Car 12v amps -- help!

[assuan]

Hi there,

Sorry, I'm not a sparky and hoping that someone can help me with a question!

I have a wireless cctv camera and reciever, they are both 12v, one is 200mA the other 500mA, if I wire this directly to a car battery (I assume a high ampage) will it 'blow them up'.... or is it that what ever they are wired to for power, must be higher ampage than the draw that these devices will pull? (if that makes sense)

Thanks in advance (please don't take the preverbial too much)

 

[telectrix]

you should fuse the supply from the battery accordingly. e.g. fit a suitable fuse to each device. i suggest a 500mA and a 800mA. depends on the cable size . the devices will draw the current they require. they will not blow up because the battery can supply 100A.

 

[bk81]

If it's for cctv your probably better getting a something like a rectifier (AC input DC output) as the battery will eventually run out.

 

[assuan]

Thanks,

Think the fuse is the way to go. The receiver will be in the car on the ignition wire and camera in a trailer, so only powered when car is on,

 

[bk81]

ahh, it's for reversing then, fair enough.

 

[assuan]

God no, I don't need reversing cameras lol
It's a horse trailer, camera is going inside so we can keep our eyes on our 4 legged passengers!!

 

[bk81]

lol

 

[ste mac]

You are aware that with the engine running the alternator will push the vehicles 12v upto a possible 14.2v. The 200mA & 500mA are the maximum current usage of the devices and are only relevant for fuse selection (as already mentioned) or for minimum output current of an AC - DC convertor / transformer.

 

[UNG]

If you are intending to run the trailer camera from the vehicles power then you will need to take a feed from the vehicles 12S socket to the trailer ( pin 6 is ignition switched ) see Caravan 12S Wiring Diagram for more info

You are aware that with the engine running the alternator will push the vehicles 12v upto a possible 14.2v.

Some newer vehicles have alternators that have an output of up to 15v I believe this is because they have lead calcium batteries which need a higher charge voltage

 

[assuan]

The trailer already has a switched live supply for an internal light that will surfice for the camera, i will use an inline fuse. It's an older vehicle, but will test the 12v radio ignitiod wire to check it's actual voltage to run the receiver

 

[assuan]

New problem, car is only giving 10.5 - 11 volts to The trailer, camera won't work. Any suggestions?

 

[ian.settle1]

If it's for cctv your probably better getting a something like a rectifier (AC input DC output) as the battery will eventually run out.

Why as a car battery gives DC?

 

[bk81]

I didn't realise at first it was for a car, not really heard of cctv in a car before

 

[bk81]

New problem, car is only giving 10.5 - 11 volts to The trailer, camera won't work. Any suggestions?

Is the output 12v where the feed is connected?

Could possibly be volt drop because of the length/cable size or joints?

 

[assuan]

No, the output on the towing socket is only 10.5 - 11 volts