AA batteries no longer the trend?

Started Oct 31, 2011 | Discussions thread
Joseph S Wisniewski Forum Pro • Posts: 34,141
3/4 and 5/4 AA...

onlooker wrote:

Perhaps a solution to the problem would be a standardized rechargeable Li-Ion AA battery? I understand that might not be in the interest of the device makers, though. Also, since the the current non-rechargeable Li-Ion AAs are 3.6C, and are incompatible with the regular ones, the issue of confusion arises. Not sure how to solve it.

Well, when the "confusion" involves smoking camera parts, we "resolve" it by making it impossible to make the mistake.

Perhaps a new standard? AAL?

There are 3/4 and 5/4 AA Li-Ion cells, 25% shorter and 25% longer than AA NiMH and alkaline cells. That's what's inside most DSLR battery packs, a pair of the smaller cells.

As I said before, perhaps not in the interest of the device makers.

It's in the interest of the device makers to deliver value to the customers.

A simple cell, the tube full of foil electrodes and chemical paste, does not do that, and it doesn't matter if it's an alkaline, NiMH, or lithium cell. It doesn't have a reliable temperature sensor, charge state monitor, or a decent contact system. It has low pressure contacts designed for flashlights. Ever had a flashlight dim? What's the first thing you do? You shake it.

Did you notice that flashes don't have battery charge meters? You can't look at a flash and see something tell you that you're at 60%. Going by the behavior, it runs fine until you're pretty near the end of the battery, then it dies, suddenly.

Like a car with no fuel gauge, so the first indication you have that you're low on fuel is when your engine sputters as you turn corners. You get around that by adding a chip inside a battery "pack". Sony has been doing it to camcorder batteries since before Lithium.

And you still typically want the voltage of 2 or 3 3.7V cells in series. For years, cell mismatch has been a royal pain that's shortened the life of primary (like alkaline) and secondary (NiCad, NiMH) cells. It leads to decreased performance (all the cells taking on the characteristics of the weakest cell in the set) and catastrophic failure modes like cell reversal.

That's why devices that have needed high reliability (2 way radios are my favorite example) have had their batteries factory-matched and spot-welded into "battery packs. Even if the average consumer buys packs of matched AA batteries, how long before they get mixed with other sets, and you have mismatches?

AA batteries are like self-medicating. You have "adherents" try to justify it with all sorts of spurious logic, but deep down inside, it has more to do with a false "feel good" moment.

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Rahon Klavanian 1912-2008.

Armenian genocide survivor, amazing cook, scrabble master, and loving grandmother. You will be missed.

Ciao! Joseph

http://www.swissarmyfork.com

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