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Buy now, pay later interest freeStarting with a small off-grid solar setup is a smart way to gain experience, assess your actual energy needs, and power a limited load.
The Renewables team at City Plumbing has positioned itself as a leading supplier of solar PV solutions, including options for off-grid setups. Offering a wide selection of solar PV components, including essential battery storage for off-grid, we also provide valuable advice and support for those looking to achieve energy independence with an off-grid solar solution.
Here, we explore some key considerations for launching your first small off-grid solar project while considering just why it’s such a compelling choice for renewable energy.
Why Start Small With Solar PV?
If you’re still not entirely sure about beginning your solar PV journey a good idea is to start small. Take the opportunity to start at the beginning and see it as a leaning curve, exploring just how solar power works, how to manage your consumption, and the nuances of off-grid living without the huge upfront commitment.
Starting small with solar PV can be the more cost-effective choice as a significantly lower initial investment compared to a whole-house off-grid system. It also allows you to target power, making it ideal for powering specific, low-demand applications first. Furthermore, as many off-grid components are modular, you can look to expand your system as your needs and budget grow.
Common Beginner Scenarios for Off-Grid Solar PV
This is a classic starting point and loads lights, charging power tools, a radio, and a small fan. Requiring relatively low power demand, there’s often no need for complex wiring into a main dwelling, and it can be a completely separate system.
Camping/RV/Van Life:
A portable or semi-permanent setup for mobile living. This will load phone charging, LED lights, a small fridge, and a laptop. Designed for portability and efficiency, these set-ups often use 12V DC appliances directly.
Backup Power for Essential Devices:
A small system that can keep critical devices running during a power cut. This will load items such as routers, phone chargers, and a few lights. Offering peace of mind, small backup power systems allow you to maintain some connectivity and basic amenities.
Essential Components for a Small Off-Grid System
Regardless of the specific application, the core components for a small off-grid solar PV system remain the same and include:
Size: For "small," you might start with one or two 100W, 150W, or 200W panels.
Type: Monocrystalline panels are generally more efficient for their size, which can be beneficial when space is limited.
Mounting: Simple mounting brackets for a shed roof or a portable stand for camping.
Charge Controller:
Purpose: Protects your battery from overcharging and over-discharging.
Type: For smaller systems, a PWM (Pulse Width Modulation) controller can be budget-friendly. However, if you plan to expand or want more efficiency, an MPPT (Maximum Power Point Tracking) controller is superior as it extracts more power from the panels, especially in variable light conditions.
Battery (Deep Cycle):
Purpose: Stores the solar energy for use when the sun isn't shining.
Types:
Lead-Acid (AGM or Gel): More affordable upfront for smaller capacities, but heavier and have a shorter lifespan if frequently deeply discharged. Require ventilation.
Lithium Iron Phosphate (LiFePO4): More expensive initially but offer significantly longer lifespan, deeper discharge capability (meaning you can use more of the stored energy) lighter weight, and are maintenance-free. Often the better choice if you plan to scale up later.
Size: Start with a modest capacity, e.g. a 50Ah or 100Ah 12V battery.
Inverter (Optional for DC-only loads):
Purpose: Converts the DC power from your battery into AC power for standard household appliances.
Types:
Pure Sine Wave: Essential for sensitive electronics (laptops, TVs, modern appliances) as it produces clean power similar to the grid. Recommended even for small systems if you're powering anything beyond basic lights.
Modified Sine Wave: Cheaper but can damage sensitive electronics and run motors less efficiently. Best avoided unless for very basic, non-sensitive loads (e.g. old-fashioned incandescent bulbs).
Size: Choose an inverter that can handle the total wattage of the devices you plan to run simultaneously, plus a buffer for surge currents (especially for motors) For a small system, a 300W to 1000W inverter might suffice.
Cabling, Fuses, and Connectors:
Safety First: Use properly sized cables (wire gauge) for the current, and incorporate fuses/circuit breakers to protect all components from overcurrent.
