Perhaps someone at BAT could be of service about warning that an inexpensive Power Converter (ie 140 watt) may kill a portable drill battery charger, or other item because the Modified sine waveform produced vs Pure sine waveform. I understand the concept, but not the best one to go into a deep explanation.
There's a lot about this on RV forums. The Square Wave (Modified Sine Wave/MSW) inverters are cheaper to produce than Pure Sine Wave/PSW. MSW works fine in many applications, but they don't play well with some electronics. I've used MSW with electronics and been OK, but many haven't been so fortunate. Probably best not to take the chance unless you're running simple stuff. For example, an old fashioned corded power tool, lights, etc.