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12V or 230V?


evilrobotshane

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On 10/10/2019 at 11:26, evilrobotshane said:

Sterling as well! Pro Combi S 2100W continuous, 6000W peak. It has a function whereby it’s supposed to go on standby when there isn’t demand on it, but that hasn’t impressed yet (maybe electric toothbrush charger is beneath its dignity, and the fridge might have already been cold). Further experiments I reckon. 

That’s a problem with standby. Lots of things that we use 240v for don’t draw enough to get the thing out of standby.

 

I have found that a lot of so called 240v stuff is actually DC with a transformer to convert the AC, and being sure you can get a plug to fit the item. It does mean having a few DC adapters but it works for me.

 

 

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50 minutes ago, mrsmelly said:

I am all mains, I will not be going back to the caveman 12volt I had years ago. Modern mains kit is vastly better consumption wise than it was only say five years ago due to saving the planet etc, no bad thing. My inverter is never switched off and when powering nothing uses 0.4 of an amp. As Richard says I had a poxy stirling a few years go I inherited on one of my boats that used  4 amps when doing nothing, absolutely hopeless I changed that one for a mastervolt. You need a decent monitoring device that tells you what use what when in use, my presnt one is a NASA, I have had victron and others they all tell you enough when you have worked out how to use them properly

I'm with Smelly. 240v fridge, TV, Satellite, washing machine (cold fill only on the inverter ......but throw hot water in drum) etc. We aint camping.  I have a 2,000W victron inverter on all the time.

 Get a BMV or Nasa battery monitor. It will save you the first time you have to replace batteries.

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2 minutes ago, Dr Bob said:

Get a BMV or Nasa battery monitor. It will save you the first time you have to replace batteries.

We got a Xantrex one,I liked the Victron BMV ,but if choosing another one, I would go with the NASA (200A).It may have less functions than the more expensive one, but the display is much bigger. I can't bloody see the Xantrex. Spose it's ok if you bluetooth everything to your smartphone.

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2 minutes ago, rusty69 said:

We got a Xantrex one,I liked the Victron BMV ,but if choosing another one, I would go with the NASA (200A).It may have less functions than the more expensive one, but the display is much bigger. I can't bloody see the Xantrex. Spose it's ok if you bluetooth everything to your smartphone.

Yup, thats the one we have at this time. I bought it as us old phaarts can see it without glasses which is a major bonus lol. Another often unknown benefit of the NASA is its fully waterproof, built for lumpy water stuff so can be mounted outside if ya so wish.

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6 minutes ago, mrsmelly said:

Another often unknown benefit of the NASA is its fully waterproof, built for lumpy water stuff so can be mounted outside if ya so wish.

Yep.NASA made it waterproof, so it could be mounted on the outside of the space station and not be damaged by rain.

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3 hours ago, evilrobotshane said:

if what I’ve read on the topic is right, higher Wattage inverters draw more power on standby

Dunno where you read this but it ain’t true. A 2kVA Victron will use much less than a 500VA Sterling for instance. 

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19 minutes ago, WotEver said:

Dunno where you read this but it ain’t true. A 2kVA Victron will use much less than a 500VA Sterling for instance. 

Agreed - general rule - the cheaper the inverter the higher its standby current and the lower its efficiency is likely to be - whatever size. Diito for the older its design as well.

Edited by Tony Brooks
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4 hours ago, Dr Bob said:

 

Get a BMV or Nasa battery monitor. It will save you the first time you have to replace batteries.

 

Surely the battery monitor will save you from NOT having to replace the batteries (or at least not as often). ??

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10 hours ago, evilrobotshane said:

 

I’m not a heavy user of electricity, mostly just a few lights and sometimes the fridge if there’s something in it to keep cool

 

The two highlighted bits are incompatible. The fridge is a huge consumer of electricity - on a typical boat, if you do the power audit it will show that the fridge uses around half the total electricity use. So if you have a fridge running you are going to be a reasonable user of electricity, whatever other appliences you might or might not be using.

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27 minutes ago, David Mack said:

 

The two highlighted bits are incompatible. The fridge is a huge consumer of electricity - on a typical boat, if you do the power audit it will show that the fridge uses around half the total electricity use. So if you have a fridge running you are going to be a reasonable user of electricity, whatever other appliences you might or might not be using.

