Sunday, November 6, 2011

Lummy, It's Dark!

As Victor Meldrew would say, "I don't beeleeve it!".

It's been so dark the last two days... I mean properly night time dark at mid-day.

839Wh generated yesterday.
Only a measly 712Wh today!

From a 2.5kWp PV array!!!

I've not had to turn the inverter off since maybe February, but today the battery bank crashed to just 26% and everything had to go back on the mains and the inverter was off - at lunchtime.  Not even the night... Lunchtime!

My base load on PV is pretty high though.  I put a clamp-on Current Cost meter (kindly donated by a friend) on the inverter output and all the network gear and DECT phones and bits and bobs around the house add up to about 80W continuous.  Quite surprising really that the battery can run all of that for a couple of days.  But the inverter has an idle power of 35W all on its lonesome, so that bumps the total DC load up to about 105W.  That's 2.5kWh per day.  And with only 1.55kWh charged in the last two days, and only 3.37kWh charged in the previous two days, it was just a question of time before the battery reached the end of its tether.

Didn't help the BBC 24 hour weather forecast being completely wrong for two days in a row, so I used too much battery power on Thursday and Friday on the promise of "sunny intervals" for Saturday and Sunday.

If things don't brighten up tomorrow, I may even have to break out the mains powered battery charger from the loft.

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