It appears that the general instructions for installing a car stereo subwoofer capacitor are dangerous, with potentially destructive effects for the future life of the vehicle's electrical system.
Most instructions I am seeing say that to install the capacitor you need to use a charging resistor, and then when it is charged, you can install it inline to the battery and just forget about it.
Except sometimes your car battery needs to be disconnected by an auto repair shop to work on the electrical system. Then the cap acts like a secondary battery and could blow things up or damage the vehicle electrical wiring if the disconnected battery terminals touch the frame. When the battery is reconnected after servicing, the cap is now subjected to a massive inrush that may blow it up or blow a fuse in the electrical system.
Sometimes your car battery goes dead and you need to do a jump start. The instant the jumper cables are connected, the cap will start charging, and depending on the gauge of the cables, the cap may blow up from charging so quickly, or possibly harm the other vehicle or charger being used to start the vehicle with the dead battery.
Finally, what exactly is preventing the amplifier from exceeding the capacitor's charge rate or discharge rate if the amp is directly connected? Why nothing at all. The amp could certainly exceed the max discharge rate when driving the speakers, and when the amp output stops now the cap is subjected to a similar huge inrush charge rate from the electrical system as it recovers.
Apparently the correct installation is that charging resistors should be permanently installed, both on the input and the output of the capacitor bank.
Though if you do this then you don't want just any old random charging resistors, but ones that are properly sized to match the actual max charge/discharge rate for the capacitor(s), to get the best performance out of them.
These resistors should be installed as a ceramic power resistor designed to handle abuse, and with temperature sensing cooling if necessary with a fan so it doesn't damage the vehicle or start a fire from getting too hot.
Though, doing it right may be a problem since the actual charge/discharge rates may not be published for the more consumer-oriented stiffening capacitors.
Most instructions I am seeing say that to install the capacitor you need to use a charging resistor, and then when it is charged, you can install it inline to the battery and just forget about it.
Except sometimes your car battery needs to be disconnected by an auto repair shop to work on the electrical system. Then the cap acts like a secondary battery and could blow things up or damage the vehicle electrical wiring if the disconnected battery terminals touch the frame. When the battery is reconnected after servicing, the cap is now subjected to a massive inrush that may blow it up or blow a fuse in the electrical system.
Sometimes your car battery goes dead and you need to do a jump start. The instant the jumper cables are connected, the cap will start charging, and depending on the gauge of the cables, the cap may blow up from charging so quickly, or possibly harm the other vehicle or charger being used to start the vehicle with the dead battery.
Finally, what exactly is preventing the amplifier from exceeding the capacitor's charge rate or discharge rate if the amp is directly connected? Why nothing at all. The amp could certainly exceed the max discharge rate when driving the speakers, and when the amp output stops now the cap is subjected to a similar huge inrush charge rate from the electrical system as it recovers.
Apparently the correct installation is that charging resistors should be permanently installed, both on the input and the output of the capacitor bank.
Though if you do this then you don't want just any old random charging resistors, but ones that are properly sized to match the actual max charge/discharge rate for the capacitor(s), to get the best performance out of them.
These resistors should be installed as a ceramic power resistor designed to handle abuse, and with temperature sensing cooling if necessary with a fan so it doesn't damage the vehicle or start a fire from getting too hot.
Though, doing it right may be a problem since the actual charge/discharge rates may not be published for the more consumer-oriented stiffening capacitors.