 

I thought that too. ALL newbies with electrical questions start off regarding themselves as 'light users' of the leccy, then go on to list reams of stuff running off a massive quiescent current inverter! 

 

While the OP is cruising every day I think he will have no problem with his list though, but eventually three or four days at a time moored up in nice places will become the norm, then the trouble will start....

 

 

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Apart from the hard wired 12v consumers like the water pump, shower drain pump and lights, the only things I really need a 12v socket for is a 12v TV which I connect when away from shore power and does use a lot less power than my mains TV/inverter. I charge the phone with the mains charger and inverter but that doesn't take long and I don't generally use the laptop while I'm away but if I did then I suppose a 12v socket might be handy for that.. 

Edited by blackrose
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9 hours ago, David Mack said:

 

The two highlighted bits are incompatible. The fridge is a huge consumer of electricity - on a typical boat, if you do the power audit it will show that the fridge uses around half the total electricity use. So if you have a fridge running you are going to be a reasonable user of electricity, whatever other appliences you might or might not be using.

Not sure I fully agree. What is a heavy user of electrickerty?

we use typically 100-120Ahrs in 24 hours. Of that 25-30Ahrs is the 240V fridge, so only 25% of our usage is the fridge. I consider we are heavy users.

I agree that if your fridge is 50% of the power usage then you are a reasonable user, but then how much is your fridge actually taking? Ours is very efficient. Some 12v ones won't be.

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20 hours ago, rusty69 said:

Don't underestimate the startup requirements of a typical 240V fridge.You may almost certainly will need to go higher than 500W

Fixed that for you. General opinion and my experience too says 1kW to be sure. There are soft start gadgets that people have used that can reduce the huge inrush current when the compressor motor starts. Not tried them myself. When cruising I can tell when the fridge kicks in. The extra draw on the alternator dips the engine revs for a couple of seconds.

 

Jen

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20 hours ago, evilrobotshane said:

 

 That’s good to know, thanks; I haven’t looked into the fridge situation much yet.  Seriously considering swapping for something much smaller, I have little use for a family-size monstrosity.

Take a look at a this recent thread that included a discussion on using freezers, chest and otherwise, as fridges. The extra insulation can reduce the amount of power required considerably. A normal domestic mains, or boat/12V caravan fridge is built to a price point and designed to get the maximum internal volume for its external dimensions. Power consumption is a factor and they have improved over the last decade or so, but the power consumption of a fridge in a house is minor, compared with on a boat, where it is usually the single biggest user. A freezer has thicker insulation. Tricking it in to being a fridge makes it a very efficient fridge. Not tried it myself, but may well when to current fridge goes to the great landfill in the sky. 

 

Jen

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I'd fit 12v sockets and if possible, replace the fridge with a gas one. Also ensure that all lights are low consuming led's, and the tv is as frugal with electricity use as possible (mine is 17w). Tricks like filling up a couple of bottles of water to make brews while you're running the engine (the energy is effectively free) are worth doing. Running the engine or a genny for hours on end is a massive pain. Why prolong that by having a wasteful inverter going all the time? 

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Just now, The Welsh Cruiser said:

I'd fit 12v sockets and if possible, replace the fridge with a gas one. Also ensure that all lights are low consuming led's, and the tv is as frugal with electricity use as possible (mine is 17w). Tricks like filling up a couple of bottles of water to make brews while you're running the engine (the energy is effectively free) are worth doing. Running the engine or a genny for hours on end is a massive pain. Why prolong that by having a wasteful inverter going all the time? 

This is the other side of the argument for @evilrobotshane to consider. Some people go all, or nearly all 12V and live frugally, others go mains and inverter and use lots of solar and engine running to keep the batteries charged. You need to make your own decision on which way to go. Keeping the batteries charged very regularly is the most important thing whichever way.

 

My own opinion is that frugal 12V living is still a good option and a couple of decades ago, was the best one for living away from a shore line. Now, modern efficient inverters and very cheap and more efficient mains equipment and buck boost voltage converters make full time mains appliance use fine, with a much larger selection of equipment available. 12V gadgets haven't improved at the same rate, due to the much smaller market.

