JAG in OZ
11th April 2021, 05:52
Hello forum members!
Thanks for the opportunity to join and ask for your help.
We are completely off-grid in the southern hemisphere with a north-facing 9.8kW PV array with a Sunny Boy and 6.6kW SMA Sunny Island, 10.2kW BYD Li-on batteries. Heat pump for hot water, solid fuel for heating in winter. We are located in the Perth hills of Western Australia so enough sun and wind. Our array is located on the car port (the separate house roof faces south).
But - we've found the batteries drain pretty low (if we have overcast weather on one day and rain the next as we move into autumn and winter, we are hovering around 25% mark) and we have to severely cut power consumption when we have a row of rainy days. We recently had the inverter stop functioning and had to buy in a fossil fuel genset while waiting the almost 3 weeks for SMA to sort that out. The solar guy has wired in the genset to the replacement inverter so that we have power if necessary (by running the genset, which is supposed to also fill the batteries once the power needs of the house are met).
To give you an idea of our appliances (all 240v), we run an electric kettle at least 5 times a day, the microwave at least 4 times a day, the electric stove once a day, the house lights are LED and motion activated (15 lights in total), the heat pump turns on every morning for about an hour, we run 4 lap tops, recharge 4 mobile phones, run two pumps (intermittently throughout the day) for water consumption (own supply), the dishwasher and the washing machine are used once a week, the fridge and freezer 24/7.
We are increasing our battery size, but we know from consumption patterns that this will still require watching consumption during overcast/rain periods. We are also looking at stringing inverters or at least having a back up inverter on hand, because SMA (in Australia at least) were crap at responding (the system is also only one year old - we are now wondering whether we shouldn't have gone with Chinese brands?!?).
Because we can have long periods with little opportunity for the sun to power the house, we have been considering a wind turbine to trickle charge the batteries overnight and when we have rain/overcast days. Our dilemma is whether to go for a 2000W system with a 14m tilt tower and guy wires, or a 600W system with a 6m pole (maybe even attached to the car port, which is separate to the house). We don't know what size we need, and our average wind speed is at least 5m/s. Is there another alternative? More panels won't solve the lack of sun issue, we have more wind in winter.
We are on a N-NW facing slope, and we have a few trees downslope. The area for the bigger tower means the lowest point of the blades would clear the highest point of the trees (about 30m away), and the carport is more exposed ie less obstacles. Winds tend to be either E, ENE or W, WSW, or SW.
We really don't want to have to rely on a fossil fuel genset hence trying to solve with a turbine. But - we've read that a lot of small systems don't pay off, that height and distance from obstacles mess up with power generation, and that power is lost the longer the cables are (from the point of generation to the point of consumption - so a completely ideal space clear of obstacles is too far from the house).
Any advice would be very welcome.;)
Cheers
Jag
Thanks for the opportunity to join and ask for your help.
We are completely off-grid in the southern hemisphere with a north-facing 9.8kW PV array with a Sunny Boy and 6.6kW SMA Sunny Island, 10.2kW BYD Li-on batteries. Heat pump for hot water, solid fuel for heating in winter. We are located in the Perth hills of Western Australia so enough sun and wind. Our array is located on the car port (the separate house roof faces south).
But - we've found the batteries drain pretty low (if we have overcast weather on one day and rain the next as we move into autumn and winter, we are hovering around 25% mark) and we have to severely cut power consumption when we have a row of rainy days. We recently had the inverter stop functioning and had to buy in a fossil fuel genset while waiting the almost 3 weeks for SMA to sort that out. The solar guy has wired in the genset to the replacement inverter so that we have power if necessary (by running the genset, which is supposed to also fill the batteries once the power needs of the house are met).
To give you an idea of our appliances (all 240v), we run an electric kettle at least 5 times a day, the microwave at least 4 times a day, the electric stove once a day, the house lights are LED and motion activated (15 lights in total), the heat pump turns on every morning for about an hour, we run 4 lap tops, recharge 4 mobile phones, run two pumps (intermittently throughout the day) for water consumption (own supply), the dishwasher and the washing machine are used once a week, the fridge and freezer 24/7.
We are increasing our battery size, but we know from consumption patterns that this will still require watching consumption during overcast/rain periods. We are also looking at stringing inverters or at least having a back up inverter on hand, because SMA (in Australia at least) were crap at responding (the system is also only one year old - we are now wondering whether we shouldn't have gone with Chinese brands?!?).
Because we can have long periods with little opportunity for the sun to power the house, we have been considering a wind turbine to trickle charge the batteries overnight and when we have rain/overcast days. Our dilemma is whether to go for a 2000W system with a 14m tilt tower and guy wires, or a 600W system with a 6m pole (maybe even attached to the car port, which is separate to the house). We don't know what size we need, and our average wind speed is at least 5m/s. Is there another alternative? More panels won't solve the lack of sun issue, we have more wind in winter.
We are on a N-NW facing slope, and we have a few trees downslope. The area for the bigger tower means the lowest point of the blades would clear the highest point of the trees (about 30m away), and the carport is more exposed ie less obstacles. Winds tend to be either E, ENE or W, WSW, or SW.
We really don't want to have to rely on a fossil fuel genset hence trying to solve with a turbine. But - we've read that a lot of small systems don't pay off, that height and distance from obstacles mess up with power generation, and that power is lost the longer the cables are (from the point of generation to the point of consumption - so a completely ideal space clear of obstacles is too far from the house).
Any advice would be very welcome.;)
Cheers
Jag