97 Sportster 1 engine died at full throttle. Then barely cranks over.

[Jim97Seadoosportster]

Very new to all this...
I was coming in full throttle 7k rpm when port engine died. Then it barely cranked over but other engine was ok. It was very slow to crank but did very slowly but not long after it was as if the battery was dead and would not crank almost at all. But the other engine was running. I shut it down and started it several times and limped back to dock.
Then the next day I tried start port engine and it only clicked, (It has a brand new starter). Then I tried the other engine and it turned over a couple times and then nothing.
So I have a battery issue but could a depleted battery possibly be the reason the port engine died fast at full throttle in open water?

 

[Chester]

Time to take it apart to see what happened. Start by removing the jet pump and make sure the impeller turns freely.

Chester

 

[Jim97Seadoosportster]

Time to take it apart to see what happened. Start by removing the jet pump and make sure the impeller turns freely.

Chester

I wish I knew what that meant, lol.

 

[Jim97Seadoosportster]

Time to take it apart to see what happened. Start by removing the jet pump and make sure the impeller turns freely.

Chester

So you do not think the battery was the cause?