Low cost pure sine inverter and drill charger.

I bought a 150w Aim Pure Sine Wave 12v/115v inverter to see if it would run my Sears 19.2v electric drill charger without the LPF I needed with my modified sine wave inverter. It doesn't and I will return it. The problem seems to be that the drill charger also uses a switch mode inverter and the two inverters interact without the LPF. I originally posted on this topic in December under "60Hz Inductor design". Dick