I recently discovered that there are batteries (for my flash for example) that are not empty when you need them! Yes yes ! Here is an article for the ignorant like me a little time before…

The real pain of batteries

For a long time, I’ve been using rechargeable batteries to replace conventional batteries, mainly for flashes, and also for a cassette recorder (that was a long time ago, I tell you). And I have always been confronted with the problem of unloaded batteries just when it is needed. Murphy's Law will you tell me? No! Law of self-discharge. The classic NiCd (Nickel-Cadmium) and NiMH (Nickel-Metallic Hydride) batteries, if they have a large enough capacity in a restricted volume, have a big defect: they do not retain their charge. You are careful: you load them carefully in anticipation of their next use. If it’s a month later, it’s too late! They are already half empty!

I do not (finally, yes, I do) even speak of their other defect: the memory phenomenon. If you recharge a battery not completely discharged, it’s as if its capacity is amputated from the remaining charge. So, inevitably, the battery loses its capacity.

Knowing this, I had bought a quick charger that proposed a discharge / charge cycle, supposed to remove or at least mitigate this memory effect. Oh yes it was fast: after an hour, the batteries were charged, and burning, or dead! Besides, gently, the charger warned me: defective battery! So I bought relatively expensive batteries for a lifetime that was barely superior to normal batteries, and I had spent my time recharging them almost without being able to use them. Find the mistake.

I discover the low self-discharge batteries

I fell a little by chance on Olivier Huet’s blog who speaks, among other things, of this topic. Two articles have caught my attention: the one called Choosing rechargeable NiMh LSD batteries, where LSD has nothing to do with Lucy in the Sky with Diamonds nor with a certain acid; and this other one: An intelligent charger changes everything.

To conclude: we now have NiMH batteries that retain their charge, but they can’t be found in general stores; and chargers that allow to suppress the memory effect, even on rather old batteries.

So I bought a smart charger and two packs of four preloaded AA batteries with low self-discharge. I don’t know how long they were stored, but, installed directly in my flash, they worked flawlessly, with a recycling time of 4 s. For now, I am satisfied!

Accus à faible autodécharge

Other types of batteries

Lithium-Ion battery

A decade ago, I would have liked to get a remote control for my K10D Pentax camera, but such an accessory, from the same brand, cost a small fortune, and I was content to tinker an electric trigger (photo opposite) with a good extension cable… and bad contacts (jack plug not really reliable). I need a remote control especially to take pictures of my train compositions.

Déclencheur électrique

At the moment, prices have dropped, and we can find this kind of remote control at less than 5 € (this one, which I bought, is a bit more expensive). And it works quite well — with a range rather less than advertised. But it is greedy. Its battery is a lithium button type CR2032. After about thirty triggers, you find yourself at 50 centimeters of the camera: there, you think it would be more intelligent to press directly the camera trigger…

Télécommande infra-rouge

And I discover — this is definitely the era of great discoveries — in this shop that there are batteries of the same size as the CR2032 batteries, in Lithium-ion technology (Li-ion, yes, as in smartphones) . Although the capacity is very low (40 mAh against at least 200 mAh for the CR2032 battery), this is interesting, except that this battery has a rated voltage of 3.6 V instead of 3 V, which may seem acceptable. But I note that the end-of-charge voltage reaches 4 V.

Chargeur pour accu bouton Li-Ion

Never mind, I try anyway: for the time being, I have done about twenty triggers without worry, and, in addition, the range is significantly increased; nothing surprising: with 33% more voltage, the current in the infrared LED is certainly damned boosted, and this worries me a little!

Nickel-Zinc battery

It’s a rather old technology but it’s only beginning to emerge, and it’s not yet mature, it seems. In any case, I see an advantage: the rated voltage is 1.6 V and not 1.2 V as for NiMH. There are electronic devices for which this difference can disrupt operation. For proof, I have an “old” Canon PowerShot compact camera supposed to work with two AA batteries. With conventional batteries, it hardly works. And it needs high-end (the little rabbit), otherwise, after ten photos, you have to replace them!

Accus Nickel-Zinc

That said, for the moment, and according to this article of Marc Doigny, the disadvantages of these batteries still clearly outweigh their advantages. Wait and see… Marc Doigny is a Belgian photographer who apparently knows a bit in batteries charging!

La Crosse RS700 battery charger
34.50 € - price 2016
Amazon.fr

Infrared remote trigger for Pentax
12.90 € - price 2016
Amazon.fr