Whats the cause of this?

 

There are several possibilities. One is a defective Ignition switch. ANother is a short somewhere in the wiring. If the car is modified-check the wiring harnesses. Now to the obvious-look carefully at the battery and its cables. Make sure that the battery is reasonably new and can hold a charge with the cables off-get it tested. Clean or replace both the Positive and Negative cables. This includes the one from the vavle cover to chassis. High resistance in wires will affect whether the battery charges properly. Hope this gets you started in the right direction.

 

once the battery starts getting corrosion on the teminals...it will start to drain slowly. also try cleaning to terminals and putting a lubricant on them.

 

And don't leave the doors open. Even with the light off there are relays using power.

 

Ecu:radio:clock all use a constant current for memory. This will also drain your battery slowly.

 

I had a prob like this b4. Couldn't figure it out but here's what happen. Apparenlty there was a trail of dried up acid leak that i guess ran down the side from one pt in time. The residue came in contact with some metal and from tehre my battery died every morning. Finally figured it out one day and i just packed insultation material allover the bottom and sat it to a plastic tray. Problem fixed...