tigerwillow1
Known around here
4kW with battery + 4kW without.
The situation on the West Coast
- Thread starter Arjun
- Start date
BORIStheBLADE
Getting comfortable
Have you been just on batteries from an outage? I'm curious how long you were able to sustain with that combo. I've been toying with the idea of something like the Tesla power or just getting a generator. Depending on the size of your house and usage 4kW seems kind of on the low side on its own.
tigerwillow1
Known around here
So many variables. I have 14 kWh of battery, with the goal of never running it down past 50%, so 7 kWh usable. This is with a dozen golf cart size batteries. I look at it 2 different ways. For short term outages, say 24 hours or less, it's a great convenience. The switchover to battery is seamless and we find out there's an outage when a neighbor calls to ask if our power is out. The highest priority consumers are 2 fridges and a freezer that take about 3.5 kWh per day, so we're pretty free to do everything except wash clothes, run the air conditioner, or use a huge amount of hot water. (Also have a solar hot water system too, so in summer the supply is close to unlimited, in winter practically nothing).
For a long term outage I think in terms of survival. In the summer the panels will leave the battery fully charged every day. The daily net output of the panels in the battery backed system is ~20 kWh per day. In the winter months net production averages 6 to 7 kWh per day, but is highly variable with the weather. When the roof mounted panels get covered with snow, we can go 2 to 3 weeks with zero production. That's where the Honda portable generator running off of a big propane tank comes into the picture. It should be able to bring the battery up to full charge every day if we're not pigs using the power. Our main heat is electric but there's a propane fireplace insert that will keep us from freezing to death. We have a separate problem of a well pump that draws 4 kW. For this I have a tractor mounted generator that I can use to have the well pump fill its holding tank, which would need to be done maybe once a week in a survival situation. The pressure pump that feeds the house from the holding tank can run off of the solar system.
For a long term outage I think in terms of survival. In the summer the panels will leave the battery fully charged every day. The daily net output of the panels in the battery backed system is ~20 kWh per day. In the winter months net production averages 6 to 7 kWh per day, but is highly variable with the weather. When the roof mounted panels get covered with snow, we can go 2 to 3 weeks with zero production. That's where the Honda portable generator running off of a big propane tank comes into the picture. It should be able to bring the battery up to full charge every day if we're not pigs using the power. Our main heat is electric but there's a propane fireplace insert that will keep us from freezing to death. We have a separate problem of a well pump that draws 4 kW. For this I have a tractor mounted generator that I can use to have the well pump fill its holding tank, which would need to be done maybe once a week in a survival situation. The pressure pump that feeds the house from the holding tank can run off of the solar system.
BORIStheBLADE
Getting comfortable
You got your situation handled pretty well! Your winter charging situation is what I was thinking about for long term outages. Using a generator to charge a wall pack. I wasn't sure if it was possible but figured it had to be.. Are you using a basic 30 amp portable generator?
tigerwillow1
Known around here
The portable generator is a Honda eu2000i, 1600 VA continuous rating. My Outback inverter/charger allows charging the battery from the generator. Something to verify you're able to do when selecting the hardware. This particular charger is picky about the incoming power and will reject some inverter generators and pretty much all non-inverter portable generators.