Cal's advice is very good. Please do heed.
What the PO made for you was a track bike, not a commuter.
Do report what ignition system is installed. And, what wattage headlight was installed.
The stock bike drew about 10 AMPS when lighting and key switch turned on. You should find out what your bike now draws, as some ignition systems and 3 ohm coils will double that systems current draw, as can a "brighter" headlight.
The stock alternator can produce 150 Watts when revved up. That's about 12 amps. At idle speed, the alternator output falls to about 4 amps. So, your operating load needs to be known in order to determine how long the battery can last at your usual engine RPM, and how long it will take to restore the battery when the engine is revved. If your bike is still drawing 10 amps, it will deplete the battery at a 6 amp rate during idle. The charging system when revved will take 3 times longer then the idle duration to restore the battery to full since it only has a surplus of 2 amps for the battery restore after supplying the electrical system. A 3 minute idle, would need 9 minutes in cruise RPM to restore it.
This all assumes your charging system is working as best it can, including connector, switch, and fuse block connection voltage losses. All of which can be measured.
If you are using the e start, that's a bonus 25 amp drain when you push the start button.
The battery is an energy bucket. If you try sucking a gallon out of a cup sized container, without an incoming supply of water greater than what's being drawn, the cup goes dry.
Your ignition system needs power to make spark. No power, no spark, no engine run. That part is pretty predictable.
Cheers,