Charge fault?

Trying to charge disconnected leisure caravan battery.
Uaing car chàrger**
On switching on charger the dial needle goes 3/4 accoss dial, in 5secs the charger safety button pops out cutting charge.b
Battery 110 amp circa six years old. last charge circa 15 months ago via **ìnboard charger (LUNAR 5BEŔTH 1998 ANY ONE KNOW WHERE INBOARD CHARGER IS, NO BOOK! Tto test it) doesn't charge making me think battery knackered.