That stinks!gschettl wrote:The main reason I want to absorb my own solar energy is because the very last step, (after the solar system was installed and functional) was to sign a contract with the electric utility to allow trading electricity with a bi-directional meter. The unexpected catch is the contract specifies they will pay me less than half for each kWh exported to the utility versus what they charge me to import a kWh. I haven't gotten my 1st electric bill yet but other local solar customers have confirmed that's what I can expect.
You may want to look at this thread on the Enphase Energy Management system (and their AC battery) and this thread on the Tesla PowerWall battery system, which future versions SolarEdge inverters will support. Both product families are expected around the end of this year and are designed to address the kind of issue you are facing. I expect SolarEdge will offer some sort of trade-in for older inverters if you are purchasing a battery upgrade. Whether these systems will be cost effective or not remains to be seen. Certainly in some parts of the world where electricity is very expensive, they will have value.gschettl wrote:Another reason is someday I'll have a battery storage system and would want to divert solar electricity to that too, before returning any to the grid.
So I'm surprised I'm not hearing of any turn-key system available yet designed to divert to batteries variably based upon the excess solar electricity being produced. My whole house egauge does a good job of showing how much is being returned to the grid moment by moment and it seem this information could be used wisely.
However judging from the few replies this post got, it would be more complicated than I'm willing to pursue.
It appears OP has a 2012 LEAF. As such, the maximum power draw from the wall is on the order of 3.6kW. In addition, the battery can only accept so much charge before it is full, depending on the SOC at the beginning of the day. With a 40-mile RT commute, maybe 10 kWh available each day is a ballpark figure. (But if you are commuting each day, likely the car is not even available for this purpose?) Without the ability to DISCHARGE the LEAF battery back into the grid at nighttime, the LEAF can only provide a limited amount ofdavewill wrote:If you can program at all, you could probably program in a Bell curve of charging rates to roughly match your generation curve.
Have you visited the demo? Can you set parameters such as "I don't want to drive my EV at all"? The intent of course to max out the storage of both batteries for use in the house at the optimum times. Will the HEMS communicate to you when is a good (or bad) time to use high level of loads? Thinking of all the "smarts" such a system could provide is tremendous. As an example, change the set point on your electric household heater/AC (God forbid!) within a reasonable range to minimize consumption and/or rates. Combined with some smarts put into heat retention in new construction, this could make a significant reduction in energy consumption - shifting power consumption to off-peak (essentially non-peak) can tremendously improve the grids efficiency and capacity with the (costly) installations we currently have.eMaS wrote:See if you can get your hands on the Honda HEMS system
we have a demo house here at UCDavis, CA
all the technical info is available at: