Restoring a fluorescent light unit, or making it LED. - Page 1
Forum section: electronics / beginners

author: paulca
author_rank: Super Contributor
timestamp: July 08, 2020, 10:51:33 am
content: I have a fluorescent light unit with 2 x 20W T8 tubes in it. No light, not even a glow is present on either tube.I opened the unit and found:2x22W starters marked H-2XThe tubes appear to be wired in series with the ballast.Neutral goes straight to one end of one of the tubes. Live goes through the ballast, then to one tube and the rest appears to be wired in series through the two tubes and starters. Both ends of the tubes have two wires going to them, so it's a bit hard to work out what is going where.I opened the starters and both are completely black, blown.I measured the voltage from the metal ground clip to each starter port and got 50VAC on one and 153VAC on the other. Curious. (240V supply)Ideally I want to replace the two tubes with T8 LED direct replacements.A full replacement LED light unit, people are asking for $200! But T8 LED tubes are only $10 each.The questions are...do I need to replace the starters (the LED tubes claim they are compatible with starters).are there any particulars I need to know before buying LED T8 Tubes and starters for this set up.Just in case anyone has experience of these, it'a a Fluval Roma 125Litre aquarium.

author: SilverSolder
author_rank: Super Contributor
timestamp: July 08, 2020, 10:58:16 am
content: I restored a 50 year old Dazor architect's lamp with dual fluorescent tubes. - I ended up just replacing the wiring, and using "low tech" fluorescent tubes again. I figured there's no way a modern LED replacement lamp or "smart" ballast is going to last 50 years...

author: paulca
author_rank: Super Contributor
timestamp: July 08, 2020, 02:50:08 pm
content: Quote from: SilverSolder on July 08, 2020, 10:58:16 amWell a traditional fluorescent lamp set in this fish tank, with it being on 12 hours a day, the bulbs last about 3 years and the starters about 2 bulbs worth.I highly doubt LED lamps and drivers will have a shorter life span.

author: tkamiya
author_rank: Super Contributor
timestamp: July 08, 2020, 03:13:00 pm
content: The T8 LED tubes I bought had an instruction to completely remove ballast of any kind. Then wire one side to mains and the other side to neutral. That's it. Much brighter and cleaner color. I like it.

author: paulca
author_rank: Super Contributor
timestamp: July 08, 2020, 03:20:00 pm
content: Quote from: tkamiya on July 08, 2020, 03:13:00 pmHave you got a link to these or similar?

author: SilverSolder
author_rank: Super Contributor
timestamp: July 08, 2020, 03:32:32 pm
content: Quote from: paulca on July 08, 2020, 02:50:08 pmThe next tube that blows, I'll take a look at LEDs again. However; the daylight fluoros work well, and double as sun lamps and PCB artwork exposure lights, LOL!

author: tkamiya
author_rank: Super Contributor
timestamp: July 08, 2020, 03:39:36 pm
content: Quote from: paulca on July 08, 2020, 03:20:00 pmhttps://www.amazon.com/gp/product/B01EMPH0QK/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1This one is unavailable now. I did this conversion 3 years or so ago.I'm sorry, no, it was too long ago for me to remember. I bought it from Amazon.One thing to remember when buying these lamps. Some of them are ONE SIDED. Only one side has LEDs and the other side is heat sink. If you need 360 degree illumination like traditional lamps, you need to avoid those.

author: Purduephotog
author_rank: Regular Contributor
timestamp: July 08, 2020, 11:18:42 pm
content: I'm going to caution you on T8 or T5 retrofit LED sources that leave the ballast in there. I got a sample (well, I stole it, lets be honest) because I was cut out of the procurement process and I believed I knew more than the guy ordering it.I wrote out 5 things wrong with it, including a falsified / incorrect UL approval. They installed them anyway.8 months later.... some of the units started failing. They replaced them. 5 months after that it caught fire and evacuated the building.Said engineer hasn't spoken with me since because I refused to cover up his f-up.Really, retrofits aren't the way to go. Get a whole unit. You don't have to deal with the ballast, you don't have to deal with edge cases... you'll get a wholly built unit that works.The ones I looked at were being sold as fishtank daylight units, and I got them from a number of manufacturers all sourcing the same materials- FR4 boards, no current limiters, no heat sink TIM, no 'hard' connection to an aluminum sink, and too small of heatsink for wattage for passive cooling. They were guaranteed to fail... and they did.

