IF I DISCHARGE THE BATTERY
You need to put a new battery in the car alarm keychain. Dozens of firms offer products in stores, kiosks, and markets. Which one to choose?
Today, no motorist can do without chemical batteries (we used to call them batteries). It is they who often determine the reliability (or unreliability) of the operation of the anti-theft key rings and many other autonomous devices useful for the driver that are not tied to the electrical equipment of the machine. These are lights (carrying), receivers, testers, timers, etc.
What should one proceed from when buying batteries when you are offered many of their types, and even at prices with a spread of several times?
We decided to conduct our own test, for which we bought the goods in the store - as every motorist usually does. A collection of 21 species was assembled, at prices (mind you!) From 2 to 24 rubles (by the way, there are more expensive ones). Recall that on sale, of interest to motorists, they offer batteries with a voltage of 12 V (usually they are used in remote control car alarms) and 1.5 V for general use for other devices.
In addition, it is useful to know that current sources can be of various electrochemical systems. In particular, with salt electrolyte or alkaline - "alkaline". In the designation of the latter you can find the letters LR and the inscription Alka, Alkaline, Alkali Mangan, Alkaline Plus, Super Energy, Professional. Some manufacturers decorate their labels with five stars, emphasizing that their batteries are the most perfect, work better, longer. However, on the products of different companies one can often find not always clear notations - there is no single standard here yet. This means that there may be confusion, an incorrect assessment of the operability of the current source, etc. By the way, getting used to a certain jargon, we call the batteries everything that looks like them, but in reality …? The "battery" of the car, as you know, is a battery of several batteries, galvanic cells (there are six of them in 12-volt acid). Our 12-volt battery is a current source in which eight 1.5-volt cells are connected in series. But a 1.5 V current source is not a battery, but just an element. So in Russian it is usually written. For example, "Element 316" …
The design of current sources is constantly changing - their operational qualities are improving. You will hardly ever see old elements in the form of a zinc cup in a paper wrapper with a not very reliable plastic stopper - remember how the electrolyte that leaked from them spoiled a portable flashlight or an electric clock! Modern power sources can even boast of an inscription indicating one hundred percent protection against such trouble. Alkaline elements containing liquid alkali are especially reliable. They are completely airtight.
But nevertheless, the main thing that interests the buyer is how long the power source will work and how much it justifies its price.
We were the first to test the three most popular 12-volt batteries used for key fobs of car security systems. All are alkaline. Each is assembled from eight 1.5-volt cells - “tablets”. Made in Southeast Asia - China and Hong Kong.
Since the car alarm keychain can consume a current of about 6–10 mA (sometimes slightly more) during operation, we decided to discharge the battery with a direct current of 10 mA to the minimum operating voltage of 8 V, at which the keychain is already unstable. How long will the discharge last?
The results are in the table. 1. The battery of the Gold PBX from Hong Kong lasted longer - 1 hour 28 minutes, the Chinese GP Alkaline lost it - 1 hour 10 minutes and the Chinese PANASONIC lagged noticeably - only 48 minutes.
By the way, batteries were bought in different places. Their packaging may contain Russian text with more or less useful information, or it may not be. In particular, such a trifle as an expiration date was not indicated on the best of the trinity. For the price, it turned out to be significantly (about 2–2.3 times!) Cheaper than the other two. To know also the expiration date …
And now we are testing 1.5-volt products. We have much more “Elements 316” - 18 types! The results are in the table. 2. We discharged these power sources with a more direct current of 50 mA, which is more characteristic of their operating conditions - from the initial voltage under this load to the final 0.9 V. The current multiplied by the discharge time shows the capacity, in our test - in mAh. And to determine the work done by the current source during this time, you need to multiply the resulting capacitance by the average voltage. For example, for the first element from the table - PHILIPS Super (Poland), the capacity was 600 mAh, the discharge time was 12 hours, which is good for a six-ruble salt element. With an average discharge voltage of 1.199 V, the useful work of the Polish Philips is 0.719 Wh.
The Belgian alkaline PHILIPS Power Life was the best in this category - 2.57 Wh. DURACELL Ultra (unknown manufacturer) was slightly inferior to it - 2.505 Wh and the equally rootless ENERGI-
ZER - 2, 561 Wh Some of the batteries we bought can only be called weaklings. Such recorders, on the contrary, are pseudo DURACELL for two rubles (also of unknown origin, with a fake discharge indicator, bought on the radio market), which issued already … 0.227 Wh.h. Next, in terms of working capacity, is the old design of the HW Hi-Watt (also without a tribe) with its “achievement” of 0.285 Wh. But … three rubles. And finally, the “Korean” Daewoo with his .286 Wh … for six rubles. Choose according to your taste. However, we decided to give this process a certain theoretical sound, asking ourselves the question: how much does the kilowatt-hour of such current sources work? We divided the price of each element for the work done and … it turned out that, having bought a cheap “Korean”, we threw money, albeit small ones, into the wind! The price of 1 kWh for him is 20, 979 rubles! The best of all current sources - the alkaline element PHILIPS Power Life from Belgium - 1 kWh costs 6, 226 rubles. And the cheapest was the energy of the TOSHIBA element (Japan), bought for only five rubles, but issued 0.9 Wh.h. Its 1 kWh costs 5556 rubles. Alkaline elements - at much higher prices! - cost-effective if used for powerful current consumers.
Compare these values at least with the cost of electricity in your apartment! It is unlikely that after this we can seriously talk about such power sources as an alternative to gasoline or diesel fuel. And if an autonomous receiver or tape recorder rides on your car, then from the point of view of economics this is absurd!
Finally, let’s try to evaluate what the assurances of the manufacturers on the batteries mean - “For hard work”, “Super …”, etc. Apparently, they talk about the ability of the element to confidently give a large current. For example, 300 mA, which is typical for their operation in some devices. The results of this test were evaluated in points as the ratio of the work performed to the cost of the element times 100.