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12volt or 24


verynearly

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When specifying a new boat what are the advantages, if any, of opting for a 24 volt system as opposed to the normal 12 volt setup. Would it make life any easier on a liveaboard and if so why?

We are 24 volt and I don't think I would go that way again. It is a lot easier buying 12 volt stuff but things are getting better.

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I have always struggled to see the advantages of 24 volt on a narrow boat, and still do.

 

It's only real advantage would seem to be that you can get away with lighter cabling, but the additional cost of the thicker wiring needed if you stick with 12 volts don't seem enough to make that so big a deal.

 

Although people will tell you it is just as easy to source anything in it's 24 volt equivalent as in a 12 volt one, a look at the stocks of many chandlers would seem to say otherwise.

 

I can't help noticing that people have said availability of 24 volt items is a non-issue on one occasion, only to be asking where they can quickly source a 24 volt item on another. :D

 

It is generally easier to find a 12 volt phone charger or laptop adaptor, for example, than anything that will run directly off 24 volts. Not high power items of course, but things many people come to rely on.

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Parglena has both 12v and 24v

24v for all domestic stuff (lights inverters pumps etc)

12v for navigation/engine (lights VHF etc)

The only exceptions are:

1 toilet 12v I couldnt find a 24v one

2 Mikuni heating the 12v one is a simpler more reliable system.

 

Would I do it again yes.

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Lot's of barges tend to have 24v systems to reduce voltage drops down long cable runs, and I remember one equipment supplier at a boat show seemed surprised that my widebeam had a 12v system. I didn't really understand why - the cable runs are no longer that a NB and I've only ever had one problem of voltage drop affecting my horn which I soon rectified - everything else has been fine.

 

Do 24v batteries last longer - or is the reduced current draw from 24v consumers just offset by 24v batteries that hold half as many A/h?

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Parglena has both 12v and 24v

24v for all domestic stuff (lights inverters pumps etc)

12v for navigation/engine (lights VHF etc)

The only exceptions are:

1 toilet 12v I couldnt find a 24v one

2 Mikuni heating the 12v one is a simpler more reliable system.

 

Would I do it again yes.

 

I think I might find two separate DC systems a tad confusing - perhaps even irritating. Two separate sets of fuses, two separate battery chargers, separate battery monitors...

 

I can't help thinking that the fact you've had to install two systems indicates that one system is somewhat inadequate? If you had to choose to keep one or the other which would it be?

Edited by blackrose
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We have 24v system and have been asked many times how can we have our lights on for hours as I do not go to bed very early and especially this time of year when you use lights etc. longer.

 

We have a 12v dropper for those items that could not purchased for 24v,our cable looms was supplied by Loomtech and are as a 12v system as it was cheaper that way.

 

Dont be put off because people do not fully understand a 24v system, especially as you are planning liveaboard and it would be disaster if you dont have enough power for your needs.

All our appliances are off the shelf items.

 

Regards

 

Andy

Edited by andy the hammer
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Dont be put off because people do not fully understand a 24v system, especially as you are planning liveaboard and it would be disaster if you dont have enough power for your needs.

I believe I "fully understand a 24 volt system", and for that reason would not have one on a narrow boat, (by choice).

 

Please explain exactly what advantages you believe it has over a 12 volt system.

 

So far as I can see very few, other than that the 12 volt system needs thicker cabling to bring losses down to the same as a 24 volt system might had.

 

To me that is only a small incremental cost, to avoid a host of extra complexity.

 

The fact that (say) a water pump is a "standard off the shelf item" does not necessarily mean you will quickly be able to buy a replacement at some remote location if yours packs up. I'd rather try sourcing 12 volt items in a hurry from small chandlers than 24 volt - a major consideration if you live aboard, and are totally reliant on a bit of kit.

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I believe I "fully understand a 24 volt system", and for that reason would not have one on a narrow boat, (by choice).

 

Please explain exactly what advantages you believe it has over a 12 volt system.

 

So far as I can see very few, other than that the 12 volt system needs thicker cabling to bring losses down to the same as a 24 volt system might had.

 

To me that is only a small incremental cost, to avoid a host of extra complexity.

 

The fact that (say) a water pump is a "standard off the shelf item" does not necessarily mean you will quickly be able to buy a replacement at some remote location if yours packs up. I'd rather try sourcing 12 volt items in a hurry from small chandlers than 24 volt - a major consideration if you live aboard, and are totally reliant on a bit of kit.

I think you are right in what you say, I can get every thing in 24 volts I need when I am at home on the same day, if I am cruising I think it would be a different matter and it would and would probably take 3-4 days.

The biggest advantage I find from being 24 volts is that I have 4 X 6 volt batteries in series, if I was on 12 volts I would have had 4 in parallel, I don't like parelleling batteries as if one fails and you don't notice it can have an adverse effect on the other three

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I think you are right in what you say, I can get every thing in 24 volts I need when I am at home on the same day, if I am cruising I think it would be a different matter and it would and would probably take 3-4 days.

