Off grid solar

Many people aspire to being completely off the grid. Simply, this means installing a big bank of batteries, and enough solar panels to manufacture all the electricity you need and then cutting your tie to the grid.

Making sense of off grid solar

The costs

It usually costs $20,000 - $60,000 to go completely off grid. This is triple the cost of staying grid connected and installing solar. There are several reasons why it’s so expensive; First, because of the need for a large battery bank to tide you through the winter months when the sun doesn’t shine very much. Second, because of the need for an expensive inverter/charger to manage your solar generation, power consumption, and generator connection (yes, you will need a generator). Third, because of the dedicated space required for battery storage. And forth, because of the design and installation cost which is much higher than that of the simpler grid connected systems.

Design complexity

An off grid system must be designed correctly. You need to think through all the appliances you will want to run to determine the total daily load that you will need to draw from your batteries. Get this wrong and you could end up running out of power or shortening the life of your batteries prematurely. Off grid solar is not a ‘set and forget’ type of system. You will need to manage your load, be aware of when the sun is shining, and be prepared to maintain your system over the years.

It can’t run everything

Off grid systems have a finite power limit. That limit is set by your battery and inverter/charger size. Unless you install a very large system there will be some things you should not expect to run from off grid solar. These are the types of loads that use a lot of electricity. For example, we advise people not to run an electric oven, dryer, heater, spa pool, swimming pool, heat pump, or charge an EV.

Having said the above, there are some very good reasons to consider going off grid.

Completely off grid and self-sufficient


Producing your own power can give you the freedom to live just about anywhere. You will avoid the huge expense of getting the grid connected if you choose an off grid solar power system.  This can save you tens of thousands of dollars if the nearest grid connection is a long distance away.


You’ll have no power bills—ever! However, you will have to factor in the initial cost and the price of replacing your batteries when they wear out.

You will be independent, self-sufficient and resilient. These last three benefits are more than enough for many people. If this sounds like you, then talk to us. We are specialists in large and small off grid solar.



What does it cost?


McNae Electrical Solutions supplies very small systems for tiny houses, motorhomes, cabins and small cottages. These start at less than $2,000 for DIY solutions. Fully installed solutions start from under $10,000. 
For normal sized homes the costs (fully installed) typically start from:

Small house $20-30,000

Medium house $40-50,000

Large house $60-70,000


A generator is also required. This can be integrated into the system with auto-start functionality so that it seamlessly provides power if there has been too much cloud or to boost the power that is available from the batteries for running large loads. You should allow from $6-14,000 for a quality auto-start generator.


Types of equipment


Off grid solar is much more complex to design and set up than a grid connected system. There are additional components required. Obviously, there is the battery bank which is much larger than any battery that you might find in a grid connected system. While a hybrid grid connected system (link here) might have 3-10 kWh of lithium batteries, an off grid system typically has 20-50 kWh of lead-acid batteries. Other components required include charge controllers, a battery monitor and a generator.


Because off grid systems must be custom designed it pays to choose a solar designer who has plenty of off grid experience. McNae Electrical Solutions employs a registered solar engineer (who has lived off grid) with the experience to correctly design your system.


And because you will be replying on your system day in and day out as your only energy source, it pays to purchase quality equipment. There are cheap off grid systems on the market, however the size and quality of the battery is usually where the compromises are made.  There is a direct relationship between battery life, quality and daily depth of discharge. With good design and proper monitoring, you can get up to 20 years from a quality battery.

Off grid water pumping


Off grid solar is not just great for your house. Many farmers rely on off grid solar to pump water around their farms.
McNae Electrical Solutions can provide water pumping solutions for any conceivable need. We can pump water as far and as high as required. Our water pumping systems are designed without batteries, so the water is delivered with smart high efficiency DC pumps that constantly adjust their output according to the sun as it shines during the day. A solar pumping solution completely replaces the need for grid electricity or diesel pumps, thus reducing costs, improving water security, and making farms more sustainable.

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The service provided by Martin from McNae Electrical Solutions was excellent and we are very satisfied with our solar power system.

John & Jan Brooks, Pohangina

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