12 volt LED problem
Discussion
Hi all, unfortunately lengthy and there’s no obvious TLDR, so bear with me.
10 1/2 years ago I moved into my house where the previous owner had been obsessed with 12v halogen downlighters. They were absolutely everywhere.
To try to get electricity consumption under control I started replacing them with branded LEDs, I learned very quickly that you need to do the drivers as well, so these were done too.
In my bathroom I’ve got 2 circuits of Philips MR11s, 2 on one circuit, 3 on another each with its own driver.
A couple of months ago, the 3 started coming on dim then maybe 15 secs later flicking off and back on at full brightness. Recently they started flashing when switched on cold. I assumed the driver was about to let go, so bought another & fitted it today but initially it didn’t help, they still seem to be flashing. I tried swapping some of the bulbs for spare Philips MR11s that had a couple of years use on them, same issue. The bizarre thing is that if I have 2 bulbs in the 3 holders, it works fine. I’ve also tried swapping in known good bulbs from the other circuit and it has the same effect. This issue only seems to happen if I have 3 cold bulbs starting. 2 cold or 3 warm bulbs is fine. It doesn’t matter which bulbs it is out of the 6 I’ve tried.
Bulbs are 3.5w each marked as 12v AC. Old driver is 12w 12v DC constant voltage, the new one is 18w 12v DC constant voltage. I know I should probably have attempted to source a 12v AC driver, but they ran fine with a 12v DC driver for 10 years. Fittings appear to be wired in parallel and will happily operate with any bulb in the string removed. Switches are straight on/off, no dimmers and I’ve not noticed similar behaviour from any of the other MR11s or MR16s in the house (yet)
Any ideas? Searching online only turns up issues with people doing halogen to LED conversions.
Any help gratefully received!!!
10 1/2 years ago I moved into my house where the previous owner had been obsessed with 12v halogen downlighters. They were absolutely everywhere.
To try to get electricity consumption under control I started replacing them with branded LEDs, I learned very quickly that you need to do the drivers as well, so these were done too.
In my bathroom I’ve got 2 circuits of Philips MR11s, 2 on one circuit, 3 on another each with its own driver.
A couple of months ago, the 3 started coming on dim then maybe 15 secs later flicking off and back on at full brightness. Recently they started flashing when switched on cold. I assumed the driver was about to let go, so bought another & fitted it today but initially it didn’t help, they still seem to be flashing. I tried swapping some of the bulbs for spare Philips MR11s that had a couple of years use on them, same issue. The bizarre thing is that if I have 2 bulbs in the 3 holders, it works fine. I’ve also tried swapping in known good bulbs from the other circuit and it has the same effect. This issue only seems to happen if I have 3 cold bulbs starting. 2 cold or 3 warm bulbs is fine. It doesn’t matter which bulbs it is out of the 6 I’ve tried.
Bulbs are 3.5w each marked as 12v AC. Old driver is 12w 12v DC constant voltage, the new one is 18w 12v DC constant voltage. I know I should probably have attempted to source a 12v AC driver, but they ran fine with a 12v DC driver for 10 years. Fittings appear to be wired in parallel and will happily operate with any bulb in the string removed. Switches are straight on/off, no dimmers and I’ve not noticed similar behaviour from any of the other MR11s or MR16s in the house (yet)
Any ideas? Searching online only turns up issues with people doing halogen to LED conversions.
Any help gratefully received!!!
OutInTheShed said:
Are they dimmable LED bulbs?
They may only work with AC
DC LED drivers often have a minimum 'bulb' power they will work with.
All sorts of odd behaviour is possible if used out of limits.
Not that I’m aware of. The thing I don’t get is that they’ve behaved themselves for 10 years, absolutely faultless, right up to a couple of months ago.They may only work with AC
DC LED drivers often have a minimum 'bulb' power they will work with.
All sorts of odd behaviour is possible if used out of limits.
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