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Speedlite 600ex-rt battery problem


I have just bought a 600ex-rt ... But the batteries I put in it (which are all new) only result in a "replace battery" sign and the flash refuses to switch on.

I have tried 3 new sets of batteries, all are top grade lithium batteries, is there a known issue with lithium batteries - the manual says they can be used?

Many thanks for any info that could help.


Solution Summary

Steps to Resolve Speedlite 600EX-RT Low/Change Battery Issue:

  • Turn the Speedlite power switch to the Off position
  • Remove the SCH-E1 Color Filter Holder
  • Turn the Speedlite power to the On position




After recently purchasing a new Canon 600EX-RT in preparation for a family portrait session, I was eager to get the Speedlite out of the packaging and onto a stand for some test shots before packing up and heading off for a weekend with my extended family.

I grabbed a package of fresh batteries, loaded (4) AA's, secured the battery cover, attached the provided SCH-E1 Color Filter Holder and powered on the Speedlite expecting to see the default factory settings on the 600EX-RT's main LCD display.

Instead I was greeted with a blank LCD and the Low/Change Battery symbol.

I was fairly sure that the batteries that I'd selected were unused, but I usually unpack batteries from their shipping material and add them to a larger container of batteries, so it was possible that used batteries had somehow made their way into the group or that some number of the batteries were simply too old. I set aside the batteries in question and tried another group of four batteries.

I was more than a little disappointed when I was again greeted with the Low/Change Battery symbol. I was fairly certain at this point that the batteries were not the issue, but just be sure I tried a third set of batteries with the same result.

I quickly searched for an online resource that might help me troubleshoot and resolve the issue and found this Canon Support forum thread.

The problem state and the proposed resolutions seem to be inconsistent and involve variations of some or all of the following:

  • Power-cycling the device a number of times
  • Opening the battery cover, moving the power switch to either the Lock or On position and then closing the battery cover
  • Holding the Sel/Set button while powering on the device
  • Holding the Clear (Reset) buttons while powering on the device

Unfortunately, none of the proposed solutions resolved the issue for me. So I gave Canon support a call and to see if this was a known issue.

I described the behavior to the support engineer and at first he too was stumped, suggesting that perhaps this was a defective device. He offered me several options for either returning or repairing my new 600EX-RT.

I was hoping for a more immediate resolution AND based on the large number of people reporting this same behavior (here in this thread) I suspected that there might be a Canon support advisory (perhaps only available to Canon support personnel) with information describing the issue along with a resolution that did not involve returning or repairing the device.

I asked the support engineer to check and he kindly agreed. After a few minutes on hold he came back and said there was in fact a support advisory that described a similar problem, but it involved the color filter holder. As previously mentioned, I had installed the color filter holder shortly after unboxing the flash.

I was dubious at first that the filter holder would cause the Speedlite to malfunction, but hoped he was right.

Steps to Resolve Speedlite 600EX-RT Low/Change Battery Issue:

  • Turn the Speedlite power switch to the Off position
  • Remove the SCH-E1 Color Filter Holder
  • Turn the Speedlite power to the On position

I performed the steps as indicated and the Speedlite 600EX-RT powered on correctly. I  placed the filter holder back on the device and power-cycled the flash a few more times, and each time the Speedlite came back up as expected.

Upon closer inspection you see sensors near the top of the flash unit and just underneath the bottom clasp of the color filter holder, as well as what appears to be a small magnet in the bottom clasp of the filter holder. These sensors are used by the EOS system to determine when the filter holder is attached to the flash unit and assist in white balance calculations when using Canon supplied filters.

For a more detailed explanation of the color filter's form and functions alongside an EOS camera, google 'Speedlite 600EX-RT SCH-E1 review'.


For a copy of the advisory google 'Canon Issues Speedlite 600EX-RT Product Advisory'

View solution in original post


Rising Star
Any luck with fresh alkaline? I've only used Eneloop Ni-MH in my 600. Sounds like a defective speedlite.

Just been out and bought some standard alkaline AA's - same result. Brand new batteries, nothing but the replace battery symbol.

If its defective, does it go back to canon under warranty? Or return to Amazon where I bought it from for replacement?

Well, that's an oddity!!!

Put the batteries in and turned it on - nothing. Turned it on and closed battery cover while in the on position - and it's started working fine. Very odd.

Thanks for the replies.

Thank you for posting this. That fixed it for me. That is a crazy problem and I would like it fixed.

just received my new 600-EXRT... directly from canon.

and i get the same problem as you guys had.


i also though there might be some trick, but closing the battery cover while  the flash is on ON with the batteries inside doesn't work.

i get the symbol with a crossed out battery - which tells me that the unit IS getting power from somewhere, how else could it display the symbol...

I have been happily using these great sanyo eneloop rechargables forever with the 580EXII (and before that with the 430EX), they are the best rechargable batteries i believe...
but when i take them out of the 580EXII (which powers on nicely, as always) and put those same charged batteries into the 600 EX-RT the symbol with a crossed out battery appears...
what's wrong???
does the 600 EX-RT need special rechargable batteries?
should it be relevant: these are the batteries:
any additional ideas?

Makes no sense. I also use the same batteries, used them in a 580EX II and a couple of 430 EX IIs. Now I'm using them in a couple of 600s.

Not an expert on batteries but maybe there is a partial charge or battery memory issue going on. I do recondition my eneloops from time to time.

thanks for the thoughts... and i also will agree: it makes no sense...
again: i am literally taking them out of the 580 and putting those into the 600...

i also wrote canon support, so let's see if they come up with a reply. i'll share

Did canon reply back to you on your battery issue.  I am having the very same problem.  This is my second speedlite.  I returned the first one.

stupid question, independent of the 600 question: how do you recondition your eneloops?