20 watt PV panel $29

[Bogo]

How did you do yours and are you getting good lamp life?

Depends on the situation. Most have current regulated power supplies. Some are voltage regulated supplies with a resistor per string of LEDs. None have unregulated supplies. I haven't powered an LED with an unregulated supply in decades.

[bdosborn]

How did you do yours and are you getting good lamp life?

Depends on the situation. Most have current regulated power supplies. Some are voltage regulated supplies with a resistor per string of LEDs. None have unregulated supplies. I haven't powered an LED with an unregulated supply in decades.

Nice, have you got any pics? Sounds like you've built a few lights.

Bruce

[notned]

My bulb -- Gold Stars led

mentions low heat

8-30 volts (12 to 24 VDC and good for fluctuating power) 1.68 watts

So I got lucky, right?

[bdosborn]

So I got lucky, right?

Yup.
Bruce

[Bogo]

How did you do yours and are you getting good lamp life?

Depends on the situation. Most have current regulated power supplies. Some are voltage regulated supplies with a resistor per string of LEDs. None have unregulated supplies. I haven't powered an LED with an unregulated supply in decades.

Nice, have you got any pics? Sounds like you've built a few lights.

Most of the LED stuff I've done over the years is quite basic electronics so I never bothered to photograph it. As an example a standard linear 3 terminal regulator can be wired up to be a current limited supply. this is a standard circuit that is often shown how to be made in the data sheets for linear three terminal regulators. It's been awhile since I've used that circuit as there have been controller chips made to do the regulation using a switching power supply circuit, and thus they are more efficient. Also this opens up lighting up strings of LEDs that have a higher voltage than the supply voltage.

Low cost current limited power supplies like these: http://www.meanwell.com/search/LDD-L/default.htm from Mean Well have made it unattractive for me to bother to make my own circuits unless I'm doing something unusual. They are meant to power the high current LEDs like the Cree XLamp series that require proper heat sinking. They, and others like them, can also be used to power a few parallel strings of lower current LEDs. You just need to match up some multiple of the drive current needed for your LED choice with the output drive current of the power supply. A 300mA output power supply will power 10 strings of 30mA LEDs, or 15 strings of 20mA LEDs. People say they will evenly load balance the current among the strings, but I've always used half ohm resistors in each string to make sure of the current balancing. If you buy the power supply controller chips yourself, and make your own power supplies, you can set them up to output whatever current you want them to.

Luxdrive modules by LEDdynamics has a bunch of power supply modules of different types: http://www.luxdrive.com/products/led-drivers/ A while back their 4015 Boost module caught my attention. I figured I could use it to drive 60 Watt bulb equivalent LED lamps in an RV off of a 12V battery bank. If you wanted to use a 24V battery bank you'd need to use their A011 FlexDrive module. The 4015 is limited to 28VDC which is lower than the end charging voltage for a 24VDC lead-acid battery bank. One nice thing about LEDdynamics is their specification sheets have nice circuit diagrams.

[bdosborn]

Those are some great links to drivers, thanks for posting them. I'm adding them to my LED Stuff bookmarks. However, most people wouldn't be able to figure out the right LED to use with the driver, how about a parts list of potential LEDs and driver combinations as well as a circuiting diagram? To get the ball rolling, I used this LED Emitter and this current driver for my LEDs. Circuiting is just power to the input of the driver with the LED connected to the output of the driver.

Got more?

Thanks,
Bruce

[droid_ca]

Hey Bruce Do you have a picture of that light that you showed a few posts back all lite up just wondering how bright those little boards are that you have installed

Sorry for going off topic here

[bdosborn]

Yup.



That's a warm, 3500K color temperature with good color rendition so it looks like an incandescent source. You can contrast the color with the el cheapo, cool, 5100K LED behind the valence. It's distinctly blue and has terrible color rendition. The diffuser on the light keeps it from being a glare bomb.



You pay for the yellow, good quality light in efficiency - The warmer the color is, the more power they use. Everyone's perceives light differently; I slightly prefer LEDS in the 4100K temperature (white with just touch of cool blue to it). The 3500K is great light though so I've never tweaked it to be a little cooler.

Bruce

[Bogo]

4100k is also what I prefer and have most of my house lit with it, but from some recent articles over at Science Daily I'm limiting it's use in the evening and night. There is good research now showing that blue light influences some of the body's internal clocks and when you are exposed to it at night it messes up those clocks. I personally have noticed that I tend to stay awake if I'm using my 4100k fluorescent lamps, and in the evening I will be yawning an hour after I turn them off and only use the 3100k lights. Same lumen level in the room, just different kelvin output on the lighting. Note, all lamps are CRI index 89 or higher.

All my LED work lately has been with pre made 12V LED strips, and custom controllers. The controllers I'm working on are for use in sculptures, and not very useful for lighting. The strips would be applicable for TnTTT lighting. I don't know how much to use as I haven't built my tiny travel trailer yet. One of the 4,500k strips I have is roughly equivalent to a 60 Watt bulb when run at full brightness. What I do know is if you have the LEDs doing direct lighting you will likely want to use more than full brightness would require as the individual LEDs are bright spots, and running them as dimmed levels makes it much easier on the eyes. For powering these LED strips from a 12V lead acid battery, a low dropout voltage regulator would be used to make sure the battery voltage is limited to 12VDC.

LEDs for the modules I listed in my previous post: http://www.ledsupply.com/creemce.php Just find a power supply that matches the current needed for the LEDs. Note, the Cree XLamp LEDs I linked to are multi chip devices that operate in parallel or series depending on how the module is wired up internally. So a single warm white one uses 350mA @ 12.8V. 1, 2, or 3 of them in series could be driven by a LUXdrive FlexBlock A011 power supply module. Additionally you will need a heat sink to dissipate the heat generated. Grounded tip soldering equipment, wire, and ???. I know I'm forgetting something.

I only chose LED Supply as they came up early in a Google search. I did buy stuff from them years ago, but those products are no longer available.

[notned]

Interesting discussion. Apologies for jumping in.

Where should the controller for the panel go? I'm thinking that it should go in the cabin next to the breaker box.

I'm reluctant because I'm thinking that will use more wire, and maybe cause issues with flexibility. Since I don't know, I'm asking for input. Thanks for your time.

[droid_ca]

Bruce how big are those chips as I'm wanting to convert some bottles into lamps and can't go bigger then 1.5 inches

[bdosborn]

Where should the controller for the panel go? I'm thinking that it should go in the cabin next to the breaker box.

The Morningstar controller is potted and sealed so it can go just about anywhere. I had mine mounted on the back of the PV panel on the teardrop. The best location is as close to the battery as you can get it without putting it in the battery box itself. That way the controller gets the most accurate reading of the battery voltage. You don't need to worry much about voltage drop and wire length with one or two 20W panels; #12 wire will work fine as the voltage drop will only be 2.5% over 20 feet. Some people go ape over wire size and voltage drop but I've never had a problem at 3% VD.

Bruce

[notned]

We had some 14 left from the rebuild and I bought some 10 that wasn't quite as much as I'd hoped.

The battery box is inside a toolbox mounted on the front of the trailer. I think we'll start there.

[notned]

We're up and running!

[bdosborn]

Dude! You rock!


Bruce