Alternative Technology Assn Forums

1. 

   Cooby
   Member

   We (two adults, one small dog) are planning to move from our urban house to our simple acreage dwelling (self built) in the next year or so, and install an off grid electrical set-up.
   The more we talk to solar companies the more confused we get as to size, cost, technical jargon, etc; so we thought we'd bounce a few questions off non vested interests.
   We currently use about 8 Kwh of electricity/day, but still want to use, modestly, most of our mod cons at our new residence - fridge, computer, lights, tv etc (stove, hot water is gas)
   Given a sunny climate, what size/cost system should we be looking at?
   What are the pros and cons of wiring for 12v or 240v?
   We have been using a 5Kw generator in our building process - can it be incorporated to help charge batteries or take some of the heavy loads for a couple of hours/week?
   What with dozens of companies offering this equipment, how does one sort out quality/value from the rip-off merchants?
   Thanks in advance

   Posted Monday 27 Jan 2014 @ 11:04:15 am from IP #
2. 

   franks
   Member

   Assume 10 kWh per day max designed usage,
   4 peak sun hours, want 2 days of battery back up, 40% gross system losses.
   size of solar array(10*1.4*)/4 min 3.5kW Solar array.

   Size of battery bank 10*2*2 (assuming 2 days battery automoty and 50% dept of discharge for lead acid batteries)
   will need 40kWh of battery storage.

   I would use 48 volt battery system nowdays is the way to go, ie 48 volt 830 amp hour lead acid or 500 amp hour lithium.

   Posted Monday 27 Jan 2014 @ 11:16:04 am from IP #
3. 

   johnmath
   Member

   We have all mod cons and use less than 4 kWh per day averaged over 12 months (Adelaide, two adults, gas cooker & hot water). Max consumption when running R/C A/C all day (46 degree days) was 12 kWh.

   The point I am making is if you halve your usage, you can halve the off-grid system size and save many thousands. Getting down to this consumption level wasn't particularly difficult, you just need to consider the electricity / energy component in every choice of energy consumer, and building (double glazing / insulation / passive heating / cooling, etc.)

   Posted Monday 27 Jan 2014 @ 8:37:07 pm from IP #
4. 

   franks
   Member

   Battery storage $300-400 kWh, PV $1 per watt or 4Wh (assume 4 peak sun hours), $1k of PV will give 4kWh of energy on average.

   Its more cost effective to over spend on PV if you can have bulk of power usage during the day.

   Posted Monday 27 Jan 2014 @ 10:27:36 pm from IP #
5. 

   wlb
   Member

   Roughly where are you?

   Posted Monday 27 Jan 2014 @ 11:35:08 pm from IP #

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