Street lighting: compatibility of bulb and ballast - Page 1
Forum section: electronics / general

author: elektrinis
author_rank: Regular Contributor
timestamp: December 05, 2021, 09:13:54 am
content: Not exactly for street lighting, but we have this huge lamp in our living room, that goes with 250W E40 bulb, with light output of 5k lumens. Time to upgrade.The lamp has a pretty complex optical system, which requires the bulb to imitate the light originating from a small spot, and compatible with E40 screw.I've found this 68W LED replacement from Philips: TrueForce LED Road 112-68W E40 730:https://www.lighting.philips.com/api/assets/v1/file/PhilipsLighting/content/fp929002007602-pss-global/929002007602_EU.en_AA.PROF.FP.pdfThe only issue is that it is designed as replacements to HCI/HQI lamps that run with ballasts, so it requires one to run (it runs on 80-100Vac). So I have looked around and found this ballast from Osram: Powertronic PTi 2X70/220...240 I.http://sillamps.com/datasheets/ZMP_56429.pdfHowever I am missing some information, like:1. Does this bulb run on higher wattage ballasts, or do I need an exact match?2. This ballast is a dual output. Can I leave one channel unconnected?3. Can I parallel both channels to run a single 150W HCI bulb?

author: Kjelt
author_rank: Super Contributor
timestamp: December 05, 2021, 09:38:14 am
content: Quote from: elektrinis on December 05, 2021, 09:13:54 amHow large is the current radiator? If it is a kind of projection bulb with a mirror , those are the extreme small spot bulbs. But 20Lm/W sounds like a halogen bulb.If it is a SON or HID bulb they have larger burners something between a few cms to ten cms. This does not always work. I have tried to replace a halogen projection bulb from an entertainment light for someone with a small hid bulb but the result was unusable.QuoteIt would surprise me if it would not run on a led driver capable of delivering 1.6Amps at 120VDC (sqr2 * 80) or the vicinity. BUT the light will be totally different due to the spectrum, you can not dim it and you get two and half times more light, do you really want that ? Also although you can find these professional bulbs online it can bevdifficult to obtain one and the prices are also quite high.

author: elektrinis
author_rank: Regular Contributor
timestamp: December 05, 2021, 10:02:37 am
content: I already have this 68W LED bulb from Philips, paid around 70 euros on clearance sale. It's an absolute beast of a bulb.I have noticed the voltage spec printed on the bulb and this lead me too googling, and I found a guy claiming he accidentally connected this to 220V AC, as the socket is the same. And it blew up inside. Apparently it still has an internal driver of some sort, imitating volt-ampere characteristics of HCI bulb.It's bit silly to have two drivers in series (ballast is basically a driver), but if that is what it takes to finally solve this issue, I'll take it.So my questions remain open...

author: Kjelt
author_rank: Super Contributor
timestamp: December 05, 2021, 10:23:59 am
content: Ofcourse 220VAC will blow it that relates to over 325VDCAnyway you want answersQuote from: elektrinis on December 05, 2021, 09:13:54 am1 IMO You need an aprox match that is you have to look at the outputcurrent of the ballast. It should be in the order of 1.5-1.7Amps2 That might work depending on the internal design BUT it only outputs 0.7A which is insufficient for your bulb.3 No absolutely not. Each output is capable of generating a kV or more ignition voltage , it is not designed to use both outputs parallel.

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 05, 2021, 02:13:19 pm
content: I wouldn't be surprised if that bulb is just a LED array plus a rectifier which would be perfectly happy to run at reduced power. I suspect it's only listed as not dimmable because HID lamps typically cannot be dimmed much if at all. If you have a variac, you could test the bulb with it but beware that if it is indeed just a rectifier, the current will rise very quickly with a relatively small increase in voltage, so do it slowly!Traditional HID ballasts are basically just inductors with a separate module to supply the starting pulse. The LED bulb won't need the starting pulse and a series capacitor might work instead of the inductor. Might also need a series resistor to limit the inrush current when initially turned on.

author: elektrinis
author_rank: Regular Contributor
timestamp: December 05, 2021, 02:49:59 pm
content: I have opened it up ant the driver inside is much more complex than just a diode bridge... So I would love some insight from someone working with these things.

author: NiHaoMike
author_rank: Super Contributor
timestamp: December 05, 2021, 02:58:50 pm
content: Got any pictures? Most importantly, check the voltage rating of the capacitor just after the rectifier.

author: Alti
author_rank: Frequent Contributor
timestamp: December 05, 2021, 04:09:00 pm
content: I have a question regarding the TrueForce bulb.Its design is peculiar, does it include the radiator on top? Any active cooling or heat-pipes?Voltage is 80-90V AC. Power 68W. Temperature 103oC. Quite a serious bulb.

author: Twoflower
author_rank: Frequent Contributor
timestamp: December 05, 2021, 04:32:44 pm
content: You should check is the color rendering of 70 is enough for you. 80 is the minimum I would consider usable for a room I spend some reasonable time. And of course the color temperature might also be different.

author: Kjelt
author_rank: Super Contributor
timestamp: December 05, 2021, 04:47:32 pm
content: Quote from: Alti on December 05, 2021, 04:09:00 pmYes looks like it has heatpipes. They did this before with the first generation household led lamps which in that time had a lower Lm/W ratio as nowadays.

author: james_s
author_rank: Super Contributor
timestamp: December 05, 2021, 07:55:19 pm
content: The bulb *may* have a conventional driver in it that will run off the line, that would work just fine off of a conventional reactor (series choke) HID ballast. It's impossible to say without more details though, we can only speculate.

author: Alti
author_rank: Frequent Contributor
timestamp: December 06, 2021, 11:17:35 am
content: Quote from: james_s on December 05, 2021, 07:55:19 pmHow about butchering the lamp and connecting conventional, regulated current source to E40?This ECG has "Automatic safety shutdown of lamps in the event of a defect or at end of life (EoL)". Does it work reliably with LED-HID? I have no idea.