I'm gonna share 2 simple steps to calculate the right size solar panel system for your amp service including some examples for 100 amp and 200 amp service.
In short --- for a 100 amp service, a 19kWh solar system is recommended and for a 200 amp service, a 38kWh solar panel system is recommended.
Introduction to electrical amp service
100 amp or 200 amp service is the electrical panel installed by your electricity provider. These panels manage the electricity flow coming from the grid to run household appliances safely.
The size of the electrical panel will vary from 50-400 amp service. For this post, we'll focus on 100 amp and 200 amp service.
Let's get started by understanding the electricity basics: amps, volts, and watts.
Introduction to Amps, Volts, & watts
- Amp (A): is defined as the number of electrons or current in simple words.
- Volt (V): is defined as the speed or pressure of the current flow.
- Watt (W) is the unit to measure the total power. (watts = Amps x Volts)
So we already know the value of amps, but how many voltages do electrical panels support? In most of the USA states the voltage coming from grid electricity will be 240 nominal volts because the electrical panel contains two 120V wires.
The solar panels are measured in watts and electrical panels or circuit boards are measured in amps. To make the calculation easy, let's convert the amp into watts.
Formula: Volts x Amps = Watts
100 amp service in watts:
240 x 100 = 24000 watts
200 amp service in watts:
240 x 200 = 48000 watts
Now you might say, great! i can connect a 24kWh solar system with my 100 amp service, well hold that thought.
How to calculate solar panel's size for Amp service
Solar panels run at their 100% capacity under ideal sunlight conditions (Direct Sunlight, Right angle of the panels towards the sun) reference.
On average you can expect 80% production from your solar panels on a shiny day.
This number can vary depending on weather conditions, your geographical location, and Season (summer or winter). So I live in Florida City and I receive 70-80% of my solar panels' full capacity.
But, there is one important factor to consider when installing solar panels for amp service, and that is --- cloud edge effect. This phenomenon can result in a temporary power surge, where the output of the solar panels can exceed their rated capacity by up to 20% when a cloud passes over them.
To ensure the safety and proper functioning of your solar system and electrical panel, it is advisable to leave a 20% buffer or room for safety.
For instance, if you have a 24kWh solar system for 100 amp service, during the cloud edge effect, it could potentially generate up to 28.8kWh of output.
While this may seem beneficial in terms of increased power generation, it's crucial to be aware of the potential risks associated with this temporary surge.
An extra 4.8kWh of solar panel output might lead to serious damage to your electrical system or even cause it to shut down completely.
How Many Solar Panels For 100 Amp Service?
Amp service/electrical panel voltage = 240-Volts
Electrical panel Amps = 100 amps
Safety buffer: 20%
240 × 100 = 24000 watts - 20% = 19,200 Watts of solar panels
For 100 amp service, a 19kWh solar panel system is recommended.
How Many Solar Panels For 200 Amp Service?
Amp service/electrical panel voltage = 240-Volts
Electrical panel Amps = 200 amps
Safety buffer: 20%
240 × 200 = 48000 watts - 20% = 38,400Watts of solar panels
For 200 amp service, a 38kWh solar panel system is recommended.
Voltage limit for solar array
It's important to ensure that the open circuit voltage (Voc) of your solar panels remains within a safe range, typically not exceeding 240 volts.
To achieve this, one option is to use a series-parallel connection for your solar panels. This connection type allows you to balance the voltage across multiple panels, preventing the OCV from exceeding the limit. If you'd like more detailed information on this topic, you can find it explained here...
How many solar panels for electrical amp service?
Here's a chart illustrating the recommended solar system size for 50 amp, 100 amp, and 200 amp service.
| Amp service size | Recommended solar system size |
|---|---|
| 50 amp | 9.5kWh |
| 100 amp | 19kWh |
| 200 amp | 38kWh |
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