Do you find battery supplies inferior to well designed power supplies?

I have to ask, because every single battery powered unit or battery supply I have ever tried sounded great for the first few tracks, then focus gets blurry and things sound lost. This has happened with every single battery powered audio device I have tried. All of these devices are regulated as well, and really kind of have to be, but I just never got the consistency that I get with Linear Supplies and or well designed switch mode supplies, for example.

Fresh charge, sounds great, play awhile, things get lost. This is battery powered DAC’s, Hubs, Battery Power Supplies with SuperCaps, etc. I only have experience with digital products using batteries, which is why I posted this in Digital forum.

Look forward to your experiences and thoughts!
No problems with my Chord Hugo.  It sounds best on batteries only.  There are colors from blue to green to amber and then to red to indicate battery level.  I don't notice any change until the level goes to amber which diminishes dynamics.  I usually get around 7 hours before a recharge.
My Jeff Rowland Criterion Preamp sounds absolutely INCREDIBLE on battery power.  
Maybe Tesla should be looking at the high end audio market for their Powerwall ;-)
I ave had a number of battery dacs and my transport is run off a battery. IMHO A Dac and amp on a battery is very quiet, but you loose the bloom that a well designed transformer supply can offer. At first it sounds great but after a while you realize the music is lifeless
and boring. Battery on my CD transport does exactly the opposite. I purchased a Paul Hynes LPS (arguably one of the best made) and on my transport the sound quality degraded some on the Dac it was exceptional.
The battery used and build have a lot to do with how good/bad the sound quality is. Remember there is still noise that comes from the chemical reaction need to produce the power. My BPS has a bank of caps on the positive and negative side. Which reduce any noise to an inaudible level. The bigger the battery the better!  I use a deep cycle Optimal Yellow Top car battery. In the On position I get pure power from the battery to the bank BG caps. In the Off position the charger kicks in and there is a 12v wall wort that keeps the transport warm and ready to use. YMMV
Battery supplies are no different from mains supplies when it comes to being able to provide sufficient "power" to handle the most demanding transient spikes.

Where battery supplies tend to fail is in theri ability to deliver enough current.

If they are unable to provide enough current to handle those spikes then the voltage will drop and your SQ will suffer.

If you are contemplating a battery power supply it is always prudent to  use a bigger "battery" than you anticipate you will need.

Connecting batteries in parallel will ensure they can deliver the required current.

Even with low power devices like dacs and preamps, batteries are lacking dynamics. But the capacitor concept of vinnierossi lio sounds interesting