Why Is My MG1 discharging my HV Battery???

What is your question?

I just bought two 2001 Prius with the intent of learning how they work. The first one I was able to rebuild the HV Battery myself at a cost of $40. I got lucky on that one, only one bad module. I bought one off eBay for $40 from a 2007 second generation battery. The second Gen is a much better battery an has a longer life than the first Gen. So, first one success. The second one I bought from a junk yard an every one of the 38 modules were bad. The best one measured .2 Volts. I replaced all with 2007 modules. The 01 has 38 modules, the 07 has 28, I had to use all modules out of one battery an 10 out of a second 07 battery. So I was able to successfully rebuild two HV Batteries and at a total cost of $1040 for the two. My problem was an still is that the second Prius will start an run normal for a few minutes. The energy flow screen shows the ICE sending energy to the MG1 and from MG1 to the HV Battery. This part is all normal. However it is discharging the HV Bat rather than charging. After a few minutes the ICE will shut down, main battery problem lights up an I get a code of P3010. I can erase the fault code leave it set a few an the HV battery will come back with enough power to go through the same sequence again. I will finally have to take the HV battery out of first Prius which is fully charged an put it in the second prius. The HV Bat. that I just ran down I put in the first prius. The car starts an runs fine on the same HV Bat that I just took out of the second Prius that tells me I have a HV Battery problem. So far I have swapped out the Inverter/Converter, Engine ECM, the battery is changed as a complete unit with the HV ECU an all relays etc. of which all work fine in the first Prius. I have just about exhausted my ideas so far as what else could be my problem. If anyone knows of anything which could be causing the MG1 to discharge my HV Battery, please let me know. It seems I have learned a lot in a month of exploring these machines but until I solve this problem I am a looser. Any help at all will be appreciated. Thanks much.