month, the Honda was purchased as an interim generator. Now, after the main genny got fixed, the Honda is our backup gen.

 

[FF]

I don't doubt his intelligence or his work but some of this stuff doesn't really have a practical use for us mere boat owners. If you believe you need a genset to boat you're going to buy a genset regardless of the cost per KWH. The fact that electricity on a boat costs more than electricity at home is irrelevant. __________________

True , BUT with planning and better operation hourly costs can be cut dramatically.

$10, per hour is lots better than $18 for some folks.

 

[ronlord]

I don't doubt his intelligence or his work but some of this stuff doesn't really have a practical use for us mere boat owners. If you believe you need a genset to boat you're going to buy a genset regardless of the cost per KWH. The fact that electricity on a boat costs more than electricity at home is irrelevant. __________________

True , BUT with planning and better operation hourly costs can be cut dramatically.

$10, per hour is lots better than $18 for some folks.

I think most of us here realize that the best set up is to pair your generator with a good size battery bank and inverter. We have two 110v refrigerators aboard, plus the other required 110v stuff like TV, coffemaker, range, and water heater. We coordinate the use of the heavy duty stuff like cooking, heating water with the charging of the batteries. A few hours of genset run in the morning and a few hours in the evening does it, with the rest of the time running on inverter.

 

[FF]

>We coordinate the use of the heavy duty stuff like cooking, heating water with the charging of the batteries.<

Does that mean co generation , the gen set coolant, with heat exchanger heats the fresh water for >free<?

Or you need to diesel fuel/noisemaker 1.5KW per hour just to heat some water?

The entire point of the Calder article is with some engineering the same lifestyle can be maintained at far lower cost.

 

[Art]

We work it simple as can be! Run our 7.5 Kohler gen about 1.5 hrs per day to keep batts up, food/coffee cooked, water hot/warm, ac refrig cold, computers and phones charged... etc. At that rate we stay on hook for any number of days.

As energy assistance-savers:

- Watch movies on 17” computer screen
- Keep small block of ice on refer’s top shelf
- Do a lot of BBQing
- Swim a lot - few showers needed
- Keep soft light in cabins with rechargeable battery hanging lights
- Heat on cool days with HeatMate alcohol heater/warmer
- Even though have one - don’t need AC at all

And - we don't have or need for or want an inverter!

Living in the temperate climate of Nor Cal and boating in the very good climate, warm fresh waters of SF Bay Delta makes life easy aboard boat – or anywhere near for that matter!

Happy Boating GenSet Days! – Art

PS: figure our gen uses about .75 gal per hr. Four day anchor out costs approx $25.00 in gen set fuel.

 

[ronlord]

>We coordinate the use of the heavy duty stuff like cooking, heating water with the charging of the batteries.<

Does that mean co generation , the gen set coolant, with heat exchanger heats the fresh water for >free<?

Or you need to diesel fuel/noisemaker 1.5KW per hour just to heat some water?

The main will heat water while we are underway, the generator has no such hookup. However, consider while we are running that generator, the batteries are getting a 90 amp charge, the stove is cooking breakfast and the water is heating for a morning shower. Lot of co-generation going on there...

 

[CaptTom]

The main will heat water while we are underway, the generator has no such hookup. However, consider while we are running that generator, the batteries are getting a 90 amp charge, the stove is cooking breakfast and the water is heating for a morning shower. Lot of co-generation going on there...

That's what I'm finding. I can run the gen set for an hour while cooking breakfast and dinner. That gives me hot water and puts enough juice back in the house bank for the rest of the day or night. I could run it just once a day if I'm underway for at least an hour or two. If it's a longer passage, I may not need the gen set at all, unless I want to use the electric stove.

The only problem would be if we needed the air conditioners running all night or all day. For that, my Honda eu2000i will do the trick. It's much quieter and more fuel-efficient, and it's a good backup if the 7.5KW diesel fails. I could certainly survive without a generator, but I'd be relying on the mains more and wouldn't want to stay anchored or moored out for as long. So a backup generator makes sense for me.

 

[ronlord]

The only problem would be if we needed the air conditioners running all night or all day. For that, my Honda eu2000i will do the trick. It's much quieter and more fuel-efficient, and it's a good backup if the 7.5KW diesel fails. I could certainly survive without a generator, but I'd be relying on the mains more and wouldn't want to stay anchored or moored out for as long. So a backup generator makes sense for me.

Capt Tom - what size AC? We have a 16k and 12k BTU, the honda won't push either one. My last boat had a 10k unit that the honda would run. I think that is about the limit unless you have one of those slow start capacitors.

 

[CaptTom]

Capt Tom - what size AC? We have a 16k and 12k BTU, the honda won't push either one. My last boat had a 10k unit that the honda would run. I think that is about the limit unless you have one of those slow start capacitors.

On my last boat, I ran the 9,000 BTU Mermaid on the Honda without a second thought, while also powering the charger and other loads.

This time I have 2 15,000 BTU Dometic units that use about 10A each. Add a couple more amps for the pump and fan for about 12A each, or 1,440 Watts. So I can run one and have a little left over for a few other small loads. The compressor start is delayed from the pump start, but even so I'm sure there's a bit of an overload for the fraction of a second while it's starting. But it does work.

 

[FlyWright]

We picked up the same adapter for our Honda gen. Makes it super easy to use when needed.

Same here...

 

[jwnall]

Where did you order that from, Al? I need one also.

 

[FlyWright]

That was a long time ago, John. I don't recall. I'd get the model number and search online...I think it was about $25-30.

Is this what you're looking for?

Marinco Shore Power Straight Adapter 83A 30A Locking to 15A Straight NIP | eBay

 

[jwnall]

Yeah, but I cannot deal with eBay. Thought you might have a recommended source. No problem -- I'll google it. I have the name now, and I have a lot of confidence in Google, even though I don't like them. Thanks.