Saturday, 27 October 2018

Kitchen Progress

The main part of the camper kitchen has been made and I’ve now started on the drawers.  This next photo shows what the kitchen will look like when not in use.
The drawers are small and their contents won’t weigh much, so I decided to butt join the corners.  Once I would have attempted to hold the pieces together whilst attempting to join them, but after working with the boat fitters at Aldermaston I’ve realised making a simple jig is easier and results in a more accurate product.
My jig made from scraps
And this is how I used the jig
I then glued and clamped the 4mm plywood drawer base to the bottom of each drawer. 
Whilst the glue cured I went and checked on our solar production.  Something didn’t make sense!
We have 6.5kW of panels and a 5kW inverter which means the maximum AC output is 5kW.  When I looked at the solar panel DC input to the inverter.  You will note in the graph below the voltage from the two sets of panels on the roof is relatively stable (yellow & red lines).  As you would expect (rising sun) the current was rising (green & blue lines).  the panels seem to be doing their job.
DC Graph
On the AC side (inverter output) the situation looks completely different.  The voltage is stable at 250V (yellow line) but the current has plunged. 
AC Graph
That seems at odds with the solar DC production.  I then downloaded the actual data from the inverter.  At 8:45AM the DC production was:
String 1  395.7V and 3.09A (=1831.77Va)
String 2  320.8V and 5.71A (=1222.71Va)
Total DC production = 3.054kW
However the Inverter output was 251.6V and 29.59A.  This means the inverter was producing 7.445kW.  But the inverter can only produce 5kW and we only have 6.5kW of panels??????
This next graph shows AC production from the inverter for the same day
26 Oct
The voltage is stable around 250V but the current is all over the place.  It was a fine and sunny day without any shadowing of the panels.
So what did the AC production look like for the same day
power 26 Oct
AC production never reached 4.5kW.  So what happened to the 7.444kW of electricity? 
Another observation.  Getting the electricity supplier to move us to another phase (lower grid voltage) has improved our production by one kW.  however the inverter still hasn’t reached its maximum capacity.
The solar installer hasn’t responded (yet) to my email or phone call.  I’m retired… and have the time to be persistent!!!
Meanwhile today I managed to get our own electricity production and consumption monitors working.  currently they are working intermittently, but still providing sufficient data to give an overall idea of what is happening.
Our base load is approximately 0.4kWh with some ‘spikes’ when appliances such as electric kettle, washing machine and dishwasher are used.  We need to be mindful to stagger the use of these appliances to prevent our consumption exceeding our production.  You can see the production is over 4kWh’s on a sunny day and we’re exporting the difference between consumption and production back to the grid.


Paul (from Waterway Routes) said...

Can you temporarily disconnect from the mains to help identify if the problem is internal or external?

Tom and Jan said...

Done that already Paul. The problem is on the solar side. I'm not sure if the inverter has a problem or it's errant reporting on the part of the software.