Electricity - no idea what to do.

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Cloona

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We have given in and decided to allow electricity on board Cloona.

So there is a 12 car battery in the cabin and we would like to
get the nav. lights, log, interior lights, electric bilge pump working.

There is also an old switch board.

I have some crocodile clips and some wire - so thought I would clip the clips onto the battery and lead the positive and negative wires to the switch board.

Do I then need a positive and negative wire from the switch board to each appliance?

All help annd advice greatly appreciated - but please be gentle I don't understand anything about this.
 
Some general thoughts. No doubt others will have a contribution to make as we are all working blind.
I would advise against having the battery in the cabin. There's a danger of electrolyte spillage and sulphation (if you intend charging it) produces heavier than air flamable gas.
Get proper battery terminals instead of using croc clips which won't give a robust connection. The type of cable is important. If your "wire" isn't beefy enough to handle the amps you will produce heat through excess resistance.
The switchboard should be fused, but an additional in-line fuse on the Pos cable close to the battery would be wise.
Each appliance should have its own twin core cable, suitable size for the amp rating of the kit. Do yourself and others involved in fault tracing by properly marking all cables from the outset. Use a busbar for the Neg returns and wire the Pos returns to the switchboard, then just run a cable from the common Neg on the switchboard to your Neg busbar.
I recommend buying a rachet crimper for your terminals.
Over to the Forum for more sage advice....
 
Considering your ignorance I would buy a few fire extinguishers before doing anything!

Any "appliance" has a rating, (meaning volts/amps/watts). Watts = volts x amps. Take a positive (+) wire from battery, through fuse of that rating, through switch to appliance. Take negative (-) wire from battery to negative. Switch on and you have a circuit. However, getting right wire size is important, too small and it gets hot, simple rule of thumb for you might be to copy what size wire is used in your car for "appliances" such as headlights, horn, side lights, cigar lighter etc, get the next size up on the basis you'll almost certainly be running longer cables, and see also the fuse size used. Best bet is to sort out a sheltered location for your main fuse/switch panel, based on what you think you'll need plus say another 20% capacity for later on, (there's always something else you'll want to add later!) Run main cables through a master switch to this, take everything from the switch panel. Switching is on positive only generally, so you'll need a connection box for the neutrals (negatives).

Get books from library as well and, have a read, as if you are really as ignorant as you say you'll find yourself in a mine field. Check also the BSS rules for wiring (Safety Scheme) so you don't do something completely crass and forgo your next certificate or invalidate your insurance.

Don't make connections by twisting and taping up unless you want to die! They get hot and cause fires. Use screwed connectors or crimped ends only, keep wiring clipped at every 6 inches or so, or clip bundles tied with cable ties kept well clear of gas/water pipes and well above water in bilges and out of way of possible damage. Keep joints/connections accessible.

Crocodile clips are good for a 12 volt light, not for proper circuits, get battery connectors and use decent double insulated battery cables. Put what you can in plastic conduit for long runs, neater and reduces fire risk from damage to wires.
 
For gods sake, don't do anything! Get someone competent to sort it out for you. There's enough power in a fully charged car battery to cause an explosion, start a fire, and even kill you by electrocution under the right(or wrong!) conditions. And you can get those conditions in a sailing boat.
Electrics on boats have to comply with important safety standards, for your own protection and those aboard with you.
Take a look at http://www.insightmarinesurveyors.co.uk/batteries.htm and you will see what I mean. Your battery should be in a ventilated box outside the cabin, be connected to the outside world via a 100amp isolator switch, have proper battery terminals not, repeat not, crocodile clips, feed power to the various devices through fuses and proper cable, and all enclosed to prevent accidental contacts and disastrous short-circuits.
Please, please, please, talk to a marine electrician, or read a book on the subject, "The 12 volt Bible" is a good one, or the Boat Safety Scheme Essential Guide. And if you feel that everything sounds terribly expensive, you're probably right, but it may be better to be alive and poor than the other alternative!
Good luck and regards
Colin
 
Many thanks for all the advice -

There is obviously no point in proceeding with this as it seems an ill conceived and dangerous scheme - so will be rethinking the whole approach ........

For the moment we could possibley try and get a trailing log and lanterns as we are unlikely to be going far.

But thanks for taking the time to make it clear whats involved includingthe dangers -
 
[ QUOTE ]
produces heavier than air flamable gas.


[/ QUOTE ]

Is that true? I thought it produced Hydrogen (lighter than air) when charging, does it produce another gas, or gasses when discharging? if so, I think I had better consider moving mine.
 
