current lamp distance - Page 1
Forum section: electronics / beginners

author: dio123
author_rank: Newbie
timestamp: January 08, 2024, 08:55:21 am
content: Good afternoon,I have a rotating lamp with an H1 12v 55w auto bulb.However, this lamp will be located +/- 45 meters away from the garage.The question that arose for me, is it with the loss of voltage and current even the lamp?Because the ideal would be to keep the power supply in the garage, but according to the online calculator I will have a +/- 5V drop using a 1.5mm2 cable.What would be the best cable? Or increase the power supply to 18v 5A which will no longer be easy to fix?What is the best solution you recommend?

author: Gyro
author_rank: Super Contributor
timestamp: January 08, 2024, 10:41:04 am
content: What about swapping the H1 bulb for an LED one, they seem to be available. It ought to drop your current consumption by a fair bit.Edit: I'm looking at this style, 3W consumption...https://www.ebay.co.uk/itm/304849956711

author: CaptDon
author_rank: Super Contributor
timestamp: January 08, 2024, 02:13:29 pm
content: Both answers are good. Increase power supply voltage to get correct voltage at lamp, do-able but as the lamp ages the voltage across it will vary and probably go up causing short bulb life. A positive is that the long cable will limit inrush current to some degree. LED headlamp, also do-able with several caveats, Many of those bulbs have a large heatsink with a tiny failure prone fan. Many are an unusable lame excuse for a headlamp and may not produce the beam pattern you want with your particular reflector.

author: BILLPOD
author_rank: Frequent Contributor
timestamp: January 08, 2024, 02:48:13 pm
content: I'm just curious as to how it rotates

author: themadhippy
author_rank: Super Contributor
timestamp: January 08, 2024, 03:10:33 pm
content: I'm just curious as to how it rotatesQuotesevral ways,slip rings being most common,but often the lamp is stationary and the reflector or lens is the revolving part

author: IanB
author_rank: Super Contributor
timestamp: January 08, 2024, 03:48:48 pm
content: Two other possibilities:1. Use a fatter cable with lower resistance (heavier and more expensive, though)2. Place a 12 V DC step down module by the bulb and send, for example, 48 V AC down the wire. Such step down modules are available as encapsulated and sealed bricks.

author: Ian.M
author_rank: Super Contributor
timestamp: January 08, 2024, 04:55:15 pm
content: Swap out to a 24V bulb and use a small adjustable 'buck' DC-DC converter module at the lamp end to get 12V for the motor (which would also let you adjust the motor speed). That will reduce the total current consumption to approx. 2.5A and the voltage drop will reduce proportionately. However I'd also go up to 2.5mm2cable.https://www.12voltplanet.co.uk/voltage-drop-calculator.htmlreckons that gives 1.7V total drop, which could be compensated by the typical +/-10% adjustment range of a typical cheap Chinese 24V 5A SMPSU

author: BILLPOD
author_rank: Frequent Contributor
timestamp: January 08, 2024, 06:07:27 pm
content: Quote from: themadhippy on January 08, 2024, 03:10:33 pmOh, the obvious evaded me, but it's like the revolving lights on the top of emergency vehicles used to be ...got it.....thanks

author: Zero999
author_rank: Super Contributor
timestamp: January 08, 2024, 06:27:10 pm
content: What's the purpose of the lamp?Rotating lamps are normally for some sort of warning.I say replace the whole beacon with an LED one. It will use less current and if you choose one with a wide voltage range, then the volt drop is a non-issue.https://flashing-beacons.co.uk/product/ic360-12-24v-r65-led-flexi-din/https://uk.rs-online.com/web/p/beacons/2399236?cm_mmc=UK-PLA-DS3A-_-google-_-CSS_UK_EN_PMAX_RS+PRO-_--_-2399236&matchtype=&&gad_source=1&gclid=CjwKCAiA1-6sBhAoEiwArqlGPv_SiF1SyQDPEQ2SXiZyhBL6SjG7OgRLKPpL4yoTuDs5dxLuc4qCHRoC4ugQAvD_BwE&gclsrc=aw.ds

author: floobydust
author_rank: Super Contributor
timestamp: January 08, 2024, 07:54:24 pm
content: H1 halogen bulb 12V 55W rated 225hrs and 1,600lm (Sylvania 31393). With LED at ballpark 100lm/W efficiency, still need around 16W or 4W/side if a square.I don't think 3W is the right rating, although cheaper chinese LED replacements use resistors instead of a CC buck converter, so they run too hot.Once tried upping the voltage to a beacon and a lamp burned out and then the motor/mech got damaged as the voltage jumped up.

