More shed lighting ideas

[lonesouth]

Dewalt 18v battery + old charger + light switch + bucktoot + 4 x cree P4s. I think I can have this wired up in an hour or so.

My dad is building a shed, but is not going to run power to it. I was thinking about how to add some light and first thought of a solar setup, but the cost would be too high. I then moved to just using some rechargeable AA's and a driver I have laying around. Then I realized that he has plenty of 18v tools and extra batteries and always has one on the charger, so that became my power source.

My initial hope was to be able to use a 3xAMC7135 board in the multilux setup, but there was not an optimum setup for that, I either had 6.9 volts to the board(too much) with 3 LEDs in series with the driver, or 3.2 volts(too little) with 4 LEDs in series. So, I moved on from the AMC7135.

The Bucktoot has an input voltage up to 28 volts and will work down to 5 volts. It can drive up to 6 1w LEDs and is up to 94% efficient. So I pla to gut a Dewalt battery charger and use it as a tap for the battery. I'll run the power from the charger (gutted and modified to be just a tap) through a standard light switch and then to the Bucktoot on out to the LEDs with will be placed on top of the rafters to provide indirect light.

I'll post some pics as I go.

 

[AnAppleSnail]

One option:

Build a socket for a battery, he can bring a charged one to the shed with him as a light switch. Insert battery, lights come on. Pull it out when you leave.

However, this requires that he come from wherever the batteries sit to the shed. Maybe that would be too much a pain. I think you're on the right track with this one. V(LED) should be close to the battery voltage to help efficiency.

 

[lonesouth]

So far so good. I was able to disassemble a dewalt charger and solder the power leads to the contacts inside. I'm assuming, but will verify later, that the charger has reverse flow protection so that the charger will not drain the battery by itself. After thinking it over, I am going to step up to a buckpuck and drive the LEDs at either 700ma or 1000ma. My plan was to use aluminum bar stock as the heatsink and I'm not sure it will provide enough dissipation at 1000ma, so I may back it down to 700ma.

One thing I did not anticipate is that Dewalt uses a funky torxs screw that has a post in the center such that removal requires a hollow torxs bit. I don't have one of those, so I simply drilled them out. I will secure later with standard sheet metal screws when I'm done tinkering.

 

[LitFuse]

Good luck with your project. If you decide you'd rather go with a solar option, I have an extra one of these. Very nice setup, just put it up and forget it. I'll sell it for what I paid ($53) plus shipping.

Peter

 

[Hamilton Felix]

Let's see:
You don't want to run power to the shed.
Solar choices run to affordable crap or expensive stuff.
It's not fun to hassle with batteries.
You only need the light occasionally.

As one who collects kerosene lamps, I have a thought....

 

[lonesouth]

Little update. I've got 5 P4s glued to flat stock and soldered in series. I haven't run any long term tests, but the stock will heat up nicely in about 15 minutes, not too hot to touch, but definitely hot. Not certain what runtime will be, but he has plenty of batteries so he can just pop in the next one when the first runs down. I've ditched the light switch idea and simply use the insertion of the battery to turn on/off the LEDs. I am also planning on putting a standard automotive relay in line from the battery to the buckpuck to disconnect the circuit when the voltage dips below the threshold of the relay coil. I'm not certain how the circuit will behave below the required voltage, but the relay should provide redundant protection for the batteries.

 

[Lightdoctor]

Get a good 1W LED headlight...it puts the light where you want it; it's very versatile and it requires no wiring...problem solved.

 

[lonesouth]

Ran the lights for over an hour last night. They got too hot to hold, but did not complain. Lit up the garage plenty. I think dad will be happy with it.

 

[foxtrot824]

This sounds like a great build, let's see some photos of it.