So this was for a ranch in the Texas Hill Country. They wanted a lighted sign on their rock wall but had no power out there. They asked if I could do it. I said yes even though I had never done a job like this. The words are a total of 12' wide with 64 blue 12vdc weather proof LEDs powered by a remote solar station I built from parts ordered online. I think It turned out great and the customer loved it. The photos don't do it any justice, this thing is bright. So bright it even lights up the entire entry way. I ran a timer and photocell in series, basically, the timer closes at 4:30 pm but the lights don't come on till the photocell makes, then at 12 am the timer opens killing the circuit. We didn't need the lights running all night so using the timer and photocell in series was the way to go. I believe it is running 3.5 amps. I have 100amp/h in batteries, I calculated I have enough power to run the lights if it was cloudy for four days straight. I've drawn up a schematic for how I wired it as well.
I like blue the sign rocks too Did you put any vent holes in it? Not sure how hot it is that way but you need vent the hydrogen gas the battery produces.