Think they was well scared off!
12v is not that hard but you do need some basic knowledge first!
so as has been said get a book first!
there must be lots of info on the web also.
 
Come off it - batteries aren't that dangerous. True, the hydrogen they produce during charging can be exploded, but only if you try really hard, eg by holding a lighted cigarette over the vents after prolonged charging. They are rated safe for mounting under car bonnets for example, in a hot environment with the possibility of HT sparks. The risk from hydrogen is nothing compared with the everyday risk of leaking butane from a galley stove.
Also you cannot be electrocuted by 12 volts. Even the 30,000 volts of a petrol engine HT system will only give you a nasty shock.

The main danger comes from the high current and heat generated if live wires touch unprotected by a fuse, so of course I agree that for any permanent installation proper clamps and a fuse box are necessary, as is cable rated for the particular purpose.
 
Yes dont be scared off!
and i never heard of 12v electrocution!
but if you deliberately short the battery with a wire
you will see the fire risk!
that's why YOU MUST put in a fuse/fuses[then it would blow and break the connection if a bare wire touches another causing a short]
12v is great so many things need it...instruments,lights mindyou i have oil lamps as well...:) cause they are nice.
 
All got a bit excessively alarmist but serves purpose if you research properly and double check.
I got the 12 Volt Bible which is OK but has too much third form physics in it. I found Electrics Afloat by Alastair Garrod more useful.
Anyway, why the sophistication of the trailing log? Some string, a twig and an egg timer should do it
 
[ QUOTE ]
Come off it - batteries aren't that dangerous. True, the hydrogen they produce during charging can be exploded, but only if you try really hard, eg by holding a lighted cigarette over the vents after prolonged charging. They are rated safe for mounting under car bonnets for example, in a hot environment with the possibility of HT sparks. The risk from hydrogen is nothing compared with the everyday risk of leaking butane from a galley stove.
Also you cannot be electrocuted by 12 volts. Even the 30,000 volts of a petrol engine HT system will only give you a nasty shock.


[/ QUOTE ]

While I agree that the risk from butane is as high, batteries can and do explode, and will spray acid over overything nearby. If thats you, you wont go boating this season, as you will have many months painful treatment ahead of you in the burns unit.

The car engine bay is very well ventilated, and the battery is located in an air stream so as to disperse the hydrogen and prevent a dangerous build up.

A Boat battery - often mounted in a box to protect it (not on my boat I would add!) - can quickly build up an explosive atmosphere in its stowage compartment. The slightest spark from the terminals or contacts is enough to set it off.

Although it is unusual, 12 volts CAN kill given the right (wrong?) conditions. True, generally speaking 50 volts is the minimum for a fatal shock but given wet and a dodgy ticker... I have certainly once or twice had a really nasty jolt off a 12 volt battery in wet conditions. And 33,000 volts at your ignition can be fatal - and most almost always is from the national grid. Its not just voltage, but amperage as well that makes the difference between a jolt and eternity! 300amps at 12 volts will throw you across the boat, I promise you! /forums/images/graemlins/shocked.gif
 
[quote- but please be gentle I don't understand anything about this.

[/ QUOTE ] OK, then please dont try to do it yourself. 1. you risk setting fire to your boat, 2. Your risk damaging expensive electric gear - particualrly electronics, 3 you will be disappointed because if you dont do it right, it will never work properly. Once damp gets in it will play havoc with it. Either find somebody who knows how to do it for you, or get yourself educated in electrical matters; its not too difficult really - easier than cooking once you get your mind round it!
 
[ QUOTE ]
The car engine bay is very well ventilated, and the battery is located in an air stream so as to disperse the hydrogen and prevent a dangerous build up.


[/ QUOTE ]
In a BMW 525 tourer the battery is under the rear passenger seat, not ventilated at all, and in the old Mini it was in the boot and in my old LandRover it was under the front passenger seat!
 
and most almost always is from the national grid.

Had 240v a few times when i was a lot younger and being stupid !
wouldn't recommend it though!
But i did survive....:)
 
Car battery isn't ideal because it won't be able to hack lots of discharge, a leisure battery or deep cycle battery is more appropriate. The 12V bible is a good book.
 
Yeah ive 2 exide leisure batterys
85 ah
they work fine and have done for years
Recommended..only about £40 each.
i guess a lot of us take for granted the basic knowledge we have i mean i learnt about electrics from having electronics at school,motorbike ,hifi messing with guitars etc ect years before having a yacht /forums/images/graemlins/smirk.gif
 
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