if you r car is over 3-4 years old and/or does alot of stop start motoring it is very likely your battery is dead or dying. I'd sugest you get a new battery for it. realistically speaking i'd say get a normal battery as they are alot cheaper and it won't hurt when the time comes to replace them again. however maintenance free batterys have no guarantee that they will last in PK so it's a big gamble.
There are a few reputable sellers who can sell you a maintenance free battery but it'll cost you alot and there is no real point on fitting it in PK since there are so many alternatives out there.