Even with the naked eye you can clearly see how the starter battery differs from the traction battery. And if you carefully compare the device, the main operational parameters, dimensions and weight, the difference will become even more noticeable. In particular, traction and starter batteries differ in cost per conventional ampere-hour, sensitivity to deep discharges and some other features. There are similarities too. But about the same as between knives and axes.
As you can understand from the name of traction batteries, they are designed to pull. But not literally, like a horse, for example. Batteries of this type are used only to power plants, and they already directly perform useful work. They pull, lift, rotate, illuminate, heat and even entertain. Any of these jobs requires a power source that could provide energy for a long time in moderate portions, and not lose its performance as a result of deep cyclic discharges.
Traction batteries: structure
The first thing you can notice the difference between a traction battery and a regular one is the structure. Structurally, these are standard lead plates (electrodes) placed in an electrolyte medium. Working parts are packed in a hermetically sealed case made of dielectric material. Two terminals are brought out - positive and negative.
The electrolyte in traction batteries can be both bulk and gel-like. Recently, the so-called AGM batteries have been especially popular, in which porous mats are impregnated with liquid electrolyte, which are in close contact with lead plates.
Applications of power batteries
Traction batteries are used in areas where stable and long-term power supply of moderate power is required. The most obvious example is various moving equipment and alternative energy systems:
- electric vehicles;
- small boats;
- electric bicycles;
- cars for driving on golf courses;
- wind and solar energy generation systems.
Traction batteries are especially common in special equipment used for loading and transporting goods. Due to the absence of exhaust gases, it can be operated indoors. Electric swimming facilities also have their advantages - environmental friendliness, lack of noise and vibration.
The current GOST states that the main function of a traction battery is cyclic discharges followed by charges. In this case, it is assumed that during the discharge, the battery gives off most of the stored energy. Starter batteries degrade during such operation. For them, more “comfortable” working conditions are a constantly high level of charge.
The name of the starter batteries also indicates their direct purpose. The task of this type of battery is to power the starter to start the internal combustion engine. This role, although short-term (3-8 seconds), but due to the high power requires a large current output. For example, to start a medium-sized gasoline internal combustion engine, you need a starter with a capacity of one and a half to two kilowatts. With a nominal battery voltage of 12 volts, a current of 100-150 amperes is required to deliver such power. And if the starter turns badly, then twice, or even three times more.
The starter battery device only in configuration has similarities with traction counterparts. They have the same lead plates in contact with the electrolyte. There is a dielectric sealed case and two terminals brought out - "plus" and "minus". However, unlike traction batteries, starter batteries have much thinner plates. This is done in order to increase the surface area of the active mass involved in the electrochemical processes inside the battery. And the larger the area, the higher the currents can be "squeezed" out of the battery.
Starter batteries are used only where these largest starting currents are needed. That is, in various kinds of equipment equipped with internal combustion engines. These are cars, trucks, motorcycles, tractors, and combines.
Similarities between traction and starter batteries
First of all, traction and starter batteries are similar in design and principle of operation. In addition, both of them are implemented today using different, and at the same time identical technologies. So, there are traction and starter batteries with the so-called bulk electrolyte, AGM, GEL, calcium, acid, alkaline, and so on. That is, there is a choice for any, as they say, taste and wallet.
But the similarities basically end there.
Differences between traction and starter batteries
As for the differences, there are far more of them than similarities. In addition, they are more significant and noticeable even to the naked eye:
- The parameters of lead plates are thinner for starter plates, and they are quantitatively larger with the same battery capacities. In traction batteries, the electrodes are massive, and there are fewer of them visually (if you look inside the case). Due to this, they better tolerate deep discharges and do not crumble longer.
- Peak loads - starter batteries are simply created for them, while traction analogues cannot physically deliver large currents. Their plate area is relatively small, and because of this, electrochemical reactions are less intense. But one should not think that traction batteries are completely weak in terms of peak loads. This is not entirely true. They are capable of something.
- Sensitivity to deep discharges - starter batteries are extremely low. Some models after two or three digits to zero lose up to half of the nominal capacity. Today, the so-called calcium batteries are most famous for this drawback. Traction batteries are more resistant to deep discharges, and do not lose their resource as a result of such operation.
- The number of charge-discharge cycles - traction batteries in this regard significantly outperform starter ones. Moreover, the latter are generally not recommended to be often discharged by more than 30%, as they quickly undergo sulfation, lose their capacity and ability to deliver large starting currents.
- Dimensions and weight - with the same nominal capacities, traction batteries are noticeably larger than starter batteries. This is due both to the thickness of the plates mentioned above, and to more massive cases.
- Cost - it is difficult to compare according to this criterion, since both options are available in both cheap and expensive versions. But some trend, nevertheless, is visible. Traction - more expensive.
There is also a bike circulating on the Internet that traction batteries are better “adapted” to high and negative ambient temperatures. In fact, the difference in this regard, if any, is very small. Traction batteries, along with starter batteries, can freeze in the cold in a discharged state, and also lose a lot of electrolyte due to overheating. In addition, at low temperatures, they accumulate and release much less energy than at optimal +20°C. This should be taken into account, for example, if you started a long swim in the same boat with electric traction in early spring.
Is it possible to use a starter battery instead of a traction battery
In theory, it is impossible to replace a starter battery with a traction one, or vice versa. Firstly, the peak power of the traction battery may not be enough for stable starter scrolling. Secondly, it is not advisable to use starter batteries where they will be in a half-discharged state for a long time and often. Rapid wear in the form of loss of capacity will make such operation extremely unprofitable.
Among other things, traction batteries are larger in size than starter batteries of the same capacity. Accordingly, difficulties may arise even in order to install the battery in a regular place under the hood of the car.
However, there are plenty of examples where these two technologies are interchangeable, and they perform quite well, so to speak, not at ease. A good example is garage-sized solar or wind power plants. In such systems it is better, of course, to use traction batteries. However, with a competent approach to the issue, starter batteries can also be charged from alternative sources.
Finally, let's get back to cars. It may not be worth using a traction battery instead of a starter one. But on the other hand, they often adapt to the role of auxiliary energy sources. That is, under the hood, a regular starter battery plays its direct role, and an additional power battery is installed in the trunk. From it, if necessary, consumers such as a refrigerator, inverter, boiler and other mobile accessories used far from civilization are powered.
By design and many parameters, traction batteries, after all, are very noticeably different from starter batteries. They have more massive plates, which, moreover, are relatively smaller. They cost more. Not very suitable for powering a starter. But they are indispensable in their areas, where a moderate return of all accumulated energy is needed without reducing the resource of the battery itself. These nuances are the main difference between a traction battery and a starter battery.