If your system is designed correctly, the difference is very little, as even in bad weather, such as prolonged rainy days, we can seamlessly automate a generator with an auto start function to ensure your home always has the power you need.
DAYS OF AUTONOMY
When buying an Off-Grid system it is essential that you know how much autonomy it can provide. The autonomy time is the daily usage times and means that with low or no sunlight during bad weather, you will have enough power to run all your appliances as normal, without the generator kicking in.
The size of the battery bank must be able to power your home during consecutive days of rain or high cloud cover.
Looking at the design of an Off-Grid system from a professional point of view, it is recommended to have at least 1.5 – 2
days autonomy in your battery bank. This is IF there is a backup generator present. Without a generator, the “autonomy” time is recommended to be increased to 2-3 days.
To calculate the size of the battery bank you take your daily kWh usage and multiply it by the number of days of autonomy you would like to have. For example, if you use 10kWh per day and would like 2 days autonomy, you would need to have a battery bank which has 20kWh of usable storage.
However, the Lithium batteries are extremely fast charging, giving the possibility of multiple daily charges even at low light conditions which will extend the autonomy. It’s a fact that in prolonged times of bad weather or storms, people normally use power more conservatively and by having a generator connected to the system, you’ll always have power available that can top up the battery bank if required.