I thought about which modes it is better to test batteries in and measured the consumption of devices that I have at home.
I assumed that the Omron tonometer would have a fairly large consumption (after all, it must have a powerful enough motor to pump up pressure). Much to my surprise, it turned out that it contains four AA salt batteries and it works great from them (I was presented with this tonometer for the new year and these batteries were already there). The pressure measurement cycle with these salt batteries looks like this.
The compressor in the tonometer works for about 25 seconds, the current consumption increases from 200 to 280 mA, while the voltage on each battery drops from 1.6 to 1.43 V. When the tonometer does not pump, but simply shows the values on the indicator, it consumes 25 mA.
The tonometer consumes 9 mWh per measurement cycle, which means that the salt batteries will last for about 50 measurements.
Having powered the tonometer from a 6 V constant voltage source, I looked again at how the tonometer consumes energy.
The current consumption is exactly the same - 200-280 mA, but less energy is spent - only 6 mWh, because the voltage is higher. If alkaline batteries are installed in the tonometer, they will most likely last for more than 300 measurements.
The most powerful battery-powered electrical device today is a flash unit. At its peak, it consumes up to 4A.
But it consumes such a large current in less than a second, and then the current gradually decreases. My unit is too slow to accurately show the flash consumption pattern, but you can get a general idea. Four amperes is a very heavy load for batteries, so all photographers know that the flash needs to be powered by rechargeable batteries, because they are not afraid of such a load at all.
The most powerful load, with a long-term high current consumption, turned out to be a ring-shaped LED illuminator. In constant light mode at maximum power, it consumes 1.95 A at a voltage of 6 V. Of course, in actual battery use, the current (and therefore brightness) will decrease as the batteries are discharged. At 3.6 V (these are almost dead batteries, each providing 0.9 volts), the illuminator consumes 0.6 A. Alkaline batteries will last for about half an hour of operation of this illuminator (while the brightness at the end will be five times less than at the beginning), so of course it is better to use rechargeable batteries here as well.
I measured how much the car alarm key fob consumes. It constantly consumes 0.02 mA, once a second the receiver turns on, consuming 1.5 mA for a short time, and when the button is pressed, the consumption rises to 30 mA. Without accurate measurements of the consumption intervals, it is impossible to predict how long the battery will last.
Another device that "drains" batteries very quickly is a radio microphone. I measured the consumption of a Chinese radio microphone system. The receiver consumes 30mA and is powered by two AAA batteries. Alkaline batteries last for 33 hours. The transmitter consumes 40 mA and is powered by a 9-volt "Krona" battery and an alkaline battery of this type will last only 17 hours, and if you put a salt battery, it will last only 9 hours.
Laser pointers with green and violet lasers (one says 10 mW, the other 5 mW) consume almost the same - about 280 mA.
Of the six lanterns that were at hand, to my great surprise, the most "consuming" one turned out to be a small one on one AAA battery (it is in the lower right corner of the title photo). At a voltage of 1.5 V, the current amounted to as much as 1.8 A (while, when the voltage drops to 1.2 V, it already consumes 0.8 A, at a voltage of 0.9 V - 0.4 A, and at 0.7 V 0.25 A).
The rest of the lamps with a voltage of 1.5 V on each battery consume 500, 835, 780, 350 and 250 mA, respectively.
Unfortunately, I don't have a single moving child's toy. I assume they consume 200-300 mA.
Now I am testing batteries in two or three modes:
• Discharge with direct current 200 mA.
• Pulse discharge (10 seconds load, 20 seconds pause) 2500 mA for AA batteries and 1000 mA for AAA.
• Discharge in "constant resistance" mode with an initial current of 1000 mA.
I think for new tests to remove the discharge with high currents (not a single real load torments the batteries so much).
The main test is to make a discharge in the "constant resistance" mode with a current of 200 mA. This means that 200 mA will be available only in the first second of testing, and then the current will gradually decrease as the battery is discharged, as it would decrease if the load was a resistor. Battery chemists say that in this mode and in the constant current discharge mode, completely different processes take place in the battery, and most devices with batteries do not contain stabilizers and their consumption decreases as they discharge, so that such a test will better reflect the performance of batteries with real load.
The second mandatory test is also to make a discharge in the "constant resistance" mode, but with a current of 1000 mA. Flashlights are a noticeable part of battery-powered devices, and that's how they drain them. It makes no sense to make different currents for AA and AAA batteries, because sometimes different models of the same devices are powered by both batteries.
Probably, it is necessary to leave the test "Discharge with direct current 200 mA" at least so that the results of new tests can be compared with the previous ones.
I have a couple of questions for you:
What high power battery powered devices do you know I forgot about?
Which test modes do you find the most correct for AA / AAA batteries? I have no opportunity to test each battery for several days, weeks, months or years, so please do not offer currents less than 200 mA. :)
In my immediate plans, tests of batteries Krona, LR41, CR2032. I am thinking of making battery testing permanent by installing a modified engine from Lamptest.ru on the sites batterytest.ru and accutest.ru (they belong to me) and upload all the data there.
P.S. Recently I received a donation from a reader with the nickname Seryozha Shoemka to buy batteries for tests. If so, we will test! :)
© 2020, Alexey Nadezhin
The main topic of my blog is technology in human life. I write reviews, share experiences, talk about all sorts of interesting things. My second project - lamptest.ru. I test LED bulbs and help figure out which ones are good and which are not so good.