Hello Everyone,
I recently finished up my first solar install with 18kw pv and some battery. I've been enjoying going through the data and trying to see how long I can run without using much/any grid power. It's really got me thinking. There seem to be 2 schools of thought on building a bigger fully offgrid system.
1. Add more panels - The idea is panels are cheap so throw more panels and MPPTs at the install.
2. Add more battery - battery is more expensive but is needed to run at night, etc. There are also some extra precautions with battery storage.
Both options seem to have their merits and drawbacks. Just thinking from the numbers I've been seeing. If you have a system that produces 2-3kwh during a bad production day but use 3-4kwh, you're net negative all day. With enough battery, you can ride that out for a little while. Now assume you run into the wonderful winter months like we do in the north, where at times during Dec-Feb, you wonder if the sun exists behind the clouds, what then?
Now, let's take and double that system. During the day, you're producing about 4-6kwh and using 3-4kwh. You're covering your load with the ability to deal with spikes. On the flip side, it gets bright and sunny out and you now can produce 36kwh which is WAY over what is needed. Assuming you're not grid tied, you're essentially leaving power on the table.
Assuming budget wasn't a constraint, what's the best option? Add more panels or add more battery, or is it a blend of both and try to rightsize.
I recently finished up my first solar install with 18kw pv and some battery. I've been enjoying going through the data and trying to see how long I can run without using much/any grid power. It's really got me thinking. There seem to be 2 schools of thought on building a bigger fully offgrid system.
1. Add more panels - The idea is panels are cheap so throw more panels and MPPTs at the install.
2. Add more battery - battery is more expensive but is needed to run at night, etc. There are also some extra precautions with battery storage.
Both options seem to have their merits and drawbacks. Just thinking from the numbers I've been seeing. If you have a system that produces 2-3kwh during a bad production day but use 3-4kwh, you're net negative all day. With enough battery, you can ride that out for a little while. Now assume you run into the wonderful winter months like we do in the north, where at times during Dec-Feb, you wonder if the sun exists behind the clouds, what then?
Now, let's take and double that system. During the day, you're producing about 4-6kwh and using 3-4kwh. You're covering your load with the ability to deal with spikes. On the flip side, it gets bright and sunny out and you now can produce 36kwh which is WAY over what is needed. Assuming you're not grid tied, you're essentially leaving power on the table.
Assuming budget wasn't a constraint, what's the best option? Add more panels or add more battery, or is it a blend of both and try to rightsize.
