Metal Halide/SON Ballast Bypass

[sampenfold]

I've been asked to fit some LED replacement bulbs to some existing Metal Halide fittings.

A bit of reading up has led me to believe I need to bypass the ballast in the fitting.

Has anyone ever done this? Can you offer any guidance as I'm going in blind having never taken one of these light fittings apart before.

 

[Darkwood]

When you bypass the controls it usually means put the supply straight to the lamp terminals, the LED replacement will have integral control but do confirm that first.
I tend to leave all the gear and wiring you disconnect in place, ready to reconnect if the LED doesn't perform like expected, had this on a lot of CFL lamps with integral control when fitting to SON fittings, after a year the lamps had failed so ended up rigging the gear tray back up and reverting to the SON's again.

 

[sampenfold]

Good idea, I will probably be leaving the ballast in place too, as I'm only swapping one lamp first to see how it performs.

Can you recommend any E40 cap 400W equivalent LED? Britesource 100W LED corn light looks like what I'm going to go for, unless I can find a local supplier then they seem to be online only.

 

[Darkwood]

I have limited success with LED's and reliability so cannot recommend any, in my experience the market is still weeding out a lot of cheap crap and the risks are too great - even with recognised branded stuff, so I'm staying clear for 5 yrs until the market has cleaned itself up and we have good value and reliable LEDs on the market.

 

[telectrix]

bloody 'ell DW. 5 years? i'm on borrowed time as it is. :28:

 

[Darkwood]

bloody 'ell DW. 5 years? i'm on borrowed time as it is. :28:

I had a bad run of LED floods, none lasting more than 1 yr and even the replacements failed - all the main wholesalers were buying them in from different companies but the component parts were all made in the same place in china ..so ended up replacing crap with exactly the same crap but just branded differently.

You have plenty life in yer Tel, the minute you tell yourself your old is the same time your body start agreeing

 

[telectrix]

yeah, but i tell myself i'm 32 but my body and birth certificate says i'm 69.

 

[Barry White]

Its heat that kills leds the corn lights have nowhere to fit a decent heatsink to disapate heat so I would go with purpose built led lights with decent heatsinks on them.
Not tried anything as big as that but as a comparison look at these images on google and note the heatsink sizes of most of them
https://www.google.co.uk/search?q=1...ved=0ahUKEwj70Izi_K7JAhWGaxQKHWEGDS4Q_AUIBygC

If you do go for it please keep us informed

 

[Clive P]

Hi,

I've had some 20 Watt Corn LED's running in some Coughtrie fittings for about a year and these have been good so far with no detrimental effects. These were to replace some SON lamps.
I would check the wattage required as these are a very bright light, you really want to match your original output to the new LED lamps. I believe the 20 watt are equivalent to about 2000 lumens.
Regards.

 

[Farmelectrics]

We changed possibly close to 200 to the corn type been in about 2 years had issues with about half a dozen not bad I suppose and I must say they give out a better quality of light for me