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Energenie Mihome switches require dimmable bulbs

Discussion in 'Home Automation' started by PaulTheOnlyOne, 10 Jan 2021.

  1. PaulTheOnlyOne

    PaulTheOnlyOne

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    I bought some Mihome switches (not dimmer switches) to be able to automate my external lights which are fitted with non dimmable LED's. I fitted the first switch only for the lights not to work. I don't really want to have to change all the LED lamps to dimmable at added expense.

    Does anyone know the difference between dimmable and non-dimmable LED's that could be the cause of the switches not working? I am surmising that the Mihome switch needs a very low current to flow through the LED when off to provide power to the switch and maybe dimmable LED's have a lower resistance when off than non-dimmable? If this is true then I should be able to fit a resistor in parallel with the lamp circuit.
     
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  3. Why Not Indeed

    Why Not Indeed

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    Or put a dimmable bulb in parallel with a non-dimmable and see what happens.
    It does mention this requirement in the amazon listing and reviews, FWIW.
     
  4. ericmark

    ericmark

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    The Energenie switch says minimum bulb size 5 watt, and I have had problems using bulbs under that size even when multi bulbs are used, I had to add a load capacitor to stop the lights flashing when off, and still the lights shimmered when on. This was mainly with G9 bulbs I had the problem, and my wife cured the G9 by getting 5 rather large G9 bulbs from the internet.

    The GU10 bulbs also shimmer from time to time, but in the main OK.

    My living room has 8 x 6 watt LED candle bulbs non dimmable and these worked OK, and dinning room 5 x 6 watt and again worked OK, however it seems the switches had a problem when using 5 of them, random switching on/off, so removed 2 switches, with 3 switches they work A1 now.

    I also used Nest Mini which means not sure what caused the malfunction, could have been the Nest Mini.

    If the bulb is removed it auto turns off, also power cut auto turns off. I had a plug in ceiling rose in dinning room which it seems had a poor connection, this would result in lights switching off. I use a socket for my outside lights I have quite a few devices now Over_all_report.jpg the list is not actually up to date, but non dimmable bulbs do work, but may flash when turned off, or shimmer when turned on.
     
  5. PaulTheOnlyOne

    PaulTheOnlyOne

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    I have the answer now. Connect a 47k 2W axial lead metal film resistor across any one of the light bulbs. This provides enough leakage current to enable the Energenie mihome switch to work. I have tested this with 2 different non-dimmable LED's and a CFL lamp and they all work.
     
  6. ericmark

    ericmark

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    The standard method is a capacitor but sure resistor will work.
     
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  8. PaulTheOnlyOne

    PaulTheOnlyOne

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    To use a capacitor you need one capable of carrying the current of 0.5mA. The question is which capacitor?; which you have not told us. I have seen capacitors used as so called lossless voltage droppers in the past and were very unreliable. As we don't know the circuitry inside the mihome switch I prefer the resistor solution (plus it is extremely cheap). Also capacitive calculations are much more complex to choose the right one.
     
  9. ericmark

    ericmark

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    I gave the link to details load-capacitor.jpg I simply went in to local electrical supplier (CEF) and asked for a load capacitor for lights and fitted it. I think they are around 4 uf but not sure, they are made for the job, as simple as that. It may actually have a resistor as well as capacitor as far as I know did not test it.

    I see no point in re-inventing the wheel, some one far more clued up to me has decided this is the method to get around the problem, and has marketed the device, the problem was the room to fit it, mine came with insulated leads all ready to fit.

    I also had shimmer when switched on, and swapped the bulbs used, original G9-small.jpg bulb was nearly same size as the quartz is replaced, and not the room inside to have any capacitors built in, the replacement G9-big.jpg far larger and when one failed I opened it, and there was an electrolytic capacitor after the full wave rectifier to smooth the supply, with a ceramic capacitor before the full wave rectifier to limit current, the latter had not been soldered on one side, so spot of solder and it worked again. Wife bought the lamps, and all it says is G9-69SMD AC 220-240V no lumin or wattage marked, but think around 6 watt, as size of a E14 candle so the covers no longer fit over the lamps.

    I have a feeling I could remove the load capacitor now, but have no intention of trying, they work so leaving it alone. Did not want wife to buy a chandelier using G9 bulbs in the first place, seems whole house we have 6 x G9 bulbs working, and now 18 spares, of which 9 are LED.

    Having a cupboard with light bulbs in when we used tungsten was fair enough I would change a bulb every other week, but with LED had one replacement LED tube for a fluorescent lamp fail, lasted less time to fluorescent, and one bulb which I have fixed as said, and been 8 years since I started using them, OK there is one carbon filament bulb that has lasted over 100 years, but the CFL was to my mind a failure, seemed odd as the fluorescent tube worked well.

    But my gripe is lack of info on bulbs, that large bulb was clearly well designed, but the small one was not, but as buyer no way to tell which is which, and the large bulb did have a assembly flaw.
     
  10. bernardgreen

    bernardgreen

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    I would hope it does have a resistor in series with the capacitor.

    Two reasons why it should.

    [1] In the event that the capacitor fails and becomes a short circuit between ( switched ) Live and Neutral then the resistor will act as a fusible link and disconnect the failed capacitor.

    [2] Without a series resistor closing the switch will put the supply voltage directly onto a large capacitance which would create a high inrush current as the switch contacts ( or solid state device ) are closing ( before they are fully closed ). This could lead to early failure of the switching contacts ( solid state device ).
     
  11. PaulTheOnlyOne

    PaulTheOnlyOne

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    I see the issue now. I raised this thread to solve the problem of Energenie Mihome switches not working with non-dimmable LED's and I gave the solution of a 47K 2W metal film resistor across the bulbs. Ericmark you have confused this with the perennial problem of dimming LED's for which I am sure your solution will work in some cases. Dimming LED's seems to be a very hit and miss affair. Personally I stick to Varilight dimmers but still have to mess around on occasion.
     
  12. ericmark

    ericmark

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    Maybe I have mislead. To dim a LED bulb the current limiting device has to be non correcting for voltage drop, often a capacitor or resistor, many LED lights use pulse width modulated control which would auto correct any volt drop. Although the switch mode volt droppers used with tungsten lamps were designed to interpreted the wave form chopping as a command to reduce average voltage, so it can be done, but not common.

    There is no reason why the electronic switch can't work with LED lamps using pulse width modulation control, if it will not cause it to flash, but one simply does not know which will work and which will not.

    I got 14 candle 6 watt E14 bulbs for two rooms, which said not suitable for dimming but worked fine with the Energenie electronic switches, they are after all not being dimmed, and they worked OK.
     
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