Large scale battery test done by me as part of an internship

[IanB]

Also, I was going to post it on Candle Power forums but I don't have enough posting priveledges, if anyone has the ability to do so I would really appreciate it. Thanks.

Done. See here:

http://www.candlepowerforums.com/vb/showthread.php?344201-Large-scale-alkaline-and-other-primary-chemistry-battery-performance-test

[billclay]

It would be helpful to see battery dimensions since you have all of these available to you.  Some batteries are a tight fit in certain equipment.   Thanks.

[rollatorwieltje]

Isn't 200mA huge for an alkaline cell? I basically only use them for clocks. I didn't bother to measure the current draw of an average quartz clock, but given how long a battery lasts it should be well below 0.5mA. In this case it would be more interesting to see the difference at extremely low current draw. Maybe some data can be derived from the internal resistance of the cell.

[tom66]

0.5mA would take... assuming 2000mAh... about 4000 hours (half a year.) I didn't have any where near this amount of time at my internship, the tests were done in about 2 weeks!

[SeanB]

200mA for an alkaline can be low, as a torch bulb can draw 1A or so, and a camera can have pulses of 4A or more during charging of the flash capacitor. A clock typically draws under 1 uA, with a pulse of under 100mA for a few microseconds every second as it operates the clock motor.

[saturation]

You can easily project modified AH for different loads uses Peukert's law.

http://en.wikipedia.org/wiki/Peukert%27s_law

The trick is establishing the Peukert constant of your battery and is a function of battery wear.  If you presume a new battery and discharge it at various rates you can set it as one.  Also, NiMH, Li chemistries will discharge close to k=1 even if old,  these cells are more limited by storage than by internal resistance.

One thing you can do is establish 2 discharge curves, one at 1A and another at 0.1A.  The difference in measured AH for that battery will allow one to calculate k for that battery.

[LaurenceW]

An interesting quick calculation - Electricity from primary cells such as these is 500-2000 times more expensive than the same energy from the mains!

[orbiter]

Great work here on these battery tests tom66.

I'm another one that gave-up using Duracell batteries a good while ago, mainly because as others have mentioned, I'm noticed they were starting to leak a lot sooner than they used to. In fact when Duracell first became available I can't remember them suffering much with leakage problems at all.

Anyway I decided to have a read through a few online battery tests etc, and what surprised me was that GP Ultra batteries generally came out pretty well in such tests, so I'm pleased that in these tests.. especially as I've been using them for ages, that the GP Ultras are still showing pretty high up on the list  

[tom66]

http://www.batteryshowdown.com/index.html

I have just added 12 new batteries, and Ikea won. Yeah. Ikea. The flat pack company.

2270mAh @ 200mA discharge, repeated for verification (got 2260mAh so considered it to be fairly consistent), 10p each cell (box of 10 for £1.)

 

And as requested, discharge graphs, and variable cut-off voltages. Plus some limited source code.

[Conrad Hoffman]

Great tester, great test, great web presentation! I've done something similar manually on a very small number of batteries and reached a similar conclusion that the bargain store batteries perform very well. The previous comment about leakage is extremely important. Though the performance of zinc is dismal, they don't destroy the device you use them in if left discharged for a brief time. Akalines are a disaster in that regard and I try not to use them unless required. The physical construction, I think, makes them inherently more apt to leak. All my AA wall clocks and similar get zinc batteries from the discount store. The temperature performance of zinc is bad, so my outdoor weather station modules get akalines. Again, great job!

[tom66]

I have to disagree about zincs leaking.

I have a pile of batteries which have been discharged. All but one zinc battery has leaked; the alkalines are fine.

Alkalines take a lot longer before leaking.

[lewis]

...Though the performance of zinc is dismal, they don't destroy the device you use them in if left discharged for a brief time. Akalines are a disaster in that regard and I try not to use them unless required. The physical construction, I think, makes them inherently more apt to leak....

Strange, I can't remember ever having a leaky alkaline, but have had many problems with zinc chloride cells leaking if they're left discharged for a while. Although other users report leaky alkalines too. Time to change all the batteries in my multimeters maybe?

[IanB]

The leakage mechanisms between the two kinds of cells are different and that can affect the outcome.

Zinc cells leak when the electrolyte eats through the zinc shell and then finds a way through the steel outer casing. This is a slow and progressive process and will generally only happen if the cell is completely dead (since consuming the cell consumes the zinc outer electrode). The leak itself is a slow and creeping leak due to a fairly dry electrolyte paste and you have a chance to catch it before it gets too bad.

Alkaline cells leak when chemical side reactions occur inside the cell and produce hydrogen gas. This gas builds up pressure inside the casing like a pressure cooker until the seal bursts, and then the cell spills its guts with a fairly rapid splurge all over the insides of your equipment. The process is relatively fast and shows little sign of impending doom. The process may also happen to fresh cells, not only discharged cells, since the gas producing side reaction can be triggered by impurities and defects during manufacturing, or bad storage conditions like excessive heat.

So while zinc cells do eventually leak, I find them to be much more stable and predictable. On balance the risk of leak damage is lower.

[Fraser]

I can confirm that I have had many Procell (Industrial Duracell) alkaline cells can leak badly whilst in equipment, and even whilst still in the new carton! Cells have been in date and not discharged. The manufacturer admitted to me that any application that applies "excessive pressure" to the ends of the battery can cause it to leak. In my case my D cell Maglite regularly caused battery seal failure.

I no longer use Duracell or Procell and the battery leak problems have ceased. I now use Kodak and Energizer Alkaline batteries.

Fraser

[billclay]

I can confirm that I have had many Procell (Industrial Duracell) alkaline cells can leak badly whilst in equipment, and even whilst still in the new carton! Cells have been in date and not discharged. The manufacturer admitted to me that any application that applies "excessive pressure" to the ends of the battery can cause it to leak. In my case my D cell Maglite regularly caused battery seal failure.

I no longer use Duracell or Procell and the battery leak problems have ceased. I now use Kodak and Energizer Alkaline batteries.

Fraser

Very interesting about the pressure on the battery end caps!  Some of my meters have a VERY TIGHT AA battery fit with "tab" contacts on the meter.  Not the kind with "spring" contacts.  There were three batteries, two Duracell, one Energizer (OK, I shouldn't mix battery types) and the two Duracells leaked all over, the Energizer was fine.

Also, it's worth noting what kind of batteries the manufacturer supplies with it's meters, Fluke supplies Energizer.

I think I just might put one of each type in a clamp, apply a little pressure and see what happens!
Has Kodak or Energizer commented about end cap pressure?

[G7PSK]

I can remember the Zinc batteries not only leaking but swelling up and getting stuck in torches and other equipment with tight battery compartments, all that disappeared with the introduction of the alkaline cells but recently they have started to have a leakage problem with the Alkaline batteries particularly Duracell, not sure if the problem is with trying to increase capacity or cutting costs on the casings.    https://www.eevblog.com/forum/Smileys/default/confused0024.gif

[bilko]

I just found a 1998 GP Ultra AA cell, unused and it is still showing 1.56V, and NO LEAKS !!

[tom66]

Funny, because we just received a pack of Powerone (Varta) alkaline cells. Expiry 2014 (would normally be 2017~2020.) Capacity just 300mAh instead of 1200mAh at 1 amp discharge, but oddly 1600mAh compared to 2000mAh typical at 200mA discharge.  So different, very odd.

But one thing we have learnt is open circuit voltage is a poor indicator of battery capacity.

[ivan747]

Great study! The results are fascinating for me. I never though IKEA batteries had such a great performance. And Duracells aren't that great. I guess they waste all their margins in marketing rather than engineering