One Flash Running Hotter?

Hello,

I have 2 flashes (Both Yongnuo 565EX II) and I noticed that the batteries in one are way hotter than the other. I first noticed when I used some non rechargeable Duracells because those were extremely hot to the touch, so recently I tried it with my new Eneloop Pros, but they are still significantly hotter than my other flash. I use both at 1/4 power and the slave flash is the one that runs hot. Is there any explanation? The slave flash is newer than the master.

Thank you,

David

Hi, Check all 8 battery contacts are clean. Also, a long-shot, but check that one unit, the hot one, has not accidentally been left on HSS. Some units can deliver the pulsing even when under normal trigger timing.
Do you have a charger that 'health checks' the cells?

Thanks for the reply! I'll take a look, but I think that my Maha charger does have that capability and I don't think my Yongnuo's have HSS.