In sci.electronics.repair, on Thu, 12 Oct 2017 14:27:20 -0500,
wrote:


I have a 300W, 12VDC to 120VAC inverter. It's worked fine in my car for
years, to power my laptop computer, a medical device I need when I am
"on the road", and even some small power tools. Recently it started
acting weird. Sometimes it wont turn on, (LED is lit). Or it keeps
cycling on and off. Often, I have to plug it into the cig lighter in my
car repeated times to get it to work.

I found out about 20 years ago that power tools need a lot more current
than I imagined, when I was out in the woods trying to use a drill with
a $20 converter. It wouldn't spin at all.

But as to your laptop, or at least as to my laptop, I just use something
that plugs into the cigarette lighter. IIUC there is substantial or
even great waste of power converting DC to AC just so it can be changed
in the laptop back to DC.

Of course how the 12 volts in the car is raised to 19v, I don't
know????? Nor do I *know* if it wastes power but I think it wastes
very little. The one below says, and I haven't measured it but I
believe it, "Power: Input 12V-16V/ 10AOutput: 19.5V 4.62A 90Watt;"

This was for the used laptop I bought this summer:
Car Charger for Dell Latitude 13 131l 2100 2110 D400 D420 D430 D500 D520
D530 D531 D600 D620 D630 D630 XFR D631 D820 D830 E4200 E4300 E4310 E5400
E5410 E5500 E5510 E6400 E6400 ATG E6410 E6500 X300 Xt
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

They have them for just about everything.

I haven't tried this one yet, because I'm not taking any car trips until
November, but I used my Acer several times with a similar charger and
everything was fine. I would park in front of a bank, McDonalds, or on
two occasions a hotel and use their wifi. All but one of these times was
at night so there was no place where I could actually go inside, and
come to think of it McDonalds was at 7 or 8AM and they weren't open yet.

But the point is that the power supply worked and the power monitor even
said the battery was being charged.

Also, using this has helped me cut down on my smoking.