Actual power budget of cruising monohull?

[a64pilot]

There is nothing inherently inefficient about 120 VAC, other than the conversion, and I don't thin that is to terrible. Not maybe when its determined what the cost to go 12 V will be.
It may be that if possible upping the Solar may be more cost effective than going to a 12 V fridge.

What kind of watermaker do you have? That may be what determines if you make water when on generator or off of the battery bank.
There are as near as I can tell two schools of thought on watermakers. The AC ones are usually less expensive, make way more water per hour, but are so inefficient they pretty much require burning fossil fuel to run one, some DC watermakers fit in this too if they are not real efficient.
Very efficient DC, Spectra comes to mind, that costs more, make way less water per hour, but is orders of magnitude more efficient and its realistic to never have to burn fossil fuel to make water if you have one, you just let it run for more hours is all.

[MarkJ]

Originally Posted by StuM

That would be 525 Amp hours.


And that would be 100 Amp hours.

Jusr like Tomfl's case, if you use 100 Amps, you will drain your 525Ah bank in a few hours.

Stu! I know its fun for you but stop being a grammar Nazi. It just sounds arrogant. And I know you are not.



Mark

[admiralslater]

I knew that was coming, however when we use the toaster or hair dryer we do draw 100 amps

[a64pilot]

Originally Posted by MarkJ

Stu! I know its fun for you but stop being a grammar Nazi. It just sounds arrogant. And I know you are not.



Mark

I understand his point, at this level we can all sort of fill in the blanks, but as soon as it gets a little more technical, it all falls apart if the correct units are not used, you just can't make sense out of it.
I blame the English language. If I ask you how fast are we going and you reply 9 miles, I shake my head and think that is a distance, not a speed, do you mean 9 miles per hour?
However if you reply 7 kts, I don't think a thing about it, why?
I ask not knowing the answer

[Suijin]

Originally Posted by a64pilot

I blame the English language. If I ask you how fast are we going and you reply 9 miles, I shake my head and think that is a distance, not a speed, do you mean 9 miles per hour?
However if you reply 7 kts, I don't think a thing about it, why?
I ask not knowing the answer

Because a knot is a measure of velocity, not distance, which would be nautical miles of course.

If you ask someone how fast you're going, and they answer 9 miles, and you're unsure of what they mean, it's because they answered in measure of distance instead of measure of velocity. But you know that!

I would not blame the English language. All the words and rules are there to make it quite clear.

I think maintaining that language fails in the communication of electrical concepts and measures is wishing for unattainable simplicity.

Amps and amp hours are very specific, and different. People just get sloppy, like your friend who said "9 miles". Stu is right to point it out and "police" it. He's doing the whole board a public service by helping to educate those who don't know the difference, or didn't think about it, and keep communication clear and relevant.

By the way, how do you pull 15 amps fairly continuously on your boat? I'm really curious to know and I think it would be educational as an example of a higher-end power budget.

[Davidhoy]

Originally Posted by a64pilot

What kind of watermaker do you have? That may be what determines if you make water when on generator or off of the battery bank.

There was a 110v AC Village Marine Little Wonder installed on my boat when I bought it, but it was not functional. I removed it and stopped by the VM store in Fort Lauderdale to see if there was anything salvageable. Turned out it was in much better condition that I thought, and just needs a good cleaning and new membrane and filters. In addition, they are converting it to 12v DC by replacing the HP pump motor and the raw water boost pump.

Ideally I'd like to avoid running the generator, except as a backup. Less fossil fuel burned, less noise, less stink, less maintenance. The water maker will create 6gal/hr, and I have a 100gal water tank. While I have no hard numbers on consumption, let's estimate 5 gal/person/day - with two of us on board that means 2 hours a day (rounded up) to keep the tank full. According to the specs for the water maker it draws 15 amps at 12v, so 30 Ahr per day from the batteries and/or solar. Seems quite achievable, unless my math is off.

The bigger question is the refrigeration - I have already reached out to Rich Boren about his CoolBlue system, and will be meeting with him at Strictly Sail in Miami this weekend.

BTW, a64pilot, I'm going to steal your concept of creating a "dinghy garage" with solar panels installed over the top of the davits. I liked the pictures you posted in another thread. Going to use some PVC pipe and cardboard cutouts for the solar panels to build a mock up to see how everything fits and looks, and make sure that my wife approves ;-). I think I can fit 3x 340 watt panels, from a purely space perspective - how it looks is another story. Aesthetics are not the deciding factor, though not to be ignored either...

