9 Tips For Choosing a Battery Charger

Battery Charger

The battery is needed to start the engine and provide autonomous power to the electronic components of the car during idle time. When the engine is running, the battery is charged by the alternator, but there are at least three situations when it is insufficient:

  1. Too low an outside temperature.
  2. A short drive with frequent engine stops.
  3. The battery is old or of poor quality.

Experts recommend charging the battery about once every three months, and this requires a battery charger.

If you have never faced the question of choosing such a device, you will probably be surprised by their variety. Chargers can be as compact and fit in your pocket as they can be huge metal boxes that weigh as much as the battery itself. And they all have their own features, as well as selected for specific batteries and depending on the task at hand. At first glance it may seem that the choice is too difficult, but if you know the basic criteria and understand how one device differs from another, everything falls into place. In our article we will analyze these criteria and find out how to choose the right charger, what to pay attention to, and what functions you can safely refuse, thereby saving your money.

Device type

How is the charger controlled?

The first thing you should pay attention to when choosing a charger is the type of control. That is, how the device works. There are three main branches: manual, automatic and microprocessor control. Each has its own advantages and disadvantages, which must be taken into account:



  • Allows you to accurately set the current parameters;
  • Can charge fully drained batteries;
  • Have an attractive price tag;
  • Stable operation;
  • Suitable for all types of batteries.


  • It is necessary to monitor carefully the whole charging process;
  • Boiling of the electrolyte is possible.



No need to monitor the operation process;
Automatic tracking of the current charge level;
Easy operation.


  • Costs more than its manual counterpart;
  • Does not give an opportunity to reanimate completely dead batteries.



  • Operates completely independently;
  • Monitors all current parameters;
  • Diagnoses the condition of the battery;
  • Has compact dimensions.


  • The most expensive charger;
  • No possibility to set parameters manually.

These are not all the differences, but even they are enough to understand which device to choose for you. Do you want to charge the battery as well as possible? Take the manual version. But it must be constantly monitored and controlled. No time to keep track? An automatic device that will do everything for you will do. Not limited in money and want to know everything about your battery? Get a microprocessor charger which will not take up much space even in the glove compartment of your car.

Digital values

What are the technical parameters of the charger?

You choose your charger based on the battery you have. The most important number is the voltage. If you have a passenger car, most likely it has a battery of 12V. Accordingly, and in the technical passport of the charger will be indicated by this figure. There are also universal models that charge 6, 12 and even 24V.

If the voltages of the battery and the charger do not match, it may cause one of the modules to malfunction. If the current of the charger exceeds the current, the battery will burn out, while if it does not, the charger will burn out. The top models are equipped with protection against such errors, which should also be taken into account.

Another important value is the amperage. The range in one device can be very large, from a couple of tens to several thousand. Note that if you have a passenger car, you just don’t need a setting higher than 55 amps. It is necessary for charging large truck batteries. Also in the documentation of the charger you can see the letters En/Eff. They mean the minimum and maximum current of the device. These are the extreme values the charger is capable of.

How it works

How does the charger work?

In order to charge a car battery, the device needs to take the voltage from the household network, convert it to the right values and transfer it to the donor. The simplest method is to use a transformer. In the past, there was no alternative to it at all. Today there are pulse devices, more advanced and convenient. Transformer chargers are still considered the most reliable and durable. In addition, they are easy to repair yourself. Except that they weigh a lot, and the size of the case can exceed the size of the battery itself.

Pulse chargers are more compact, but also more expensive. In addition, if it fails, you are unlikely to repair it yourself. What device to choose in this regard, it is difficult to say. If you have a large garage, and you will not carry the device with you, you can take a reliable transformer version. It will serve for many years without a complaint. However, the pulse modules can not be called low-quality, but the choice of model and manufacturer will have to be more thorough.


For what types of batteries is it suitable?

The car battery can use different systems of energy storage. The cheapest batteries use antimony storages. Many people try to eschew them, preferring the more expensive, yet reliable ring batteries. Unfortunately, chargers are not able to tell the difference, and it is very important. For example, antimony batteries should not be charged with current higher than 14 volts. They boil over quickly. Whereas ring batteries require 16 volts or higher. We are talking about 12V batteries. Complex GEL and AGM require even more care. Before you choose a device, determine what kind of battery you have, and then take the unit with its requirements in mind. This applies to automatic and microprocessor models, because in the case of mechanical models you can set the parameters manually, which once again speaks in their favor.


Is it possible to adjust the parameters?

An automatic charger always produces the same current. There are models with several modes, but still the supply will be stable. Ideally, if your dispenser has modes for specific batteries. If it doesn’t, then pay attention to the previous selection tip.

Manual models are the most interesting. They allow you to set the desired voltage and type of charging. For example, the amperage is picked up depending on the battery capacity and is about 10%. It’s not so simple with the voltages either. A 12V car battery needs to be charged at 13-14V. Ring type batteries are from 16V, and helium and fiberglass batteries are from 18V. The microprocessor charger is the best option if you have multiple batteries and they are all different. It is able to adjust to the peculiarities of the battery and will set the right parameters by itself.


Can the charger de-sulfate?

During the operation of the battery, a deposit is formed on the walls of the plates. These are the sulfates that reduce the performance of the battery. It is impossible to remove them manually, unless you decide to disassemble the case. The only way is to use a battery charger with desulfation mode. Most often it is found on manual machines, less often on automatic ones. While charging you just need to activate it, and the fouling will peel off the plates, thereby increasing the service life of your battery.

Desulphation is necessary not only for antimony and calcium batteries, but also for fiberglass and even helium batteries. Their plates also get soot, but much less often, and it depends on how often and how intensively the car is used.

It should be noted that this mode is not as common as we would like it to be, and in addition, it significantly increases the cost of the charger. If you are ready to spend an extra couple of thousand rubles and want to extend the battery life, it makes sense to look for a charger of this type.

Availability of a starter function

Does the device have a starter function?

There are chargers with a starting function, labeled ROMs. Not only can they charge the battery, but they can also start your car if it’s completely dead. For example, you forgot to turn off the headlights overnight, or the temperature outside has dropped drastically, and now your car is completely immobilized. With ROM, you don’t have to remove the battery and drag it home or into the garage. It is enough to connect the device directly to the terminals and make the start. Very convenient, but not everyone needs this feature. For example, if your car is parked in a warm garage and you never forget to put out the lights, you can save on it.

Extra features

What are some auxiliary options?

The simplest manual or automatic device simply delivers current to the terminals without diagnosing the battery in any way. If your battery dries out, or has a jar shorted out, you’ll never know it. The best option in this case is a microprocessor-based battery charger that can calculate all battery parameters such as performance, capacity, and structural integrity.

It is also preferable to choose a charger with a set of safety features such as emergency shutdown, over-current protection, and polarity reversal. The more extra features your charger has, the better you are protected against errors, but you will have to pay for them separately.

Form Factor

What affects the weight, shape and size of the device?

Transformers are the most bulky and heavy devices. They are difficult to carry from place to place and are better used as stationary, if there is room for them in the garage. It should be noted that today such devices are less and less common. They have been almost completely superseded by pulse chargers with much smaller dimensions.

But the smallest form-factor has a microprocessor. This device can fit in a car pocket or glove compartment. In this case, the charger is also a diagnostic tool, and is often equipped with a start function. Ideally, always have it on hand. Such a kind of car helper. True, the price of such devices is often shocking. The choice of form-factor is a purely individual question, besides there are a lot of variants with the most diverse filling on the market.


Please enter your comment!
Please enter your name here