Code U1123, Hybrid Battery Problems?

I bought the vehicle listed above Hybrid to replace a previous one I lost in a collision. I bought it "as is" from a dealer that said it had run fine until it sat a long time and developed a "hybrid battery fault" and he could not sell it. I ran codes and got a U1123. I bought a new 12V battery and installed it. When I tried to start it, the engine would jump just a bit each time but would not start. I bought a 430V converter and attempted to charge the hybrid battery for over 18 hours. I attached the leads to the two posts under the driver's side passenger seat. It only charged up to 114V but quickly dropped after I removed the converter. When I tried to start it, the engine jumped with more force, but it did not start. I had a new hybrid battery installed by Hybrid To Go but it still won't start and the navigation radio display says, "charge insufficient to start vehicle, leave key in ignition and connect jumper cables". This message is referring to the Charge Assist Mode for the hybrid battery. We tried to charge it according to the manual's instructions but still have the message. The owner of the Hybrid battery company insists the battery is new with Toyota cells inside. Any thoughts?