[aprssig] TAPR Dayton Solar Talk

[Brian B. Riley]

Not exactly ... the system shuts down when the grid goes out not just to prevent backfeeding the grid, but also to prevent burning up your loads. The output of directly PV-powered inverters sans the grid would vary so much it would raise holy hell with your equipment.

So cobbling the system to disconnect from the grid but supply power locally is only feasible in a battery based system. 

I have remained non-grid-connected for 21 years. I have 2.7 KW of PV panels (mixed bag ranging in age from 2 to 21 years old) and a 40 KW 24volt battery bank and 3.5 KW sine wave inverter on autostart, all this running the main household.  I also have separate  600 W PV array feeding a  7KW 12v battery bank and a 300W sine wave inverter that runs constantly. This system provides power for the N1BQ-3 APRS digi, my ham station, the cordless phone base, the satellite TV receiver, the satellite Internet transceiver/modem/router, and charging power for cordless devices.

I run the numbers every three or four years and so far I have not come close to justifying a $21K expenditure to bring the grid to my doorstep.

--
cheers ... 73 de brian  riley,  n1bq , underhill center, vermont
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On May 22, 2011, at 6:03 PM, KBØNLY wrote:

> Solar is getting cheaper..  However one point for those that read that well thought out email from Bob.
> 
> Grid tie solar is only functional when the grid is powered.  So in the case of a power loss it shuts down as well to prevent backfeeding the grid, so you can not be off the grid with grid tie solar.  However you can go with solar that uses a battery bank and a whole house inverter that has a grid tie option, when the grid fails it switches your household to the inverter and draws from the battery bank, like having an automatic transfer switch and generator but its an inverter and batteries charged by solar instead.
> 
> Lots of new options for solar these days and only getting cheaper!  Maybe in another 20 years I can afford it myself.. LOL
> 
> 73,
> 
> Scott KBØNLY