"A second battery is never a good idea as it's an added strain on the alternator to charge two batteries AND supply power for the car. The ONLY time a second battery is useful is if the audio system is to be used with the car off."

"A second battery is never a good idea as it's an added strain on the alternator to charge two batteries AND supply power for the car. The ONLY time a second battery is useful is if the audio system is to be used with the car off."

It is a true and false statement at the same time. A lot of people use secondary batteries with there systems without it affecting there alternators. It will come down to listening habits and how hard you discharge the batteries and so on, if you slam hard all day long then yes it is true and investing in a battery charger would be feasible to take some strain off your alternator. A second battery will be useful whether car is on or off if you need the power, power makes power (no way around that).

to me that statement is false, provided your stock alt is 50amps +

BUT it is also a true statement as it does make the alt work harder ALSO my alt went bad after 5-6years of charging 2-3batteries at a time (stock 125amp alt) so on the long run yes if your alt is stock AND a pile!

"A second battery is never a good idea as it's an added strain on the alternator to charge two batteries AND supply power for the car. The ONLY time a second battery is useful is if the audio system is to be used with the car off."

It is a true and false statement at the same time. A lot of people use secondary batteries with there systems without it affecting there alternators. It will come down to listening habits and how hard you discharge the batteries and so on, if you slam hard all day long then yes it is true and investing in a battery charger would be feasible to take some strain off your alternator. A second battery will be useful whether car is on or off if you need the power, power makes power (no way around that).

power makes power!! i like that statement lol!!

5 cells in my car and i have never played it with the car off...... daily driver.

statment is true when talking about a dual cell set up with an isolator inline.