24v Electrics on Boats

[marylouise]

Cheap droppers are definitely inefficient, loosing 50% of the power as heat.

Switch mode voltage converters are much like inverters and can be 90% efficient.

Run as many of your overnight loads as possible, such as lights and fridge, on 24v and you'll loose nothing noticeable

[John V]

Have come across this problem several times and the correct answer has been different each time. The worst answer has normally been where people think that they can just "tap off" 12 volts from the centre of their battery bank and leave everything else the same. This always results in major battery problems with one battery overcharged and boiled to death and the other barely charged at all. One way that this system can work is if you scrap your 24v alternator and replace it with two 12v alternators, You will have, however, just doubled the chance of alternator problems and also still have the problem that if you have flattened the battery supplying the 12v you have also effected the 24v supply.

If you only have only one or two 12v items the best bet is to use a separate electronic dropper locally for each one, so that your wiring remains 24v throughout. If you must use lots of 12v appliances or ones that draw hefty amounts of power then you should bite the bullet and install a completely independent 12v system with its own battery and alternator. You need to decide which is cost effective, to change your appliances or change the system.

 

Incidentally have recently come across a Dutch built commercial vessel where the 12v centre point of the domestic batteries was wired as a third pin on all the low voltage sockets throughout the boat, this was charged with the two alternator system.

Edited September 27, 2012 by John V

[OldGoat]

I have a 24V system and have been think of adding 12V alternator to the 24 V alternator is a lister SR3 engine and seems to have room to do this, as have I have problem with flat batteries as TV is 12V, water pump and fridge.

What would be better to have a 2nd 12V alternator or or buy Sterling Power 24v [12-12v] Battery Balancer? Boat yard said sterling is not very good? what else would I use?

 

 

I was just about to say "if the load is small then run it on a tap, if bothered run some appliances on 0-12V tap and the others on 12 to 24V"

BUT then I saw the awful word FRIDGE. That latter WILL unbalance the system.

 

 

 

Two suggestions:-

 

Are you sure the fridge is 12v only - I have an aged compressor type that is 12 or 24v

 

When building the boat, I bought a solid state truck 24 to 12V converter for the radios and IIRC the navigation lights. It's great, 12 years on still running, doesn't even get warm. Much less expensive than fitting a second generator and extra battery.

[ditchcrawler]

I have a 24V system and have been think of adding 12V alternator to the 24V alternator on my Lister SR3 engine and seems to have room to do this, as I have problem with flat batteries as TV is 12V, water pump and fridge. LED 12v Lights are series and parallel.

Would it be better to have a 2nd 12V alternator or buy Sterling Power 24v [12-12v] Battery Balancer? Boat yard said sterling is not very good? what else would I use?

I run 24 volts and my lights and pumps are 24 volt, if I had a low voltage fridge that would be 24 volt as well, most fridges are 12/24 volts anyway, are you sure yours isn't.

[Bertpadlock]

Hello All

 

Lorry indicator bulbs are good for the lighting fitments if they match, they are 24v and give off a nice light.

 

Regards

 

BP

[bargemast]

Hello All

 

Lorry indicator bulbs are good for the lighting fitments if they match, they are 24v and give off a nice light.

 

Regards

 

BP

 

Why use lorry indicator bulbs, they give of a lot of heat, I use warm white LED bulbs 10-30 V DC, and am very pleased with the light they give.

 

Peter

 

 

 

 

 

[Bertpadlock]

 

 

Why use lorry indicator bulbs, they give of a lot of heat, I use warm white LED bulbs 10-30 V DC, and am very pleased with the light they give.

 

Peter

 

 

 

 

 

 

I get mine for Freeeeeeeeeeeee!

 

BP

[bargemast]

I get mine for Freeeeeeeeeeeee!

 

BP

 

Well I suppose that that is a good enough reason to use them, and even more if you don't care much about your electricity consumption.

 

Peter.