lojack_1776

If you understood how to design a DC to AC inverter you would see how much it costs to create an inverter and power it. Consider that every amp of 120ac requires 10 amps of 12dc, if the inverter was 100% efficient, which they are typically 85-90% on a good design. So if you want a higher wattage inverter, you need to increase the size of your wire and increase the amperage of your alternator. You will likely need to add another battery as well. Another challenge for inverters is peak instantaneous current handling. Designing an inverter to handle current surges is very expensive and creates an efficiency tradeoff. So complaining about your 400W and saying it is useless to me is whining, I have found plenty of uses for mine. If you need more wattage, pony up and start building one up. You will be able to do it a lot cheaper than an automotive manufacturer will charge you for it.