What is the Appropriate Current for a 12V/24V Car Battery Charger?
2 Answers
A charging current between 5-7A is generally suitable. When the charging current approaches or falls below 0.5A, it indicates the battery is fully saturated. To charge both 24V and 12V batteries, several conditions must be met: Direct charging is usually not feasible unless the 24V charger has built-in current-limiting and voltage-stabilizing control circuits. Such intelligent chargers are capable of performing this task. If the charger lacks these features, modifying the circuit connection is necessary, requiring some hands-on skills and relevant circuit knowledge. Car battery charging requires constant current and constant voltage external charging equipment (such as a charger). Without relevant control circuits, external rectifier circuits (like bridge rectifiers) can be connected at the output end to achieve the purpose. Simply put, the normal charging current can also be calculated based on the charger's power and the battery's power. Using a non-controlled circuit (non-intelligent) charger for a 12V battery might immediately cause the battery to "boil," leading to severe consequences. Therefore, one can use calculation methods to directly connect variable resistors or series-parallel combinations to achieve the goal. This requires calculations based on the relevant parameters of each electrical device.
I've been repairing cars for over 20 years, and the charging current for car batteries really depends on the specific situation. For 12V car batteries, the capacity is generally between 20-100 ampere-hours, while 24V truck batteries are mostly 150 ampere-hours or more. The safest charging current is 10% of the battery's capacity. For example, a 60 ampere-hour battery is best charged at 6 amps. If you're in a hurry, don't exceed 20%, or the battery may bulge. In cold weather, you can slightly increase the current by 0.5 amps due to slower charging, but in hot summer temperatures, you should reduce it by 1 amp. Remember to set the charger correctly—charging a 12V battery with a 24V charger will definitely burn it out. Smart pulse chargers are the most worry-free option as they automatically adjust the current and cut off when fully charged.
