2020 CRV

The batt has gone low/won't turn over.
The 1st time I thought it was because a interior light was left on. I didn't notice a light
on before or after charging it.... charged it everything was fine.

Few week later same thing ????

Months later, happened again. same as above, no obvious reason for it going low.

Any ideas on what it might be ?

 

Go buy a cheap voltmeter. Turn the car off, unhook the negative battery terminal. Hook the meter between the terminal and negative battery post, and switch the meter to amps. If you see a reading then something is on. Find it and kill it.

If you don't see a discharge, then you need a new battery or possibly an alternator. If it's a 2020 and still has the original battery, I'd bet you have a bad battery.

Over time constant series of charges/discharges will cause the lead to flake off the plates. It will collect at the bottom of each cell and eventually short out a cell. There's an easy test for this (none of the parts store guys know how, though) if your battery has caps, but the symptoms of a shorted cell are exactly what you are describing.