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Working out the current draw of LED lighting

Posted: 13 May 2012, 19:43
by jamesandtheopenroad
Hi

Now, I'm no electrician (or mechanic, or plumber, or carpenter - but hey, that's not stopped me so far!) and I am planning to put some LED lighting in my van.

No, I'm reading up on all this electricity gubbins and trying to get my head around it. I've drawn up a wiring diagram to work with but want to calculate what ampage they will draw once wired in.

There are three lots of 240v LED (12v with a 240v driver), so I plan to cut the driver off and wire them into the lighting circuit on my Zig. They will be 2 x 7.5w and 1x 1.5w.

By my reckoning, at 12v the 7.5w will draw 0.625a/h
the 1.5w will draw 0.125a/h
giving a total draw of 1.375a/h across all three.

Then on a leisure battery of 80amps, that'll give around 58hrs use.

Is that right, or am I a dunce?

Thanks peeps.

x

Re: Working out the current draw of LED lighting

Posted: 13 May 2012, 19:58
by kevtherev
OK till you got to the time...

That is the variable.

Re: Working out the current draw of LED lighting

Posted: 13 May 2012, 20:03
by jamesandtheopenroad
Thanks Kev, but what do you mean about time being the variable? As in, it'll be dependant on the other gizmos consuming power in the circuit, or something else?

Re: Working out the current draw of LED lighting

Posted: 13 May 2012, 20:13
by kevtherev
jamesandtheopenroad wrote:Thanks Kev, but what do you mean about time being the variable? As in, it'll be dependant on the other gizmos consuming power in the circuit, or something else?

yes and the condition of the battery

Re: Working out the current draw of LED lighting

Posted: 13 May 2012, 20:16
by jamesandtheopenroad
Cool, really appreciate that.

Re: Working out the current draw of LED lighting

Posted: 14 May 2012, 07:29
by ghost123uk
When it comes to LED lighting, unless you are planning to go MAD with the quantity, I find you don't need to worry about the consumption as it is going to be insignificant. Unless (like me) you just like to know these things ;)

Re: Working out the current draw of LED lighting

Posted: 14 May 2012, 08:48
by jamesandtheopenroad
Yeah, it's just trying to understand stuff I guess. Also, I want to do it properly so it'll help work out what gauge wire and size of spade connectors etc etc i'll need, just stuff like that really.

Re: Working out the current draw of LED lighting

Posted: 15 May 2012, 03:36
by AngeloEvs
Conventionl LEDs will continue to emit light for longer than the Ampere Rating of the Battery. The battery can fall well below 12V - they will dim eventually but still emit light even with very low current draw due to a heavily discharged battery.

Re: Working out the current draw of LED lighting

Posted: 20 May 2012, 14:11
by CovKid
There are downsides to LED lights - particularly on the outside. Generally if you exit vehicle, taking key with you and don't have some lights-left-on alarm, you'll generally be left with just sidelights. I replaced all these with LEDs to avoid having a flat battery if I ever forget but it doesn't stop neighbours helpfully pounding the door to tell me I've left my lights on. I never have the heart to tell them it wouldn't matter if they were left on for a week :shock:

Re: Working out the current draw of LED lighting

Posted: 01 Jun 2012, 10:26
by Timwhy
My Westy has all LED's in the cabin for lighting and with them all turned on. There's hardly any draw from the house battery, I've checked this on my solar charge controller.

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Re: Working out the current draw of LED lighting

Posted: 01 Jun 2012, 15:49
by CovKid
Unless you've gone overkill, its hardly worth working it out. I've had whole arrays running on just 2xAA batteries - for a week or more.

Re: Working out the current draw of LED lighting

Posted: 03 Jun 2012, 08:52
by Hacksawbob
Love the knife holder and the vw cooker extensions Tim :ok

Re: Working out the current draw of LED lighting

Posted: 03 Jun 2012, 11:36
by Timwhy
Hacksawbob wrote:Love the knife holder and the vw cooker extensions Tim :ok


I bought the grate from Frank, here's the link for them.
http://www.frankcondelli.com./grill.htm" onclick="window.open(this.href);return false;

The knife holder is a home magentic knife holder that I had to run through a Thickness Planer to get the right depth. It would not allow me to close the cover without taking some material off of it. Then had to use just long enough screws as not to go completely through the cover. It works out well at keeping the knives in place, I also put a drying cloth on the cutting board while the cover is closed. This seems to keep the knives from getting jolted loose, when opening the cover.