The secrets of eneloop batteries

Jan Panteltje wrote:

ies, and these are in everything I use, AAA and AA. These rechargable batte= ries are supposed to have very low self discharge, say still 80% full after= a year, come charged, and are cool for in digital camera, as normal rechar= gables are always empty when you need them. OK, some weeks ago, and I charg= e these with some Duracell charger, one cause the LED on the charger to fla= sh indicating 'bad battery'. And indeed it would not even power my mp3 play= er. I had spare, but last week the second and third caused the same problem= . So, I ordered new ones, but kept those 'defective' batteries. Then yester= day, as I was very curious as to WHY those batteries 'failed', and the new = batteries came with a link to

I have had this problem with standard NiMH batteries and an automatic charg= er. It seems to do some tests on the battery and when they get old or are s= eldom used these tests start to fail even when the battery can still be cha= rged and used. I think it measures battery internal resistance and if too high deems it as= defective. I have another charger based on timer for these batteries. I ha= ve found if you charge a battery for a while in another charger or power su= pply then the automatic charger will accept the battery. Also if you let th= em sit for long time unused their internal resistance seems to rise even wh= en there is charge left, and when put back to daily use their internal resi= stance lowers.

Sanyo sells or provides a charger for ENELOOPs. When they first hit the market, you got a plastic case that held batteries, the charger, and some adapters where you could put a AA cell in where a C or D cell goes. Later they sold the batteries plus charger, but no plastic case. Now they sell the charger and batteries separately.

I swear by ENELOOPs and use them everywhere. They are easily the best rechargables I have ever used. I put them in alkaline packs for transceivers (yes, I know, not kosher since the pack has no protector), flashlights, etc.

For charger chips, the overvoltage limit is generally 2V per cell. I suppose a manufacturer could get more aggressive if the charger didn't have other safety circuitry.

This issue of using NiMH in place of alkalines has caused a few manufacturers to put a resistor in series with the battery. I saw that on my Petzl MYO headlamp.

I like ENELOOPs. They don't leak.

How should this be interpreted ??

If they were making money with these batteries and accessories they would not have separated the package.

If they are making better money on the batteries alone, they would keep the accessory package as a "starter kit".

What gives ??

Simply gouging the customer ??

hamilton

It is called building the business. It is possible they lost money on the initial sales with the expensive packaging and free charger. This is common in all industries.

I never did the math, but the first version of a chip, assuming it even could be sold from the first mask set, must cost a fortune. Even a lean and mean organization can't pull off a chip design and run of wafers for under a million today by the time you pay engineers, layout, buy tooling, etc.

Cable news channels are classic business tales of dumping million after million to build the business. CNN and FNC both lost money for their first decade.

...

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Hi Jan

The reason for the low voltage and high internal resistance it that your battery equipment:

• discharge of one or more cells to a too low voltage (even reverse voltage!)
• the batteries has different characteristics

To get more life and easier charging from 2+ cells of LSD-NiMH (or LiFePO4) you need a accumulator controller with each accummulator packet, that monitor each cell.

Battery management system:

E.g. like this - but not for LSD-NiMH - only for Li-ion (not LiFePO4):

You could use a ultra low power microcontroller for BMS or stack fault monitoring?

/Glenn

On a sunny day (Sun, 23 Sep 2012 10:18:03 +0200) it happened Glenn wrote in :

Looks like a nice chip, but incorporating it in my Canon camera will be a challenge ;-) I use the eneloops mainly for consumer stuff I have. I ran some compare test this morning, trying to get 160 mA charge current into a as 'defective' marked AAA needs 1.9 V, while only 1.6 V owith a non defective AAA. So it seems the observation that Ri is higher than normal is true. My conclusion is that the high Ri defective onces can still be used in low current applications like my mp3 player, but likely not in the camera (flash draws a lot), and can only be charged from the lab supply. From now on, (blaming the Duracell charger? but it works fine with Duracells) I will charge all eneloops with the lab supply, it is fully programmable any ways, I can even control it from a script on teh PC if need be.

Sanyo no longer exists. Panasonic bought them several years ago, and stopped using the Sanyo name early this year.

On a sunny day (Sun, 23 Sep 2012 15:11:01 -0400) it happened "Michael A. Terrell" wrote in :

They still use the Sanyo name, its on the eneloop website:

So, they haven't updated the website. Big deal. Sanyo no longer exists.

Here is one of many news stories about the end of Sanyo:

On a sunny day (Sun, 23 Sep 2012 15:56:10 -0400) it happened "Michael A. Terrell" wrote in :

Well, the eneloop batteries I just bought last week have SANYO written all over them :-)

On a sunny day (Sun, 23 Sep 2012 16:01:07 -0400) it happened "Michael A. Terrell" wrote in :

The date 'April 1' is a bit suspiciuos no?

Correct.

Panasonic and Sanyo were always very close. IIRC, Sanyo was started by a cousin.

Idiot.

Sadly, Panasonic may not exist in a few years, the way their business is going.

The start of the second quarter is suspicious? You've never owned a real business.

over them :-)

Old stock. Like Motorola ICs.

Asian version of 'All in the family'? ;-)

Aren't they classed as 'Too big to fail'?