how should i know
battery no longer can store a electrical charge, a charging system failure, a parasitic draw,
A bad connection or heavy draw.
bad armature bushings
apparently you have a draw or a short when the vehicle is shut off, disconnect the battery when not in use and see if the battery stays charged.
Disconnect the negative cable and connect (insert) an ammeter between the battery and the battery cable. Remove the fuses one by one and see which causes the current draw to drop.
Either a short to ground, or too much current draw in that circuit.Either a short to ground, or too much current draw in that circuit.
over time the battery loses capatinace, or ability to hold charge... or u have aparasitic draw. something like a fan or light that runs wen the engine dosent
The spec for ignition off draw (all components off, key removed) is .035 amps or less. It can take 5 minutes for the computers to "time out" and go to "sleep".
can a bad alt draw the battery down with the key off
draw them
Usually the Anti-Theft/Security features will draw the most power. You can measure the current draw from the battery (with the engine off) if you have access to a multimeter. It should be in the mA range.
Either the battery is bad or you have a drain in the system. Test the battery first to see if its o/k and if it is then use a multimeter to measure the milivolt draw and start pulling fuses till it goes away. Remember that if you have the door open while you're pulling fuses to tape the pillar switch down so it won't be a draw, that goes for a hood light also. Some places to check for a draw are glove box/interior lights, alternator & radio.