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Mar 22, 2017 19:20:00 GMT
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Howdy fellow car lovers, I'm in the process of rebuilding a car, a Dolomite 1850 if anyone is interested and I've almost completely rewired it I know how to work out what Ampage of wiring I need for most stuff but one thing that puzzles me is USB chargers I am fitting a twin USB/ power socket in rear to be fed via the main fuse box www.vehicle-wiring-products.eu/product.php/1136/double-usb-single-power-socketSo question is what amapge wire would be best taking in consideration the length of cable about 12'? |
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Mar 22, 2017 19:55:06 GMT
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Basically anything you've got to hand will suffice. I'd probably use 1.5mm2 cable, fused at 5A, but you'll get away with 1mm and 3A no problems at all.
Those USB converters have a switch mode supply inside, which are about 80% efficient. 5v 2.1A out is 10.5W. It'll probably draw 13w, so about 1 amp tops at 12ish V.
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93fxdl
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Mar 22, 2017 21:41:57 GMT
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Slightly off topic, I would suggest fitting a lighter type socket, that way items which plug into them can also be used and a plug in USB adaptor to convert it when needed
Ttfn Glenn
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Mar 22, 2017 22:12:51 GMT
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and don't forget cars run at 14v with a healthy alternator, so that needs taking into account when sizing up wiring.
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fad
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Mar 22, 2017 22:53:41 GMT
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As said. You wont be drawing more than 2A on a USB from the psu, so input current will be even less.
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fad
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Mar 22, 2017 22:54:28 GMT
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and don't forget cars run at 14v with a healthy alternator, so that needs taking into account when sizing up wiring. For a regulated psu, a higher input voltage will actually lower the current drawn. P=IxV. On the output, V=5v, fixed. If the psu can throw out a max of 2A say, gives you a max power of 10w. To get 20w from the psu, a higher input voltage (14 rather than 12) must draw a lower current. It's running on attery only that would draw a greater current |
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Last Edit: Mar 22, 2017 22:57:31 GMT by fad
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Mar 23, 2017 23:02:17 GMT
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Slightly off topic, I would suggest fitting a lighter type socket, that way items which plug into them can also be used and a plug in USB adaptor to convert it when needed Ttfn Glenn Its a double socket, one is a power socket that takes cig lighter plugs and the other is the twin USB. its going in the rear seats so will only be used by the kids for their phones and gadgets which are usually USB powered. Front will have just a power socket. |
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93fxdl
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Mar 23, 2017 23:27:26 GMT
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Slightly off topic, I would suggest fitting a lighter type socket, that way items which plug into them can also be used and a plug in USB adaptor to convert it when needed Ttfn Glenn Its a double socket, one is a power socket that takes cig lighter plugs and the other is the twin USB. its going in the rear seats so will only be used by the kids for their phones and gadgets which are usually USB powered. Front will have just a power socket. With kids and their gadgets you can never have enough power points, then you have things like Sat nav,.dash cam, cool box, phone charger, etc etc. I believe power points / lighters are fused at 10amp so should be cabled for 15amp Ttfn Glenn |
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Mar 23, 2017 23:30:04 GMT
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Cheers Glenn
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fad
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"I believe power points / lighters are fused at 10amp so should be cabled for 15amp
Ttfn Glenn"
Didn't think of it that way. Fault currents... good point.
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