Something like the above. Assuming it supplies up to 4A at the correct polarity and with the engine off to avoid voltage spikes. Thoughts?
Most 12v batteries in cars will actually be at 13.5 volts or thereabouts. Youâd want to put a meter on the 12v socket and see what voltage youâve got. Also bear in mind that in the event of a fault occurring youâve got the potential to get a lot of current flowing so check the size of the cig lighter fuse too. It might be worth adapting that cable with an inline fuse holder and a smaller (1A QB or similar) fuse.
Theoretically if itâs a smooth, regulated 12v supply itâll work.
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Thanks for the info! Will find a meter for it and check before I go plugging in anything expensive. Internal fuse is â5A, 3AGâ. Good?
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That means the fuse wonât blow until the current drawn by whatever you plug in goes above 5A. Having a source that will supply a greater current than you need isnât an issue in itself but itâs good practice (essential in my view) to âfuse downâ to the current rating your device requires, hence the suggestion to fit a 1A fuse after the accessory socket.
An analogy would be the domestic circuits in your home. Assuming youâre in the UK youâll have an 80 or 100A main fuse before your electricity meter. Then in your consumer unit youâll have a 32A circuit breaker (or 30A fuse) for the ring main for your sockets and your bedside lamp or alarm clock will have a 3A fuse in the plug top.
So should a fault develop in the lamp youâll only get a fault current of 3A x1.5 flowing into the lamp. In the instant that a fault occurs youâve got the potential for a huge current to flow and if you didnât fuse down with the 32A breaker and 3A fuse that current would only be limited by the 100A fuse at your meter. You want the 3A fuse to go first. This is called discrimination. Plus you really donât want hundreds of Amps flowing through the plug and flex of the lamp or your ring main wiring.
Same applies to your DT. the accessory socket will supply 5A happily and if a fault did develop in the DT then that 5A has the potential to cause a great deal of damage before the fuse goes. By adding a 1A fuse you reduce the potential for the larger current to flow.
Hope this makes sense?
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obvioulsy dont drive and make beats at the same timeâŚ
wait till your at traffic lights âŚ
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Very useful, thank you!
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If you want to make sure no more current can flow into your DN than what it needs just change fuse to a smaller vale/current rating. Not sure what current the DN needs to run.
I would not under any conditions, plug any of my gear into that thing. Do not do this. You can get small inverters, that you could just plug the powersupply that came with your device into. That does not look safe.
Why not? With the engine off a car battery should supply a relatively steady 12 to 12.6V.
I guess that makes sense. Yeah, your car battery is 12 volts, but I myself just would not do it. Maybe if you ran a wire directly from the 12 volt car battery. But, I donât knowâŚMaybe a cell phone charger for your lighter, then a myvolts usb cable. MaybeâŚjust start smokingâŚ
Please donât just run a cable from the battery directly for the reasons I gave above. An unfused direct feed off a car battery will give around 45A at closer to 13V or more. Thatâs asking for magic smokeâŚ
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