To test your battery try this:
1. Start your car then leave it running for 5 mins
2. Immobilize your engine so engine cranks but dose not start(pull out fuel pump fuse)
3. Using a multi meter check battery voltage, it should be 12.2v to 12.8v
4. If voltage is ok crank engine for 15 seconds (immobilized) if the battery voltage falls bellow 9 volts when cranking then its time for a new battery!!!
To check for drain do this:
1. Disconnect battery live terminal
2. Using your multi meter set to amps put one lead on the battery positive terminal and the other lead onto the lead you disconnected
3. Any reading on your multi meter above 0.3 amps would indicate a vehicle drain
Hope this helps
