upTime may be increased twice within the same hour

[0xCAFEDECAF]

SolarMeter/Solarmeter.ino

Line 131 in 8f2cf97

upTime++;

If UpdateTime() in line 140 sets the time backwards, upTime will be increased twice within the same hour.

Example: at 02:00, UpdateTime() is called, setting the time to 01:58 .
if(iHour != lastHour && iMinute == 0) --> lastHour = 2, iHour = 1 --> differs, but iMinute == 58 != 0
But two minutes later, lastHour = 1, iHour = 2 and iMinute == 0, so upTime is increased again.

[0xCAFEDECAF]

Maybe it is a good idea to put lines 131...147 under a condition, like this:

        // Skip if last NTP update was recent.
        // Notes:
        // - If updateTime() adjusts the time, the hour may jump, but t will be equal to lastNtpUpdate.
        // - Assuming updateTime() does not set back the time by more than 5 minutes.
        if (now() - lastNtpUpdate > 5 * SECS_PER_MIN)
        {
            upTime++;
            // save the daily values every hour
            for(byte i = 0; i < NUMSENSORS; i++)
            {
                sensors[i]->Save();
            }
            // Preferrably do time update only when no sun is shining. A time shift can distort the
            // "average" output of pvoutput: if the current period becomes (let's say) 12 minutes instead
            // of 10 due to a 2 minute clock backwards setting, the average may be above the peak value,
            // that is very ugly.
            if (lastHour == 2)
            {
                UpdateTime();
            }
            #ifdef USE_MAIL
                if(lastHour == MAIL_TIME)
                {
                    SendMail();
                }
            #endif
        }
    }

lastNtpUpdate must be declared before loop():

extern time_t lastNtpUpdate;

void loop()
{
    ...