Boat Rentals

[PrivatePilot]

Our van has a 6k DC air conditioning uses 50a at full tilt water cooling should double the efficiency. 300 amp lithium battery bank can run it for 3 to 4 days normally

When you're working with a DC power source, DC air conditioning is going to be far more efficient for sure.

Not sure how much more efficient a water based heat exchange system makes it, or not - there's extra consumption overhead of course with the need for water pumps and such of course.

As for your DC setup, if your AC uses 50A when running how does it run for 3-4 days on only 300ah? I have a 280AH Lifepo4 in our camper and we have a 1250BTU AC (just for spot cooling, that bit of cool air blowing directly on you in bed makes a huge difference) and after an 8 hour sleep I've used about 75% of the battery. Yeah, we're running it through an inverter so there's losses there, but still, even without that we might get 12-15 hours tops I'd expect, and that's only a 1250BTU AC, not 6KBTU.

 

[Scuba Steve]

When you're working with a DC power source, DC air conditioning is going to be far more efficient for sure.

Not sure how much more efficient a water based heat exchange system makes it, or not - there's extra consumption overhead of course with the need for water pumps and such of course.

As for your DC setup, if your AC uses 50A when running how does it run for 3-4 days on only 300ah? I have a 280AH Lifepo4 in our camper and we have a 1250BTU AC (just for spot cooling, that bit of cool air blowing directly on you in bed makes a huge difference) and after an 8 hour sleep I've used about 75% of the battery. Yeah, we're running it through an inverter so there's losses there, but still, even without that we might get 12-15 hours tops I'd expect, and that's only a 1250BTU AC, not 6KBTU.

50 amp at full tilt usually at around 8 to 10 once the van is cooled then shuts off for a while.

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[crankcall]

We’ve tried a couple systems over the years , AC ac in our camper , only way that made sense , but off grid useless . AC in one boat off Gen set or shore , in the big fifty nine ft boat refit , two Dometic DC ac units , went to a Balmar 400 amp alternator on an electric clutch , you could engage the drive off the yanmar turbo diesel . No Gen set , twin carbon foam airplane batteries from OceanPlanet . Current setup is Dometic DC unit , close up boat and I can get two hours to take the stink out , solar would help a lot but it’s ugly . Best answer is never leave the dock , but that doesn’t help . There are a lot of options now , the International boat builders exhibit in Miami this yr had many things to consider, but it’s all very expensive, and payback is never . For a few yrs I used a freestanding AC one twenty volt I bought at home depot and stuck in the quarter berth , it only worked at the dock , I couldn’t carry enough battery to run an inverter . But every third night was pleasant .


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[Mad Mike]

Keep the gen set imo. If the unlikely event the kholer packs it in , seven grand and your back in business with three wires and four bolts . Pop in a yanmar or Olin diesel gen and your ten g’s and running forever. Those main engines are design to run under load , not an alternator load , they will just eat themselves at idle for a twenty five g replace . Dude that specd the Kholer didn’t drop it in to jack the price , it’s a good idea .


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I'd agree if you're talking about a looper or something that spends a ton of time at sea. This is a rec boat, soulds like it's mostly a floating cottage hooked up to shore power for 95+% of the hours it's wet. When it's not docked at home, it's probably steaming a few hours a day where the mains will charge the house batteries at about 20% per hour AND power anything that needs electricity.

When not steaming, 2x200AH house batteries give you 4800KW, enough to run a fridge, lights, cooking, and 5K-BTU A/C at 20% duty for 26 straight hours without running the mains. If the AC wasn't necessary, you're looking at 2-3 days.

As for running the mains, you might expect wear on a conventional engine, but not a marine build. The main issue with long low loads is lubrication -- all marine engines use high-volume oil pumps these days, so this is not an issue.

I can't think of a situation where a small inland waterway rec boat needs a gennie over a good set of house batteries.

 

[PrivatePilot]

400ah at 12v is 4.8kw.

Now you half that capacity if you’re running lead acid since ~50% is typical max discharge, maybe 70% if you’re running true high end deep cycle/golf cart batteries, the weight of which is going to rapidly exceed the weight of a generator. And routine 70% deep discharges is going to drastically shorten their lifespan.

Let’s so some math because I think there’s some wild over estimations happening here.

Let’s go with a conservative 10A@120v load from the AC, that’s 110amps DC load from the inverter, so say 28ah from the batts at that 26% duty cycle.

Let’s say 5a DC for the fridge (both at an again conservative 25% duty cycle, so 1.25ah.

And let’s say 5A constant for other loads like lighting, anchor lights if at anchor for the night as well as we often do, charging stuff, whatever else, 5ah.

Total, we’re talking ~34ah draw on the house batteries.

So 200ah usable (400ah total) capacity lead acid is going to run the above calculated loads for 5.8 hours at a 50% DoD on the lead acids Not days. Not even close.

If we’re talking 400ah of lithium, then things change with a 100% DoD ability, but there’s also considerations specific to them when it comes to their setup, and even then we’re talking just over 11 hours maximum before they’re dead, and then those alternators need to work their hearts out for several hours to recharge (wear + measurable fuel usage), and you need DC-to-DC hardware to control things and avoid shock unloading the alternators when the BMS’s on those lithiums hit voltage cutoff, something that very commonly destroys alternators when hooked up directly to lithium banks.

