Genset operating cost , per lifetime hours

[rslifkin]

I don't disagree and have no real experience with inverters, but I assume you would need a big increase in battery capacity and even then it's not unlimited. I don't usually bother running the air cond. at anchor, but if it was extremely hot and needed to, I could run it all day/night. And since I need it to run the stove, cooking breakfast tops off the batteries instead of draining them like an inverter would.

It definitely requires more battery power. At this point, with solar, decent batteries (more would be nice) and an inverter, we pretty much only start the generator to make dinner (or rarely if we want to cook a real breakfast). Hot water for showers heats up while dinner is cooking. Things like coffee don't require the generator, and unless we get a really dark, cloudy day, we don't need it for battery charging even if we stay in 1 place without shore power for a few days. So it typically runs 45 - 60 minutes for every day we're away from power.

 

[Marco Flamingo]

I often hear on Trawler Forum that economical people aren't real boaters and if you take the time to make practical expenditures you should not own a boat. I admit that I do research and tend to make pragmatic purchases. But I throw a $100 bill over the side every hour to remain in the TF big spender club. Should it be more?

 

[grahamdouglass]

My Generator story

When I bought my boat in 2007 it had an original Onan 3kw genset. Within the year it had to be fixed. In the fall of 2008 I took it to a very expensive generator shop and after a long 4 to 5 weeks, with an escalating bill I was told it would cost $3500 if I wanted my genset back. I told them they were crazy and they could keep the genset.

In May of the following year I noticed a used genset that was the exact model as my old genset for $500, it needed a new head gasket, exactly what my old genset needed. I bought the genset, fixed the genset for $100 and installed it.

In 2019 I bought a Northern Lights 5wk genset, with 700hrs on it for $5000. It was a great install, I sold my old genset.

So what was the kilowatt hour per use? I have no idea and it would it would cut in to my leisure time to figure it out.

 

[Bacchus]

Knowing $/hr for generator operation may help drive power systems decisions. The more it costs to run the generator, the sooner things like big house batteries, solar panels, and inverters pay for themselves through reduced generator use.

If you already have a gen I doubt simply running less hours could ever justify the expense of adding, batteries, solar, controllers and inverter. Plus if you have a gen running it is a good thing not running it is bad.

If you don't have a gen weighing cost of a gen install vs batteries, solar, controllers and inverter might be a realistic decision.

 

[O C Diver]

Regarding usage and alternatives, there are some things such as air conditioning that aren't practical with solar, batteries, and an inverter. The trick is to realize at what point continuing to grow the battery bank and solar is a loosing game for the minimal amount that the additional solar and batteries are utilized.

Ted

 

[rslifkin]

If you already have a gen I doubt simply running less hours could ever justify the expense of adding, batteries, solar, controllers and inverter. Plus if you have a gen running it is a good thing not running it is bad.

If you don't have a gen weighing cost of a gen install vs batteries, solar, controllers and inverter might be a realistic decision.

It wouldn't be worth going for no gen use, but reducing it to 1 good, loaded run every day or 2 when away from the dock won't hurt the gen. And it means that you'll probably never wear the gen out on top of having somewhat lower maintenance costs for it.

 

[Captain DJ]

While on the Cost of Electricity and generator topic, let me run my idea by you fine folks:
I have a 7.5kW Onan that is about 40+ years old, pretty neglected and corroded, but still runs. It smokes and rattles and I could put more work into it and make it look & perform better.
I also realize that most of the electricity I use comes from my inverter and a fairly large collection of 6v flooded cell batteries in series and parallel. I think somewhere about 480 amp hrs. at 12v. I have purchased an almost new 1 cylinder Kubota diesel with a high output 12 v alternator. This super small, one-cylinder Kubota should consume way less diesel than the BIG Onan, maybe 1/3. It should be much quieter and easier to isolate vibrations. It is already set up for a wet exhaust and was used one season in a sailboat.
My thinking is that with somewhere around a 15% efficiency loss to create 120v with the Onan to run the inverter to store the energy in the massive (and soon to be expanded more) 12-volt house bank, perhaps a quieter, gentler, more efficient approach would be to let the high output alternator be driven for longer periods than I would want to run the older 120v Onan.
I am hoping to gain efficiency, albeit increase hours of use, but have a solution that adds to solar panels on cloudy days or when the house bank starts to dip down to 75-80% of capacity. I have never heard of a trawler genset that just puts out 12v, but it seems to make sense for my application. No AC, gas for cooking, and diesel furnace & hot water. It is always a combo of 12v drainage with equipment, lights, windlass and the 120v items like fridge and microwave and computer & cellphone chargers (which themselves, these last two, use transformers to convert back to a low voltage). Simply reducing the number of times the energy is converted/inverted from 120v to 12v and back to 120v should save some and with newer batteries LiFPo or something else in 5-8 years when my AGM and flooded cells are old, simply solar, wind and the occasional super quiet little 1-cylinder Kubota can fill in the gaps to keep us barely humming along to stay in that pristine and peaceful bay a few days longer, without becoming the typical stinkpot.

