Difficulty using multimeter to measure amps of an inverter.

[Handmade Matt]

I have an inverter I want to measure the amps drawing when I'm running this laptop for example.
I can measure fine when I'm not plugged into the inverter... Powered up and on standby the inverter draws 0.3amps but as soon as I put a load on it the display on the multimeter jumps around a bit up to a couple of amps and then the inverter sounds it's warning buzzer and turns off displaying it's red warning light. A few seconds later the power comes on again and the meter jumps around and then the inverters warning kicks in again, this continues...

Does my meter put a resistance on the input for the inverter which the inverter detects as a problem with the power supply?
Are there any ways around this so I can take readings do you think?

Many thanks.

[epsgunner]

Um.. your only supposed to measure AMP in line with the + side of things..

Hooking meter for AMPS to + and - will lead to FRYING of something..

It would be + lead of meter to HOT side of wire.. - lead of meter to HOT side of inverter..

Current would then go thru the meter.. caution.. most meters are rated for only 10 AMP and not higher.. make sure meter it plugged into the proper jack on the meter front before turning meter on..

I could be wrong on the above.. so wait till someone else chimes in on this..

[Handmade Matt]

Thanks for the response. This is exactly how I am using the meter and am still experiencing this problem.

[epsgunner]

Suggest a Killawatt meter for $25.. HD and Lowes and Amzn have them..

Measures watts and amps.. plugs in the front of the inverter..

[Sunking]

Um.. your only supposed to measure AMP in line with the + side of things..

No that is not true at all. Makes no difference at all, youjust have to get the meter's polarity correct if using a needle movement type meter. Digital meters, polarity makes no difference.

[Sunking]

Does my meter put a resistance on the input for the inverter which the inverter detects as a problem with the power supply?

That is a possibility, remote, but possible. What is the full scale AMP of your meter?

In-Line current measurements of a meter use what is called a Shunt inside the meter. A shunt is nothing more than a power resistor. As current flows through the resistance which develops a voltage drop across it that the meter measures and displays as a current. That voltage drop could be enough to cause the inverter to trip off line from under voltage. I suspect your meter is either not capable of measuring the amount of current you are trying to measure, or uses some really high resistance non standard shunt. But it is only a guess.

It is best and safer to use a Clamp-On Amp Meter for current measurements.