author: paulca
author_rank: Super Contributor
timestamp: July 09, 2020, 08:14:31 am
content: Are you cautioning on T5/8 retrofit *with* ballast or T5/T8 LED tubes in general?I don't mind rewiring the "hood" of the tank, as long as I don't need to fiddly with the seals or tube mounts and as long as I can get the end-cap seals to screw back on. The top of a closed fish tank at 25*C is a formidable place for constant condensation and algae growth.

author: Ian.M
author_rank: Super Contributor
timestamp: July 09, 2020, 08:39:21 am
content: Don't expect LED retrofit 'tube' assemblies to deliver more than a small fraction of their rated life in a poorly ventilated high humidity environment. I would strongly recommend replacing the fluorescent tubes like for like, and possibly retrofitting good quality name brand electronic starters.

author: paulca
author_rank: Super Contributor
timestamp: July 09, 2020, 10:29:10 am
content: Quote from: Ian.M on July 09, 2020, 08:39:21 amI'm starting to realise without replacing the whole head unit/lid this is probably the better option.An official LED lid from the manufacturer of the tank is £160-190 ... I figure your reply is the reason why it's so expensive.The generic LED units available are not much cheaper, but they sit on a stand above the tank and expect either the tank is open to the air or covered with glass sheeting, leaving the LED unit outside above. Neither is appealing. Open tanks water level drops fairly rapidly And fish have been known to leap out, not mentioning the smell as well. Sourcing the correct dimension of glass or acrylic sheets to cover the tank is a pain.Replacement tubes and starters however is probably around £50.

author: SilverSolder
author_rank: Super Contributor
timestamp: July 09, 2020, 12:45:02 pm
content: Quote from: paulca on July 09, 2020, 10:29:10 amIf you buy a pack of 10, they can be quite cheap, around $3 each. If they don't last so long, it may make sense?

author: paulca
author_rank: Super Contributor
timestamp: July 09, 2020, 03:00:43 pm
content: Quote from: SilverSolder on July 09, 2020, 12:45:02 pmKinda, but I need daylight bulbs as the tank has plants in it.. or did until the lights failed, now it only has moss. I think my tank currently had one WarmGlow and one Daylight bulb. 20W each. Poor colour spectrum flourescents make the fish look weird and mute various colours.I don't know if they designed them with the environment in mind or if it's just charging the aquarium hobby over the odds for standard tubes.

author: SilverSolder
author_rank: Super Contributor
timestamp: July 09, 2020, 04:01:41 pm
content: Quote from: paulca on July 09, 2020, 03:00:43 pm32-Watt 4 ft. Alto Linear T8 Fluorescent Tube Light Bulb, Daylight (6500K) (10-Pack) - is $29.99 at the local Home Depot.I would be willing to eat my hat if the tubes are not a standard type!(Note: I do not wear a hat! )

author: paulca
author_rank: Super Contributor
timestamp: July 09, 2020, 06:25:33 pm
content: These are the bulb set the tank came with:https://www.ebay.co.uk/itm/POWER-GLO-with-FREE-AQUA-GLO-T8-LIGHT-BULBS-LIGHTING-AQUARIUM-FISH-TANK/401889905942?hash=item5d92814d16:g:kWEAAOSwwU1dgjaMThey claim 18000K giving it a distinct blue tone, but of course the full output spectrum is more important.Still £20 a pair. Chances of them being delivered unbroken... probably 0.

author: SilverSolder
author_rank: Super Contributor
timestamp: July 09, 2020, 08:17:22 pm
content: Quote from: paulca on July 09, 2020, 06:25:33 pmI am no aquarium expert but a quick browse shows plenty of aquarium lamps for sale rated in the 6000K area.