Regards,
David

[Davidhoy]

Originally Posted by a64pilot

I understand his point, at this level we can all sort of fill in the blanks, but as soon as it gets a little more technical, it all falls apart if the correct units are not used, you just can't make sense out of it.
I blame the English language. If I ask you how fast are we going and you reply 9 miles, I shake my head and think that is a distance, not a speed, do you mean 9 miles per hour?
However if you reply 7 kts, I don't think a thing about it, why?
I ask not knowing the answer

And let's not even get into George Lucas' mangling of units in "Star Wars". Since when is a parsec a unit of time?!?

[a64pilot]

Originally Posted by Suijin

By the way, how do you pull 15 amps fairly continuously on your boat? I'm really curious to know and I think it would be educational as an example of a higher-end power budget.

I get that from the charger as its digital and I assume that after a week on float, the majority of current the charger is making sort of bypasses the bank, the charger is a power supply at that point, my regular ammeter is analog and not as easy to read. This is when I'm plugged into shorepower of course
But it's easy, the fridge pulls 5 or 6, the KVH Satellite dish pulls some, the Dish receiver pulls some, the TV more. I think the TV system will pull 7 or 8 total, system being all three of course. So that get us to 11 to 13 and we haven't included any lights and the parasitic requirement of the inverter, plus if I have the little icemaker going its another 5 or 6.
At night I will often light the cockpit and deck light to keep from being hit as my little anchor light is not all that visible, and we are both on CPAP
The inverter is the one that is tough to determine, as it has huge cables, it goes straight to the bank and it has no shunt, it tells me AC amps, but that is of course approximately a 10 to 1, meaning of course if I'm using 1 amp at 120 VAC, its about 10 at 13 VDC if you include inverter losses.
The 15 is a swag, but is a planning number that I believe if I use, I will have excess. It's like having a planning fuel burn knowing that you actually use less.
But run the blender, or the toaster, the Wife's hair curler etc., the vacuum cleaner, maybe recharge the phones, the Ipad's, the Milwaukee drill I use for the winch, maybe do a little work on the boat, recharge the drill battery etc., it all adds up pretty quick, some loads like the toaster are short lived, but huge loads while they are there.
Not often, but the air compressor for the Hooka will draw some serious amps

I think it is going to take a month or two for things to settle down and me get a good grip on power consumption, the two week once a year vacation just wasn't as useful to determine consumption as I hoped, largely because we were moving a lot and often motoring, and had the kids on board.
I'm hoping for an excess, or that is the plan anyway, if I'm equipped for more than I need, the excess will just mean we don't have to ration and the battery bank will live longer

[a64pilot]

David,
When you talk to Rich about refrigeration, also talk to him about converting your watermaker to DC. I think that may not be a good idea. He can explain better than I can.
I don't want to run a generator either, but at one quart of fuel an hour, once a week is less than one gallon of Diesel, I can live with that, and at that usage, it ought to last many years

[admiralslater]

Originally Posted by a64pilot

I understand his point, at this level we can all sort of fill in the blanks, but as soon as it gets a little more technical, it all falls apart if the correct units are not used, you just can't make sense out of it.
I blame the English language. If I ask you how fast are we going and you reply 9 miles, I shake my head and think that is a distance, not a speed, do you mean 9 miles per hour?
However if you reply 7 kts, I don't think a thing about it, why?
I ask not knowing the answer

You are right it just makes things easier when we use the correct nomenclature. I type this on an IPad so it is difficult with thick fingers to go back.
BTW I am back to 95 %of capacity with a net Imput to the banks of 20 amps per hour .
Does anyone know if the link is subtracting the load before it comes up with the number ie 30 amphr from the panel minus 10 amps for load equals 20 amp hrs on the link.

[SV THIRD DAY]

I find that people live in fantasy land when it comes to how many Amp hours of power what wattage of solar panels will produce per day....something I see over and over with new cruisers in their first year of "away from the dock cruising".

A good example would be the last two weeks when my 570W solar string has put out an average of 78Amp Hours per day. That's real life numbers with a data logging solar controller not guess or a best case calculation spreadsheet. Now since most cruisers don't have 570W of solar can they make it on 78Amp hours per day....ahem....that Honda 2000 is looking better the more you learn.

It's a good thing I have another 450W string of solar or I would be in daily deficit myself.

Passing through LAX on my way to Miami....could even a small percentage of the hoards tramping through this airport live entirely off Solar? But as someone who does and still need a generator run here and there...I know the answer....

