Camping hook up - Transformer

[Desie]

Guys

Tell me if this is a stupid idea.

I have a 12v car battery powered cool box that I take camping. I cant see any reason why not, but someone enlighten me if there is, that I cant use a standard 20-60 transformer to convert the 230v hook up to power my cool box inside the tent.

Cheers

 

[RF Lighting]

You would need a proper step down transformer.

A standard lighting transformer is electronic, and will not power normal 12V appliances.

 

[mattylad]

As someone wot dont know the regs... IMO

Assuming the camp site has RCD protected outlets:
You'd need a proper camping power lead with the blue plugs on, then a box with the 3 way socket in & an ordinary socket outlet, then as RF said, a proper transformer.

It may run using a "mains adapter" but it may need more, what does it say its current drain is?

Whatever power supply you use for it, you ought to make sure that its in a waterproof enclosure as its common place for the inside of a tent floor to get wet too (unless you put it on a pole).

 

[viewer]

You could use a battery charger. I did this without problems. Not very efficient but then....

 

[BS3036]

I'm surprised that no-one so far has said that you don't attempt to run a 12V dc device from an ac supply.

 

[ColJack]

if it's DC then I would have thought that it's got a diode in it to prevent reverse polarity so it would half wave rectify the AC anyway..

 

[BS3036]

if it's DC then I would have thought that it's got a diode in it to prevent reverse polarity so it would half wave rectify the AC anyway..

So the transformer would require a rating of twice that specified by the driven device, even if the device was prepared to be driven by alternate cycles of a sine wave and a peak voltage 1.414 times higher than the rated voltage. Seems a bad idea to me.

 

[mattylad]

Using a "transformer" is a bit too technical for the average diy'r, its much better to call it a "power supply" or "mains adapter" as they are more commonly called.

Messing about with transformers, diodes, capacitors is a bit advanced & will generally cost a lot more than readily available power supplies.

I'm surprised that you guys are even discussing it.

If the original poster can identify the "amps" that the fridge uses then we can point him to a power supply that is available on Ebay/maplin.

 

[JACKC]

I have been through this my self with the battery charger, not very good way as didn't work for long. Halfords do a power supply unit with 15amp / 12v dc output with an outlet socket for a cigarette plug. Costs about £15 4 years ago, it works a treat. I have also doubled up 2 of the 16 amp blue sockets back to back with a blue plug so I can run more equipment from 1 socket when camping.

 

[BS3036]

Halfords do a power supply unit with 15amp / 12v dc output with an outlet socket for a cigarette plug. Costs about £15 4 years ago, it works a treat.

Exactly what we've got. Bet they cost slightly more now though.

 

[ColJack]

Using a "transformer" is a bit too technical for the average diy'r, its much better to call it a "power supply" or "mains adapter" as they are more commonly called.

Messing about with transformers, diodes, capacitors is a bit advanced & will generally cost a lot more than readily available power supplies.

I'm surprised that you guys are even discussing it.

If the original poster can identify the "amps" that the fridge uses then we can point him to a power supply that is available on Ebay/maplin.

the OP asked whether he could use a lighting transformer ( the ones that are used for low voltage lighting )..
BS3036 pointed out that since it's a car fridge, then it's most likely DC and won't like the 12V AC from just a step down transformer..
I sugested that it's likely got a diode already in the fridge to protect against reverse polarity, which if it also comes with "croc clip" leads as well as a cigarette plug, then it will almost certainly will have..

no one mentioned constructing a makeshift power supply

 

[mattylad]

This is a transformer:

This is a mains adapter/power supply:

I'm merely suggesting that talking about a "transformer" should actually be changed to talking about a power supply and that the OP should some back to the thread & let us know the details of the fridge so that we can point them to a power supply available from maplins etc.

Or were y'all referring to one of these:

 

[plugwash]

if it's DC then I would have thought that it's got a diode in it to prevent reverse polarity so it would half wave rectify the AC anyway..

That may be but I certainly wouldn't rely on it. And IIRC half wave rectification is generally bad for any significan load because of the DC component it introduces in the transformer secondry.

 

[breezer]

def the 2nd one (more fun)