author: wizard69
author_rank: Super Contributor
timestamp: July 09, 2020, 10:36:05 pm
content: There are two types of Florescent Bulb replacements out there.Style #1 is designed to work with the ballasts in place. I do not suggest using these at all, they are more trouble than they are worth. There area couple of reasons for this. One is that the bulbs only work with certain ballasts and unless you inspect an entire installation you have no idea what blast is in which fixture. The second is that ballasts should be disposed of properly.The other type of bulb is the ballast bypass unit. These require removal of the old ballast and other associated electrics. Essentially you end up with a completely new fixture with 120 VAC running straight to the bulb.The ballast bypass method does require rewiring the fixture but it isn't a huge task for somebody that understands basic home wiring. I have a shop area in the cellar with lights with various dates of installation and prepacked the old bulbs with Ballast Bypass LED models as they burnt out. A couple of things noticed right away.The first thing noticed is that they produced far more light per "bulb" than the old florescent.Because of the additional light output I actually removed one bulb from each fixture which ended up saving me considerable money.I forgot what the color temperature was, but the bulbs produce a much whiter and cleaner light. In a shop where you need to see colors correctly this is fantastic.Not one of the "bulbs" has failed yet.Now all of that being said when I went to do the other half of the cellar where there was hardly any lighting at all I went with new round (6" dia I believe) fixtures.I installed these on a somewhat tight grid and so far they have been great. I forget the wattage but it is hardly noticeable.

author: Purduephotog
author_rank: Regular Contributor
timestamp: July 09, 2020, 11:19:18 pm
content: Quote from: paulca on July 09, 2020, 03:00:43 pmYou don't so much need "Daylight" as you need "PAR"- Photosynthetically Active Radiation. You should visit the some Reef forums for a good series of suggestions.

author: paulca
author_rank: Super Contributor
timestamp: July 10, 2020, 09:42:12 am
content: Reef / Saltwater tanks seem to favour blue tinted lights, to give that tropical water look in a small tank.I did a bit of browsing around and for aquariums they are often talking about things like "triple phosphor" and displaying spectrum with 3 spikes but a wide band underneath from red through and high into the blue.In normal daylight (as my tank has no lights), the fish look bland and lack colour. So the fish tank bulbs are partly designed to bring out the colours, sparkle and glint in fish for asthetics. In addition to providing a nice spectrum for plants. (PAR?).Pure "grow lights" can be used, but they tend to mute the useless green light and produce a kind of pink light. I know some people use one grow light and another colour correcting light for aesthetics.Even though I may be ripped off buying specific aquarium bulbs, if they last 3 years, £20-30 to not have to do many evenings research sounds fair to me.

author: paulca
author_rank: Super Contributor
timestamp: July 10, 2020, 09:46:51 am
content: Quote from: wizard69 on July 09, 2020, 10:36:05 pmI would be "fine" doing this. However ... it seems that the two bulbs are wired in series. In the UK we have 240V supply. I'm not clued up enough in the standards of flourescents or LED replacements to fully understand if it matters if they get 120V in series or 240V in parallel.It seems to matter to the starters which appear to be sold for 1, 2, 4 tube sets specifically. My tank as what appear to be, two 2x starters in series.It would not at all surprise me that the company Fluval decided to delibrately make their lighting unit custom to lock you in to their supplies.

author: paulca
author_rank: Super Contributor
timestamp: July 10, 2020, 09:52:39 am
content: My take on the wiring is...Live -> Ballast -> Tube 1 Right end terminal 1 -> Tube 1 Right end terminal 2 -> Starter 1 -> Tube 1 Left end terminal 1 -> Tube 1 Left end terminal 2 -> Tube 2 Left end Terminal 1 -> Tube 2 Left end Terminal 2 -> Starter 2 -> Tube 2 Right end Terminal 1 -> Tube 2 Right end terminal 2 -> Neutral.

