State of charge.To check the state of charge, you need a hydrometer. To check, open both bars and insert the end of the hydrometer into the opening. If necessary, tilt the battery slightly. Using a rubber bulb, suck in enough electrolyte so that the float floats freely. Depending on the state of charge, the electrolyte has a different specific gravity, which is determined by the immersion of the float in the electrolyte. When the indication is 1.28, the battery is fully charged, at 1.12, the battery is completely discharged. Intermediate values characterize the corresponding degree of charge. The hydrometer indication is given in "kg / l"
Charging the battery. A deeply discharged battery can be topped up with distilled water only after charging. During charging, the electrolyte level rises and a normally filled battery can "boil away" for this reason. At the beginning, the charging current should not exceed 10% of the battery capacity. Depending on the design of the charger used, the charging current is gradually reduced automatically. The battery is fully charged if the density of the electrolyte does not change over the next two hours. Usually, the battery plugs should be unscrewed and lie freely on the filler holes. Thanks to this, the detonating gas, consisting of oxygen and hydrogen, can freely evaporate. Since splashing of electrolyte is inevitable during intensive charging, the battery environment should be protected with newspapers or similar. If charging is carried out in a closed room, it should be well ventilated. Under no circumstances should the battery opening be illuminated with an open flame. When using a home charger, the battery can be left on the car. The wires also do not need to be disconnected. The situation is different when using a fast charger. To avoid damage to the alternator diodes, electronic control units, car radio, etc., disconnect the wires from the battery.
Removal and installation. The battery is located in the engine compartment and is secured to the console. Before removing, disconnect both wires from the battery terminals. Be sure to disconnect the negative wire first. When installing a new battery, clean the terminals and lubricate them with terminal grease. Connect the positive wire first.
Starting the engine with a discharged battery. The simplest way is to use "cigarette lighter" cables, which should have a large cross-section and powerful terminals for connecting one battery to another. When buying such cables, it is better not to spare money and buy copper wires. Aluminum wires, although cheaper, heat up so much that the insulation melts and when disconnecting the terminals, you can burn your fingers. First, connect the positive cable to both positive terminals, and then connect the negative cable. The donor car's engine should run at medium speed so that the generator produces sufficient voltage. If the battery is discharged quite strongly, you need to drive quite a long distance. In this case, the battery will be charged enough to start the engine. Pushing and towing are well-known methods of starting the engine with a discharged battery.
The official source is on the portal (ToyotaMan.ru)