Did engine swap now possible bad HV battery?

I picked up a 2005 Prius with 117k miles on it that had thrown a rod in the engine. The car sat for about 30 days so some battery discharge was expected. It was badly neglected and went too long between oil changes and probably ran low on oil. I picked up a used engine with 87k miles from a local junkyard for $300 and had it installed by my mechanic who has 'some' experience with Prius's.

The car started right up no problem but the idle became rough and began to stumble then threw 2 codes: P2111 and P2103 which are related to the throttle body. After running for a few more minutes, we got the red triangle of death and a new code P0A80 for HV Battery failure.

First we decided to swap out the throttle bodies to resolve that issue and figure out the HV battery later. So with the throttle bodies swapped, the engine idle is normal now and the codes P2111 and P2103 are gone.

Since this car sat for approximately 1 month is it possible the battery is too far discharged to recover? There were no HV battery issues prior to the engine failure. Shouldn't I run it and drive it for a while to see if we can get some charge into the HV battery before starting to rebuild the battery pack?

Also, assuming we need to rebuild the HV battery, what is the best source? Ebay? I'm in Greensboro NC if anybody knows of somewhere local. I don't think Taylor Automotive in Sanford sells them anymore.

Thanks

 

Since we replaced the throttle body and did the force charge we've driven about 30 miles with no red triangle. We'll continue to monitor. Thanks for the input guys.