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Dimmable LED's

I recently changed all 16 of my old 1990's 'festoon bulbs' in our boat for 'Lumo LED 9 Touchlife' lamps . The results are fantastic apart from 1, the last one I fitted, which is nearest to the battery bank. This bulb appears to have a mind of its own and is out of control. I have replaced it thinking it must have been a rogue and even turned the cable connections around, all to no avail.
Any ideas?

Asked by: Chris Marriott  | 5.17pm, Monday 17 April


WW says:

These LED units should work on a wide range of voltages (from 10 to 15V) so I would doubt that it is the supply; turning the cable connections round is not usually a good idea as most LED systems don't deal with reverse polarity (diodes only work with current in one direction) although there would usually be a diode to prevent damage.
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Have you checked as to which circuit this bulb is attached? If it links to other circuits, such as water pumps, then the stop-start current loading and voltage changes could trigger the system to change the switching settings. Tracing the cabling may be a good idea- sometimes builders wire in circuits in the oddest ways!
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It might be worth checking the voltage of your system at the point of the lamp- with the engine running and/or any battery charger turned on- it may be indicative of a fault here (anything over 14.8V should be considered risky and worthy of further investigation). A multimeter used on the voltage setting is very useful to be able to probe this.
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Let us know how you get on...!

Mark Langley  | 11.36AM, Thursday 20 April

It could be a bad connection in the wiring between the fuse box and the light. Check all the connections on that circuit and you will probably find one that is loose. Try and trace the wiring especially the earth return wiring and check the condition of the cables and joints.

Rupert Smedley  | 9.28AM, Monday 24 April

By 'mind of its own', does that mean the light is going on or off of its own accord, flashing, or what?

Andrew Denny  | 9.57AM, Thursday 27 April

This might sound daft, but ensure that the touch-panel is very clean, as it could be that the switch (which is a conductive-resistive sensor) may be false-reading... Otherwise if the power supply is stable (and reads constant at the terminals of the LED lamp on a multimeter) then it may be a faulty unit.

Mark Langley  | 10.46PM, Thursday 27 April


Readers say:

Thanks for the answers. The tiny blue light in the middle remains on all the time, whilst the bulb either slowly lights up then dims or it just flashes full on/off. I have 2 solar panels the voltage controller rarely drops below 14v. Thanks

Chris Marriott  | 6.53PM, Thursday 27 April

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