I recently replaced my alternator and battery. I also repaired a faulty cable between the two. Now I'm having the problem of my battery going dead after a few days of it sitting and a lot of my fuses have power going to them what could be causing this?

  • Was this a problem before you replaced the alternator and battery? – CharlieRB Feb 14 '17 at 12:32
  • No never happened before – Donnie Bowshier Feb 14 '17 at 18:33
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    Why did you replace the alternator and battery in the first place? Not exactly sure what you mean by "a lot of my fuses have power going to them". It is normal for a fuse block to have power. You need to double check your work. There is a possibility you have a loose connection, wire crossed or something shorting out. – CharlieRB Feb 14 '17 at 19:54
  • Does this ONLY happen when the car sits? If you get it running, does it start to give indications (dimming lights will be the most noticeable) that the battery is draining? You can try driving a bit at night or even idling with you high beams on pointed toward a wall and see what it does. If it does start to loose voltage, and the lights dim, then there's something wrong with the alternator. If not, then you can start moving to the fuses to try and see where the draw is coming from. (NOTE: All this testing and debugging will be MUCH easier with a multimeter.) – kyle_engineer Aug 2 '17 at 20:41

Measure the current which is drained from battery when everything is turned off. Common multimeter with 10A fuse should handle this. If it is high current (higher than hundreds of mA), then something drains power and remains turned on even if it shouldn't. If the current is high, try to go through fuses one after one until you find the fuse with high current flowing through it. You can investigate further based on what it is.

If there is no drain, then measure voltage generated by alternator when engine is running. It should be something over 14V. If it gives less, it might be faulty.

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  • Although I would recommend checking the alternator first since it is a simpler test to eliminate. – kyle_engineer Aug 2 '17 at 20:39

In addition to the excellent suggestions to check for drains when the car is "off" and also that the alternator is producing the correct voltage when running I think this stands out:

I also repaired a faulty cable between the two

I'd be checking that cable out to make sure the repair is solid and that it isn't shorting or providing a poor connection.

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