Hello. I've been having a lot of fun with my DIY LL project. I have no prior experience but Volt makes it so easy! I use a 600W transformer, 14 gauge wire and about 40 LED lights (ranging from 2-7W each). From the transformer in the side yard there is a run that goes directly to the backyard. There are about 15 Volt well lights all daisy chained together. Looks beautiful! There is another run from the transformer in the opposite direction to the front yard. Here there are path lights (2W) and 3-5W spot lights including a hub with 7 tree lights. I spliced a "T" into the front yard wire so that I could put 5 fixtures along a side fence. It looks great. However, now I'm getting greedy and would like to cap my project by adding 4 mini all-star spotlights (MR11 3W) along the low roof so I can illuminate the second story. This means I need to splice a second "T" line into the front yard wire which will ascend a drain and run along the gutter where the 4 spotlights are. The T line will terminate at the end of the gutter. Do I need to be concerned that I am adding a second T line coming off the main line? So far everything has worked beautifully and I do not perceive any voltage drop or other issues.
Typically, as a general recommendation we recommend around 10 fixtures or 80W per run off a transformer. But, working with LED is quite flexible given the low wattages and wide input voltage ranges, so there is definitely wiggle room to this guideline. It sounds like you have at least 12 fixtures on the front line already (potentially more including the path lights?). For adding the lights on the second story, running a new main line to the transformer would be the safest bet. But, if it is ultimately far more convenient to splice into the nearby main front yard line, a volt meter would be the most handy way of determining if the mini spotlights on the gutter run are receiving adequate voltage for max lumens. Ultimately, with the 600W transformer, you could bump the power tap up to 15V from the 12V if needed as well.
