What Causes an Alternator to Overcharge?
In most cases, generator overcharging is caused by a defective voltage regulator. As the name suggests, the voltage regulator regulates the overall output of the generator in relation to the voltage, preventing the production of excessive output voltage.
Each generator works in conjunction with a manufacturer-specific voltage regulator, most of which are integrated into the generator itself. In most cases, this regulator prevents the generator from delivering a charging rate above 13.5 to 14.5 volts. However, failure of this critical component will result in a relative loss of voltage regulation.
Although it is more common for the generator to fail and prevent voltage production, voltage regulator failure and the resulting overcharging are also relatively common. Such conditions are usually diagnosed using a quality digital multimeter.
Can a generator be overcharged if it is poorly grounded?
Yes, a faulty earth connection can cause a generator to be overcharged. Your generator relies on a clean, safe ground path to properly regulate its voltage output. If the ground wire becomes loose, corroded, or damaged, there will be abnormally high resistance in the circuit.
This resistance blocks the voltage signal being sent between the generator and the engine computer (ECM). Without the correct voltage signal, the generator will not be able to regulate its output voltage accordingly.
As a result, your vehicle’s electrical system will begin to overload. The ECU will detect the overvoltage condition but will not be able to correct it because a poor earth connection would interfere with the signal.
Can I continue driving? It is never recommended to continue driving with an overcharged generator. This will almost certainly lead to battery damage as the electrolyte will boil. Additionally, continually operating the vehicle above its designed operating voltage can adversely affect sensitive circuitry in various control modules.
In the worst case scenario, driving for an extended period of time while overcharged can result in costly repairs to the electrical system, far exceeding the cost of replacing the failed generator itself. The longer you drive your vehicle in this condition, the greater the likelihood of such damage occurring.
In all cases, the root cause of your vehicle’s overcharged condition should be diagnosed and corrected as soon as possible. This will prevent many further issues and may reduce the need for additional secondary repairs.
If you are unsure whether you can perform such repairs yourself, make an appointment with a trusted service center as soon as possible. How to Fix an Overloaded Generator
In most cases, generator overcharging can only be resolved by replacing the faulty generator itself. This eliminates this type of concern since the generator’s voltage regulator is connected to the generator assembly itself, completely isolating the cause of the original overcharging problem.
It may be possible to rebuild an overloaded alternator and replace the problematic voltage regulator, but this tends to be less practical than simply replacing the vehicle’s entire alternator.
The practice of retrofitting generators has largely fallen into disuse, except in special circumstances.
