solder

Hey everyone first time actually posting in this forum. I apologize this is a little long. Well anyway, I'm gonna get right down to it. My RX 2/3 worked just fine yesterday morning. I put it in my backpack and left for work on my motorcycle. Everything seemed fine until I realized my batteries...

Any suggestions for what type solder to use to repair soldered connections in mods? My istick tc 100w started acting up, took it apart and discovered that the soldered connections between the main pcb and switch pcb had cracked. Chinese engineering at its finest, nothing else secures the two...