SPEEDLITE 580EX "behaving erratically"

[JLH1947]

My flash is behaving erratically and the red light won't go green, even with fresh batteries. HELP!

[deebatman316]

The speedlite is working correctly. The red light means it's fully charged. When the light is green it's partially recharged. All of Canon's speedlites work this way.

[deebatman316]

How is acting erratically please explain. Also is this the original 580EX or the 580EX II. 

[JLH1947]

I was helping a friend shoot a wedding using a borrowed EOS R5 and using lithium AAs. I noticed the flash unit getting hot to the touch so I swapped out the batteries with some alkalines. After that, the flash would occasionally overexpose the subject and sometimes flash on its own. This original 580EX has been a workhorse. Is it time to put it out to pasture or worth repairing?

[deebatman316]

Are you sure it was fully slid into the hot shoe. I've seen this before when the flash wasn't in the hot shoe all of the way. Make sure you turn the flash on first then the camera.

[deebatman316]

Did the speedlite say E-TTL or TTL on the screen when it was overexposing. A speedlite set to TTL will always overexpose on a digital camera. When a speedlite falls back to TTL this usually means the speedlite is NOT communicating with the camera correctly.

[p4pictures]

Just to add that the lithium AA batteries can get really hot when used heavily, high power flashes in short succession, and I have seen them melt plastic when used extremely hard. It’s possible the batteries have overheated your flash causing damage to the electronics.