The battery in my 2015 Honda Jazz ( yeah I know) has died. I have put it on trickle charge and got it from 7.6 volts up to 13.7 volts but I doubt it will last. The car was OK when I parked it up and the next morning all the electrickery had drained away. How do I tell if it is a battery fault or something wrong with the charging system. Also the battery is 35 amp hour 290 A , do I have to buy the exact same. It is a Varta and they do a 35 amp 400 A version will that be OK?