Putting a switch on a 12v battery

[Maybedaisy]

Hi,

I have a 85a/h Leisure battery that I want to use in to light my horses stable. I have an Inspection Lamp with crocodile clips to attach to it.

However I want to mount the battery out of reach obviously and put the light quite high up. The problem being that I need to be able to reach either the lamp or the clips to turn it on/off.

Is is possible to place a switch between the lamp and the battery so that I can use that to turn it on and if so what would I need.

 

[breezer]

a switch, believe it or not.

but what rating is the lamp as a suitably rated switch will be required

 

[xerxes]

Preferably, a switch rated for use with direct current, to handle the arcing that will occur across the contacts.

 

[ban-all-sheds]

However I want to mount the battery out of reach obviously.

Out of reach of you, or the horse?

How will you get to it/get it down for recharging?

 

[TicklyT]

A car accessory shop would be a good place to try for a DC rated switch.
Direct current requires a different type of switch to domestic AC rated switches to work reliably.

If your lamp is, say, 21 Watts, then it draws a bit less than 2 Amps. A 48 Watt lamp would draw about 4 Amps.

 

[swbjackson]

Probably better off with a caravan accessory shop. Most caravans have 12v lighting circuits.

Mike

 

[davelx]

I'd suggest you also incorporate suitable fuses/circuit breakers and a proper main DC isolator.

Shorts in a 12V DC circuit run off a lead acid battery can cause a fire in no time if there is nothing to protect the wiring.

 

[luminaire]

You could use something like this switch somewhere accessible between the battery terminals and the lamp.

 

[Maybedaisy]

Thanks for you replies.

The battery will be out of both our reach on a shelf in the overhang at the front of the stable. I have done this before and use step ladders to get it down for charging.

The light is 12v with a 50w low voltage bulb.

 

[RF Lighting]

I'd suggest you also incorporate suitable fuses/circuit breakers and a proper main DC isolator.

Shorts in a 12V DC circuit run off a lead acid battery can cause a fire in no time if there is nothing to protect the wiring.

I think this is the most important thing to consider.

An apropriate fuse as near to the battery as possible is a must.

 

[Maybedaisy]

ok thanks. There is an electrical suppliers near where I live. I'll take the whole lot in and get them to give me what I need.

Is there a risk of sparks without the switch as we have used this type of arrangement for years.

 

[TicklyT]

A switch like the one Luminaire linked to is probably OTT. That one is designed to handle a couple of hundred amps.

A 16 Amp switch like the ones sold in little plastic bags for a couple of quid at Halfrauds would be adequate. You could pick up an in-line fuse holder and a couple of bolt-up battery terminals there too.

French cars used to have battery terminal clamps that incorporated a form of switch, where turning the clamp wingnut isolated the battery.

 

[viewer]

If you're only using a 50W lamp then it might be worth getting a cigarette lighter socket which you could fix permanently to the battery and use a plug with a suitable fuse - many extension
cables have a 10A fuse inside the push in plug. Wire the cable to the switch (supporting the part which goes into the switch &/or could be snagged). This way the battery can easily be disconnected for charging or a charger with a car plug could be fitted directly when needed. Many solar battery chargers use this system.

 

[breezer]

Bad idea.

fag lighter sockets are not designed to carry a high current for long periods of time (which he would be doing with a light)

Better sticking to the proper clamps

 

[blondini]

I would ditch the 50w halogen and get a 12v flourescent like this one. http://www.campingandleisure.co.uk/catalog/product_info.php?cPath=7_18&products_id=1194 It will give the same amount of light for a quarter of the current drain and greatly extend battery life between charges.

Then wire in an ordinary in-line cord switch, such as you would use for a mains table lamp, at a convenient location on the cable. It only needs to be capable of switching 2 amps ac to be able to switch the 1 amp dc that the above lamp will draw.

I would suggest an in-line car type fuseholder and fuse which you could probably get from any car accessory shop. Get one with screw connectors for ease, and wire it straight off one of the croc clips.