We’ve been a little obsessed with our electricity usage lately. All prompted by the fact that we’ve had solar panels and battery storage installed. This came with the ability to track our usage a little easier and I built a nice addition to this website that shows how our solar panels are performing. I added to this feature over the weekend, adding an algorithm that takes into account the amount of energy left in the battery at the end of the day. This means that the calculation of energy from the panels more accurately reflects their actual yield. Not only does it subtract an accurate amount from the yield to take into consideration the amount of energy put into the battery by force-charging, but it also adjust this to take into the consideration the round-trip efficiency of charging and discharging the battery.
Today, it’s pouring with rain and they are barely performing at all. It’s not all bad though as we force-charged the battery overnight so we are still using cheap-rate electricity from the battery despite the rain.
Sunday was a sunny day though so we fared much better. We still only produced just over 6kWh from the panels but that was enough to recharge the battery, keep us going all day and the cheap rate electricity in the battery lasted until almost midnight. You can’t beat free electricity from the sun… or can you….?
More Free Electricity
For the second weekend in a row Anna and I popped into town to do some Christmas shopping. Whilst there we plugged the car into the free chargers at Tesco. Not only do these give us electricity for free, but they are a little quicker than the Zappi that we have as our home charger. The Tesco Podpoints charge our car at around 10.5kW compared to the 7kW of the Zappi. They are free too, compared to the 14p per kWh at home.
That means that spending a couple of hours in town doing some Christmas shopping and having lunch in Yr Athro gave us around 20kWh of charge in the car. 20kWh of free electricity from Tesco is 3 times as much as we got from the sun – bargain!!!