12V DC Garage lights - Page 1
Forum section: electronics / beginners

author: paulca
author_rank: Super Contributor
timestamp: July 08, 2019, 07:59:54 pm
content: So hopefully this will be an easy one, but you guys always surprise me with insight, ideas and things I didn't think of.The garage lights in the new house are basically shot to hell. Looks like it was DIY wired to have 3 x 2m fluorescent lights switched in the kitchen. None of these work anymore.My plan, as I have a small hobby solar system already out there is to put 2 x 12V LED wide angle spot lights in place of each fluorescent lamp, making 6 12V LEDs in total. If these are something like IKEA MR-16 bulbs at around 5 watts each, that's 30W and ~3A.I can reused the existing 1.5mm twin and earth wiring. The idea I have is to mount a box on the wall with a 2.5mm barrel jack socket. (or just a hanging 2.5mm barrel socket on a cable). This will allow any 12V wall wart to power the lights should the solar battery be dead or should I sell the house and take the solar with me.From this box A 10A fuse will protect the battery and wiring from shorts. I will run the + over to a normal household pull cord at the door and the switch + back to the lights in parallel. The normal main pull cord should have no trouble switching 3A DC.I don't expect the garage lights will be used more than 5 or 10 minutes a day and I think my small solar system (50W with 100Ah) will surfice.Now you get to tell me, "What could possibly go wrong!"

author: paulca
author_rank: Super Contributor
timestamp: July 23, 2019, 07:10:12 pm
content: Well... anyway, thanks for the help, but these turned out just fine.Shut off the lights breaker, measured no voltage in the garage lights. Cut the feed cable, nothing happened. Later I found the RDC had tripped due to neutral to earth leak.Moved the lighting end of the feed over to my pull cord switch. Wago clipped the GNDs and put the + through the pull cord. I know it's an AC 10A pull cord, but the lights only pull about 3A max, so I figure it will be fine switching DC.From the pull cord I re-used the previous lighting 1.5mm twin and earth, to get to each beam where the lights previously were. Added a wire across each so I could put a light at either end. Lots of wago clipsSo the feed comes from a 100A marine battery, solar charged via a 10A EPEver MPPT, through a boat switch panel, so there is a light master and a 5A fuse. That goes to the pull cord.Surprisingly it all works. The downside is it's a bit ugly, but it's a garage! If I forget to turn them off the battery will last nearly a week.Also the LEDs claimed to be 5W each, but.. in reality they only pull about 3 tops. However I half expected this and the thing I was most interested in where the enclosures/brackets and I can later wire sockets in them and replace the bulbs with MR16s of my choice.

author: james_s
author_rank: Super Contributor
timestamp: July 24, 2019, 12:24:30 am
content: I didn't even see the thread.The problems that come to mind are voltage drop at 12V depending on the length of the wire could be significant. Also a lot of those Chinese LEDs are nowhere near the power they claim to be. Some of the COB types seem to be ok though.

author: paulca
author_rank: Super Contributor
timestamp: July 24, 2019, 08:32:21 am
content: Quote from: james_s on July 24, 2019, 12:24:30 amThe cable used is 1.5mm solid core and total length to the furthest light is around 5 meters. I don't see any noticable brightness drop between the closest and furthest light, but I haven't measured the voltage at the furthest point.Yes the COB LEDs are nowhere near their stated 5W which should pull 30W for all 6 lights, circa 2.5A, but they only pull half of that from the battery. As I mentioned I can, if I want put an MR16 holder in the light enclosures and open myself up to a much wider choice of 12V bulbs.