Question about diagnosing panel

Hi everyone.

So, I have a 300 watt panel.

My panel initially shows a decent output when put in the sun, then the output gradually decreases to almost zero amps.

I'm curious if it could be from a hotspot or short somewhere.

What do you ask think? Any ideas?

Thanks!

Is the battery full or is there a load?

How are you testing your panel output?

@chrisski & @crossy Sorry, didn't get a notification about replies.

This is a panel that's completely disconnected and using a meter across the cables.

It starts fine, middle of the day, direct sun with zero shading. Initially has a decent output (around 4 amps) and slowly drops to 0.

I've done the test twice.

Could I have maybe multiple hot spots or something so the bypass diodes aren't able to just bypass the bad spot?