Would it be safe to charge a 12V 7Ah SLA battery with a typical auto battery charger?

I think my battery is biting the dust. It is not charging well with that little wall charger. Been charging now for about 18 hours and still won't spin my starter strong enough to turn over an engine.

I was going to go out and get a new battery, but I am not confident that it will be charged by tomorrow morning with the wall charger.

Thanks,
Patrick