author: Ian.M
author_rank: Super Contributor
timestamp: July 10, 2020, 11:06:56 am
content: It helps if you understand how fluorescents were wired before electronic ballasts.For traditional magnetic ballast fluorescent fittings, each tube always has the starter wired in series in between its filaments. The remaining terminals are the feed to the tube. In 220V-240V countries, the ballast is a simple series current limiting inductor. In 115V countries, ballasts for longer higher wattage tubes are impedance limited autotransformers to provide enough voltage step-up for a stable discharge. Shorter twin or four tube fittings often wire the tubes (each with its own starter across it) in series pairs. Long tubes typically require a ground near to the tube glass for the length of the tube to strike reliably (by encouraging a weak glow discharge from the filament to the glass before the middle of the gas column has ionised).N.B. For tubes wired in series, periodically reversing (end for end) one of them can help even out cathode wear that would otherwise result in DC imbalance, which rapidly accelerates into severe flickering, sputtering of the cathode and failure.It may be worth considering upgrading to a pair of starterless HF electronic ballasts (if you can find somewhere to mount them out of the high humidity zone), to improve efficiency and tube life, and also provide redundancy so one tube can fail without taking out the other, so your aquarium's plants don't die again! Keep the old magnetic ballast - they are useful for low EMI electronics workbench lighting, (even without a fitting, as long as you've got spare tube-end and starter connectors, you can mount a tube in terry-clips under your bottom shelf over the bench with a glare-guard strip protruding downwards from the shelf edge)

author: paulca
author_rank: Super Contributor
timestamp: July 10, 2020, 12:42:51 pm
content: Thanks.The failure mode of these lights was very weird. I am used to the lights stuttering or just glowing at the ends (usually failed starter) or not starting or glowing at all after a while, the filaments are burnt out. I think one of the first set of bulbs failed that way and I replaced both tubes and it was fine for more years.However these guys just stopped working intermittently. ie. you would power them on and nothing. Nothing at all. No glow, no blink, no stutter from either bulb. Then a day later (I left them on the timer) you would walk into the room and they were on perfectly fine. Almost like random for a while, until they stopped coming on at all.Both starters are burnt black in the little glass discharge thing.But it's odd the way they failed.Speculation: If an endcap leaked and allowed humidity to build up at the electrode ends could that have created enough of a short to burn the starters and/or both bulb filaments out?

author: Ian.M
author_rank: Super Contributor
timestamp: July 10, 2020, 01:21:49 pm
content: Sounds like one of the starters went bad. A traditional starter has a bimetallic strip in what's effectively a neon bulb. Its heated up by the discharge and moves to short out the starter, allowing significant filament current to flow. It then cools and opens striking the tube. If the tube discharge is sustained (and its still got sufficient emission), there is insufficient voltage across the tube and thus the starter to re-strike its own discharge, so the starter stays open while the tube's running. Due to the high currents involved the starter electrodes tend to momentarily arc and sputter the glass envelope when the contacts open, and the sputtering can act as a getter adsorbing gas from the starter till its striking voltage rises to the point it no longer strikes, leading to the situation you experienced where it only strikes on mains surges.

author: SilverSolder
author_rank: Super Contributor
timestamp: July 10, 2020, 01:41:29 pm
content: Can you get electronic starters that are more reliable?

author: Ian.M
author_rank: Super Contributor
timestamp: July 10, 2020, 01:55:59 pm
content: Quote from: SilverSolder on July 10, 2020, 01:41:29 pmYes and I recommended that, but unless their PCB is conformally coated, there's a chance they'll actually be *LESS* reliable in a condensing humidity environment. Say what you like about the deficiencies of a traditional glow starter, but at least they've got decent creepage distances.Moving the starter sockets so that electronic starters are in the central well with the ballast to get them out of the high humidity zone, and sealing up their old holes would be advisable. I don't know if the central well is top vented - if not it needs to be.

author: paulca
author_rank: Super Contributor
timestamp: July 10, 2020, 04:29:05 pm
content: That whole central well is sealed and not high humidity. The tube fittings and mains wire input are all sealed well. So I can probably get electronic starters.Starter specs are just gang count and wattage? So I just need any 2x 20W starter?

author: Ian.M
author_rank: Super Contributor
timestamp: July 10, 2020, 06:00:20 pm
content: Starter specs are basically the tube's running voltage drop concealed in a lookup table so you need to check both the wattage and the T number for the tube diameter are valid for your chosen starter. Also starters for series pairs need a much narrower margin between 'wont strike' and 'must strike' so you need to check your chosen starter is rated for that usage.