Comparison car Inverters

The method of connecting the auto-inverter to the on-board network or car battery.

— In the cigarette lighter. Connection to a standard car socket DC 12V; traditionally, the role of such an outlet is played by the cigarette lighter socket (hence the name), but many newer cars also have a separate socket. This option is the most convenient — after all, plugging the plug into the socket is much easier than pulling cables from the battery to the inverter installation site. On the other hand, it is only suitable for models with a rated output power (see below) up to 300 watts — high power creates extra loads on the on-board network and can lead to overheating and damage to the wiring.

— Crocodiles (to the battery). Connection directly to the battery using cables with alligator clips. By itself, a direct connection to the battery allows you to create quite powerful devices — the 300 W limit, typical for power from the cigarette lighter (see above), does not apply here. However, it is believed that alligator clips provide a less dense and reliable connection than cables (see below), and are less suitable for high currents. Therefore, the rated power of such inverters usually does not exceed 1500 W. On the other hand, such a connection is more convenient for quickly connecting and disconnecting the inverter.

— Cable (to the battery). Connection di...rectly to the battery using cables with flat terminals, which are clamped into the battery terminals when connected. This design provides a tighter contact than the "crocodiles" described above, but is less convenient when connecting and disconnecting the inverter. It is typical for high power inverters.

— In the cigarette lighter / crocodiles. Universal models that allow connection both through the cigarette lighter socket and directly to the battery using crocodile clips. The technical features of both connection options are described above. Here we note that the rated output power of such inverters can exceed 300 W; in such cases, when operating from the cigarette lighter, care must be taken not to connect a load of more than 300 W to the device.

The rated input voltage for which the autoinverter is designed. This indicator must correspond to the rated voltage of the battery used with the device:

— 12 V. The most popular battery voltage used in modern transport: used in the vast majority of passenger cars, also found in motorcycles and trucks.

— 24 V. This option is typical for heavy equipment - buses, trucks, tractors, etc.

Note that the actual battery voltage during operation can vary within a few volts - mainly due to changes in the charge level. But autoinverters are created taking this feature into account and can operate normally in a certain voltage range. Therefore, in the general characteristics it is quite enough to indicate the nominal voltage of the battery; the specific operating range is often given only in detailed documentation.

The total power supplied by the autoinverter in normal operation. In other words, this parameter can be described as the highest rated power of the connected load, at which the device is able to work without failures and overloads for a long time (comparable to the discharge time of the battery used for power).

Accordingly, when choosing according to the rated output power, it is worth proceeding from the energy consumption of the intended load. At the same time, it is worth choosing an inverter with a margin of 15-20% — for example, for a laptop with a consumption of 150 W, a device with at least 175 W is recommended. This is due not only to overload protection, but also to the fact that many inverters are able to deliver the claimed power only when the battery is fully charged, and as this charge is exhausted, it decreases.

It is also worth considering that some devices, such as car refrigerators or household vacuum cleaners, consume significantly more energy when starting up than during normal operation. Therefore, when choosing an inverter for such devices, it is worth focus not only on the rated, but also on the peak power — the power that the auto-inverter is capable of delivering without consequences within a few seconds.

The highest total power supply (peak) that the autoinverter can deliver to the load for a relatively short time is 2-3 s. Usually, this power is higher than the nominal one (see above) by 30-50%. At the same time, if you choose an inverter for maximum power, the same rules apply as for the nominal one — the device performance should be 15-20% higher than the total power of the connected load. And to work with devices that consume a large amount of energy at startup (vacuum cleaners, power tools, etc.), it is also worth specifying the peak power of the inverter — it should not be lower than the "starting" load power.

The value of the output voltage that the car inverter produces. In the vast majority of cases, this is 230V. Some models of auto-inverters suggest the possibility of supplying through power from the on-board car network with a voltage of 12 V or 24 V, which is necessary for organizing power supply to low-voltage consumers.

The shape of the graph of the voltage produced by the autoinverter.

- Pure sine. The classic alternating voltage graph has this form - incl. and what is present in 230 V household networks. Thus, a sine wave indicates a high quality of the output signal - the voltage changes evenly, without sudden changes and as close as possible to the parameters of conventional sockets. This allows you to connect almost any load to the autoinverter - even audio systems and other delicate electronics that are sensitive to power quality. On the other hand, such quality requires the use of complex control circuits and has a noticeable impact on cost, but there is a real need for it not so often. Therefore, a sinusoidal signal is typical mainly for premium autoinverters.

— Modified sine. This term (also called “approximate”) means that this output signal shape is only approximately similar to a sine wave. As a rule, such a graph looks like “steps”, sometimes quite large. This is enough to power most types of load used in cars - from lamps and power tools to televisions and laptops; At the same time, the autoinverters themselves are not as expensive as models with a pure sine wave. Their disadvantage is the inability to work with sensitive electronic devices, but this point cannot be called critical: the list of such devices is quite small, and they are used very rarely in cars.

Efficiency of the autoinverter.

Efficiency is the ratio (in percent) between the amount of energy that the device delivers to the load and the amount that it consumes from the vehicle's on-board network. Accordingly, the higher this indicator, the more efficient the work and the less loss during conversion. In fact, this means that, other things being equal, a device with a higher efficiency will allow the load to run longer on battery power; this is especially important at high power consumption.

In modern auto inverters, efficiency values of 80 – 85% are considered average, 90% or more are good.

The number of standard sockets for 230 V provided in the design of the auto-inverter.

The more outlets, the more electrical appliances can be connected to the inverter at the same time. At the same time, the specifics of using automotive converters is such that they rarely have to be used for several devices at once. In addition, simultaneous connection requires appropriate power (see "Rated output power"), and the sockets themselves also significantly affect the dimensions. Therefore, most often in modern models one outlet is used — this, usually, is enough. However, high-end powerful inverters can have two outlets.

Protection systems provided in the design of the autoinverter.

— Against short circuit. A short circuit occurs due to a sharp drop in load resistance to very small values (for example, due to insulation breakdown or circuit contamination in a device connected to an autoinverter). As a result, the current increases critically, which can lead to damage to both the load and the inverter itself, and even fire and injury. This protection prevents such consequences by turning off the power in the event of a short circuit.

— From overheating. Protection against critical temperature increase of the autoinverter: when heated, the system turns off the device, preventing damage and other undesirable consequences. Note that overheating is not necessarily a sign of a problem — it can also occur during prolonged operation in normal mode (which does not negate the need to turn it off to avoid trouble).

— From overload. Overloads occur when the power consumption of the connected device(s) exceeds the output power of the auto inverter (see above). Such situations lead to work in emergency modes, which is fraught with breakdowns and even fires. Some of the consequences of such situations can be handled by other protection systems (for example, the overheating protection described above), but in this case it is easier to prevent the cause than to deal with th...e consequences.

— From incorrect connection. A system that protects the auto-inverter from connecting with the wrong polarity: detecting a mismatch between “plus” and “minus”, the protection turns off the device, preventing breakdowns and other troubles. This function is found only in models connected directly to the battery (see above) — it is impossible to reverse the polarity when plugged into the cigarette lighter socket.