Can you charge a 12v 12ah battery with a 12v 7ah charger safely?

Yes, you can charge a 12V 12Ah battery with a 12V 7Ah charger, but it may not be optimal. The 7Ah charger will charge the 12Ah battery more slowly than a charger with a higher output. Additionally, if the battery is significantly discharged, charging with a lower capacity charger could take a long time and may not fully charge the battery if the charger cannot provide enough current. Always monitor the charging process to ensure safety.