For a very long time I have been thinking of setting up a 300 watt solar panel and micro inverter and use it to supplement my always on house power usage. My only real concern was my power company states they will shut off our power if they detect watts of power backfeeding the grid without first going thru the netmetering process.
This week I found legionsolar.com and they are selling what I was thinking about making and solved the potential backfeed issue with a power regulator that uses clamp on cores to sense power use from the grid and will automatically shut down any or all their micro-inverters so they will only produce power if they aren't going to backfeed the grid. They sell them in 300 watt increments. After talking to one of their engineers he explained that the regulator shuts off individual inverters to prevent backfeeding. Example you install 900 watts because that is what is always being drawn during sunny hours at your house. But for some reason, say a breaker trips and some of your stuff stops drawing power and now you are using 620 watts, the regulator will shut off just one of the inverters so you cannot produce more than 600 watts. (it will leave 2 providing power) Kind of a sledgehammer approach but it should get the job done. I was hoping it could just tell the inverters to lower their output but that may not be technically possible... .
Its a pretty interesting way to do it. The inverters and regulator talk via WiFi (not your WiFi) The micro-inverters only turn on, if the regulator is sensing enough power is being consumed. The base kit is $599 for 300 watts then you can add extension packs of 300 watts each later up to whatever you require. I am considering pulling the trigger on one of the base units just to see if it really works. My homes constant draw is a little over 600 watts, so if the 300 w kit works out I my get one of the extension units. They suggest you take your always on power draw and multiply that by 1.4 which seems reasonable to me.based on panels only rarely produce the power they are rated for unless you get perfect conditions.. -Bill
PS. I asked about UL listings. They are not there yet.
This week I found legionsolar.com and they are selling what I was thinking about making and solved the potential backfeed issue with a power regulator that uses clamp on cores to sense power use from the grid and will automatically shut down any or all their micro-inverters so they will only produce power if they aren't going to backfeed the grid. They sell them in 300 watt increments. After talking to one of their engineers he explained that the regulator shuts off individual inverters to prevent backfeeding. Example you install 900 watts because that is what is always being drawn during sunny hours at your house. But for some reason, say a breaker trips and some of your stuff stops drawing power and now you are using 620 watts, the regulator will shut off just one of the inverters so you cannot produce more than 600 watts. (it will leave 2 providing power) Kind of a sledgehammer approach but it should get the job done. I was hoping it could just tell the inverters to lower their output but that may not be technically possible... .
Its a pretty interesting way to do it. The inverters and regulator talk via WiFi (not your WiFi) The micro-inverters only turn on, if the regulator is sensing enough power is being consumed. The base kit is $599 for 300 watts then you can add extension packs of 300 watts each later up to whatever you require. I am considering pulling the trigger on one of the base units just to see if it really works. My homes constant draw is a little over 600 watts, so if the 300 w kit works out I my get one of the extension units. They suggest you take your always on power draw and multiply that by 1.4 which seems reasonable to me.based on panels only rarely produce the power they are rated for unless you get perfect conditions.. -Bill
PS. I asked about UL listings. They are not there yet.
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