[aprssig] TAPR Dayton Solar Talk

KBØNLY kb0nly at mchsi.com
Thu May 26 13:22:35 EDT 2011


Judging by your install and the cost to bring the grid in I take it your 
remotely located.  Being in urban america I can't justify the cost of solar, 
but if I was facing $21k for grid power you can bet I would have a big solar 
setup like you.

How long do the batteries live before replacement??



-----Original Message----- 
From: Brian B. Riley
Sent: Thursday, May 26, 2011 11:41 AM
To: TAPR APRS Mailing List
Subject: Re: [aprssig] TAPR Dayton Solar Talk

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
   Home of the
      K107 Serial LCD Controller Kit    FT817 Power Conditioner Kit
      Propeller Platform                          Freeduino systems

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

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