Just an idea that is related to this topic, methinks.

 

[garychurch]

20Kw Northern Lights
$5 per hour
12,000 hours life prior to rebuild if well maintained.

Average Run Time Per Day at Anchor 5 hours or $25.

 

[Rich wilmer]

Gen sets

If your boat is in calif. California has banned lawnmowers, leafblowers and generators ..so how to figure cost versus run time is no longer pertinentl...??

 

[O C Diver]

20Kw Northern Lights
$5 per hour
12,000 hours life prior to rebuild if well maintained.

Average Run Time Per Day at Anchor 5 hours or $25.

I assume a 12 KW generator burns over 2 gallons per hour. Seems like $5 per hour wouldn't cover the fuel plus any maintenance.

Ted

 

[backinblue]

I assume a 12 KW generator burns over 2 gallons per hour. Seems like $5 per hour wouldn't cover the fuel plus any maintenance.

Ted

I wouldn't be surprised if we are paying close to $5/gal this summer.

 

[catalinajack]

By framing the metric as cost per hour operated, the cost/hour of a generator that sits unused will be nearly infinite. Most of our generators burn between 1/2 to 1 gallon per hour of diesel which is pretty straightforward, oil changes and most other maintenance is based on hours run with a minimum of once annually. Very few recreational boaters wear out their generators through proper use, it is certainly possible but in reality is just isn't very common, they die by neglect, corrosion (improper placement), improper exhaust configuration or underloading.

Therefore I would propose that if you graph out the cost per life expectancy, it will be an asymptote approaching (but never reaching) a minimum of about $2.25/hour. edit: actually $3.25 would be a accurate and still extremely optimistic lowest limit, assuming you get 1 hour of life for every dollar the generator cost (including install). Again this would be extremely optimistic.

Gdavid, quite correct. In accounting, the generator, once purchased, is known as a sunk cost meaning that, whether used or not, the cost does not increase. For us, especially those whose boats came equipped with a generator (s), the costs of operation are the current costs, primarily fuel, oil, and filters. The capital cost remains the same whether used or not..

 

[catalinajack]

I just put together a basic example. Let's take an 8kw Phasor generator (Kubota engine). Figure it'll last 10k hours with good maintenance. And let's assume that on average, it's run at half load, so putting out 4kw.

Over that 10k hours, it will burn about 3200 gallons of fuel based on the spec I can find (at the 1/2 load average). So figure $4 / gallon and we're looking at $12,800 in fuel or $1.28 / hour.

Let's figure that between oil changes and impellers you spend $100 every 100 hours of runtime (on the high side). So another $1 / hour. Probably that again for replacing hoses, belts, and other wear items over time. So we'll call maintenance and repairs at $2 / hour.

The unit costs about $10,000, so break that down over the 10k hour life and that's another $1 / hour. Let's add another $5000 for install, so make it $1.50 / hour total equipment cost.

That all adds up to $4.78 per running hour. If we look at cost per kwh of power produced, we're just shy of $1.20 / kwh.

Some reasonable assumptions but only relevant on a new install. There is no capital cost for a generator that comes with the boat. As for oil changes, a modest-sized unit such as my 7.7kw Westerbeke, takes three quarts of oil. So, $12 for oil, maybe $5 for a filter comes to 17 cents/hour, not anywhere close to $1/hour. My 12.5kw Kohler takes 7 quarts, so maybe 40 cents/hour. Impeller. Fourteen cents per hour.

 

[Bryant]

Genset

Assuming your new purchase boat has a new zero time gen set , it might help wanabee folks to know the total cost of operating it till shot and then replacing it.

Assume oil changes , filters, winterizing ? all by Da Book.

The true total hourly cost of operating might be a help, to new folks .[/QUOTE

A genset is a Diesel engine. A well and properly maintained Diesel engine should run for 10,000 hrs. I have my engine professionally serviced every 100 hrs. I have the transmission and generator serviced at that time as well. A normal service for all three with no issues runs $1000. I just had to have my generator engine mounts replaced so that added to the costs. My generator burns 1/2 gal of diesel per hour. So figure that cost.

 

[backinblue]

Assuming your new purchase boat has a new zero time gen set , it might help wanabee folks to know the total cost of operating it till shot and then replacing it.

Assume oil changes , filters, winterizing ? all by Da Book.

