Our Solar systems
In common, Batteries should be full loaded frequently to obtain there expected lifetime. Based on the local situation and the load during the day and night (discharge) a calculation of capacity of the array and batteries is required. What helps is an oversized array (if the charger is supporting this) and heavy loads during the (sunny) days. Helpful is a charger that supports a PLC protocol (like Modcom) and a PLC that switch loads on and off.
The solar panels.
In common: panel specification is based on 20oC and 1000Watt per m2. The sun power is measured on a horizontal area and is the maximum on our location is 1338 W/m² at 30/04/2018 at 13:04:38.
What is on the solar panels is depending on moisture in the sky, the altitude and the azimuth and how the panels are positioned to the sun.
From the start in 2005 we bought 14 panels, Keyocera 12V 125 W for on the roof, configured as a 24Volt installation. De charge controller was at that time a Morningstar Tristar 60Amp PWM. In 2010 we have extended the system with 8 panels 24V 180W on a pergola. At the same time we have replaced the 60AMP PWM charger with 2 X 60AMP MPPT charger. The panels were split in two groups one 24Volt and one 48 Volt Group. These chargers can be used for both 48V en 24V arrays to load a 24V battery. They are also capable to handle “over sized arrays”. Reason to do so is that 14 panels 12V can be configured as an 48V array. In 2016 we have extend the amount of panels with 12 X 100W 12V panels mounted on the south wall of our house. This gives great opportunities in the winter with low sun elevation and snow. Roof panels are dead by that.
the chose made for Morningstar tristar 60Amp MPPT is the fact that these can be used with higher voltage, over sized arrays, more then one in parallel and they have a network connection with the ability to check them web based, download statistics via free software and last but not least they are supporting the MODCOM client protocol.
Both chargers are via the network connected to a TRILOGIC Nano-10 PLC which can act as a MODCOM server. I wrote some software that, based on load conditions of the battery and the available solar power, the redundant power is used to heat an electric boiler (1400W)
In 2005 we used 4 traction batteries 12Volt 256AH in serial parallel configuration which give a 24V battery 512AH. After 4 years without any relevant deep de-charging the batteries went dead(!). The point is with serial batteries you can equalize the batteries by over voltage during short time (standard program of the charger). Batteries in parallel you can not and if there is a slightly difference between both banks one is charging the other during the night. In 2009 we bought 12 cells OpzS 1320 AH(C20). We avoiding deep charging max 40% till 60% capacity and they are functioning without any problems.
A sine wave inverter (instead of a pseudo sine wave) is imported for the use of
Refrigerator and freezer, all equipment with a transformer (Radio’s) and motors depending on power frequency (Water Pomp etc). A pseudo sine wave is in fact a modified block wave and contains higher harmonic frequencies (multiply of 50/60Hz) what can generated high voltages in equipment. We have chosen for a Victron Multiplus 5000/24/120, Capable to handle a load of 5KW and charge the battery with max 120 Amps with a generator. The inverter is configured in the power assist mode what makes switching from an to a generator seamless.
For additional support in the winter during havey snow we have Honda generator EM50is with remote start. We are using this generator 10 hours a year at the most.
We have both all our equipment for as far as it is rated with an Energy label A or better. As an example: recently we bought a new refrigerator with an A+++ label. All our lights are LED. We use the following equipment:
Refrigerator 200 liter and freezer 200 liter
Electric combi oven (with microwave), used in the summer. In the spring and fall we are using a propane oven and in the winter we are using a wood oven, used as well for heating the kitchen.
Radio, PC’s, satellite receiver, TV’s adsl modems, network equipment etc.
Kitchen equipment like coffee machine, mixers etc
Garden equipment like Hydraulic splitting machine for fire wood. Shaw machines, concrete mills etc
In the summer we are using minimal 8KWh per day with a maximum of 20KWh and in the winter 3,5 KWh per day.
During a thunderstorm in august 2018 we were hit by a lighting and as a result one Charger controller died and has to be replaced. Beside our ADSL modem, some other equipment has died as well. I am not sure how to prevent incidents like this in the future.