Battery loses charge
I replaced the Gill battery two months ago when I purchased my C172. Now the new battery loses its charge overnight, so it needs to be charged in order to start the engine. With the battery disconnected there is infinite resistance between the circuit terminals (master and radio master switches off). With the battery connected to an ammeter in the circuit, there is no detectable current flowing in the circuit (switches off). The 2-month-old battery has two cells with low specific gravity. I don't understand what is causing this.