LED Filaments - How to power them at ~17mA 50V-60V with a 5-12V DC supply? - Page 1
Forum section: electronics / beginners

author: dawson345
author_rank: Newbie
timestamp: August 02, 2016, 08:26:29 pm
content: Hi EEVBlog Forum!I have long enjoyed the EEV Blog and I think Dave is an inspiration to the industry! I myself have developed a keen interest in electronics which has been supplemented by the show. I mainly develop projects with Arduinos, MSP430's and Raspberry Pi's.Unfortunately I have limited understanding of power supply circuits and the characteristics of powering LED's.My project goal is to use an LED Filament as a bike light inside a reflector powered by a 5-12V battery.The LED filaments can be found on their Ebay page here -1W DC50-60V 17mA COB LED FilamentI have tested the LED's with my bench top power supply and they work great!Any ideas would be appreciated.

author: Richard Crowley
author_rank: Super Contributor
timestamp: August 02, 2016, 08:35:15 pm
content: Hi, @dawson345. Welcome to the electronics community!Your question generates some project design decision questions.We don't understand why you want to use a "LED filament" in this application?Those "LED filaments" were designed to simulate the appearance of white-hot tungsten in antique, horribly inefficient incandescent light bulbs.Their high design voltage and rather low efficiency are two major strikes against being any kind of reasonable light source in a bicycle light.Are you trying to make some sort of "steam punk" retro-looking show piece?Or are you trying to make a modern design, reasonably high-efficiency LED light (head-lamp?, tail-light?) for your bicycle?

author: dawson345
author_rank: Newbie
timestamp: August 02, 2016, 09:27:14 pm
content: Hi,I suppose my primary goal is to achieve a bright and wide beamed light, I really like the look of LED Filaments so I thought I would challenge myself.I thought they were supposed to be more efficient (in light bulb form) than standard LED bulbs?I'm willing to experiment with this project, I'm not asking for a definitive solution.I think a pulsed output would be sufficient like a joule thief, I could imagine that would use very little energy?

author: Richard Crowley
author_rank: Super Contributor
timestamp: August 03, 2016, 02:09:33 am
content: Liking the look of the filament and achieving a bright and wide beamed light with good efficiency (because of power from a battery of limited mass) may be conflicting requirements that you may need to make trade-off choices.I don't believe the filaments were designed with efficiency as a priority because they were designed to operate on high mains voltages.I strongly suspect that more conventional LEDs would be more efficient at battery voltages.Any time you have to convert power (for example generating a higher voltage from a battery source) you loose efficiency.But maybe you can budget for a larger battery mass, and or shorter operation period?

author: Zero999
author_rank: Super Contributor
timestamp: August 03, 2016, 08:04:34 am
content: I have some LED filament bulbs and would say they're as efficient or even more efficient than standard LED bulbs, although I haven't conducted any scientific tests to confirm this.However, running from a battery does involve an extra power conversion so it may not be as efficient.You could use a higher voltage battery.