Mazda 3 Owner's Manual page 249

A capacitor is incorporated as the device for storing the generated electricity, which can
store and use large amounts of electricity instantly.
Variable
Voltage
alternator
High-current electricity fl ows through the following areas, therefore do not touch them.
Variable Voltage alternator
DC-DC converter
Capacitor
NOTE
When installing high power consumption devices such high-output speakers, consult
an expert repairer, we recommend an Authorised Mazda Repairer.
A difference in the fuel economy may occur depending on use conditions such as with
the A/C and headlights.
If the capacitor is to be disposed of, always consult an expert repairer, we recommend
an Authorised Mazda Repairer. For details, go to the following URL.
http://www.mazda.com/csr/environment/recycling
Capacitor
CAUTION
When Driving
i-ELOOP
DC-DC Converter
4–109