charging laptop using underrated power inverter

ok, so I have a 150W Duracell power inverter that I bought to charge my Dell Latitude e6520 (yeah its an old computer) for an upcoming road trip.

I realized that this isn't enough power for my computer's charger (which requires 120v 1.5a).

Is there a safe way that I can charge my computer using the power inverter? Could I potentially make a sort of current limiting circuit my computer won't draw the whole 1.5a? Or could i limit the power draw in my computer's software?
(or is there possibly already a current limiting circuit in a power inverter?)

Thanks.

Is this just hand wringing or have you actually tested the inverter?

Paul

I would expect any decent inverter (or any power supply device) to have built in overload limiting. Duracell seem to be a quality manufacturer of batteries, I would imagine that if they make other things, such as inverters, they would be of good quality. Connect it up, see what happens. Make sure it doesn't over heat and be ready to disconnect if it does.

And no, adding external current limiting to a power supply of any kind is not going to be easy and will be more trouble than it's worth. You'd be better off buying a more powerful inverter and learning from the mistake.

How do you know the power supply needs 1.5A? If that is what it states on the label it will be the maximum, that does not mean it needs that much all the time.

Ideally check this kind of thing before buying...

Current ratings on mains equipment are really to allow you to select an appropriate fuse. Go by the power
rating for a more realistic estimate of actual steady-state current (take with a pinch of salt due to power
factor not being ideal).

For instance if you have three 1.5A pieces of equipment on a 5A fuse or circuit, you'd know adding a fourth
could be a problem. The limiting factor is often the inrush current spike.

The grey area is how well your inverter handles inrush current - many power conversion circuits can get
into a cycle of tripping out, restarting, tripping out, etc etc if presented with too tough a load.

author=PerryBebbington link=msg=4667253 date=1594101151]
How do you know the power supply needs 1.5A? If that is what it states on the label it will be the maximum, that does not mean it needs that much all the time.

I tested the wattage of the charger when I was using my computer using a "Kill-a-watt" meter. It turns out it never even got above 70W. I then connected it to the car inverter and it worked perfectly.

Thanks for the update, always good to find out what happened after someone has been given help.

The inverter only has to supply what the charger actually uses (except for the switch-on-surge) and its nominal power rating is basically the "continuous" rating based on heat dissipation.

If the laptop drew 150 W, you would have a warm lap! Its maximum draw will be when it is both running and charging its battery.

As Mark mentions, switchmode power supplies have bad power factors, so 120 V at 1.5 A does not necessary equate to anywhere near 180 W. :astonished: