Why does the battery in my 07 octavia lose all power overnight even though EVERYTHING is turned off.I bought a new battery but this still happens.At the moment I disconect the battery after use to be sure the car starts.I also removed the radio fuse overnight but still had problem.
HelloI'd first check the easy things like is the boot light or any other interior light staying on then check that the main battery connections are tight and in good condition also check the earth strap to the engine / gearbox. Next I'd check the current drain aspect, the best way to find what circuit is causing the excessive currant drain is to fit a current sensing multimeter in series with the positive battery lead on the car and the battery, or use a current clamp meter on the battery positive cable.
Also check that the alternator is actually charging the battery in the car by taking a battery voltage reading with the engine off then another with the engine running. The 2nd reading should be higher than the 1st and climbing steadily. And also check that the alternator is secure to the engine as this provides the ground for the charging circuit and make sure that the engine / gearbox earth strap is secure and the contacts are clean and bright.
And one last thing is – how old is the battery? – As even good quality ones need replacing every 5 years and faulty battery just won’t hold a charge
Alternator is fine and battery is new i also removed radio fuse overnight.
HelloOK, in that case you'll need to get a current meter and try the fuse method measurement I've mentioned above
Where can i get a current meter and how much approx
HelloA lot of multimeters have up to a 10Amp capacity for measuring current and can be found in automotive suppliers and Maplins or good old ebayhttp://www.ebay.co.uk/itm/AC-DC-Multimeter-Electronic-Tester-Digital-Clamp-Meter-Multimeter-Current-/360456398769?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item53ece027b1orhttp://www.ebay.co.uk/itm/Digital-Multimeter-Electrical-Test-Voltage-Current-Tester-DMM-Ammeter-Automotive-/400278960504?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item5d327c3978