MCM Electronics Pro Elec Battery Test - Results

Posted by John on Jul 17, 2014

Pro Elec Battery Test Results

Recently, we started carrying our own line of Pro-Elec batteries, and around the office we were wondering how they really stack up against the major brands.

We had the discharge rates and expected run-times from the data-sheets, and most major brands do publish power-curves, but those didn't really give a good head to head comparison. So we grabbed an Arduino, Data-Logger Shield, and a few packs of AA size batteries from stock and got to work.

Without further adieu, here are the results, graphed out.

What we learned

Per the graph above, we learned that while the Pro Elec battery had a lower initial voltage and it lasted longer. Great. That's simple. But there's more to it.

Because batteries are used in millions of different applications, there will be instances where having a higher initial power output will be better. We'll try to qualify some of these instances below.

Low Draw and Analog Devices

Things like remotes controls, flashlights, even projects with your Arduino (without running a motor) all would benefit from the Pro Elec batteries. Generally, these devices can operate well on a very low voltage.

High Draw and Digital Devices

For high draw and mission critical digital devices, a name brand battery may provide a longer life. It's obvious the name-brand batteries are optimized for this category of use; they all died sharply between 10 and 12 hours, once they got down to one volt. If, however, your device will operate on as little as .8 volts, our test showed the Pro Elec outperforming the competition. If your device needs closer to 1.2 volts, a name-brand cell will last longer.

*Nearly all AA battery consuming devices will say they need some multiple of 1.5V. In reality, few need the full 1.5V, as the batteries would only last ~30 minutes. Since every device is different, test your device to find out it's actual power requirement.

Value

What we've not covered yet is the topic of value. Say your device dies once the batteries reach the one volt threshold. All of the batteries in our test died between 10 and 12 hours. Typical brand name batteries have a per-cell cost of around $1. Pro Elec AA batteries currently have a per-cell cost of around $0.25 (both based on purchasing in bulk). For your device, the Pro Elec battery is four times the value.

The Test

Read all about how we conducted our test, and how you can do the same at home using an Arduino, Data-Logger Shield and a few other odds and ends here.

Category

Product Reviews

Comments (4) -

charltonef
charltonef
7/19/2014 5:56:29 PM #

This is a good test with results, and useful energy per battery is important, but how do they do at avoiding chemical leakage?  Reliability can be very important, and repairing damage gets old fast.

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John
John
7/21/2014 10:50:33 AM #

That is a great question.  Unfortunately it doesn't have an easy answer.

Alkaline batteries leak because once they are fully discharged; the residual chemicals continue reacting, and produce a small amount of hydrogen gas.  Even though modern batteries have a small space in them to regulate the pressure buildup, eventually there will be enough pressure to break the batteries' seal.

Once the seal is broken, those same residual chemicals begin to react with the air, giving off potassium hydroxide, potassium carbonate, and a few other things; none of which is good for electronics.

This is not so much a design-flaw suffered by any particular brand of battery so much as it is a design limitation built into the basic chemistry of alkaline batteries, our Pro-elec batteries have the same leak-prevention features as the name-brands to help keep leaks to a minimum, but while they will not leak more than other alkaline batteries, all alkaline batteries will eventually suffer that fate.

The good news is that there are things you can do about it:
1) Always remove dead batteries from a device, even if you are not going to put in fresh batteries.  Dead batteries left in place will eventually leak.
2) Never replace just some batteries in a device.  Having fresh batteries trying to force current through dead ones will dramatically speed up the process, and cause leaks much more quickly.  Replace them all, or none at all.
3) Never mix brands of batteries in a device.  As you can see by the chart, different brands of batteries discharge at different rates.  So even if you put in all fresh batteries, if one brand lasts longer, it will still be trying to force current through the rest, causing leaks.
4) Finally, remember that heat speeds up chemical reactions, so dead batteries left in a hot environment will leak more quickly than ones in a cool environment.

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John
John
7/21/2014 10:52:51 AM #

cont...

As for what to do once a leak occurs:
Potassium carbonate is highly hygroscopic, which means that it attracts and absorbs water (Which is why it often appears wet or runny) and it can dissolve in water but not in alcohol (so, you know which one to use.)  It is also a strong base, so you don't want it on your hands.  Therefore the best way to clean it up is using white vinegar followed by water.  The weak acid in the vinegar will work to dissolve and neutralize the base, while the water will rinse it away.  Generally I am not a fan of mixing water or acid with electronics, but if you have to clean up a battery mess, then this is the way to do it.

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rcates1
rcates1
7/24/2014 2:13:15 PM #

What is the time scale are you using? Is that metric?

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