Q: Battery leaked acid while charging? Is it safe to drive?

If the battery was dead, the question is "why?". If the car sat idle for weeks, that would explain it but otherwise, the fact that the battery was dead means the battery is too old to be reliable, the charging system isn’t working properly and/or there are parasitic loads draining the battery when the car is off. With regard to the charging mishap, that could be due to a fault of the charger. If the charger is old or unregulated, for safety reasons you might want to discontinue use of it to avoid future problems. Normally, in a circumstance like this, you would simply load test the battery to determine if it is still serviceable but if your battery has vented liquid acid, I would simply discard the battery and buy a new one. To answer your question, "is it safe to drive the vehicle given that the battery has leaked acid", the only reliable, and "safe" course is to buy a new battery. Once the battery has vented violently like that, it is just not wise to leave it in place. It is basically a defective battery at this point. Once you install a new battery, be sure to test the charging system and also check for parasitic loads.

If you want these steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request installation of a new batteryand the responding certified mechanic will get this taken care of for you including the charging system check and a check for parasitic loads. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.