Why My Camera Does Not Work With "Good" Battery?

[elliott]

What does the charger show for the amount of charge supplied when you charge eneloops, out of interest?

They usually peak at 1.51v, I've seen as high as 1.53v, which I assume could come down to room temperature differences.

That's the voltage--it doesn't tell you much of value. What you need to look at is the charge shown on the display as mAh or Ah. This will start out at zero when you put the battery on charge and will keep climbing until the charger stops.

That would entirely depend on how far I let them run down before charging. Sometimes I run them down all the way, sometimes I don't. My camera shuts down long before they are totally dead.

[IanB]

That would entirely depend on how far I let them run down before charging. Sometimes I run them down all the way, sometimes I don't. My camera shuts down long before they are totally dead.

That's entirely OK. If the charger shows over 3 Ah and they were not fully discharged before you charged them there is even more reason to be concerned.

[elliott]

That would entirely depend on how far I let them run down before charging. Sometimes I run them down all the way, sometimes I don't. My camera shuts down long before they are totally dead.

That's entirely OK. If the charger shows over 3 Ah and they were not fully discharged before you charged them there is even more reason to be concerned.

I don't believe I've ever seen it go above 2500mAh in the 3 years that I've owned it. I've just put in a set from my flash, which will use them all the way down to 1.0v, I usually don't run them that low because recycle times at full power are annoying. I am running a discharge cycle to get them down as far as I can. Then I'll run a 200mA charge cycle and see what happens. These also happen to be the oldest set of Eneloops I own, I marked them when I bought them so I always keep them in matched sets.

[saturation]

Couldn't agree more alm, as always.

For the OP, to extend alms comment, for primary cells a best test is to load the 1.5v cells at half mA rating, or ~ 500mA.  Most 'battery tester' device are often crude voltmeters that don't draw substantial load.  As mV changes represent a larger change in the batteries capacity when the loads are small, a high resolution and accurate DVM down to the mV is needed, even if the measurements are just relative.  Here's a sample representation of the slope of the curves relative to mA draw.  However, at 500mA the difference is fairly obvious.

Voltage (optionally under load) is about the only measure you have for primary cells, short of tracking voltage and current over time like they do for some Li-ion battery packs.

I guess you could measure the voltage at two different currents and use this to estimate the internal resistance, but I'm not sure if the internal resistance versus charge curve is any steeper than the voltage versus charge. Using voltage to estimate remaining capacity of alkaline batteries shouldn't be that bad, the curve is fairly linear, as opposed to some other chemistries.

[maia]

This thread is very interesting. I always wondered if good battery are worth their money, or if the cheaper ones are better? It looks like that it doesn't make a huge difference and the quality is not foreseeable! Thank you for this useful information.
But I think it's funny that the camera did not even start...

[elliott]

That would entirely depend on how far I let them run down before charging. Sometimes I run them down all the way, sometimes I don't. My camera shuts down long before they are totally dead.

That's entirely OK. If the charger shows over 3 Ah and they were not fully discharged before you charged them there is even more reason to be concerned.

The old Eneloops all peaked between 2050mAh and 2100mAh at 200mA after the full discharge.

[david77]

That sounds about right, I measured my 2-3 years old Eneloops with about the same values when I finaly got my MAHA charger last week.
I'm still in the process of analyzing & refreshing all the cells that have accumulated over the years but the Eneloops seem to hold their capacity very well. A few cheap LSD's have lost a lot more of their stated capacity, they are also 2-3 years old.

[IanB]

The old Eneloops all peaked between 2050mAh and 2100mAh at 200mA after the full discharge.

I'm not clear. Is that the mAh measured on discharge, or the mAh measured on charge? It seems like those numbers refer to the discharge, but what we are interested in here is the charge.

[saturation]

Ideally the charge ~ discharge mAH, but in reality the battery may not hold the full charge expected by the mA x hour input that the charger estimates.  So, the best measure is a timed discharge at a specific mA.

Unless you use a defined standard such as the IEC protocol, discharging a battery at high mA rates reduces the mAH rating of a battery, and at a very low mA rate increases it.  Its one reason why the Maha Powerex c9000 use of the IEC protocol makes it more appealing, this procedure provides a standard to compare one battery against another in terms of its mAH capacity.

The old Eneloops all peaked between 2050mAh and 2100mAh at 200mA after the full discharge.

I'm not clear. Is that the mAh measured on discharge, or the mAh measured on charge? It seems like those numbers refer to the discharge, but what we are interested in here is the charge.

[IanB]

Ideally the charge ~ discharge mAH, but in reality the battery may not hold the full charge expected by the mA x hour input that the charger estimates.  So, the best measure is a timed discharge at a specific mA.

