Don't try to dampen it electronically!
The laptop is drawing current as it needs it, and trying to dampen it (with a choke for example) will only stress other components in the train; IF it is even successful.
With dancing currents from transient type loads such as laptops, you're best off averaging it 'in your mind'. Sadly enough, that's really the best way, unless you have a means of averaging it mathematically (which aint gonna happen with an analog meter).
I run up against the same problem, only in the digital realm. Unfortunately, I just have to deal with it. It's a REAL PITA with digital meters because the numbers change just fast enough to drive you nuts!
If you're going to attempt ANY kind of smoothing, use a VERY large capacitor after the meter, as the last thing the inverter (or laptop) sees. Put any choking or ballast BEFORE the capacitor. It still might not help.
Either way, limiting current is an evil of smoothing it out. And computers don't tolerate flaky power well.
My advice to be blunt? Don't do it at all.
Laptops can draw anything from 50% to 200% of their "rated" current on the label. All depends on CPU load, hard drive access, screen activity (white vs black believe it or not
even on an LCD panel causes significant variations in power requirements), whether or not the internal battery is charging, and so on.
Seen WAY too many PC power supplies come in fried thanks to even just running from a generator (hurricanes are common around here). Every year it's the same thing. Hurricane comes, followed by bad power supplies. If they don't like the relative 'cleanliness' of an ICE driven generator, imagine how they will react to the variations the current limiting will cause. With a laptop powered by an inverter through it's brick, damage is a little less likely, but chances are, you'll piss the inverter off, and cause it to trip out constantly, leading to more variations when the laptop ends up on it's own battery and then decides it needs to charge.
I think I've made my point.
Steve
EDIT -
What you CAN do, is use a buffer with a shunt, and average the signal coming out of the buffer to drive a meter movement. Chances are though, the movement you have won't work that way since most battery charger meters are made with a heavy coil of wire (repulsion type), and don't respond to small, low current signals. There isn't a 'shunt' in the traditional sense in there. You'd have to get a d'arsonval movement type and calibrate the scale yourself instead to go this route.
