Quick Answer: As a general guideline, a 1500-2500 watt heater running an average of 6 hours per day would require a 2000-3000+ watt-hour solar generator and 500+ watt solar panels.
Determining the right size portable solar generator to power a heater depends on several key factors. These include the power consumption of the heater, the solar generator's capacity and output, the climate and sun exposure where it will be used, and the desired backup time from the battery. Considering these variables will help choose a solar generator system capable of reliably powering a heater for off-grid use or during power outages.
Assessing Heater Power Consumption
The first step is calculating the power consumption of the heater you want to operate. Space heaters are typically 1500-2500 watts, while larger heaters like those used for off-grid tiny homes may be 5000 watts or more. The heater's wattage rating is key for determining how large of a solar generator is required.
Also important is the type of heater. Some use maximum watts only for short burst heating cycles while others pull a sustained high wattage. For instance, an oil-filled electric heater may have a 1500W rating but only use about 600W on average over time. Understanding the sustained average power draw versus the peak rating is crucial for properly sizing the solar generator.
Considering Solar Generator Capacity
With the heater power consumption known, the next step is to select a solar generator with suitable battery capacity and power output. Common portable solar generator capacities range from 500Wh to over 3000Wh. The battery capacity affects how long the unit can power devices before needing to recharge. Meanwhile, the solar generator's continuous and surge wattage ratings must align with the heater's requirements to avoid overload.
As a baseline, a 1500W heater running an average of 6 hours per day uses about 9kWh of electricity. So, a 1000Wh solar generator would only sustain it for a little over an hour. Something in the range of 2000Wh to 3000Wh or more would be better aligned for powering a 1500W heating unit for multiple hours daily.
Sizing the panel wattage for recharging also merits consideration. The solar panels must resupply enough watt-hours throughout each day to match the heater's usage. Cooler climates and limited sun exposure make higher-wattage solar panels more critical for adequate charging.
Accounting for Environmental Factors
Solar panel output varies considerably between regions due to differences in solar radiation levels. Photovoltaic solar panels also experience substantial declines in current and voltage output as temperatures drop. As a result, properly sizing a solar generator system to power a heater depends greatly on the environment where it will operate.
Areas like the southwest United States average 5-7 Peak Sun Hours (PSH) daily. One PSH means generating 1000 watts per square meter for that hour. So, a 250W solar panel in a 6 PSH region would produce around 1500Wh on an average day. By comparison, cold northern areas may only get 2-3 PSH in winter, meaning that the same 250W panel yields 500-750Wh under those conditions.
Sizing solar components accordingly for each climate helps ensure reliable system performance year-round. Overrating panel wattages to compensate for lower solar potential and wintertime losses is prudent for locations with adverse conditions. Otherwise, the solar generator risks inadequate charging to continuously power the heater.
Considering the Desired Backup Time
The final key variable for appropriately sizing a solar generator system to power heaters or other loads is the desired backup time. Backup time means how long the fully charged battery can sustain the heater before needing solar recharging. Solar generator manufacturers often provide backup time estimates to help consumers determine if a unit meets their needs.
For heating uses, higher battery capacities between 2000-5000Wh with 500W+ solar panels generally work best for powering 1500-2500W portable heaters for 4 or more hours daily. Such a system provides off-grid flexibility and sufficient emergency backup to maintain indoor temperatures for a period of time. Those wanting longer continuous heating support from a solar generator may consider wiring multiple units together into an expandable modular setup.
The Bottom Line
Choosing the right solar generator, panels, and accessories for heating applications largely hinges on four variables-the heater's power demands, the environment, charging considerations, and intended backup support needs. Carefully calculating these elements before purchasing systems helps ensure the products selected can reliably operate heaters within a defined scope. Modular expandability also provides future flexibility if heating requirements change. Considering these guidelines paves the way for creating resilient off-grid or emergency heating powered sustainably through solar energy.