I bought my 2900 maha PowerEx batteries and charger maybe 6 months ago, and initially LOVED them. The 2900 power allowed me to go so much longer without changing, esp. when I had them in the flash and in the battery pack. After I started using off camera flash, I could have my flashes on 1/32 all night and never have to change them once.

But over the last couple months, Ive noticed some weird, unpredictable behavior from the batteries. They would be working fine...then all of a sudden the flash would stop flashing. The ready light would still come on, indicating there was enough juice left, and yet even if I tried changing to another a fully charged set I would still get the same result--NO FLASH. But when I put regular disposables in on a whim they worked fine.

At first I thought it might be the flash, and had sent my flashes in twice to be checked--but Friday when it happened AGAIN after I had just gotten my flash back from CPS in perfect health I started realizing it might not be the flash. So after trying the same batteries in 2 different flashes (both the used set and a newly charged set), trying to get them to work any way I could, I again switched the rechargeables out and put disposables in their place--and they worked fine again! Which proves the problem is the rechargeables.

The real problem is that this phenomenon comes and goes, and I have no way to predict it. It might be that was one day, and then after a day or two of rest I test the flashes out again with the powerex batteries and they work fine, and stay that way for weeks until they mess up again.

Even when it is happening, it is very puzzling that the batteries allow the flash to turn on and even the ready light to come on, but not to flash (either via the test button or the shutter button).

Any ideas?

NiMH batteries discharge on the shelf between charging. They work great under a load but need to be charged as close to when they will be used as possible. I normally charge batteries no more than 2 days before an event and never have problems.

If your batteries are not taking a full charge it is probably time to refresh them. You will need a charger with a refresh or conditioning mode. This takes some time but it will prolong the usable life of your batteries.

sorry...was it not clear that I was talking about fully, freshly recharged batteries here? I never wait more than 1-2 days between charge and use.


Any other ideas?

Dirty contacts is the next thing I would suspect. Try cleaning them with a pencil eraser.

thanks! I'll try that. Also got the maha people to advise me to use the dump/slow charge mode on my charger a few times on the batteries.

well, yet another reason i dont use rechargeable AAs.... they're weak and a pain in the butt to use. i pop 4 alkaline AAs in my flash before a shoot and connect my quantum 2x2 to the flash, which provides more than enough charge to shoot an entire wedding without changing batteries, and the recycle time is nearly instantaneous.

just my .02....

check out the quantum pack here: http://www.bhphotovideo.com/c/product/2688...MH_Battery.html