Unless you use a defined standard such as the IEC protocol, discharging a battery at high mA rates reduces the mAH rating of a battery, and at a very low mA rate increases it.  Its one reason why the Maha Powerex c9000 use of the IEC protocol makes it more appealing, this procedure provides a standard to compare one battery against another in terms of its mAH capacity.

All true, but the question at hand is, "Does the charger terminate charging reliably when using a 200 mA charge rate?"

For that we need to look at the mAh supplied during the charge. For a 2000 mAh eneloop we expect the charge supplied to be in the 2200-2400 mAh range. It would usually be less at high charging rates and more at low charging rates. However, it it went much over 3000 mAh, for example, we would suspect that the charger was not detecting a good termination signal.

Although the IEC protocol specifies a 0.1C charge for 16 hours, it is not clear that routinely charging batteries in this way is good for them. On the eneloop datasheet, for example, the performance measurements are obtained using a recommended fast charge of 1C to a -dV of 10 mV (which typically occurs after 1.1 hours). They give no indication that this is unduly hard on the cells.

Eneloop data sheet: http://eneloop.com.sg/products/download/Datasheet_-_HR-3UTG.pdf

[elliott]

The old Eneloops all peaked between 2050mAh and 2100mAh at 200mA after the full discharge.

I'm not clear. Is that the mAh measured on discharge, or the mAh measured on charge? It seems like those numbers refer to the discharge, but what we are interested in here is the charge.

Those numbers are the charge, the discharge didn't matter because they were already at 1.05v when I started the discharge, I just wanted them to be as low as possible before charging.

[benemorius]

The old Eneloops all peaked between 2050mAh and 2100mAh at 200mA after the full discharge.

I'm not clear. Is that the mAh measured on discharge, or the mAh measured on charge? It seems like those numbers refer to the discharge, but what we are interested in here is the charge.

Those numbers are the charge, the discharge didn't matter because they were already at 1.05v when I started the discharge, I just wanted them to be as low as possible before charging.

That certainly looks like proper termination for aged eneloop cells as you expected, though they don't look quite as good as new. Their discharge capacity will be a few hundred mAh below that, and I'm certain they came out of the factory with at least their rated 2000mAh capacity. You might be interested in trying one or more IEC cycles on them to bring the capacity back up, though I don't think there's any way to do .1C for 16 hours on a bc-900, unless termination fails of course.

Ian makes a point that is worth everyone taking note of, though. Low charge rate termination failures are common for old cells, as well as on the first charge of new cells, and even on otherwise perfectly healthy cells. This is true regardless of the charger. It is well known that -dV termination is not fully reliable for NiMH at low charge rates and it is all but inevitable that a cell will eventually begin failing to terminate once it ages sufficiently. Don't be surprised if that day is in the far future for your eneloops, though. I've seen a number of brand spanking new eneloop AAs terminate properly at 200mA. They're nice cells indeed. Termination failures are actually much less common for healthy cells than some people realize. Even still, most consider that it is better to charge at >=.5C than to risk even one missed termination. Healthy cells honestly won't get that much warmer at .5C than at .1C, and there are plenty of knowledgeable people happily charging away at 1C.

[saturation]

If the battery doesn't trip the dv/dt algorithm, the charger has 2 backups: a raw timer based charge and a temperature cutoff sensor. 

I don't think the IEC protocol was designed for charging, but more for characterization or 'reconditioning'.

I've charged eneloop AA at 1C and while the cells do not get above 45^oC with a C9000 [ it has gotten unacceptably hot on the Lacrosse charger which I no longer use at high current] it stays closer to 35^oC at 0.5C.  Also, I consistently get more mAH on slower charge rates.

However, its good to know eneloop will unlikely suffer reduced calendar life charged at 1C.

All true, but the question at hand is, "Does the charger terminate charging reliably when using a 200 mA charge rate?"

For that we need to look at the mAh supplied during the charge. For a 2000 mAh eneloop we expect the charge supplied to be in the 2200-2400 mAh range. It would usually be less at high charging rates and more at low charging rates. However, it it went much over 3000 mAh, for example, we would suspect that the charger was not detecting a good termination signal.

Although the IEC protocol specifies a 0.1C charge for 16 hours, it is not clear that routinely charging batteries in this way is good for them. On the eneloop datasheet, for example, the performance measurements are obtained using a recommended fast charge of 1C to a -dV of 10 mV (which typically occurs after 1.1 hours). They give no indication that this is unduly hard on the cells.

Eneloop data sheet: http://eneloop.com.sg/products/download/Datasheet_-_HR-3UTG.pdf

[alm]

Also, I consistently get more mAH on slower charge rates.

Charge or discharge?