cooktop lighting suggestions - Page 1
Forum section: electronics / projects

author: KM4FER
author_rank: Regular Contributor
timestamp: January 25, 2015, 08:03:34 pm
content: I bought a camping trailer with a gas cooktop with a fumehood over it.In the hood is a socket for a 12 Volt light bulb with an ON/OFF switch. The label says 10W max. Obviously somebody didn't pay attention to that or their calculations were way off. I can't read any labels on the bulb.The replacement bulb I purchased doesn't fit the socket and since my experience has been that lighting from a single bulb like this can be harsh with lots of shadows I have been considering a redesign. Factors that have to be considered are:1. It can get hot under the hood.2. Water vapour and condensation are a big factor.3. Power is 12V, 2A max.4. Intensity control would be nice.My preliminary thought was to arrange perhaps 10-20 white LEDs around the perimeter using high temp (teflon?) insulated wire. Given the large temperature variance current control per LED is probably in order.Here's the what I have to work with.So my questions are:1. Are LEDs suitable for an application like this or should I stick with incandescent?2. Given the environmental conditions what else do I need to take into account? Potting of components?What would you do?Thanks...earl...

author: Seekonk
author_rank: Super Contributor
timestamp: January 25, 2015, 09:53:39 pm
content: I like the strip LED lighting which has clear coating on iy they call waterproof. I cut it to length, solder on the wires and dab some hot melt glue on it, and finish with some heat shrink. Just make sure to super clean the metal before sticking on.

author: ajb
author_rank: Super Contributor
timestamp: January 25, 2015, 11:43:24 pm
content: That looks like an automotive type bulb--the quick and easy solution would be to get an LED replacement bulb that matches and stick that in there.Pre-made LED tape would be the easiest DIY solution, but you won't easily be able to do constant current control since its designed to run straight to a 12V supply with current limiting resistors built in. Also I wouldn't expect LED tape to have very good color rendering, so it may make your food look a little funny. Good quality LEDs that are designed for the lighting market would be a better bet in that respect.Is the supply for the bulb AC or DC? Is it well regulated? That definitely ought to factor into your driver selection.You should definitely consider making the assembly easy to clean, given the environment.Maybe you can find an LED mini-fluorescent replacement tube that would fit the space--maybe one on each side of the hood?

author: rdl
author_rank: Super Contributor
timestamp: January 26, 2015, 12:01:17 am
content: That's almost certainly some kind of automotive bulb, the type called "wedge base", but there are many different kinds of them. You might try looking around at SuperbrightLEDs.com to see what they have. You might find something there that would work for this.https://www.superbrightleds.com/cat/led-vehicle-replacement-bulbs/

author: T3sl4co1l
author_rank: Super Contributor
timestamp: January 26, 2015, 03:16:05 am
content: If you're going with LEDs, I'd suggest some sort of guard, not even so much for moisture as for grease spray: imagine what's going through the air when you toast up your morning strips of bacon!Undesirable effects of grease spray probably include, softening, yellowing, swelling and crazing of various plastics (e.g., LED lens, or those jelly things the strips are made of), plus difficulty cleaning up (it gets sticky after a little while).The LEDs recessed behind a semi-sacrificial lens or plate would be good. Glass sealed with an O-ring would never wear out and would be easy to clean, but you don't need to go so overboard just for this; a polycarbonate or acrylic plate will probably do as well.As long as the back side is well ventilated, what's going on below doesn't matter. You'll want to make sure there's some circulation behind, where the LEDs are. This could be passive in the structure, or active (hey, you could tap some suction from the vent fan, so it draws clean air over the electronics, from somewhere else; or draws interior air still, but through an air filter).Tim

author: KM4FER
author_rank: Regular Contributor
timestamp: January 26, 2015, 02:21:10 pm
content: WOW !!! I hadn't realized there were so many LED options available in automotive bulbs.Now a couple of those multi-LED units combined with some of the nice shiny stainless steel sheet I have as reflector and I think I'll be set.Thanks everybody.earl...