# 600EX-RT - invalid dead battery indication & fix



## Jim Saunders (Aug 11, 2014)

One of my lights came up the other day with a dead battery indication; I thought nothing of it because it had been in a bag in my car unattended for a week or so. The indication persisted after charging the batteries, and after replacing them with known-good ones.

What worked as a fix was to connect an external battery pack and turn the flash on; after that it turns on normally without the external battery. I don't know what causes this, but that has been the fix. I'll report back if it happens again.

Jim


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## Skirball (Aug 12, 2014)

There's been various reports of issues with the battery indicator when using NiMh rechargeables. Something that Canon is aware of, but they simply put a statement in the instructions to only use alkaline, and added some B.S. about the battery geometry not being compatible. I haven't really followed the issue closely since I don't have 600ex-RTs, but I'd guess the issue is sporadic at best since I'm sure there are thousands of 600s out there using rechargeables. Glad you found a workaround.


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## Mt Spokane Photography (Aug 12, 2014)

Battery geometry can be a big issue. That little nub on the positive end varies in length from AA type to type. Some electronica will accept them all, but some have a barrier that stops the short nubs from making contact. I had this issue with electronics I import, some batteries would not make contact.

However, that obviously is not Jims issue.


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## Skirball (Aug 12, 2014)

Mt Spokane Photography said:


> Battery geometry can be a big issue. That little nub on the positive end varies in length from AA type to type. Some electronica will accept them all, but some have a barrier that stops the short nubs from making contact. I had this issue with electronics I import, some batteries would not make contact.
> 
> However, that obviously is not Jims issue.



Battery geometry shouldn't be a big issue. It's not exactly rocket science to design a battery holder that can firmly make contact with a battery given some tolerance. I just don't see it as a complicated design requirement, and certainly not for a $600 piece of equipment. As to applicability to Jim's issue, I agree, this shouldn't be the cause of it, but it is what's stated in the instructions for the 600ex. And every time I've heard of similar complaints with the 600ex someone puts alkalines in and the problem goes away. So either Canon poorly designed the battery contacts, or they put some fluff in the labeling instead of design a battery indicator that can handle various rechargeables.


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