Laptop shuts down on Treadmill

I have two Dell Inspiron laptops: a 3552 and a 3558.  Both are less than 18 months old.  When I use either one while I am on my tread mill (2 hp motor), after about 20 minutes of operation they die. Screen goes black for no apparent reason.   Sometimes they reboot themselves, sometimes they are difficult to restart.  The Event Viewer tells me they experienced a critical kernel-power error 41.  There was no apparent power interruption, and besides, the batteries are installed and healthy.

Both laptops have recently been “clean installed” with Windows 10 v.1709.

I have run SFC /scannow.

I checked drivers on the Dell support site and got an update to BIOS.

I ran all the Dell hardware diagnostics:  All OK.

I ran the Intel utility to check for any updates:  None available.

I preformed a Windows RESET of windows 10:  Same issue.

I have bypassed the power strip I was using: Same issue.

I have removed the power supply and run only from the batteries: Same.

One laptop (3552) was having problems installing KB4054517, so I “hid” that update: Same issue.

I turned off the trackpad and used only an external mouse: Same issue.

I am wondering if there is some kind of electrical interference involved.  Besides the treadmill, there is a table fan, a Magnavox TV with external speakers and a Roku stick nearby.  Wifi connection is coming from an Eero wifi unit within the same room.  I am not sure what has changed:  I have used these laptops or similar laptops on this treadmill for years.

Another thought: Static Electricity generated as I walk on the treadmill?  This laptop crashing problem started as the weather got colder and drier.  I do not notice a static discharge, but the crashes seem to occur just as I touch a key.

Next steps?  Any guidance would be appreciated.

Thx,

MikeT in VA