Battery Life in the 580EX

I recently bought the 580EX flashgun and I have found that if it is left with batteries inserted and the compartment lid closed with the unit switched off, they discharge within 4 days or so. I have never experienced this before with any other make of flashgun. Has anyone experienced this?

I did! I had brand new batteries in there, took about 4 pics with flash to test out, a week later, they are automatically discharged!!

had mine a little over a month and haven't changed the batteries yet

You might want to consider the exact type of batteries you use. There is a huge difference in the self-discharge rates among types such as primary lithium, alkaline, NiMH, and NiCd. Further, some batteries were made with poor quality control, and they quickly become "leaky". There has been a recent push in perfecting NiMH AA-size batteries, with big increases in battery capacity. However, even if you get premium batteries like that, you still have to charge them in a good charger to get good results. If you overcharge a good battery a couple of times, then it becomes "leaky".

---Bob Gross---

I used brand new Energizer, but in the other hand, I thought I might had forgot to turn the switch off maybe? until I read this thread, I know I am not the only one who had the problem.

OK. Energizer brand. What type of battery?

---Bob Gross---

I use Duracell Alkalines in my 580EX, always leave the batteries in and rarely remember to shut the power switch off. I've had it about 3 months and am on my 2nd set of batteries, maybe 200 flashes total.

I use UniRoss 2000mAh Ni-mh batteries, two sets one in and one standby. I used the same batteries in a Sigma EF-500DG Super without any problems of self drain. They have been in there for 3 or 4 weeks without a problem. Use them in the Speedlight and they are fully drained within a week, even when not using the gun.
Page 10 of the instruction manual has a footnote about the Speedlight's settings being retained in memory even with it switched off. Could it be that this feature is the culprit?

There is a particular type of power fault that can occur in just about any electronic product that has a fiberglas circuit board with the main power switch mounted on it. A very fine web of copper salt crystals will "grow around" the switch, and the net result is that there is a low power drain even with the switch Off. This isn't good, and it isn't common, and it is easily repairable (Dremel tool or X-Acto knife), but it causes lots of users to pull out their hair.

The root cause of the crystals is generally insufficient cleaning of the circuit board during manufacture, sometimes caused by use of impure water. Then the crystals continue to grow whenever the power is available in batteries. If you can't get to the repair, then the only work-around is to remove the batteries when not used. That's a pain.

---Bob Gross---