Q: We have charged both batteries 100%, replaced the voltage regulator and altenator, but when we use the lights the battery drains

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What could cause the battery to continue to drain?

The last suggestion received was possibly a altenator fuse or the altenator we just replaced was bad.

My car has 90000 miles.
My car has an automatic transmission.

Hi, thanks for writing in. It sounds like the wire from the batteries to the alternator could be faulty. If this wire is not performing as it should the voltage from the alternator will never reach the batteries to charge them. I would recommend checking this wire for corrosion or damaged insulation. If you’re uncomfortable or unsure of what to check I would recommend having this performed by a professional. If any damages exist to the wiring from the battery to the alternator I would recommend having that issue resolved in order to maintain a working charging system. Here at YourMechanic, we can have a technician come to your home or office to inspect and diagnose this issue for you, and make or suggest the necessary repairs.

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