MC4 Connectors: Standard for solar panel connections, ensuring weatherproof and secure links.
How to Start Small With Your Off-Grid Solar PV System
Define Your "Small" Needs:
List Devices: What exactly do you want to power? (e.g. 3 x 5W LED lights, a 30W laptop charger for 2 hours, a 10W phone charger for 4 hours)
Calculate Daily Watt-Hours (Wh): Multiply each device's wattage by its daily usage hours, then sum them up. (e.g. 3 * 5W * 4 hours = 60Wh for lights; 30W * 2 hours = 60Wh for laptop; 10W * 4 hours = 40Wh for a phone. Total = 160Wh per day)
Consider Peak Power (Watts): What's the highest total wattage you'll need at any one moment? (e.g. if lights, laptop, and phone are all on, that's 15W + 30W + 10W = 55W) This determines your inverter size.
Sun Hours: Look up the average "peak sun hours" for your UK location. This is the equivalent number of hours per day that the sun shines with 1000 W/m² intensity. It varies by season and region (e.g. 2.5-3.5 hours in winter, 5-6+ hours in summer) Be conservative, especially if you want winter power.
Panel Sizing: (Daily Wh needed) / (Peak Sun Hours) = Minimum panel wattage. Add 20-30% for system losses and cloudy days.
Example: 160Wh / 3 hours = 53W. A 100W panel would give you plenty of buffer.
Size Your Battery:
Backup Days: How many days of no sun do you want power for? For small systems, 1-2 days is common.
Usable Capacity: Remember that lead-acid batteries should only be discharged to 50% to prolong their life, while LiFePO4 can go to 80-100%.
Calculation: (Daily Wh needed) * (Backup Days) / (Battery Voltage, usually 12V) / (Usable Depth of Discharge, e.g. 0.5 for lead-acid) = Ah required.
Example: 160Wh * 2 days / 12V / 0.5 = 53.3 Ah. A 75Ah or 100Ah 12V battery would be a good start.
Select Components:
You can find pre-packaged small off-grid kits which simplifies the process and ensures compatibility or, alternatively, buy components individually.
Example Small Kit Components (for a shed):
- 1 x 100W Solar Panel
- 1 x 10A MPPT Charge Controller
- 1 x 100Ah 12V AGM Deep Cycle Battery
- 1 x 300W Pure Sine Wave Inverter (if needed for AC appliances)
- Cabling, fuses, MC4 connectors
Installation and Testing:
Safety: Always disconnect power sources when working on wiring. If unsure, consult an electrician.
Wiring Order: Typically, connect the charge controller to the battery first, then connect the solar panels to the charge controller. Finally, connect the inverter to the battery.
Monitoring: Use the charge controller's display or an app (if available) to monitor battery state of charge and power production.
Cost for a Small Off-Grid System in the UK
- Basic Shed/Camping Kit (100W-200W panel, small battery, basic charge controller, maybe small inverter): You can find kits starting from £150 - £500.
- Slightly More Capable System (e.g. 200W-400W panels, 100Ah LiFePO4 battery, MPPT controller, 500W-1000W pure sine inverter): This could be in the £800 - £2,000+ range, depending on brand and quality.
- DIY vs. Professional: DIY saves on labour, but ensure you have the necessary electrical knowledge and tools. For permanent installations, professional installation might be legally required or recommended for safety and compliance.
Choose City Plumbing For All Your Off Grid Solutions
Starting small is a practical and educational way to dip your toes into off-grid living with solar power. You'll quickly learn your actual power habits and what it takes to sustain them, which will be invaluable if you decide to expand to a larger system later.
At City Plumbing, our extensive solar PV range is competitively priced to help homeowners make the switch to renewable energy. With industry-leading brands, we offer solutions to get you started with off-grid living. For further information, check out our dedicated Renewables Hub, or browse the City Plumbing Website.
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