Cursor (typing) all over the place.
 

I have a bizarre problem: as I type on my laptop, the cursor moves randomly to another part of the screen where it resumes the typing. Explained in another way, I suddenly discover when looking at the screen that my typing is showing all over the place.

This is not linked to the arrows or the touchpad and it started when I was using an old Toshiba laptop powered by an old sine-wave inverter itself powered by a 1.5Kw battery bank charged by a 12Volt solar system which all gave no problem for a couple of years.

I have now replaced this old inverter and the old Toshiba with a brand new Asus notebook and a brand new sine- wave inverter but the same problem persists.

I have a number of other gadgets also running from the inverter like a flat TV screen, a satellite Internet modem with VoIP and lights but the same problem exists when they are all turned off.

I also have a 12Volt "Danfoss" compressor-operated fridge/freezer connected directly to the battery bank and I suspect it could be the culprit.

I have ordered a DC to DC converter to run the laptop and bypass the inverter.

My question is: should I install some sort of filter between the battery bank and the inverter? Or have a similar protection for what is run from the inverter.?

If yes, could you advise what? (I am not an electrician).

Thank you for your help.