They drain overnight with the flash powered off? That sounds like an electrical malfunction. I can leave eneloops in there for weeks/months and they have plenty of power left, same with my three 600EX-RTs.
Yes, they drain in about a day. My 380EX doesn't exhibit this flaw.
Yeah, that's what I thought--a short somewhere in the circuitry. I tend to suspect other MR-14's may have the same problem, but don't run into a lot of owners of the model. If folks here have had the same experience, please chime in as I would like to know if this is common or if my unit is abnormal.
I wish CPS would let you use an annual service check on a flash or lens.
Of course, since your flash is the MR-24 the internals could be a little different despite apparent similarities. And only green elves with polka-dots know precisely where each is assembled.
I own one but have no trouble with batteries. I can leave them in for weeks without using and they work just fine. If they drain in a day with the power off it looks like an electrical problem to me. Do the flash or the batteries feel warm? The power needs to go somewhere.