G9 Bulb Replacement Qs

Thanks Brian

Think I'll stick with non-LEDs then

Phil

Thanks NT

But it looks like the increase in size moving to LED would have the bulbs sticking out of the shades. Think I'll stick with non-LED till I change the fitting.

Phil

Hi all

I have a light fitting in the hall which I am quite happy with. The down side is that bulbs keep failing. It takes push in G9 clear 40w bulbs which are housed in frosted glass "shades" 38mm inside dia.

The questions are: Would LED equivalents be more robust/last longer? I prefer brighter light these days - can LEDs produce decent white light? Which suppliers are recommended for quality?

Thanks

Phil

Thanks Jeff

I suspect you are right about the heat issue. Although the fitting is as-supplied, the glass shades are horizontal 38mm I/dia around 50mm long. Also, being in the hall they have foot traffic regularly above. So maybe vibration also plays a part.

Phil

Hi Adam No I am aware of the need to keep skin oils or whatever off the glass.

Phil

very much so.

yes. Get the CCT you want - filament lamps are typically 2700K warm white, halogens 3000K, cool white or daylight are much colder/bluer.

NT

We've some similar fittings- 5 I think- each takes 2 x 40W G9 Quartz bulbs.

I've tried several LED bulbs which, supposedly, have the same output (lumens) and found them totally unsatisfactory. Price doesn't seem to make a difference.

Now, I've just stocked up on G9 bulbs.

Our fittings are large enough that I could strip out the holders and fit another type, which I have considered. (We like the fittings.)

G9 LEDs are rather small so tend to suffer from overheating.

I would investigate the cause of the premature bulb failure first, loose connections possibly in the lamp or the wall switch can cause filament bulbs to fail early.

Richard

Are you touching the lamps with your fingers when you fit them?

Quite. LED quoted light outputs seem to be measured with a different meter to halogen.

G9 leds are inherently not as bright a G9 halogens (yet?). They might quote a high lumen output on the pack, but IME they have often only half the brightness of a halogen, You won't get anywhere near the light output of a 40W halogen, even with a 6W led: - 630 lumens vs 330 (- 700* see below) lumens.

A couple of years ago I replaced 12 G9 halogens (42W) with supposedly brighter 4W leds. They were nowhere near as bright. And a couple have already gone south.

Running them slightly lower voltage can really help with lamp life. Either a dimmer or a series capacitor or choke to knock just 10v rms off can help. Ultimately though you've got a problem light fitting, low power mains halogens never lasted well, and close fitting shades make alternatives hard to use. Reduced light level can normally be made up from other fittings.

NT

Got a wiring diagram for that?

The choke or capacitor just goes in series with the feed to the fitting. Values need to be calculated for each total lighting wattage.

NT

The hotter the filament is, the weaker it is, so reducing voltage slightly can help resist vibration to a [to me] unknown extent.

NT

other way is a series diode.

Weren't filament bulbs in trains and buses underrun to help prolong their life? Also, I think that the term "robust" for their construction is hardly sufficient for the bulbs used in Tube trains - the movement and vibration in the carriages was quite remarkable at times.

But also reduces the temp of the quartz envelope so the halides have less effect and cause blackening of the bulb.