author: Ian.M
author_rank: Super Contributor
timestamp: January 08, 2024, 08:53:05 pm
content: I suspect the O.P. specifically wants an incandescent bulb rotating beam beacon, presumably for its visual effect, possibly as an advertising display. A xenon or LED strobe beacon has a very different appearance, and many people find the harsh omnidirectional flash visually distracting.The problem with retrofitting a LED bulb is they are very unlikely to have a uniform light output with respect to viewing angle, so the visual effect of using one with a rotating reflector will be significantly different. Also it may be a PITA to fit anything other than aH1 lamp. Its possible modifying it to use a vertically mounted LED spot bulb and replacing the rotating reflector with a 45° mirror to 'throw' the spot beam horizontally would produce the desired rotating beam effect. Some experimentation would be advisable e.g. with a mirror on a turntable and a gooseneck spotlight centred over it, before hacking up the existing rotating beacon.Availability of H1 24V 55W halogen bulbs as I suggested earlier isn't great, as most truckers prefer 70W or even 100W bulbs but they aren't too hard to find online. Higher voltage and lower power non-LED bulbs are rare like hens teeth, though 35W H1 HID bulbs and 24V-36V 35V HID ballasts are available if you don't mind the price.Floobydust has a good point about not simply upping the voltage to compensate for voltage drop in the wiring, with the 12V bulb directly in parallel to the motor due to the risk of motor burnout if the bulb fails, but if the motor is powered from a buck regulator, as I proposed, that objection goes away. It would be helpful if the O.P. could measure the motor current @12V with the bulb removed.

author: dio123
author_rank: Newbie
timestamp: January 10, 2024, 05:56:36 pm
content: The rotating light is model lap122.Initially I thought about using an H1 LED, but I only found it with a heatsink underneath which I couldn't install, due to lack of space.The effect of the lamp is that when the alarm is triggered, the light will flash on the warehouse street to deter thieves.If it eventually works, it will be about 5 minutes to 10 minutes.I wanted to avoid having a box with a 12v source on the street.

author: Zero999
author_rank: Super Contributor
timestamp: January 10, 2024, 07:13:14 pm
content: Quote from: floobydust on January 08, 2024, 07:54:24 pmDon't forget a halogen will be much less efficient than those figures, because lots of power is lost in the amber filter. If an amber LED is used, rather than white, it should be possible to use an even lower power one.Quote from: dio123 on January 10, 2024, 05:56:36 pmIs it possible to use a higher voltage LED and a DC:DC converter for the motor?Why not simply replace the whole beacon with an LED one?

author: Ian.M
author_rank: Super Contributor
timestamp: January 10, 2024, 08:37:32 pm
content: Get a high intensity LED or possibly Xenon strobe as for security, a harsh flash is desirable. I wouldn't be surprised if the energy saved vs the rotating lamp would allow down-sizing the cable CSA enough to pay for the beacon! Save the rotating lamp for an application with short wires where its aesthetics are beneficial. Security industry ones are specifically designed to wall mount and tie into an alarm system and many are available with an option for a backup battery and anti-tamper loop so they cant be disabled by cutting the wiring.

author: floobydust
author_rank: Super Contributor
timestamp: January 10, 2024, 10:17:26 pm
content: OP, you could run a second cable, in parallel. If it's a mains extension cord, I use all 3 conductors together for (+), another cable for (-), with the ends chopped off.You could power the lamp from higher voltage. That needs a mains say 15V PSU that can be activated by the alarm panel which requires an extra relay I think.You could use an LED version (and they have 15 different programmable flash patterns) or xenon strobe. Either uses much less power.Where is the remote siren? 12V at an extra 0.8AQuote from: Zero999 on January 10, 2024, 07:13:14 pmThat ballpark I gave is wrong, not sure where.H1 halogen is rated 55W ~1,600 lumens, which is 30 lm/W. I use LED efficiency of 100 lm/W to get 16W LED equivalent.But beacon standards, SAE Class II the LED ones are 12V 0.5A for only 6W which is around 1/10 the power of the halogen bulb.Amber LEDs also come as white phosphor-converted (PC amber) which are 2x more efficient than amber. But it might be fake, because the spectral output is much wider.Example CreeJE2835coloured orXP-E2.