18 and 17 string ternary lithium battery chargers are not universal.
According to the design principle of the battery charger, the output voltage of the charger should match the total voltage of the battery in series. The total voltage of 18 strings and 17 strings of ternary lithium batteries is 18 times and 17 times the voltage of a single battery, respectively. Therefore, the output voltage of the charger should match the total voltage of the two batteries in series for normal charging. Since the total voltage of 18 strings and 17 strings is different, the ternary lithium battery chargers for 18 strings and 17 strings are not universal.