Quick 12v Socket Question

[DDJC]

I seem to have three types of 12v lighter sockets

1. socket marked as 12v 120w, works when the engine is on or off
2. unmarked socket works when the engine is off, next to the external TV aerial socket
3. socket marked as 12v 8 amp, works when the engine is on or off.

What sort of things should be plugged into each one, depending on power usage? Which is more powerful, the 120w or the 8amp?

Cheers,

 

[rod_vw]

Watts = Volts x Amps

Consider the battery (engine or leisure) to be nominally 12.6 volts.

To answer the other questions we need to know a lot more about your vehicle and whet accessories you may wish to power.

 

[Abacist]

So you have 10am and 8 amp sockets in the cab which I use for a Sat Nav and a front facing cctv camera. I have an iPod running of a usb socket linked into the radio for foreign touring when the radio is useless with over 3000 songs on it played at random.

Don’t use the sockets for an air compressor for your tyres as that blew the fuse in mine unless it is less than 120 watts but leave a safety margin so say 100 watts.

I made up an extension lead with crocodile clips and wire directly to cab battery for tyres.

 

[DDJC]

So you have 10am and 8 amp sockets in the cab which I use for a Sat Nav and a front facing cctv camera. I have an iPod running of a usb socket linked into the radio for foreign touring when the radio is useless with over 3000 songs on it played at random.

Don’t use the sockets for an air compressor for your tyres as that blew the fuse in mine unless it is less than 120 watts but leave a safety margin so say 100 watts.

I made up an extension lead with crocodile clips and wire directly to cab battery for tyres.

I do the same for my compressor. Crocodile clips onto the battery.

 

[DDJC]

Watts = Volts x Amps

Consider the battery (engine or leisure) to be nominally 12.6 volts.

To answer the other questions we need to know a lot more about your vehicle and whet accessories you may wish to power.

Mainly only the boys DVD players, and charging USB cables. We often EHU, but in the boot/garage, we do sometimes use a travelling fridge in the summer as an overflow. That is plugged in to the 12v when travelling. It seems to work off both, but which one would be better? The 120w or the 8amp?

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[Ian_H]

In a similar vein when Highbridge fitted the UK 240V AC sockets in our new Globecar last year, the 12V sockets they fitted alongside are marked 6A. I felt a bit cheated by that as its well short of the 10A I expected and does limit what we can connect. The apparent wrong wiring that means both 6A sockets and some lights are protected by a 10A fuse should get addressed at the service/warranty work this year......

 

[pappajohn]

Pics of sockets will help.

 

[DDJC]

Pics of sockets will help.

Happy to oblige!

 

[autorouter]

To actually answer the question, The maximum amps from a 12V 120W socket is 120/12 = 10A (Amps = Watts / Volts). The maximum watts from a 12V 8A socket is 12 x 8 = 96W (Watts = Volts x Amps). So the 120W socket is a bit more powerful than the 8A socket.

DVD players and USB charging is usually quite low power, an amp or two at most. Since watts = volts x amps, that means the power is about 12W to 24W. However a modern laptop with a 'high power' USB-C charger can take up to 100W, which is about the limit of the 8A socket.

The fridge should have its power requirement marked on it, on a label somewhere. If you're not sure, you could post a pic of the label.