Hi there! Thanks for writing in.
A 5kw solar system requires at least 200Ah of battery storage. To calculate this, you can use the following formula:
5kw = 5,000 watts
5kw x 3 hours (average daily sun hours) = 15,000Wh of energy per day
200Ah of storage will hold enough energy to power the entire house for about 3 hours. So if you have a 5kw solar system that runs from dawn until dusk every day, it’ll need 200Ah of storage capacity.
You will need two 200 Ah batteries for a 5kw lithium ion battery. The capacity of the battery is measured in Amp-hours, or Ah. A 100 Ah battery will be able to discharge at a current equal to its capacity for 100 hours. So, a 200 Ah battery will be able to discharge at a current equal to its capacity for 200 hours.
The solar panel you choose will determine how much power your system will generate, so it’s important to make sure that the number of batteries you purchase matches up with the wattage of your panels. For example, if you have a 2kW solar panel and choose to use 400Ah batteries, then you’ll need four of them—two in each battery compartment (or “string”).
If you have multiple strings—for example, one string per room—then you can add more batteries for redundancy purposes. In this case, each string would need two 200Ah batteries connected in parallel; this means that if one battery fails in one string, there will still be enough power from the other connected batteries in that string to keep going until repairs can be made.