Or a ground short in your wiring.
The Poster said that his shop charged the battery and checked his charging system, then it went dead 2 days later. Does not state that he rode the bike during those 2 days. Better clarification could help. And explain what the charging check was.
I would charge a battery. Install the battery. Check the voltage and write it down. Then I would start the bike and check the voltage at idle and write it down. Then I would run it up to about 5,000 rpm and check the voltage and write it down.
After doing all that, I would take it for a good ride. About 30-60 miles, but stay close to home so you don't get stranded. As soon as I pull into the garage I would kill the key and check the voltage.
If the battery is still above 12v at that point, it's not a charging problem.
More than likely it is a shorted wire, a light staying on, an alarm draining the battery, etc..
If it turns out to be a short, do not buy a Shorai or Ballistic. It will be money tossed down a drain. You must find the reason first. The dry lithium batteries are considered not to be salvageable if drained below 6v. Sounds like you would ruin one within 12 hours of shutting off the bike.
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