I’ve been meaning to write about a set of interesting new rechargeable AA batteries I came across for a while now. Last year (wow, has it really been that long?) I came across a review on engadget of some PowerGenix NiZn (Nickel Zinc) rechargeable batteries which promised better performance, higher voltage than NiMH, and greater capacity. I was compelled to invest in some otherwise experimental and new rechargeables for a few reasons:

Doing indoor photography with my girlfriend – especially weddings – it becomes apparent just how many AAs you can go through quickly. So many that it’s relatively expensive and prohibitive to keep up and carry all those batteries around. They’re expensive, and just don’t last long enough. One or two hundred shots or so, if I recall correctly.

SB600 Flash

Anyhow, right after getting them and charging them, I decided to shoot a wedding with my SB600 flash and the NiZn batteries. I was immediately floored at how fast the flash recharged and how performance never seemed to fade like alkalines do. Usually, flash performance seems to fall off exponentially with the generic alkaline batteries – eventually the time it takes to recharge gets so long you can’t take photos of anything. So what’s useful about the NiZn was the hugely fast, super quick recharge time.

That’s also… the problem. While shooting that wedding, I managed to somehow completely blow out the flash. This thing was under 2 months old, used at a few other weddings, without what I’d consider very many activations at all. The SB600 apparently has no thermal cutoff at all, allowing the whole thing to overheat. Whatever the case, while shotgunning some photos of the dance floor in low light, it stopped working. The flash didn’t feel notably hot, but the flash showed an error on the screen and wouldn’t work from then on. Anyhow, I shipped the flash back into Nikon and had a replacement about a month later, but the point is that I’m now far too scared to repeat the “experiment” again.

It seems that two things are possible:

  • The SB600 lacks adequate/any thermal protection preventing the flash from overheating or being fired too quickly
  • The SB600 possibly relies on alkaline AA battery performance to prevent the flash from being overheated
    • I realize that the NiZn PowerGenix batteries are 1.6 volts (as opposed to the 1.5 standard for alkaline, and 1.2 for NiMH). At the same time, there should definitely be regulation of some kind preventing failure.

The batteries themselves are remarkable in their performance, but it’s that which scares me out of using them in the flash where they’re needed most.

NiZn PowerGenix AA Batteries

What brings this all up is that engadget compared the PowerGenix batteries to some of the other new (and exotic) choices from Energizer and Sanyo Eneloop, and I left a comment.

I purchased the NiZn batteries after your initial review and was super stoked when they came. I’m an avid digital photographer, and replacing flash batteries at a wedding actually gets expensive enough to make buying a bunch of rechargables worthwhile.

That said, I had a brand new SB600 (just like yours) burn out with no warning while shooting with the NiZn batteries. I had to ship the whole thing in and get it replaced. I browsed the Fred Miranda forums some time later and found a bunch of people with the same issue – the SB600 relies on Alkaline batteries simply not being able to drive enough power quick enough when shotgunning that flash to avoid burning out. There isn’t any thermal safeguard.

So be warned, even though you’re testing on an SB600, if you actually do go out and abuse the batteries like you would at a big event firing the flash a lot, you WILL nuke your stuff. I’m too scared to use my NiZn batteries now.

That Fred Miranda forum thread I mentioned is here.