I'm Doug Mycko, owner of SolarMan Consulting. I've worked with off-grid solar on the Big Island since 2006, and one of the first questions almost everybody asks is, “How much is this going to cost?”
That's the right question. But before I give somebody a number, I want to know what we're buying the equipment to accomplish.
What Determines the Price?
The major cost drivers are battery storage, inverter capacity, solar-array size, racking, electrical balance-of-system equipment, generator strategy and how much installation work is involved.
Real SolarMan DIY Equipment Examples
The examples below illustrate how equipment packages can move from a basic system to a much larger whole-home system. They are useful for understanding scale, but they are not a substitute for sizing the house.
| Example package | General equipment level | Approx. equipment price* |
|---|---|---|
| Budget off-grid package | 6 kW-class inverter, ~1.5 kW PV, ~5.4 kWh lithium battery, racking/cables | $5,000 |
| Intermediate package | 4 kW-class inverter, ~3.7 kW PV, ~16 kWh lithium battery, racking/cables | $8,200 |
| Larger NV8 package | Larger off-grid equipment package | $11,000 |
| Top-shelf package | 12 kW-class inverter, ~4.4 kW PV, ~16 kWh lithium storage, racking/cables | $12,500 |
| Top-shelf plus | 12 kW-class inverter, ~7 kW PV, ~32 kWh lithium storage, racking/cables | $19,000 |
*Illustrative SolarMan equipment-package pricing. Prices and product availability change. Installation, permitting, site work, generator, shipping where applicable, and project-specific electrical materials may not be included. Get a current quotation before purchasing.
See Current SolarMan DIY Off-Grid Kits →
Why Battery Storage Changes the Price So Much
Solar panels produce energy. Batteries determine how much of that energy can be stored for nighttime and poor-weather use.
A customer who needs lights, refrigeration and basic loads overnight has a very different storage requirement from a customer who wants whole-house air conditioning through the night.
Adding lithium battery capacity can move a project price substantially, but undersizing the battery can leave an otherwise excellent system dependent on the generator.
Read: How Much Battery Do I Need for Off-Grid Solar? →
Air Conditioning Can Move You Into a Different System Class
Running a mini-split for an hour during strong sunshine is one thing. Running multiple heads through a warm night is another.
Overnight A/C increases battery-energy requirements and then increases the amount of solar energy that must be produced the following day to refill those batteries.
Read: Running Air Conditioning on Off-Grid Solar →
Water Pumps Affect Inverter and Battery Sizing
A pump may not add many kWh to the monthly energy total, but its motor-starting surge can require more inverter and battery power capability.
This is why two homes with similar daily kWh can still need different equipment.
Read: Off-Grid Solar for Well & Catchment Pumps →
How Much Solar Array Do You Need?
The PV array has two jobs: run daytime loads and replace energy removed from the batteries.
If a home uses 20 kWh overnight, the next day's solar production needs to recover that energy while still carrying whatever the home consumes during the day.
Big Island microclimates matter. A design for a wet East Hawaiʻi location should account for local solar conditions rather than assuming every day behaves like a clear Kona afternoon.
Use the Whole-System Solar Sizing Calculator →
Does Buying More Panels Fix an Undersized Battery?
Not necessarily. Panels and batteries solve different problems.
More PV
Can increase daytime production and improve battery recovery when solar energy is available.
More Battery
Increases stored energy and, depending on the battery design, may increase available power capability.
A well-designed off-grid system balances both rather than overspending on one side while leaving the other undersized.
How Much Inverter Do You Need?
Inverter size is driven by simultaneous loads and surge—not just daily kWh.
A house might consume modest energy overall but still need substantial instantaneous power when a pump starts while the microwave, refrigerator and other loads are operating.
This is one reason I start with a load list before choosing the inverter.
Don't Forget the Generator
A generator is often part of a practical Big Island off-grid design. It provides recovery during prolonged poor weather and backup when unusual loads or service conditions arise.
