The two batteries will charge each other when connected. The premise of being able to charge is that the polarity is the same, and the high voltage is charged to the low voltage.
Voltage is a kind of physical potential energy, also known as potential. The potential energy indicates that the current of the high potential will flow to the low potential in order to find a balance between the two potentials. Just as the water at the top always flows to the bottom, in order to balance the two waters.
Therefore, two batteries in parallel, and the polarity is the same, there will be two potential balance phenomenon, that is, the high-potential battery will charge the low-potential battery. Smart businesses, understand this principle, launched a variety of \"charging treasure\
If the polarity is different, in the case of low potential (voltage), the opposite currents are mutually repulsive, that is, they will not charge each other. In the case of a wide difference in potential (more than 3 times the voltage difference), because the battery power supply has a certain internal resistance, it will not be able to withstand the potential energy of high voltage and be broken down by high voltage, forming a short circuit or explosion.
Two batteries can not be positive and positive negative parallel charging because the two battery voltage can not be exactly the same, easy to appear in parallel to another discharge, if the discharge current is too large, may lead to the destruction of the two batteries are rarely used in parallel or charged in life, because the performance of the two batteries can not be exactly the same, easy to produce self-discharge, unless emergency use, Generally not recommended parallel use, emergency parallel use must be measured before the same voltage to parallel
Two batteries can not be positive and positive negative parallel charging because the two battery voltage can not be exactly the same, easy to appear in parallel to another discharge, if the discharge current is too large, may lead to the destruction of the two batteries are rarely used in parallel or charged in life, because the performance of the two batteries can not be exactly the same, easy to produce self-discharge, unless emergency use, Generally not recommended parallel use, emergency parallel use must be measured before the same voltage to parallel