# >10 Amp LED dimmer?



## Ichthyologist (18 Aug 2013)

I have finished building a 1000mm light bar with 10 x 10w LEDs. I cannot find a PWM dimmer rated over 8A. I tried one and it runs too hot to touch. Any ideas? Split the circuit And use 2 dimmers? I was also looking at PWM speed controllers for low voltage DC motors - anyone have any experience of them?


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## jy_oc_hx (19 Aug 2013)

My first choice would be to split the circuits and run 2 or more dimmers.  Possibly even be tempted to go with 4 separate ones to keep the temperature low.  Obviously depends on the cost of the modules and amount of work involved.  I don't think the ones for low voltage DC motors would be high enough frequency or if they were i should imagine they are expensive,  but I'm no expert on them.  I'll have a look about or if you could send some info on the LEDs you have used and the PWM controllers you've been looking at.  
Could even go so far as to build your own.  I think we built some on our HNC course for electrical and electronic engineering.  Again I'll have a look about in my notes and see if i can find the calculations and schematics.


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## Ichthyologist (19 Aug 2013)

I have ordered a 10 amp speed controller meant for controlling robotics, it runs at 16kHz. If this works I will report back. It is 12 GBP on e-bay.
I have also seen master / salve PWM units that might be an option but that start to push the project budget.


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## jy_oc_hx (20 Aug 2013)

16kHz will be more than adequate.  Around 170Hz is the limit where your eyes will notice the on/off of the lights.  £12 is cheap enough to avoid building your own. If you were to build your own it is only a very simple astable 555 oscilating circuit that can use transistor pairs to switch the larger lighting load.  But the transistors that switch the load may be the difficult part of the circuit, because when you start switching loads at high frequency that is where the problems with cheap circuits will show them selves.  My advice would be to start at a low (relatively speaking) frequency and work your way up.  Just keep an eye on the temperature of the unit.  It may need a bigger heatsink than what it comes with.  It also may not be rated for long duration loads.  But half of the fun of do it yourself projects is the learning and fiddling.  Looking forward to hearing how this works out and I'll keep my fingers crossed for you.


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## Ichthyologist (21 Aug 2013)

It works, and I have not burnt down the shed testing it. Link to the controller will follow.


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## Ichthyologist (21 Aug 2013)

I Can't get a link from the mobile eBay app, search:

12V - 40V PWM - Motor Speed Controller - 10 Amp - Suit: ARDUINO - RASPBERRY Pi


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