The true total hourly cost of operating might be a help, to new folks .[/QUOTE

A genset is a Diesel engine. A well and properly maintained Diesel engine should run for 10,000 hrs. I have my engine professionally serviced every 100 hrs. I have the transmission and generator serviced at that time as well. A normal service for all three with no issues runs $1000. I just had to have my generator engine mounts replaced so that added to the costs. My generator burns 1/2 gal of diesel per hour. So figure that cost.

OMG, if I did that for everything on my boat I'd realize what a complete waste of money boating is and have to give it up. Financial analysis and justification will never yield a positive result. Ignorance is bliss!

 

[Iggy]

Man, you guys are too much. Ok, in a general way its good its know what cost are. But to get so down and dirty is just crazy.

Its also a balancing act, when to run the inverter, the genset and to install or use solar panels. As someone just said, don't own a boat if your not going to though money at it.

I just spent 6K on a cover and about to drop 5k on batteries. I can't take the money with me so I am just going to enjoy my self. Yes, there is a line to draw. But if running a genset at $5 or $6 an hour drives to nuts, well life is just too short!

 

[hollywood8118]

There are so many variables to generator costs its really hard to put any real numbers as a generalization of cost. I think the larger the genset the longer it will last as long as its not overloaded in use. I know the 30kw units I have seen in the charter boat business in the Caribbean that run pretty much constantly to run ac etc. seem to go over 30000 hrs without a complete rebuild. My 7.5 kw onan rattler has 1500 hrs and was never properly ran after a rebuild by the PO and I really need to do a top end on it as oil consumption is excessive. So my units cost per hour is very high.

As battery tech and tech in general goes up I imagine a all electric boat with big battery storage and with AC is not too far off in the future. There no doubt will be a trickle down effect from the electric car industry that will help this.

HOLLYWOOD

 

[koliver]

I wouldn't be surprised if we are paying close to $5/gal this summer.

Already there in So Cal at many road pumps.

 

[backinblue]

Already there in So Cal at many road pumps.

Doesn't surprise me especailly in CA. In CT, fuel docks for diesel can sometimes be less than road diesel due to tax differences. Given the way things are going, I expect a very expensive summer for all types of fuel.

 

[Bryant]

Genset cost

OMG, if I did that for everything on my boat I'd realize what a complete waste of money boating is and have to give it up. Financial analysis and justification will never yield a positive result. Ignorance is bliss!

The OP asked a pretty straightforward question so I tried to give him an answer addressing that. Many newbies to boating assume that the cost is simply buying a boat, insurance, slip fee and fuel. It’s helpful to know whether you can really afford a given boat before you buy it rather than after.

 

[OldDan1943]

Interesting post. For me, the cost v. runtime is irrelevant as I am an electric boat. Lots of 120vAC items on ASD.

Yes, an interesting discussion but, if we had any sense at all, we would not own a boat.
I have long maintained, 'It is my generator and I will run it as I need it.'
I do the required/necessary maintenance. I figure it will outlast me but, if there is a problem, I will have it repaired and if necessary, replaced.
Folks are trying to figure out the cost/KW. It is not that we will put that money in a jar or box. We just play by ear.

 

[backinblue]

The OP asked a pretty straightforward question so I tried to give him an answer addressing that. Many newbies to boating assume that the cost is simply buying a boat, insurance, slip fee and fuel. It’s helpful to know whether you can really afford a given boat before you buy it rather than after.

I get that and sorry if you think I was discarding anything anyone said. That said, I think if I listed everything that I spend money on as a boat owner and user, the cost to run the generator is pretty far down in the list. First, the generator is not really a necessity and you could be just fine never using it if the cost was prohibitive. However, if the money to run the generator is a make/break decision point, you can't afford to own the boat. When I bought my 8 year old used boat it had like 20 hours on the generator (not necessarily a good thing) and after 3 seasons that I've owned it probably has 100 hours on it. I plan to give it more runtime during the season going forward.

Prior to this boat I've owned only sailboats, which had very modest systems by comparison. For example I remember buying a boat that was my first with pressurized hot and cold water and though that was a luxury. When I was shopping a few years ago I almost bought a used Back Cove from a dealer in Maine. The broker made a point of making sure I knew there was no generator. I never had one before and didn't see the need, but am glad I have one now.

 

[OldDan1943]

blacknblue, you are in 'hog heaven'. Now you have pressurized hot water and a generator. Do you have A/C and heat? I'll bet you do not have a alcohol cook stove. With all those luxuries, you are knocking on heaven's door. TEASE
Ain't life grand?

 

[backinblue]

Thanks Dan. Yes I have AC/heat electric stove AND a microwave!! I even have a TV that gets less use than my generator. Funny but I almost caught one of my boats on fire with those "safe" alcohol stoves, but that's a story for another time. Life is good, but I do feel like I am knocking on heaven's door at times, although I'm not sure that heaven is my eventual destination.