So, you need to buy a new one, but one that has served faithfully for at least five years. We’ll talk about her choice.
The most important principle - you need to buy where the buyer is indeed always right, and not only until he has given the money. A reputable seller is friendly, competent and honest - the goods will be checked before your eyes, the sale date will be noted in the documents and you will not forget about the warranty, yours and the manufacturer. Nevertheless, some knowledge when buying does not hurt.
It is more advisable to take a battery flooded with electrolyte at the factory. Firstly, her case is probably not damaged during transportation - otherwise the electrolyte would have leaked. A battery with mechanical damage under warranty cannot be exchanged. Secondly, the quality of the factory electrolyte is likely to be up to standard. The presence of an eye - a charging indicator and a carrying handle - is a matter of taste; Convenient access to banks is much more important.
The fact is that the domestic voltage onboard machines is not famous for stability, therefore, as practice shows, overcharging, electrolyte boiling out and premature battery failure are possible. But if the jars are with corks, then you can top up water in a timely manner.
The second selection criterion is the date of manufacture deposited on the body indelibly. The fresher, the better. Talk that after a year of storage the battery as new is from the evil one (see ЗР, 2004, No. 11, 12; 2005, No. 4). Aging can only be slowed down, stopped on a battery brought into working condition (filled with electrolyte and charged), while no one has succeeded.
During operation, sponge lead of the coating is converted to sulfate (discharge) and vice versa (charge). These crystals are small and easily pass from one state to another. When stored, especially without periodic training and recharging, some crystals grow quite large and easily do not dissolve. There are special tricks that allow you to somehow reanimate a sulfated battery, only for this you need equipment that most motorists simply do not have. But let's leave the details for now. The main thing is that the battery should be fresh and immediately start working after purchase.
In the attracted, if possible, measure the density of the electrolyte. In the middle zone of Russia, it should be in the range of 1.27–1.28 g / cm3 at a temperature of + 25 ° С, and it is strictly the same in all banks. If there are no traffic jams on the banks, we will check the battery EMF - an indirect indicator of density (see table). It is better to measure with a digital voltmeter - its resistance is much higher than that of a pointer, so the result will be more accurate. The dependence of the battery EMF on the electrolyte density in the range of 1.05–1.28 g / cm3 is easily calculated by the formula E = 6 (0.84 + p), whence the density p = E / 6 is 0.84 [g / cm3].
However, if an electrolyte of a higher density is poured into a discharged battery or there are latent defects in it, then this cannot be detected by measuring the emf alone. Therefore, the last and main check is to measure the voltage with a load plug. Discharge current - starter (usually about 200 A). If the terminal voltage remains stable for three to five seconds, the battery is good.
The choice can be considered complete. By the way, ceteris paribus, preference should be given to the battery that has a large mass. Such a lattice is probably thicker, and there is more active mass in them, which means that it will be more durable than its light counterpart.
If the battery does not have hidden factory defects that usually occur in the first six months to a year (which is why it is important to find out the warranty conditions), then its further life depends on compliance with the operating rules. They are simple. First, check the charging voltage on the car. To do this, 10-15 minutes after starting the engine, when the energy spent on the starter is replenished, turn on the dipped beam and measure the voltage at the battery terminals and the generator. Engine turns at the same time 1000-1500 rpm. The difference should not exceed 0.1 V, and the voltage itself should be within 13.6-14.6 V (unless otherwise specified in the operating instructions). If the readings diverge from the recommended ones, we will find and eliminate the cause - the contacts in the charging circuit may have oxidized or weakened, the generator or voltage regulator is faulty. It is worthwhile to pay attention to the conditions under which the battery "lives". For example, on the "Lada" it is adjacent to the exhaust manifold - he constantly fry it from one side. The simplest tin screen will be very useful here.