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If a car battery is drained overnight or after several weeks of being parked without being driven then you should be able to count of an external charger to replenish the charge, right?
Well, what if the battery fails to charge with the charger connected, what do you do?
Fortunately, there are some fixes you can do and the best part is that you may be able to do them on your own (without a technician) provided you have the skills to do them safely.
Read on to learn why your car battery may not be charging and what you may be able to do to get it charging again!
Why Your Car Battery May not Be Charging
If an external charger fails to charge a car battery, check the following:
1. Is the battery charger plugged into the wall outlet and switched ON? As simple as that may sound, it may just be that it is not plugged in, the wall outlet is not switched ON, or the charger power ON switch is still OFF.
2. Check that the charger power cord and both battery cable leads are intact. Inspect all the cables for signs of damage. It could be that there’s a cut cable or a cable with a kink with broken wires under the insulation. Contact a qualified electrician to replace the damaged wires.
3. The charger may have a blown fuse. A blown fuse can stop the flow of current from the wall to the charger or battery. The fuse can blow if the battery cables are reversed:
i.e. (positive battery clamp connected to the battery post marked negative and vice versa instead of connecting positive battery clamp connected to the battery post marked positive and negative to negative).
4. The battery voltage may be extremely low. If the battery voltage is as low as 2 volts or less, some chargers are not able to charge it. Use a charger that is able to charge batteries whose voltage is low such as the NOCO genius.
5. The battery may be aging or damaged. A damaged battery will likely not be able to accept charge. You can have the car battery inspected by taking it to a reputable auto repair facility.
Signs a Charger or Battery is Faulty
If the car battery is not charging, you may not be sure if it is the battery or the charger that is faulty.
Probably the simplest and most efficient way to confirm which of them has a problem is to use another charger or battery.
Test the battery at a reputable auto repair shop. If it checks out faulty then you have confirmation.
To test the charger, use it to charge a known working battery and check if it shows the normal working status. If it doesn’t then you probably have a faulty charger.
1. Why a Battery Charger May be Plugged in but Not Charging
If a battery charger is plugged in but still not charging the battery, inspect the charger for an error message to quickly locate the likely fault. It is possible that:
- the battery leads are loosely connected and there’s corrosion interfering with the battery clamp and battery post connection.
- the battery leads are interchanged and the charger has shut down to prevent damage
- one or more fuses on the charger are blown, or
- the battery is deeply discharged or damaged and not able to accept charge
- the charger is faulty
2. What Causes a Car Battery Not to Charge Fully with a Charger
If the car battery is not able to fully charge, it may be because the wrong charger settings have been used on the charger.
If it is AGM, confirm that it is set to charge AGM batteries.
An aging battery voltage may not rise to the expected maximum battery voltage.
Has your battery been in use for several years? You can arrange to have the battery tested at a reputable auto repair facility to confirm its health.
In some cases, using a battery sulfator may be able to restore the battery’s ability to charge fully.
You may be interested in this post. Car battery dead – Will a desulfator revive it?
3. What Battery Charger to Use to Charge a Completely Dead Battery
Not all battery chargers can do this. Some battery chargers may be able to charge car batteries whose voltage is under 10V.
Use a charger that is able to charge batteries whose voltage is low such as the NOCO genius.
If the charger is not able to charge the car battery, it may be that the charger is not plugged in or switched on.
A damaged power cord or battery leads can stop a battery from charging.
Do not rule out a blown fuse, drained or damaged battery, or even a faulty charger too!