12v socket problem.

[ontheroadagain]

I have installed an additional 12v socket inside our motorhome. I am getting power to the socket, but the voltage is low (12.1v). When I connect a 12v fan for example, it rotates, but very slowly. The wires were taken from the 12v socket in the garage and it has the same problem. I have never used the 12v socket in the garage so it is quite possible that this problem has been there since new. I suspect there is a bad connection somewhere but where and how do I find it? The other 12v socket for the tv works fine.

 

[peterc10]

You probably need thicker wires. How long are the runs?

 

[ontheroadagain]

The socket in the garage was fitted by Adria so I would expect the wiring to be adequate. From there to the new socket is only 500mm. I think the problem may be at “ the other end” but I don’t know where that is as the wires disappear under the raised floor area.

 

[pappajohn]

How many watts is the fan?

12v sockets are usually rated at either 120w (10a) or 180w (15a)

If the fan is much higher wattage then it will run slow and the wiring could get hot.

Then of course, it also depends on the distance from the socket to battery.......distance could be causing volt drop.

 

[ontheroadagain]

How many watts is the fan?

To be honest I don’t know. I will need to check. It is only a small fan so I didn’t expect it to be a problem. The socket in the garage which I connected to is rated at 10 amps.

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[Lenny HB]

The socket in the garage was fitted by Adria so I would expect the wiring to be adequate

Sounds like you expect miracles, manufactures will often fit what they can get away with to reduce costs.
If your distribution unit is towards the from of the van the socket in the garage will have quite a long cable run. For 5m of cable you would need 6mm2 cable I very much doubt they will have used that size cable.

 

[autorouter]

I'd start with the simplest test. Can you take off the garage socket and look to see if the connectors look solid and the wire looks undamaged? See if the voltage is low at that point too.

When you say the voltage is 12.1V at that point, what is the voltage at the battery? If you plug in a device with very low current demand, is the voltage drop not so bad, or just the same?

You may need to look at the other end of the wire. I presume it comes from a 12V distribution/fusebox, what make/model is it? You could remove the fuses one at a time to see which fuse it is on, and check the voltage at the fuse end.

 

[ontheroadagain]

I'd start with the simplest test. Can you take off the garage socket and look to see if the connectors look solid and the wire looks undamaged? See if the voltage is low at that point too.

When you say the voltage is 12.1V at that point, what is the voltage at the battery? If you plug in a device with very low current demand, is the voltage drop not so bad, or just the same?

You may need to look at the other end of the wire. I presume it comes from a 12V distribution/fusebox, what make/model is it? You could remove the fuses one at a time to see which fuse it is on, and check the voltage at the fuse end.

Connections look good and the voltage is low in the garage too even with the new socket disconnected. The battery voltage was over 13 as it was connected to ehu. Distribution box is Nordelettronica NE237. As you say I will need to look at the other end or perhaps as Lenny HB has said, the original wiring may not be adequate.

 

[ontheroadagain]

Sounds like you expect miracles, manufactures will often fit what they can get away with to reduce costs.
If your distribution unit is towards the from of the van the socket in the garage will have quite a long cable run. For 5m of cable you would need 6mm2 cable I very much doubt they will have used that size cable.

Distribution unit is under the dinette seat so I would say 4 or 5m from the socket. The strange thing is that it is a similar distance to the tv socket and that works fine. I didn’t measure the wires and I am no expert, but the wires look more like 4mm2.

 

[ontheroadagain]

You probably need thicker wires. How long are the runs?

Runs are 4 or 5m.

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