12v or 24v?

[Graham_Wright]

Son has just bought an ex trawler converted to an alongside live-aboard.

Power is all mains and he needs to re-equip with sea going tackle.

There is virtually no low voltage equipment on board.

Should he go for 12v or 24v?

Any opinions welcomed.

 

[dunmor]

engine will most likley be 24v. things like diesel heaters are cheaper if 24v.

 

[epervier]

Son has just bought an ex trawler converted to an alongside live-aboard.

Power is all mains and he needs to re-equip with sea going tackle.

There is virtually no low voltage equipment on board.

Should he go for 12v or 24v?

Any opinions welcomed.

How is the boats batteries set up? that may give you a clue how to go forward,
assuming it has an engine fitted, what voltage is on the engine starter,alternator/dynamo.

For example my boat is mainly 24volt, engines 24volts webasto 24 volts, fridge 12-24 volts, sailor vhf radio 24 volts, radar 24 volts,lighting 24 volts, 12 volt dropper for icom vhf dsc radio, tv, fm radio, plotters, cigar socket for charging phone etc.



another clue, look at the voltmeter 0-18volts gauge, 12volt system. 0-36 volts gauge 24volt system

 

[Graham_Wright]

How is the boats batteries set up? that may give you a clue how to go forward,
assuming it has an engine fitted, what voltage is on the engine starter,alternator/dynamo.

Very good point, especially the starter.

For example my boat is mainly 24volt, engines 24volts webasto 24 volts, fridge 12-24 volts, sailor vhf radio 24 volts, radar 24 volts,lighting 24 volts, 12 volt dropper for icom vhf dsc radio, tv, fm radio, plotters, cigar socket for charging phone etc.

Another good point.[/QUOTE]

another clue, look at the voltmeter 0-18volts gauge, 12volt system. 0-36 volts gauge 24volt system

There isn't one!

Thanks

 

[PaulGooch]

Follow the positive cable from the starter to the battery. Does it have a cable going from the positive terminal of the battery that the starter is connected to, going to another battery ? If not, the starter is 12v.

If yes, does it go to the positive or negative ? If positive, 12v again. If negative, it's 24v.

 

[Glyn-2008]

Son has just bought an ex trawler converted to an alongside live-aboard.

Power is all mains and he needs to re-equip with sea going tackle.

There is virtually no low voltage equipment on board.

Should he go for 12v or 24v?

Any opinions welcomed.

If he is starting from scratch with regards to some sort of domestic system, it is worth bearing in mind that the cable size for a 24 volt system is smaller and therefore cheaper than a 12 volt system. This is because if you double the voltage you half the current (amps). Also, percentage voltage drop on long cable runs will be lower with the higher voltage.

 

[prv]

If he is starting from scratch with regards to some sort of domestic system, it is worth bearing in mind that the cable size for a 24 volt system is smaller and therefore cheaper than a 12 volt system.

Are 24-volt versions of equipment, more expensive, though? Or available at all? You can always run a stepped-down spur around the nav table for instruments (though a lot of electronics accepts up to 30v these days) but can you get cheap LED cabin lights that will take 12v?

I don't know the answers to these questions because I've never had to equip a 24v boat, but worth investigating before taking the plunge.

Pete

 

[Glyn-2008]

Are 24-volt versions of equipment, more expensive, though? Or available at all? You can always run a stepped-down spur around the nav table for instruments (though a lot of electronics accepts up to 30v these days) but can you get cheap LED cabin lights that will take 12v?

I don't know the answers to these questions because I've never had to equip a 24v boat, but worth investigating before taking the plunge.

Pete

For the horns and nav lights there will not be much difference in price. The Raymarine (and many others) Radars run from 10-30volts so they are ok. I am sure the led lights will be available in 24volts as well as 12volts although we have used 12volt 10watt downlighters from B&Q in our boat. The only problem that I can remember from my Marine Electronics days was that the VHF radios and Stereo CD players (from cars) were 12volts plus any other items such as Laptops and hand held GPS units that would be plugged into a 12volt socket. In order to obtain 24volts, he will need 2 batteries anyway and a 12volt supply for these odd items can be supplied from 1 of those 2 batteries. Personally, if the engines are on 24volt, I would opt for a 24volt system every time.