I'm not familiar with the Excaliber brand however most packs pull between 6 and maybe 10 amps when running in my experience. There is likely info out there on their web site if you need better than a guess. I don't believe adding strobes to a pack that has available outputs increases its draw much but I might be wrong. An easy rule of thumb is look at the pack's on board fuse, if it's a 10 amp, draw likely is below 6. If it's 15 amp then probably closer to ten?