[a64pilot]

I have what I hope is a three legged stool, a large alt with external regulator, Solar and generator. I hope to run the genny once, maybe twice a week, but hope once, on wash day
I do not have the actual experience to back it up, just I couldn't figure out how we could do without something burning fuel to make electricity once in a while. I just couldn't make the numbers work, not without us camping.
I read a statement here when I first joined that after I thought about it for awhile made sense, it was "once you decide you need refrigeration, your on a slippery slope"
Makes sense, cause that fridge is going to require other systems to make it work.
Once I decided we would want a generator, that made other decisions easier. I guess once you make a deal with the Devil, your done?

[Paul L]

Originally Posted by a64pilot

I get that from the charger as its digital and I assume that after a week on float, the majority of current the charger is making sort of bypasses the bank, the charger is a power supply at that point, my regular ammeter is analog and not as easy to read. This is when I'm plugged into shorepower of course
But it's easy, the fridge pulls 5 or 6, the KVH Satellite dish pulls some, the Dish receiver pulls some, the TV more. I think the TV system will pull 7 or 8 total, system being all three of course. So that get us to 11 to 13 and we haven't included any lights and the parasitic requirement of the inverter, plus if I have the little icemaker going its another 5 or 6.
At night I will often light the cockpit and deck light to keep from being hit as my little anchor light is not all that visible, and we are both on CPAP
The inverter is the one that is tough to determine, as it has huge cables, it goes straight to the bank and it has no shunt, it tells me AC amps, but that is of course approximately a 10 to 1, meaning of course if I'm using 1 amp at 120 VAC, its about 10 at 13 VDC if you include inverter losses.
The 15 is a swag, but is a planning number that I believe if I use, I will have excess. It's like having a planning fuel burn knowing that you actually use less.
But run the blender, or the toaster, the Wife's hair curler etc., the vacuum cleaner, maybe recharge the phones, the Ipad's, the Milwaukee drill I use for the winch, maybe do a little work on the boat, recharge the drill battery etc., it all adds up pretty quick, some loads like the toaster are short lived, but huge loads while they are there.
Not often, but the air compressor for the Hooka will draw some serious amps

I think it is going to take a month or two for things to settle down and me get a good grip on power consumption, the two week once a year vacation just wasn't as useful to determine consumption as I hoped, largely because we were moving a lot and often motoring, and had the kids on board.
I'm hoping for an excess, or that is the plan anyway, if I'm equipped for more than I need, the excess will just mean we don't have to ration and the battery bank will live longer

A64
Maybe you need to start turning things off when you aren't using them A continuous 15 ah usage on a boat your sized is way over the top while cruising. You will be a slave to generating power with this usage. It will be a lot easier to save 30-40% of that usage than to generate it over the years.

[StuM]

Originally Posted by admiralslater

You are right it just makes things easier when we use the correct nomenclature. I type this on an IPad so it is difficult with thick fingers to go back.
BTW I am back to 95 %of capacity with a net Imput to the banks of 20 amps per hour .

ROTDLMAO This is why I keep asking people to use correct units.

No such thing as "amps per hour" in any realistic scenario. Amps is a rate. 20 Amps is 20 Amps regardless of how long you are putting it in. Do you mean that you are putting 20 Amps back into the batteries or do you mean you have put 20 Amp hours back into the batteries. Its impossible to tell from your statement.

Does anyone know if the link is subtracting the load before it comes up with the number ie 30 amphr from the panel minus 10 amps for load equals 20 amp hrs on the link.

Depends where your link is connected.

And again, are you talking about Amps of Amp hours here? You have mixed the two, so I don't know whether you are talking about the total energy put back into the battery since charging started (20 Amp hours) or the rate at which you are putting energy into the battery (20 Amps).

The Link should be wired so that it tells you what is going into the battery, not what is coming out of the panels. It should tell you both Amp hours that have gone into the battery since charging started and Amps currently going into the battery.

[SV THIRD DAY]

Originally Posted by StuM

he Link should be wired so that it tells you what is going into the battery, not what is coming out of the panels. It should tell you both Amp hours that have gone into the battery since charging started and Amps currently going into the battery.

Honestly....cruisers that really want to stay on top of and understand their power balance will have an amp hour counter on the output of their Solar panels at minimum to an Amp hour counter on their battery output. Me being an scientist data type have the a dedicated Amp Hour counter on each of my two strings of solar panels, one on my wind generator, one on the alternator and one on the battery charger. So I know exactly where my power is coming from and in what percentage on a daily, monthly, and yearly basis. Then well you gotta know where it's going. So I have one on the total bank outlet plus one for my freezer and one for the refrigerator.

Sure that is overboard but I find all the time in talking to cruisers that they have no idea or understanding of their power balance.