LED light upgrade

Hi Del, don't worry about the old tube voltage, the gear inside the fitting is the part that requires a set voltage which will in a camper normally be either nominally 12V (sometimes up to 24V) for running off the vehicle DC battery(ies) or nominally 230V AC if for use when plugged into the mains via the EHU. Just to slightly muddy the water some/most electrical control units, Zig and the like, will also provide a 12V DC supply from the EHU mains.

All that matters is whether you have 12V DC or 230V AC mains coming down the wire that feeds your existing striplight.
There may be information printed on the old unit that will tell you whether it was made to run on DC or AC but it is always possible that a lamp might have been modified by a previous owner to suit the way they used the van.
What voltage were the bulbs you have already replaced? If 12V then maybe more likely to be 12V at the striplight BUT NEVER take that for granted as mains voltage can kill or injure.

In the absence of any information the easiest next step is to just measure what is at the incoming wire supplying your striplight. Any inexpensive digital multimeter will do this job. I see they start at less than £5 on ebay but buying one locally for a bit more will allow you to judge the quality for yourself and whether you would be happy working with it.

Once you know what volts are there you can look for a suitable replacement.

I did have a quick look for a LED replacement of your length but found only 200mm to 600mm then a jump to 1200mm and longer. You might have more luck searching.

If your supply is 12V I would just do as you mentioned: strip out the existing guts and use as many lengths of those LEDs cut from a tape reel as suits your needs.
Thank you for your help, I have a multimeter but I've got hospital appointments today and tomorrow so I haven't had chance to check it out yet but there is a label that says 12v in between the switch and the switch for the extractor fan so I think it's 12v but the label may be referring to the fan switch? I'll report back asap.

Regards,
Del
 
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I meant in my van Trev... it's this...
I did see those but 21" is longest they sell and mine is around 33" long.

Regards,
Del
 
Del
I still reckon that the quickest check is to try it without mains hook up and if you have one any inverter turned off.
I think you will end up with multiple units if you want the same light level. Not a big deal as they can often be linked.
Sounds like you have a 12v supply nearby if you need it.

When I upped my lighting over the work top I had to use 2 x 12" lights because of cupboard joints.
No great inconvenience to have switch independently - actually don't use both much as it happens.
 
Soldering is the downfall of many,secret is a liquid flux,dip wires in and dab some on new joint ,use a good gun type high wattage iron and bingo the worlds your oyster or is it the little people.
 
Del
I still reckon that the quickest check is to try it without mains hook up and if you have one any inverter turned off.
I think you will end up with multiple units if you want the same light level. Not a big deal as they can often be linked.
Sounds like you have a 12v supply nearby if you need it.

When I upped my lighting over the work top I had to use 2 x 12" lights because of cupboard joints.
No great inconvenience to have switch independently - actually don't use both much as it happens.
Depends whether there is some form of inverter as part of the fluorescent tube "gubbins". Simplest to strip out the lot and use 12V LED wired directly to 12V.
 
Am alternative view:

If your fluorescent tube is operating off 12V, i.e, not through some external inverter, then I'd probably just keep it as-is.

Whilst not quite as efficient as LEDs, they are still pretty good. And powerful, it might take quite a few LEDs to match the light output.

The tubes themselves are voltage-agnostic. That's the function of the driver circuitry in the fixture, ballasts, starters etc. The ones designed to run from 12V have a tiny inverter/starter in the fixture. If it is working OK, I'd keep it. There are also some advantages.

If it's just to illuminate the galley when in use and off otherwise, particularly so.

I've tried LED strips for general lighting and don't like them, the bare LEDs do not diffuse the light, having a lambertian profile when used without a diffuser, each LED acting as an individual source . Distracting unless they are out of line-of sight. OK for ambience when sensibly placed, particularly the multicolour ones, if that's your thing.

I've replaced all my inefficient halogen bulbs (30 or 40 Watts) in the original fixtures with drop-in LED clusters (2-3 Watts)which are excellent. They all have small ground-glass shades or other diffusers and can be pointed where I want, e.g for reading.

I suppose it depends how tight you are for power, off-hookup. If the fluorescent tube will break your power budget, is used for more than an hour or two per evening, then yes. But rather than try to modify it, I'd replace with purpose-designed LED fixture.
 
I've chucked out every light in our Chausson and replaced them with led strips. To be fair our high cupboards have a deep lip and they are mounted behind these. They are absolutely brilliant, as you can't see the fittings but get the full benefits of the lights. I have them zoned so I can control what areas are on/off and dim them to suit. I also fitted rgb strips above all the wall cupboards (there is a small anti squeak gap below the ceiling) again controlled by a remote with 15 million colours. Smart. I also replaced the ceiling lamps, unclipped the lenses, took off the halogen lamp circuit and stuck on a similar led lamp with 3M tape. Real good as well. All I needed was the led tape, control units, 2 remotes, flex and a gas soldering gun from Aldi. I've also got the tape in my car port, back door and attic. Bob.
 
