What watt power transformer should I be using?
You can use a power supply like the one pictured, rated for the amount of LED's you will be driving. Read the specs on the lighting. They should tell you how many watts per a given length of the strip. So if it says, for example, that needs about 1 watt per meter, then a 15-foot section would require a 5 watt power supply. Take your total length of 76 feet, and divide by the strip's requirements. It wouldn't surprise me if you ended up somewhere in the ballpark of 20 to 30 watts.
Can I run 14 gauge wire directly from a circuit 15 amp breaker to the transformer?
No. You can't put the power supply inside the wall, and you can't bring the wire out of the wall without going through a junction box. The best way to do this is to put a cord on that power supply, and plug it into an existing outlet. There is no need whatsoever to add a new circuit or connect these directly to a circuit breaker.
Can I plug in all 5 circuits of LED strips on top of each other to the output of the transformer?
Yes, you can wire multiple strings in parallel at the power supply. If the sections are short, you can also wire them end-to-end. Double-check the specs for maximum length of a single run.
Is this the recommended way of doing what I'm trying to accomplish?
The recommended way is to plug into an existing outlet. If your lighting requirements added up to 1000 watts, you'd want a new circuit. At 20, 30 or 50 watts, it is ridiculously small in household circuit requirements.
I would also like to add a on/off switch, do they make a wall switch for 12v?
Any switch can be used for 12v. I would put the switch before the power supply. Put a cord on the power supply like this cord with switch.
Can low volt wires come right out of the wall, or do they need a junction box before being connected to the LED strip lights?
The low voltage wires don't need a junction box, but they do need a junction plate, like those used for phone jacks.
There are multiple ways of looking at this, high quality 12V LEDs are hard to find and can be quite expensive... however some people are very satisfied with the 12V LEDs that are available. Transformers also waste energy but the efficiency can vary greatly. As long as you are on the grid, I would use higher voltage LEDs since they're cheaper and you'll use less energy. But if you do go off grid, you can run the 12V right off your batteries. This can be a nice advantage, especially if you use a 12V battery bank; however, most quality off grid systems use 48V as a first preference or 24V as a second choice, so you would most likely need a DC to DC converter (or power supply) in order to run 12V anyways.
I guess that is really is a matter of preference but I would go for the simplicity of easier to find, high quality, higher voltage LEDs, with no transformers wasting your energy unless it is important to be able to use it straight off a battery
Thanks,
Maxfield Solar
Best Answer
You can just remove the transformer and wire the devices direct to the 12V circuit (paying attention to polarity of course).
Current is drawn by devices, and your power supply must be able to support it. There's nothing you need to 'do' other than ensure your supply can provide the current your devices need.
Note that a 50W panel at 12V is 4.16A, so it may not charge the battery fast enough for your situation -- even if you're only using the 5.2A lights (as opposed to the full 10.4A load with the lights and pump running).
This may or may not be a problem depending on what you're doing. If your battery is rated at 100 AH (amp hours), and you're not charging it, it should in theory power the LED lights for about 19 hours (calculator). This isn't exact because battery capacity can be affected by load, charge level, and other factors.