Adventures in Rechargeable Batteries

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forgot to write: yes I do prefer more programming-based content, but this is good brain-trainging too.

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I think the only place where I’d see a benefit with rechargeable batteries is at work, in my mediocre “noise-cancelling” headphones. The only other battery-operated gadgets I can think of are:

  • Remote controls (self-discharge kills it)
  • LED or MAG lights (used so infrequently that self-discharge is a problem here too)
  • Digicam (uses its own special battery pack)
  • Cordless phones and cell (use their own batteries/chargers)
  • Various tools like laser levels and stud finders, again used infrequently

I think that’s it. What else takes batteries? The only thing I can think of that really rips through batteries is a portable audio player, and since I don’t take the bus, I don’t need one of those.

Oh and josh, it’s actually not like putting a moped motor in a pickup, it’s more like filling the gas tank 1/3 of the way. It’ll run perfectly fine, you’ll just have to refill it sooner.

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Nice article :).

It’s amazing how much of our lives could be dramatically improved if all the best technology was widespread.

~Jason (stalepretzel)

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I’m amazed that so many people still buy disposable batteries. Myself and my family are a few of the culprits. It’s just not convenient to have to re-charge batteries after re-use, it’s so much easier just to throw them in a drawer and make others figure out whether or not they have any juice left in them ;D. On a more serious note though, this has woken me up to just how much re-chargable batteries would save in the long run.

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You had me laugh at enjoys recharging batteries.

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2017-update - what is the recommended smart charger nowadays? Preferably one with more than 4 slots.

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I just upgraded to these, I should update this blog post too!

And

https://www.amazon.com/gp/product/B00MXCIK32

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Modern (by which I mean since the aughts) NiMH batteries, such as Sanyo/Panasonic Eneloop, have quite low self-discharge, so they work fine for remote controls. They don’t last as long as alkaline, yes, but you still get many, many months from them. Though it’s possible that other countries were more than a few years behind Japan in switching to these.

They always do, the only question is, what is the juice useful for? It depends entirely on the power draw characteristics of the device, but alkaline batteries no longer suited for your flashlight may be able to run e.g. certain remote controls for months yet.

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The power draw of a device definitely makes an “unusable” battery for one purpose still useful in another. Case in point: Alkaline batteries I use for portable radios are failing to provide enough power are reused in my mouse and wall clocks. So, I have to change my mouse battery every 6 months instead of a year. Same for the wall clocks - every 8 months instead of 2 years. If they can’t run those low drain devices, they’re definitely “retired.”

I did try exchanging 2 AA batteries (in special holders) for 2 D-cells in a portable fan as an experiment. The D-cells lasted nearly 24 hours with the fan on high, but still provided enough power to let the fan at least move the air a little. The AA’s lasted about 10-12 hours before petering out completely. I’m using the AA’s as a replacement in some flashlights as the weight difference between D-cells and AA’s is quite a lot. (And how often does on run a flashlight non-stop?)

Rechargeable Alkaline batteries used to be a thing. Ray-O-Vac developed rechargeable alkalines decades ago. They held their charges without developing a “memory” as the NiCa batteries did. I used their D & AA batteries a lot. The batteries could take many recharges before finally weakening, but one set of batteries in a flashlight I used very often (volunteer firefighter & Capt. of Fire Police) would still last me several years. When I finally tried to buy more batteries and was unable to find them 5-7 years later, I contacted the company. They thanked me for using their product but was sad to inform me they no longer were making them. I still have the charger stuck in a closet somewhere.

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Rechargeable alkaline cells have been a thing for a long time and still are: they’re just one of many, many battery technologies that consumer don’t (or no longer) see. Remember when “lithium” cells were always primary instead of rechargeable? (Well, if you’re under fifty or so, you probably don’t. They’re still all over the place, but nobody seems to think of them as “lithium” any more.)

While few systems other than NiCD have a memory effect, and memory effect was never as big a deal as thought, anyway, a lot of systems are affected by voltage depression and other things which can look similar to memory effect. Some are easy enough to cure; in NiMH for example a couple of full charge/discharge cycles will usually restore a cell to full capacity.

If you ever really want to get into it, I have some notes on battery technology with links to a book that really gets into it. I bet the book is fascinating to at least some degree even to those without an EE background.

Oh, and funny thing it took me far too long to learn: the greatest source of wear on consumer LiPo batteries is often keeping them at full charge (or empty). If you don’t take your tablet or laptop or whatever off the wall adapter much, get something that lets you keep it charged to around 50%. (If you do take it out a lot, you can still keep it at 66% or 75% if that does the trick for most of your travelling, and fill it before going out if you remember in time.) This can extend the life your your battery by literally a year or two. (There’s a reason that when they ship these devices, they ship them half-charged, rather than empty or full.)

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