These are the batteries that are talking about, and the battery contains electrical energy.
If handled improperly, it can be dangerous. There is always the risk of injury, damage to the battery or starter and fire. Portable jump starters have a variety of built-in safety features, which is a good thing.
Short-circuit protection – prevents large currents from flowing from positive clamp to negative clamp when accidentally touching together
Overcurrent protection – prevents damage to the actuator by
preventing it from supplying current beyond the peak limit
Overload
protection – prevents the current received by the jumper packet from exceeding
the manufacturer's specified current while charging
Overvoltage protection –
prevents the voltage received by the jumper group from exceeding the voltage
specified by the manufacturer during charging
Overcharge protection – when
the battery of the jump starter is fully charged, this will “float” to charge
the device and prevent excessive voltage from being applied to the
battery
Most jump starters have these built-in protections, but always check
the listed safety features to ensure safety. However, there must be an optional
security feature.
Reverse polarity protection prevents damage to the battery when you connect the cable clamp to the battery terminals.
Red is positive and black is negative. The positive cable is connected to the positive terminal and the negative cable is connected to the negative terminal. Messed up, you may kill the battery forever. You may also damage other parts of the electrical system.
Linsheng explains: The excellent portable jump starter has reverse polarity protection. If the cable is not connected properly, the warning light will illuminate. Some even sound an alarm. The best part is that the circuit is not complete, so you have the opportunity to switch cables before driving.