Keep on trying to retrieve NTP time as long as the time is unknown

[0xCAFEDECAF]

SolarMeter/Solarmeter.ino

Line 155 in 8f2cf97

for(byte i = 0; i < NUMSENSORS; i++)

My suggestion would be to insert the following lines here:

    // Keep on trying to retrieve NTP time as long as we don't know the time.
    // In a situation of power line restore, the uplink (home router) might still be rebooting when the
    // call to UpdateTime() is made within setup() above.
    if (now() < 1451606400UL) UpdateTime(); // 1451606400UL is 2016-01-01 0:00:00