Mercury Battery Sealed?

Willhound

Wanted to check fluid levels in my batteries today but can't seem to pry a cap plate off this Mercury battery? Didn't want to force anything. Are they totally sealed?
And is it possible to tell the age of the battery from the serial number?

Black_Diamond

Looks like a sealed battery. Unless someone put a date on it, hard to say how old it is. Take it/ them to an auto parts store and they can load check the battery to tell you the condition it is in. Always free checks. 

Willhound

Pretty sure this battery is toast. It's charging and showing 13.1 to 13.4 volts but won't crank the starter so I suspect one of the cells is dead. Starter works fine on the other bank. I realize a load test would tell for sure, but by the time I run to the boat, run back and forth etc, and I'm pretty sure the battery is at least 5 years old so will likely just change it.
I have two deep cycle batteries on a house bank.
Go straight starter battery? Or dual start/deep cycle?

reneechris14

1000 cold cranking amps either way.

Willhound

Thanks @reneechris14. That settles it. The dual I have easy access to is only 650. To get 1000 I have to go straight starting.