You need to use a multimeter to measure it.
(1) Make sure the engine of the car has been turned off and check if all power is disconnected to prevent the power from being left on to threaten safety;
(2) Wear insulated gloves and other protective equipment, then find the negative terminal of the power supply and clean both battery terminals to ensure better measurement;
(3) Multimeter connected to the DC file, if it is a 12V car, you can connect the DC file of about 17V, and then the red pen of the multimeter connected to the positive terminal of the power supply, the black pen connected to the negative terminal of the power supply;
(4) Observe the multimeter to determine the resting voltage of the battery;
(5) Start the car again, read the voltage, if the voltage is lower than 10V, it may need to charge the battery, otherwise it can not make the car run normally and continuously;
Cars generally use batteries with a voltage of 12V or 24V. For a 12V battery, the voltage before running is about 12V and after running, the battery voltage is around 14V. If the load voltage of the car is lower than 11V, the car may have difficulty in starting, etc., and it will also reduce the performance of the battery. For a 24V battery, the load voltage is about 22V or more, and when the car is running, the battery voltage is about 28V.
(1) Zero the multimeter mechanically before use, so that the multimeter pointer points to the position where the voltage is zero;
(2) When connecting the multimeter with the battery, be careful not to touch the metal part of the pen with your hand to prevent large measurement errors and inaccurate results;
(3) Set the multimeter to DC when measuring the car battery, and do not change gears during the measurement process, otherwise the multimeter will be damaged. If necessary, you can choose to disconnect the meter pen to shift gears and then measure again;
(4) Be careful to place the multi-meter horizontally when using it, otherwise there may be errors;
(5) After use, switch the multimeter so that it is in the AC voltage maximum gear.
When we start the car, if the vehicle can not start or start slowly, the vehicle can not continue to run and so on, we need to check which part of the car is faulty, at this time to measure the battery voltage can determine whether the battery is damaged. Moreover, when we don’t use the vehicle for a long time, we should measure the battery voltage regularly, so as not to shorten the life of the battery when the battery voltage is too low.
The voltage measured by the multimeter when measuring DC and AC is the effective value, the operation and the manufacturing defects of the multimeter may make the measured voltage inaccurate, so the voltage measured by the multimeter is only the approximate value.
In order to prevent battery damage, you should use the multimeter to measure the battery regularly. When the battery is dead you can find it in time and charge the battery with solar power system, thus avoiding a situation where the car won’t start.
