A 'Failing Grid' Solar Power Project.

This project can 'solar power' the vital appliances in a small house! It is not cheap - but neither is the price of future electricity! Or the cost of replacing the contents of your fridge and freezer (which you WILL loose at the next power failure). As a former research tech with the Nat. Power Grid, I know the neglected state of the grid, its design compromizes and that there absolutely will be an increase in blackout frequency.

Feedback welcome.. (via the 'Contact Us' page.)

* Totally 'Off-Grid'?: If you have significant amounts of frozen food, it is NOT practical to go Totally 'Off-Grid' with a small solar setup like this.. With two rainy day, you will need grid power to keep those items preserved. And, power from a petrol Generator is far too expensive.

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Click here to see the 'Tech Notes' page.


The list of required equipment includes:
4 x N70T batteries ($1000): 1kW of Solar Panels ($800)
An Inverter (2kW pure sine) ($200): A 40A Charge controller (3 stage, programable) ($200)

From a 2015 "Freezer Backup" project..
With just one solar panel (250w) and one caravan battery, the unit below can keep a Freezer (60 watts) running 24/7 in the event of a power failure. For Fridge, Freezer & lights (140w), the same unit needs four PV panels (1kW) and four 100ah batteries. (eg. N70T)

Small home - Solar power supply

 

Technical Notes:
Note 1: 'Solar' is NOT totally Free Energy..
The minimum electricity usage for a tiny house is about 3 kWh/day or $1/day..
To run 3 kWh/day on Solar will require a 300Ah battery. Eg.  4 x N70T batteries = $1000.
The 3 kWh of solar at 30c/kWh will save $1/day.
Saving $1/day; it will take about 7 years to payoff the battery pack and the 1kW Solar panels, Controller & Inverter. Sadly, after those 7 years, the battery pack will probably need to be replaced! 
Thus, it might be 10 years before you will have any "free electricity" (and then for just 4 years until the batteries need replacing again!)

Click here for more 'Tech Notes'.

Can you add something to this article??

New points/corrections are most welcome.. (via the 'Contact Us' page.)


Construction Notes:

c1. Duplication is the key insurance.. While you are without grid power, if some component of your 'solar unit' fails, you won't have time to buy replacement parts before you loose the contents of your freezer. A dual (duplicated) solar system will allow you to function on half power. You may loose your TV and Microwave - but not your fridge and freezer.

c2. 

c3. The  'Anderson Connectors' (to the batteries)..
We used 50 amp 'Anderson Plugs' wired in parallel to allow a 100 amp draw.
That is only 1.2 kw - but enough for a cottage or during a Grid failure.


Battery Leads

The above 3 plugs connect to the 3 sockets shown in the main image as "to the Battery".

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c5. For long life, the 'Lugs' on the 'battery to inverter' cables (and the Anderson plugs) need to be soldered.. Without an expensive 'Crimping tool', these large 'Lugs' will be hard to attach.. The options are.. Totally fill the lug-cups with solder: Modify an old pair of 'vice grips': I used a small block of very hard wood with a half circle groove - then I hammer/indented the lug with a hand shaped bolt.

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Basic Circuit Diag.

 

Circuit Diag.

Setup for soldering big Lugs on fat Cable..
(The Lug shown below is from a 50amp 'Anderson plug'.)

Solder-Lugs

Use a Gas powered mini-torch and Soldering iron. (both at the same time on 7mm battery cable!)

Solder Jig

Use cheap pliers as the jaws will get heat affected.
Don't use paper, cloth, wood to hold the hot lugs (the lug will be tarnished by toxic gases)

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