Car battery amps
 

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[Closed] Car battery amps

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I've just bought a little screen for a reversing camera for a car. It's meant to wire into the car electrics but i want to use it externally. So what kind of amapage should i be looking for on a 12v power supply?


 
Posted : 16/07/2012 9:38 pm
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Unclear what you mean. Externally to what? What is the 12V supply?


 
Posted : 16/07/2012 9:41 pm
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12v power supply is a plug-in transformer, like thekind of thing used to charge many electronic devices.

Externally means external to the car, like in my house.


 
Posted : 16/07/2012 9:43 pm
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Typically around 5 watts so less than 0.5 amp, but a 1 amp setup would probably do.


 
Posted : 16/07/2012 9:45 pm
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No motors and just electronics, very little I'd think. Does it have a label stating the wattage? If so just use Ohms Law to find amps.


 
Posted : 16/07/2012 9:46 pm
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Oh right.. there should be a sticker on the back giving wattage? Then divide by 12 to get the current requirements.

A car lighter socket can only supply 10A so it'll be less than that. A lot less, most likely!


 
Posted : 16/07/2012 9:49 pm
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Ok, i have a 12v 1A transformer from an old modem, so long it doesn't kill my screen.

No, no wattage,it came from hong kong via the internet


 
Posted : 16/07/2012 9:53 pm
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How does the screen plug in? If it's a thing that goes into the cigarette lighter, there could be a voltage regulator in there. You positive that the screen's 12V?


 
Posted : 16/07/2012 9:58 pm
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No it's a thing which wires up rather than plugs in, yeah it is 12v


 
Posted : 16/07/2012 10:05 pm
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12v 1amp will likely be enough unless its some aweful cheap thing (in which case it will have a 2amp electric heater inside it lol).

Freely available on ebay. Depends what connector you need, but I generally just buy the cheapest thing going and stick my own connectors on it etc.


 
Posted : 16/07/2012 10:45 pm
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BTW average car battery is 40-60aH, but electronic things only draw what they need, its the correct voltage you have to supply them with.


 
Posted : 17/07/2012 10:12 am
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Brickman what is that funny little ad that comes up with your text?

Anyway, plugged it in with a 1A 12v transformer and nothing happened. There is a 2A fuse in lead to the screen, but surely that is just surge protection.


 
Posted : 17/07/2012 1:17 pm
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When you say transformer, do you mean a complete power pack black box thing, or just a transformer on its own?


 
Posted : 17/07/2012 1:18 pm
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Surely he means one of these transformers..
[img] [/img]


 
Posted : 17/07/2012 1:24 pm
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Anyway, plugged it in with a 1A 12v transformer and nothing happened.

are you feeding it some video?


 
Posted : 17/07/2012 1:31 pm
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Just a power supply like you used to get as a phone charger

No, not feeding it video yet, wanted to see if it would power up


 
Posted : 17/07/2012 1:37 pm
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No, not feeding it video yet, wanted to see if it would power up

I take it there's some sort of power indicator then?

There's plenty of monitors that wont visibly power up without a video source being present


 
Posted : 17/07/2012 1:39 pm
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If its a reversing camera, wouldn't it only operate when you are in reverse? Or as above, no video input, no power on.


 
Posted : 17/07/2012 1:47 pm
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I'd expect the backlight to come on though.


 
Posted : 17/07/2012 1:48 pm
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I'd expect the backlight to come on though.

not on all, the power is triggered by the video


 
Posted : 17/07/2012 1:49 pm
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erm no, no power indicator


 
Posted : 17/07/2012 1:55 pm
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ok so it works with a camera feed

ta


 
Posted : 17/07/2012 1:59 pm
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Ok, just in case people happened to be interested. I just got a Raspberry Pi and was looking to see if i could run it on a mini screen. I can!

Hooray!


 
Posted : 17/07/2012 2:17 pm
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Can you read the text though?


 
Posted : 17/07/2012 2:51 pm
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Some of the time, but not all of the time


 
Posted : 17/07/2012 3:30 pm
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SamCooke - Member
Some of the time, but not all of the time
POSTED 42 MINUTES AGO # REPORT-POST

😆

Edit: Respect for having a bash with the Pi - I need to do something with the one I bought.


 
Posted : 17/07/2012 4:13 pm

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