was setting parameters last night batt went dead shut off ,so I charged it plugged it back in "full charge 6.6v correct polarity " and it will not power up any suggestions ? thanks budah

Start by checking the battery to ensure it did not fail during the charge process. Check it under load eg a 5W globe should do it.

Worse case scenario the EEPROM in the 4PKS got corrupt during the power failure if the write to it was incomplete. If this is the case then rewriting the data from a known good 4PKs will do the job. Or possibly a fuse blew in the 4PKS.

thank you I will try that tested batt was fine under load

After some thought a corrupt EEPROM should only result in corrupt settings values.

Did you try to power the 4PKs with a Lithium Polymer battery ?