600 EX-RT smells like burning when fires

[curtisround]

One of my 600EX-RTs started to smell like burning rubber when firing! First, the recycle time increased, after which we switched batterries. That made no difference and after a couple more hard-to-get fires, it started to smell (just at the very top). There was no indication that it was over-heated. Tested it a few days later: still firing but still smells. Otherwise, everything else appears normal. 

Any idea what this indicates? Fixable?

Thanks

[TCampbell]

What type of batteries are you using and after you smell the strange odor, have you ejected the batteries to see if they are hot?

[jrhoffman75]

There is a Canon bulletin relative the use of lithium batteries in Speedlites. Canon says DO NOT use them.

[RobertTheFat]

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@jrhoffman75 wrote:
There is a Canon bulletin relative the use of lithium batteries in Speedlites. Canon says DO NOT use them.

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I've used a lithium battery pack (the kind that clips on your belt and powers two lights at a time) for a couple of years with no problems whatsoever.

[jrhoffman75]

http://usa.canon.com/cusa/support/consumer?pageKeyCode=prdAdvDetail&docId=0901e02480dd684d

[TCampbell]

I use NiMH batteries (Eneloops) with no problem.  But part of the Canon warning has to do with how often you fire the flash.  If you're shooting fast and frequent, batteries can heat up.  

I picked up a Canon CP-E4 pack which holds 8 batteries to power the 600EX-RT.  You can configure the flash so tha tthe 4 AA batteries inside the flash only run the electronics but not the flash-tube (the external pack runs the flash tube) or you can configure it so that all 12 batteries (the 8 in the CP-E4 plus the 4 inside the 600EX-RT) all work together to power the flash.  But the combo speeds up the recycle time and reduces the load on any individual battery cell because there are so many more batteries to run the flash.

[digital]

I use NiMH as well. I bought some at my local photo store. Ansmann. Great batteries but if I were purchasing again I'd probably go with eneloops. Not that there is anything wrong with Ansmann.

The photo store told me that using alkaline batteries like Duracell are not great. Not that they would cause a burning issue I don't think but they are actually underpowered especially when burst shooting. I used to use them on my 580 ex flashes before I switched to rechargeables and I don't recall a smell..

[curtisround]

Thanks guys! We haven't used that flash since but the other wedding another flash started taking a really long time recycling and then the screen went red so I shut it off and checked the batteries and they were hot. I switched batteries and it worked just fine after. We use rechargeable Duracell NiMH's. We just tried the old flash that was smelling and it still flashes but smells pretty bad with every flash.