Purchase the appropriate large-section electrical wires from a Renault service station. If such wires are already available, make sure they are in good condition.
Both batteries must have the same nominal voltage of 12 V. The capacity (Ah) of the charged battery must not be less than that of the discharged one.
If the electrolyte in the battery is frozen, defrost it before charging the battery.
Also make sure that both vehicles do not have electrical contact with each other (due to the possibility of a short circuit when connecting the positive terminals) and the discharged battery is connected correctly. Turn off the ignition on the car.
Start the engine of the vehicle from which the battery is being charged and let it run at medium engine speed.
Fig. 1.113. Additional battery connection diagram: 1 – positive terminal of the discharged battery; 2 – positive terminal of additional battery; 3 – negative terminal of additional battery; 5 – negative terminal of the discharged battery; A – positive wire; B – negative wire
Connect positive (+) wire A to terminal (+)1 of the discharged battery, then to terminal (+)2 of the charged battery (fig. 1.113).
Connect the negative (–) B cable to terminal (–) 3 of the charged battery, then to terminal (–) 4 of the discharged battery.
Make sure that the A and B jumper wires are not in contact and that the positive (+) A wire is not in contact with any metal parts of the vehicle with a charged battery.
Start your car's engine, then disconnect wires A and B in reverse order (4-3-2-1).