"How can I make my system produce more than standard voltage charging"に関する回答Hi! For a start, it's probably not voltage you need more of, but current or capacity. If you need more power while the vehicle is running, you will need to retrofit an alternator that can deliver more amps than the one you have currently installed. If you need more power when the vehicle is off, you could either replace your battery with one that has a higher amp-hour rating, or retrofit a second battery wired in parallel. This would double your capacity, letting you run your stereo for twice as long while the engine is off.