Originally Posted by The Gritz Carlton
Even though the top surface is flat and it's labeled maintenance free...you can still pry those flat tops off and it's just like a capped battery underneath. I don't think there's such a thing as Maintenance Free.
Not completely false ... sometimes true
... some Maintenance Frees are truly that, at least from a water replenish capability perspective (no pry-offs). And certainly some do have a valve plate that can be removed. However once removed I'd recommend treating them just like any other non-maintenance free FLA from there on out.