Ferrari 488 Pista dynamo only 13.3 Volts

First, you should check the voltage at the battery with an external volt meter.

I have a vintage Ferrari with a Lucas alternator. The charging spec is 13.9 to 14.3 volts at 3000 rpm. The service manual suggests that if the voltage is out of spec, the problem is likely the voltage regulator. In modern cars the voltage regulator is usually part of the alternator itself. You might need to remove your alternator and have it checked and serviced.

 

Suspect charging rate is computer regulated and adjusted to best suit demand and performance. With less need for current the charge rate should vary to decrease parasitic drag on the engine thus increasing both power and fuel consumption. Different than the old days. Suspect if not within spevs it would generate a warning light,

 

Decrease fuel consumption . Suffer from typing impairment

 

One would expect the system to initially boost the voltage in order to clean the battery internals, then let the voltage drop for all the above mentioned reasons.

 

There is a battery state of charge sensor in the system and the alternator output and battery charge level is monitored and controlled by engine management. This is also a Lithium Ion battery so the management is a lot different then you may be used to. Under hard acceleration the alternator will be turned off and under hard decell or braking it will be commanded to full output in many circumstances.

 

The alternator is designed to charge on deceleration, as other have already pointed out. It far from unique to Ferrari. You can read more about the process and how larger auto companies have implemented “smart charging” features here:

https://gearsmagazine.com/magazine/high-output-a-look-at-todays-charging-systems/