Canon 600EX II-RT drops link- HELP!

[Phillyphoto]

Scenarios I have tried: 

Using Canon Transmitter ST-E3-RT as the master and (2) 600 EX II-RTs as slaves.

Using A 600EX as master and B 600EX as slave.

Using B 600EX as master and A 600EX as slave. 

I get the same result of the slave dropping link. The time varies. Sometimes it drops link in 4 mins, sometimes 10mins, sometimes 20 or more minutes. The only way to relink them is by turning everything off and back on.

All channels are the same. Yes, I have scanned for the best connection as well as every other channel and AUTO.

All IDs are the same. 

Not near a wifi-router or airport, I'm in a row home in Philadelphia. 

Using NiMh rechargeables and using freshly charged batteries for every test. Batteries are about 2 years old. 

I have spoken to 2 Canon service reps and neither of them has any idea what the problem is. I really don't have the money to spend on sending everything in for "repair". 

Any help is greatly appreciated, thanks!

[JimOsdale]

Really unfortunate, trying to figure this out for everyone, while Canon continues to ask if the hot shoe is clean, and are the batteries fully charged! While I spent thousands of dollars with Canon on their high-end radio controlled flashes, I had to buy cheap Chinese transmitters/receivers to use wireless flash triggering with my Canon flashes. Using Godox hardware with Canon flashes at least they stay connected with no disconnects at all.

[7thWheel]

I am actually having the opposite happen.  At home they seem to work find and stay connected.  When I went to the Halloween Parade, Mermaid Parade, Asbury Park Zombie Walk and Easter Parade this year I had the issue of the flash disconnect.  

[tseager]

No. Still looking for a solution. Very frustrating. I have six Canon 600EX II units, and get from 3 shots to 3 minutes, before I have to reset them all, all at once.

[silverdoggg]

Try the Godox X2t Trigger and X1r receivers it works flawlessly with the 600ex rt II speedlites 

[RoxannaRouleau]

I have been having the exact same issue. I have a canon 5d mark iv, st-e3-rt, 430ex iii-RT, and a 600EX ii-RT. The exact issues you described happen with my transmitter and flashes. It also happens when I remove the transmitter and use my 600EX ii-RT on camera as a master and use the 430EX III-RT as a slave. Either way, the slave(s) always disconnect and stop linking. I have searched channels to find strongest connection. It happened while I was working 2 different weddings and also at my home when I was trying to figure out what is going on. Did anyone ever get any type of answers of assistance? 

[MMCphoto86]

Nope - it seems to be an ongoing struggle. Canon insisted nothing was wrong with my flashes even though I showed the tech a video of the links dropping. I bought all new 600 EX RT-ii units only to have them drop again this past weekend. The only thing I can determine is that it's a new wireless interference of some kind like others have suggested in this thread; I realized it now tends to happen whenever I'm indoors. I just bought the Yongnuo 600ex equivalent like @steppy suggested and might try going the transceiver/receiver route with Godox products if the Yongnuo flashes don't work. 

[RoxannaRouleau]

I would like to add that I just brought out my old yongnuo 600ex-ii rt and linked them up with my canon transmitter and flashes. Both of the canon flashes dropped the link and the yongnuo stayed linked with the transmitter. So frustrating this is happening. My canons are not that old either.

[MMCphoto86]

Agreed, super frustrating! I shoot weddings too and receptions have been extra stressful due to this issue. Is there a reason why you stopped shooting with the Yongnuo flashes?

[RoxannaRouleau]

My yongnuo could not keep up with wedding receptions. It would over heat so quickly and stop working. The batteries would be extremely hot too. So it was just unreliable. My canons can fire for the whole day and not over heat. They have been great for family formals and receptions until just recently when the link drops. After reading this thread I feel like calling canon will be pointless.

[crlyhds]

I understand maybe trying a different manufacturer. I have 4 600EXII-Rt flashes and the ST-E3-RT transmitter. That is a $2400 investment. With no guarantee that a different mfg would not have a similar problem, I need would prefer a different solution.