The generator needs to be matched to the inverter/charger and expected house loads. Oversizing it does not automatically increase battery-charging speed.
Read: Generator Charging & Off-Grid Solar Troubleshooting →
DIY Equipment vs. Turnkey Installation
SolarMan supplies equipment, designs systems, troubleshoots and provides commissioning support. Some customers are experienced DIY builders; others work with licensed trades for the portions of the project that require them.
An equipment-only price should never be confused with the total cost of a professionally installed project. Labor, permitting, trenching, conduit, structures, site conditions and electrical work can materially change the finished cost.
Why Cheap Equipment Can Become Expensive in Hawaii
Price matters, but serviceability matters too. Hawaiʻi adds shipping time and freight expense when equipment has to leave the island.
Before I recommend equipment I consider:
Warranty Process
What happens when something fails, and how difficult is it to prove the failure?
Replacement Logistics
Does equipment have to be shipped to the mainland for service?
Parts Availability
Can the failed component be replaced, or does the entire product have to go back?
Technical Support
Can somebody knowledgeable actually help diagnose the system when it is down?
Repairing an Existing System Can Cost Less Than Replacing It
If you already own an off-grid system, don't assume you need to start over. Many problems can be isolated to a battery, charge controller, board, wiring issue, programming problem or other component.
That is particularly relevant to the many existing OutBack systems still operating around the Big Island.
Solar Repair & Troubleshooting on the Big Island →
Repair or Replace an OutBack Solar System? →
What Should You Budget for?
Instead of asking only, “What does an off-grid system cost?” I recommend answering these questions:
What Must Run?
Refrigeration, pumps, cooking loads, office equipment, shop loads, A/C and anything else important.
What Runs Overnight?
This drives battery storage more than many customers expect.
What Can Run Together?
This helps determine inverter power and battery current capability.
How Much Generator Use Is Acceptable?
A customer wanting almost no generator runtime needs a different design from someone comfortable using backup generation after cloudy days.
Big Island Off-Grid Solar Doesn't Need to Be Guesswork
We can estimate the loads, size the battery, determine inverter requirements, size the solar array and then choose equipment that fits both the house and the budget.
That is a much safer way to spend money than starting with a package price and hoping the house fits the equipment.
Want a Real Price for Your Off-Grid System?
Tell me what you're trying to power, where you are on the Big Island, whether you want air conditioning, what size water pump you have and how much generator use you're comfortable with. Then I can build a system around your actual requirements and quote the equipment.
Doug Mycko
SolarMan Consulting, LLC
Big Island, Hawaiʻi
808-313-0608
www.SolarManHawaii.com
Related Big Island Off-Grid Guides
Frequently Asked Questions
How much does an off-grid solar system cost in Hawaii?
Cost depends heavily on battery storage, inverter power, solar-array size, loads and installation requirements. SolarMan equipment-package examples range from smaller packages around $5,000 to larger packages approaching $20,000, before project-specific installation and other costs.
What is the most expensive part of an off-grid solar system?
Large lithium battery banks and high-capacity power equipment can represent a substantial portion of system cost. The exact mix depends on how much energy and power the home requires.
Can I build an off-grid solar system for $5,000?
A smaller equipment package can be possible around that level, but whether it can power your home depends on your loads. Whole-home A/C, large pumps and substantial overnight consumption generally require more equipment.
Is DIY off-grid solar cheaper?
DIY can reduce labor expense for work the owner can legally and safely perform, but equipment sizing, code requirements, permitting and work requiring licensed trades still need to be considered.
Should I spend more on batteries or solar panels?
Neither should be sized in isolation. Batteries determine stored energy while PV determines how quickly that energy can be replenished. A balanced system needs both sized around the load.
Prices shown are examples and may change without notice. Obtain a current written quotation. SolarMan Consulting provides off-grid solar design, equipment supply, troubleshooting and commissioning support. Electrical installation requiring contractor licensing should be performed by appropriately licensed personnel.