 

Jen

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21 minutes ago, Jen-in-Wellies said:

Now, modern efficient inverters and very cheap and more efficient mains equipment and buck boost voltage converters make full time mains appliance use fine, with a much larger selection of equipment available.

 

There is however, the increased safety risk (or is it reduced?) of having 240Vac all over the place inside your steel boat in a watery environment, along with the association with rapid hull degradation/pitting/need for overplating for insurance purposes.

 

Given that most services can be run on 12v thus avoiding the above potential problems, I have chosen the  12Vdc route in my boats. 

 

 

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10 minutes ago, Mike the Boilerman said:

 

There is however, the increased safety risk (or is it reduced?) of having 240Vac all over the place inside your steel boat in a watery environment, along with the association with rapid hull degradation/pitting/need for overplating for insurance purposes.

 

Given that most services can be run on 12v thus avoiding the above potential problems, I have chosen the  12Vdc route in my boats. 

 

 

The hull galvanic corrosion and pitting is only an issue if the boat is on a shore line. A continuously cruising 240Vac boat won't have that. It could happen to an all 12V boat with a mains battery charger on a shore line. The safety risk is reduced with a properly wired in consumer unit with RCD, properly wired galvanic isolator, or isolation transformer with a good boat earth. A lot of boats are potentially dangerously wired.

 

It is a decision that the OP has to make. To me it is finely balanced, with good arguments on both sides. Since his boat is already mainly (see what I did there!) 240Vac, to me it makes sense to stick with that. It is a relatively minor consideration, compared with keeping the batteries charged.

 

Jen

Edited by Jen-in-Wellies
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9 minutes ago, Jen-in-Wellies said:

The hull galvanic corrosion and pitting is only an issue if the boat is on a shore line. A continuously cruising 240Vac boat won't have that. It could happen to an all 12V boat with a mains battery charger on a shore line. The safety risk is reduced with a properly wired in consumer unit with RCD, properly wired galvanic isolator, or isolation transformer with a good boat earth. A lot of boats are potentially dangerously wired.

 

It is a decision that the OP has to make. To me it is finely balanced, with arguments on both sides. Since his boat is already mainly (see what I did there!) 240Vac, to me it makes sense to stick with that. It is a relatively minor consideration, compared with keeping the batteries charged.

 

Jen

 

Yes I agree it is a finely balanced argument. One I had one with myself too. 

 

I elected to stick with 12Vdc as I have no need for toasters, electric kettles, hair dryers, 48" widescreen telly and all that sort of stuff in my boat. I quite agree others have different needs, especially families living aboard. 

 

The 'problem' with 240Vac is a lot of boaters (in fact a lot of the male population in general) quite fancy themselves as electricians and have a somewhat cavalier approach to installing 240Vac in the manner you describe and simply resort to massive bodgery. We've all seen it. 

 

A heavily bodged up a 12Vdc installation is far less likely to kill the user than a heavily bodged up 240Vac installation, other than by fire perhaps.

 

 

Edited by Mike the Boilerman
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On 11/10/2019 at 12:29, evilrobotshane said:

 

 That’s good to know, thanks; I haven’t looked into the fridge situation much yet.  Seriously considering swapping for something much smaller, I have little use for a family-size monstrosity.

I have a wee LEC fridge freezer. 50cm wide undercounter unit. Has a small freezer, which I generally use to freeze several of the blue picnic cold packs. It's reasonably well rated energy use wise. Not as good as some of the 60cm units - but they wouldn't fit.

Overnight I switch the inverter off usually and if there's something in the fridge I will chuck the picnic cold packs into the fridge to keep it cool.

 

I have a Mastervolt 100/2000 combi cahrge inverter. It has a fancy setting on it where it sits effectively off and every 2 seconds (or something) searches for a load demand - if it finds one (of significant size) it switches on. In the searching mode it uses 0.5 Watts. I find this idea for the fridge. 

 

I looked at 12V fridges and it wasn't the right choice for me.

 

I bought my Mastervolt Mass Combi 100/2000 for ~ £550 off ebay (and sold the Mastervolt Mass Sine 2000 that it replaced for ~ £360).

 

 

 

If you're interested in doing an electricity audit there's a decent spreadsheet I used that I could dig out for you

Edited by sirweste
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