The biggest advantage I find from being 24 volts is that I have 4 X 6 volt batteries in series, if I was on 12 volts I would have had 4 in parallel, I don't like parelleling batteries as if one fails and you don't notice it can have an adverse effect on the other three

Thats true as I have discovered this year when one half of my bank developed a shorted cell.

 

Now for others the reasons why I have a split system

Navigation equipment ( VHF radio, GPS, chart plotter etc)is one thing that is harder to find in 24v, this wont affect most narrow boats as they don't need it.

The engine came with a 12v system so I kept it as it was cheaper to do that than replace the starter motor etc.

Its really no different to having two alternators one for domestics and one for the starter you would still need, if you want that sort of thing, two battery management systems.

 

The really big reason for 24v is that it is more efficient to invert to 240v from 24v than 12v in fact 48v is better than 24 and 96v is better than that, but one has to be sensible and stop somewhere.

Apart from lighting and pumps all the equipment on Parglena is 230v as I find the quality better. As I have said before getting a decent stereo on 12v was almost impossible until recently when class T(d) amplifiers were introduced.

 

As for availability I carry spares for essential stuff as there are very few suppliers when you are at anchor.

 

And finally have you ever tried to join 6mm cable to a light fitting its very difficult to get a decent joint and I make joints like that for a living.

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The really big reason for 24v is that it is more efficient to invert to 240v from 24v than 12v

 

What we specified when we had the boat built was that all white goods was bog standard off the shelf products,my partner wanted to use her hair dryer when ever she needed.

 

Alright my pumps may cost a little more and a little harder to get,but should I have any problems with a washing machine,fridge or tv then there is a Curry's always near by.

 

What is the cost of a Shoreline fridge?

 

What I am saying is do not dismiss 24v without throughly looking into it and dont listen the boater's that give you the sharp intake of breath and say no way when they dont understand the benefits.

 

If I owned weekend/holiday boat then 12v would do, but a modern live aboard with all mod cons then that is different.

 

Regards

 

Andy

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We decided on 24v because at the time a 24v 3kva Victron combi was the same price as a 12v 2.5kva one + larger alternators are cheaper in 24v. All in all glad we went 24v, higher voltages do have advantages, most of our cable runs aren't a problem as stuff is run off the Victron, 300+ watts of lighting from 5amp flex, bowthruster batts charged from 2.5 mm arctic, could have gone all 230v but water pumps were difficult to source at the time.

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Parglena has both 12v and 24v

24v for all domestic stuff (lights inverters pumps etc)

12v for navigation/engine (lights VHF etc)

The only exceptions are:

1 toilet 12v I couldnt find a 24v one

2 Mikuni heating the 12v one is a simpler more reliable system.

 

Would I do it again yes.

 

 

Barge Maurice A will be the same...but with no exceptions :P

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Ummh, Lincoln is also 24v as set up that way when built - victron 24v 3kw, again... plus alternator and starter on engine..

 

We also inherited 24v loomtech looms (uninstalled) which cost 700squid..

 

so we reviewed the options re layout ( she was only spray foamed/battened and had portshloes/hatches fitted)

couple of weekends with graph paper we converted the plan to the floor and then laid out the looms to check for position.

 

It all was in pretty much the right place. we converted2 24v sockets to power the shower discharge pump and one the fridge.

 

Otherwise it was fine..

 

we have a 24v fridge room lights (halogens but looking to cenvert to leds now I have a supplier(in HKG)

 

batteries are price x2 which is the only dwonside, but seem to last.

we use 230 v for centralheating/cooker pump/timer (heriatage) and a sony flat screen tv ...and one room uplighter...

 

without running a genny or engine we last 3-4 days.. on half life to knackered batteries....

 

No major issues on getting pumps (unbridge boat centre has most in stock), ditto bulbs

 

We dont have too many issues re battery space and could squeeze andother pair of 110amp in... which we might do next year if funds improve..

 

Only item that we have had to get a transformer to drop to 12v for is the envirolet composting toilet....

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we have a 24v fridge room lights (halogens but looking to cenvert to leds now I have a supplier(in HKG)

 

 

Can't workout where HKG is but I have not had a problem getting 24v leds for the last few years, Lots are now something like 8-30volt rating.I get mine from ultraleds I have bought cheaper on ebay but I have found Ultraleds to be better quality.

Edit to correct voltage

Edited by ditchcrawler
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When my folks had their barge fitted out, they originally specified a 24v system.

 

After much discussion, the yard convinced them that a 12v system should be fitted.

 

Worst mistake they made.... Now they spend all of their time cruising around Europe.... Europe is definitely geared up for 24v, not 12v.

 

In the UK, 24v stuff is available from coach and lorry builders and it's far cheaper than marine swindlers.

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