Optimate Query

Just wired up my Optimate to my Speedmaster and noticed that the fuse glows and flashes when it is charging. Is this normal?? Never noticed it on any of other bikes.

 

That’s the one. Straight from the battery to the Optimate.

 

Just been back to check again and changed the fuse. They are the mini blade fuses which I have not seen in an Optimate before so I changed the fuse to a 25amp and it was fine. Decided 25amp was probably a bit too big so put a 5amp in and that is now fine. It’s charging and not glowing so it must have been a dodgy fuse? I have never seen a fuse glow and flash before. Strange. All seems ok now so hopefully it’s sorted. Thanks for input.