Why Your Car Alternator May Be Burning Out (+Solutions)

Depending on the type and model of your car, replacing a faulty alternator can set you back several hundred dollars.

Particularly worrisome is when you are replacing a burnt-out.

It is normal to fear that the replacement might burn out as well unless you figure out why the previous alternator burnout in the first place.

So in this guide, I will govern the common causes why an alternator might burn out, what you are likely to see if the alternator has burnt out, and lastly what to check and fix if you have multiple alternators burning out.

What Causes a Car Alternator to Burnout?

When an alternator burns out, usually it is as a result of the excess heat buildup beyond what it is able to handle when it supplies high current to the car’s electrical system over a long period.

This may be caused by:

# 1. Faulty battery such as one with a shorting cell. If a car alternator attempts to charge a battery with a shorting cell, the current draw from the alternator will be unusually high resulting in overheating and burning out of the alternator.

#2. Attempting to charge a deeply drained car battery. Similarly, a deeply drained car battery draws a high current which can also result in overheating and burning out of the alternator.

What Happens when an Alternator Burns Out

When an alternator burns out, you can have any of the following: burnout diodes, voltage, or burnout stator windings

Symptoms of a Burnt out Alternator | What Happens

If your alternator is burned out, there will usually be a burning smell coming from the hood. The dashboard battery light will come on followed by a loss of power in the car. when the battery power runs out.

Why Multiple Car Alternators May Keep Burning out (+ how to Prevent It)

If your car alternators keep burning out, there are three possible causes that you need to investigate:

# 1. Poor connections between the alternator output (B+) terminal and the battery positive terminal when the alternator is running. This leads to leakages of high currents from the alternator diodes to the battery via alternate pathways (breaking down insulation), overheating, and burning out the alternator.

Related Post: Why the car alternator voltage output may be low and how to check it

# 2. A bad or failed battery that presents a lower than normal resistance and strain on the alternator. When this happens, there is an excessive current draw from the alternator, then overheating and eventually burnout of the alternator. So, if the alternators keep burning out, have the car battery tested at a professional testing station.

#3. Charging a Deeply discharged battery. Also, a deeply discharged battery draws a large current from the alternator which leads to overheating and eventually burnout of the alternator.

If your battery is drained, you can charge it first using an external charger so that the alternator does not supply high currents for an extended time.

In summary, any of the above conditions combined with poor airflow around the alternator can contribute to the alternator burning out.

Final Word

Replacing an alternator can be costly depending on the type and model of your car. But take heart, alternator burnouts are preventable provided you confirm and fix the root cause of the burnout in the first place – whether a bad battery, bad or loose connections.

When fitting a new one, make sure it is fitted according to manufacturer recommendations.

Hopefully, you have a better understanding of why your car alternator may have burnt out and also know what pitfalls to avoid in the future.

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