My wife purchased a set of six (6) LED "puck" lights (pictured above). They are the kind you can stick anywhere for some extra light. This set is even comes with a remote control to turn them on, off, dim, brighten and set a time delay for off. The remote control uses infrared so getting all six lights to respond at the same time can be a trick. We have five (5) in fairly close proximity under a set of kitchen cabinets and controlling all of them at once works out pretty well, just stand back a little so all the lights receive the iR signals. Individual lights in separate locations are not a problem to control. And, if you don't have the remote with you each light can be manually operated (on/off) by pressing the dome on the top. Hmm, sounds like a commercial for them so far, keep reading!
However, and this is a big HOWEVER, there is a problem with these puck lights. They eat AAA batteries for breakfast, lunch and dinner! After putting in 18 new AAA batteries (3 for each light) twice in two weeks I said that's enough of that crap, no more batteries for you!
Apparently there are thousands of these particular remote controlled puck light sets out there. They are being sold across the country at (can I say Costco here?). And I do not believe that the battery issue is an isolated one. As I was writing up this Instructable a friend happened to stop over and was very interested in what I was up to. He was interested because his wife bought the same set of lights and they also eat batteries like crazy. In fact they have stopped using theirs because of the battery issue.
This concludes this news flash, had this been an actual emergency you would have been instructed to ...
So anyway, it's time to hardwire these babies. I opened one up for a look see - the only really important points I guess are that the batteries are wired in series, so the lights are using 4.5v. And I also found not one, but two infrared receivers - one on either side of the puck light. That starts to explain the hunger for batteries as those have to always be listening for a signal. Though I can't imagine the power required would be that great for the IR receivers but maybe they went super cheap and those little suckers are using a lot more than we'd think.
Update: I looked at the spec sheet for a similar infrared receiver - HS0038A2 (no part number is present on the iR receivers in these lights). The power consumption for that receiver is listed as 50 mW. All of my calculators are telling me that a 50 mW draw on 5 V is equal to 0.01 Amps. Which shouldn't be an issue - right?
Hardwiring them was very simple, so if you find yourself in the same position keep reading. But, if it's not worth it to you and you're just going to throw them out, my mailing address is PO Box...
Items You Will Need:
one (1) USB wall charger
one (1) USB cable
small gauge wire (length depends on you and where you want the lights
one (1) 50 gallon garbage can (for all the dead batteries you've accumulated so far)
soldering gun and solder (Side Note: If you solder a lot, look into a "soldering station", it will make your life so much easier. The link is to the one I use and I've had it for 3 - 4 years with zero issues.)
Step 1: USB Chargers, What Else Are They Good For?
In the pic above all of the puck lights are on at 100% (two are missing their tops - no peaking boys). I'd like you to guess what's powering them. Oh come on, try and guess! Fine, I'll tell you - even if the title for this step should have clued you in. :-))
They are all being powered from one (1) USB wall charger.
These puck lights use three (3) AAA batteries each (in series) for a total of 4.5v. The USB wall charger puts out 5v. Those AAA batteries have the potential to supply 1000 mAh (not for very long). However, in normal use they'd typically be providing around 10 mAh. The USB wall charger is rated at 1 amp (1000 mA) which in this case is plenty.
We have the lights, we have a USB wall charger, and we have 36 dead AAA batteries; so where to next?
What do you say we figure out which wires to run where?
Next step please ...
Step 2: Where Oh Where Do My Little Wires Go, Where Oh....
All we have to do is determine the beginning (positive) contact and the ending (negative) contact in the battery compartment and hardwire to those points. If you have the same puck light set from Costco, remove the batteries from one light and look at the battery compartment. Turn the light so that the name "Capstone Industries" is at the top. Your positive contact is in the upper left corner and your negative contact is in the lower right corner. Even easier, look at the first pic above - those are your + and - contacts.
Step 3: Kiss Those Batteries Goodbye
The first pic above shows you how I wired my puck lights. Oh, I did daisy chain them (the wires from the first light continue on to the second light and those wires continue on to the 3rd and so on) without any noticeable loss of power at the end of the chain.
So, in a nut shell;
1. Positive wire out from USB charger to Positive battery connecter in 1st puck light
2. Negative wire out from USB charger to Negative battery connector in 1st puck light
That's it, your done. That light will work now. If you want the other five lights to work as well just connect the positive and negative from the 1st puck light, to the 2nd puck light and so on.
I did use my rotozip tool to put a slot on each side of the puck light for the new wires. Gets them out of the way so you can put the lights back into their bases. I also zip tied the incoming and outgoing wires together for a little strain relief.
I've included a quick wiring diagram as well, it has two wiring options for you. Mine are daisy chained as shown in the upper wiring example.
And finally, the last picture shows my puck lights back in place. See the wall outlet, see the USB charger in that outlet, follow the wire.
Thanks for reading and I hope you find it helpful. As always, please do not be shy about pointing out any errors or omissions in this Instructable. I'd much rather fix 'em then let it mess somebody up.