# Heat warning on 600EX-RT



## notapro (Jun 24, 2014)

Has anyone ever observed heat warnings on 600EX-RT flash units?

I had three inside a softbox, and after some 498 shots, I got a slower recycle time and noticed that the LCD panels were glowing red. That was unsettling. I replaced them with three other 600EX-RTs, and after just over 500 shots, I got more red LCDs and slower recycle times. I had the units set at 1/8 power. Fortunately, it was time to switch to natural light.

I didn't use again any of the flashes for more than a week, and everything seems fine. Might the life of the flash tubes have been shortened significantly in any way? I suspect not, but I am curious nonetheless.

On a side note, the ST-ET-R3 lasts for an extraordinarily long time between battery changes. I've replaced batteries in the flash units four or five times, while only twice in the transmitter.


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## Mt Spokane Photography (Jun 24, 2014)

I've seen people who had overheats, the light serves as a warning, the flash will shut down to protect itself eventually there should be no damage done. 500 is a lot of flashes if done over a short period. The amount of power used is a big factor. Air circulation is yet another variable, as is the air temperature.


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## notapro (Jun 24, 2014)

Thanks for your reply, Mt. Spokane. It was around two hours for each set of 500 shots, there was no air circulation in the softbox (where it would matter, yes?), and the ambient temperature was 78 F (25.5 C). I don't know whether that many shots in four hours is fast or slow, but I'm glad the flashes are working nicely and that I need not be concerned about them.


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## RLPhoto (Jun 24, 2014)

I hit an overheat warning once when shooting 50-100 frames near 1/2 and full power. It was on a key light with shoot through umbrella. I ended up putting two lights instead and solved the heating problem. I tend to work a lot slower with speedlites because of there limited power and limited battery life. Hence I shoot much less frames than I would be with strobes and only overheated my 600s once. 

However shooting 500+ frames out of a speedlite for hours straight, I could see them getting hot.


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