None of these calculations taken into consideration other heavy loads like the stove, coffee maker, etc. 20 minutes of using the stove to prep a meal would easily draw hours off of these useable calculations additionally.

 

[Mad Mike]

This is a fairly standard chart for small boats.

It doesn’t account for AC, probably because most mariners aren’t running a/c unless they are at the dock or in tropical waters.

Your alternators will return 80 ah/hr to your batteries while running, and supply all the juice needed to run the boat.

I can tell you I’ve owned 30+footers for decades, the last 2 I pulled the genies to save money and improve reliability.

 

[PrivatePilot]

If you’re debating my math, please point out where it’s wrong.

I stand by my point that even 400ah of lead acid batteries won’t even run the AC and other house loads for an 8 hour sleep, assuming you go to bed with the house batteries at 100% SOC, not down to 50% already because you anchored at 5pm and are now going to bed at 10pm. Unless you’ve, again, been idling your mains.

I’m a bit baffled at your 26 hour claim, so again, please explain where you came up with that number from?

My math is iffy at times, but looking at my conversions and amp hour figures, I’m pretty sure they’re correct, or at minimum certainly not off by ~75%.

I’m kinda familiar with batteries and this sort of stuff. This is one of my Lifepo4 builds which is in our camper currently, built from scratch. 280ah lithium iron phosphate. Will run our 1200BTU air conditioner via a pure sine inverter for about 10 hours.

 

[oioioi]

Not so great news.....

Theodore Tugboat replica partially sinks at Ontario dock, awaits effort to refloat

The Theodore Tugboat replica that was long a fixture in the Halifax harbour is listing heavily with its red-capped head just above water after partially sinking Tuesday in Ontario.

toronto.citynews.ca

 

[PrivatePilot]

I saw that today on a few FB groups I follow.

Sad, but Theodore is well loved so I'm sure this won't be the end.

 

[oioioi]

I saw that today on a few FB groups I follow.

Sad, but Theodore is well loved so I'm sure this won't be the end.

I'm sure it will live on.
Interesting how it originally came from Nova Scotia.

 

[Mad Mike]

If you’re debating my math, please point out where it’s wrong.

I stand by my point that even 400ah of lead acid batteries won’t even run the AC and other house loads for an 8 hour sleep, assuming you go to bed with the house batteries at 100% SOC, not down to 50% already because you anchored at 5pm and are now going to bed at 10pm. Unless you’ve, again, been idling your mains.

I’m a bit baffled at your 26 hour claim, so again, please explain where you came up with that number from?

My math is iffy at times, but looking at my conversions and amp hour figures, I’m pretty sure they’re correct, or at minimum certainly not off by ~75%.

I’m kinda familiar with batteries and this sort of stuff. This is one of my Lifepo4 builds which is in our camper currently, built from scratch. 280ah lithium iron phosphate. Will run our 1200BTU air conditioner via a pure sine inverter for about 10 hours.

View attachment 71440

Nothing wrong with the math, more with your assumptions on how much power is required at sea. And your battery discharge limits - deep cycles should only discharge to 50% in a constant cycle application like an off grid house, golf cart, or a tow motor. Day use rec boats follow occasional use guidelines of 80% discharge on lead acid house batteries.

Mariners adjust consumption down considerably while unhooked, that’s why I added the chart. In a thousand nights on the water in Ontario, I don’t recall ever using ac away from the dock.

So let’s say you’re a heavyweight glamper and need a constant 2kw to feed an a/c, stereo, big screen tv, a few laptops and lights. How many nights a year? 10?

Now, let’s look at the economic basics.

Genie annual (lof, winterizing) $100.
Fuel surcharge for hauling a gennie? On a typical 34 cruiser, 600lbs of load increases consumption by 5%. At a typical running consumption of 30gph and fuel st $2/l, you’re looking at about $13/hr while cruising as the cost to carry a gennie. Overall that’s about

The no load west of running a couple of hours a day on a modern main is infinitesimally small, I doubt you could calculate it.

Fuel cost between a gennie and main are near zero.

Anyhow, if you like genies, keep them! Im not a fan as you can see, to me boating is expensive enough without unnecessary equipment and cost.

 

[crankcall]

My only hate of Gen sets are the cheap pricks that don’t have a built in , don’t have enough battery to run an AC unit all night so they sit a champion genset on the swim platform and run that all night . In a crowded anchorage . All night . The Thousand Islands are a mess July/ Aug with the Quebec navy and the shittbox powerboats .


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[PrivatePilot]

My only hate of Gen sets are the cheap pricks that don’t have a built in , don’t have enough battery to run an AC unit all night so they sit a champion genset on the swim platform and run that all night . In a crowded anchorage . All night

Which is why my sister, BIL, and me are all good with the built in.

Not having AC has really sucked on past trips. It will be a huge plus on the new boat. We all want to be able to use it whenever, wherever, for as long as needed.