CrankyCoder said:
OffGridInTheCity said:
There are several options. Mine is but one of many. But to share - I'm off-grid and producing 9megwatts/year, delivering 240v@50a to the house thru automatic transfer switches. My goal is to double this to 18megawatts/year - e.g. 240v@100a AC available to feed into the house.
I think the scale of your end goals will affect your decision. If you know where you want to wind up, you can plan to get there in an incremental way - and that might answer some of your questions.
In my case, my PV array, Controllers (Midnite Classic), Battery (18650s), BMS (Batrium), Inverter (AIMS), and Transfer switches are all seperate units. This lets me add more PV+Controller or more battery or more inverting or more power distribution - one at a time (as long as the overall system/wiring sizes etc allow).
If you know/share your goals in more detail I think you'd get more helpful advise than my random comments here
I have no intention of being off the grid where I am. However, utilizing as little as possible does appeal. My goals are the following bullet points
day to day
* during they day, i would love to be able to run the house from solar and excess charge batteries
* at night pull from the battery until certain point then go to grid.
since I live in a hurricane/storm area power outages are a concern. during this time my goal would be.
* (this can be a manual thing) home automation and what not identifies power outage and restricts lights to lower brightness ect for "power saving"
* during they day, i would love to be able to run the house from solar and excess charge batteries
* during the night with power saving mode on, the whole house should be able to run for a decent portion of the night till sun rise.
Looking at my power bills. During the highest bill of the year i average about 60kwh per day. the daily average over the whole year is about 45kwh.
Hope this provides some additional info to get some feed back
Good info.
>I have no intention of being off the grid where I am. However, utilizing as little as possible does appeal. My goals are the following bullet points
>day today
>* during they day, i would love to be able to run the house from solar and excess charge batteries
>* at night pull from the battery until certain point then go to grid.
>since I live in a hurricane/storm area power outages are a concern. during this time my goal would be.
>*(this can be a manual thing) home automation and what not identifies power outage and restricts lights to lower brightness ect for "power saving"
>* during they day, i would love to be able to run the house from solar and excess charge batteries
>* during the night with power saving mode on, the whole house should be able to run for a decent portion of the night till sun rise.
My 'off-grid' system is designed to meet exactly the goals you list here. When I say off-grid I don't mean 'no grid'. It means that the power generation is not 'tie'ed (not connected)to thegrid electrically. When my system has enough power (battery reaches a specific charge level) the inverter turns on and this throws the automatic transfer switch relays so that the inverter supplys power to portions of the house instead of the grid. When the battery runs downthe inverter turns off and grid takes over. All automatic.
There are certain 'hybrid' (grid-tie with batteries) that meet your goals as well - see this link on the site
https://secondlifestorage.com/t-Wha...ould-I-use-What-is-a-hybrid-grid-tie-inverter
>Looking at my power bills. During the highest bill of the year i average about 60kwh per day. the daily average over the whole year is about 45kwh.
My 24panels = 7kw system produce9,500kwh / year. That's an average of 26kwh/day. Winter is 14'ish kwh/day. Spring/Fall = 30'ish kwh/day. Summer is 45'ish kwh/day.
Per your info - 45kwh/day * 365 = 15,425kwh / year. In southern oregon that would be 11kw PV array. 11,000/300 = 36panels.
My house is wired to consume anaverage of 2,400 watts/hour which means the 45kwh/day generated is consume as30kwh of PV directly (during the day) and 15kwh frombattery into the night.
With that kind of profile,at 60% DOD that would be a 25kwh battery.
To recap:
Array size (2kw, 7kw, 11kw) is a key metric to the Hyrbrid or Grid-Tie Inverter or Off-Grid/MPPT-Controller you chose.. and perhaps how many you need in parallel. As I mentioned, to handle 7kw PV array I have 2 Controllers in parallel. The size of your system dictates what you need to purchase. For a larger system you need to purchase large spec equipment or be sure you can parallel multiple smaller ones..
Minimum effective battery size would be relative to your PV array, home power draw, goals. I gave you the example of 7kw PV array, home use of 2400kw/hour, 60% DOD would be on the order of a (minimum) 25kwh battery size.