I did my main lights with a mixture of soft and p/white which i can switch either on.
 

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Depends whether there is some form of inverter as part of the fluorescent tube "gubbins". Simplest to strip out the lot and use 12V LED wired directly to 12V.
Yes it does but I really dont think any motorhome manufacturer would go to the expense of fitting one for an individual light.
Happy to be proven wrong of course.
 
That's great - so if the OP's 21w T5 runs off 12v (which we don't know and I still doubt) then I agree with earlier posts that leaving it makes sense as Del's unlikely to find a single linear led light to match the output and getting a led tube tube to fit isn't possible(?)
 
Hi Everyone,

Well this afternoon I got time to check the voltage and it is indeed 12 volt at the switch. I've now taken out the complete unit as the extractor fan was a bit noisy and I thought I would take the opportunity to change that at the same time. It should be easy enough to bypass the flourescent light unit (see picture) and use either a stick on strip or modify another unit to fit inside the cover.

Regards,
Del

Hymer Light Unit.jpg
 
Del
That's good to know - the label was right!
I stand corrected about there being a stand alone inverter for this light.
As others have said you'll have a job matching the output with led and the fluorescent is far more efficient than halogen.
 
Del
That's good to know - the label was right!
I stand corrected about there being a stand alone inverter for this light.
As others have said you'll have a job matching the output with led and the fluorescent is far more efficient than halogen.
Stick in one of the jobies from ebay,cost £2 and easy sort,good luck.
 
Agreed, you'll probably have a struggle to match the output of your striplight with an LED conversion, never mind a DIY job. Even if you could, the efficiency is unlikely to be much better.

According to https://www.stouchlighting.com/blog/fluorescent-vs-led-vs-cfl you might manage at best 50 lumens/watt if you somehow optimise the retrofit perfectly. Not meaning just sticking some LED strips inside. Whereas you might expect 30 lumens/watt from a properly designed fluorescent fixture, which I think you probably have.

This is useful lumens out, not datasheet headline figures.

Hence my suggestion to just keep it and save hassle and expense. The tube will probably have a wattage consumption marked on it. Multiply that by 3/5 and that should give an indication of how many watts of LEDs might be required to match it, in a perfect world.

Not all LEDs are the same, there are still some pretty grim ones out there, generally you get what you pay for.

It took me three goes to find replacements that I was happy with, one of the basic 12V only simple ones literally burned out within hours when on hookup (seeing nearly 14.5V), a lot of the energy was just wasted in (under sized) dropper resistors, burning hot, and the output fluctuated significantly as the voltage dropped. I tested, and found they were taking nearly five Watts at nominal 12V. Maybe the LEDs were getting the specified 2.5W, the rest was just being burned up as heat. So much for efficiency, a total fail.

Horrible CRI (colour rendering index), important to me. I found the same with my cheap LED strips, though they didn't burn out, the heat being more distributed than in the tight clusters where they had crammed in as many LEDs as would fit, with no thermal path to take away the considerable heat. No sophistication, just cut to length, daisy chain together, maybe even add a correctly sized fuse in case something shorts out along the strip. Highly unlikely admittedly, failure modes expected to be open circuit, not shorts.

AFAIK all the fixed voltage strips are just crude arrangements of LEDS in series with dropper resistors and associated inefficiency. The good ones don't do it that way, they are fed with an efficient constant current driver, but I've not seen those in use on 12V, and they are not inexpensive.

The clusters I finally chose are much more sophisticated, they have a regulator built in to cope with 12-24V nominal, I tested them and they held steady from as low as 6V to 30, where I stopped, and barely got warm.

Halogens, for all their relative inefficiency, deliver perfect CRI, a continuous spectrum, the closest thing to daylight. If you are critical about colour, studying photographic prints, paintings, other artwork, nothing else compares. That's why one of the lights over my table sometimes gets a halogen bulb put back into it, to study the photobooks that my partner enjoys making, and my hopeless attempts at painting.
 
Just a quick update, I went with the stick on LED strip, I used around 900mm of the LED strip and wired it direct to 12v that was feeding the little inverter and it's working a treat 😀 Thank you all for your advice.

Regards,
Del
 

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Del, well done. I just love the strips above all the windows, in the wardrobe, under bed, etc in our motorhome. Go one better, do all your motorhome with strips connected via Milight controllers and a single IR remote - brilliant, easy to wire, cheap and very effective. Bob
 
All I did in the Swift we had was take 5he fitting to bits. Stick on a length of LED strip. Connect up the 12v wires and put it back in again using the push connectors. Took about 10mins per fitting.
 

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