Battery cables sizing

# Understanding Battery Cable Requirements for Sunsynk Batteries

When setting up your Sunsynk battery system, it’s essential to use the correct battery cables to ensure optimal performance and safety. The standard battery cables for Sunsynk batteries are 25mm in size, which can handle a maximum charge/discharge rate of 122.5 A. However, if you are using an inverter with a capacity of 8 kW or larger, you will need to consider upgrading to a larger power cable size to fully utilize the maximum charge/discharge rates.

Here’s a quick overview of the maximum charge/discharge rates for various inverter sizes:

- **3.6 kW Inverter**: Maximum charge/discharge rate of 90 A

- **5.5 kW Inverter**: Maximum charge/discharge rate of 120 A

- **8.8 kW Inverter**: Maximum charge/discharge rate of 190 A

- **10 kW Inverter**: Maximum charge/discharge rate of 210 A

- **12 kW Inverter**: Maximum charge/discharge rate of 240 A

- **16 kW Inverter**: Maximum charge/discharge rate of 300 A

To match these rates, you will need to use appropriately sized power cables. Here’s a breakdown of the required cable sizes:

- **25mm Cable**: Supports up to 122.5 A

- **35mm Cable**: Supports up to 150 A

- **50mm Cable**: Supports up to 210 A

- **70mm Cable**: Supports up to 225 A

- **95mm Cable**: Supports up to 300 A

**Example**: If you have a 16 kW inverter and want to take full advantage of the 300 A charge/discharge rate, you will need to install a 95mm battery power cable.

Using the correct cable size is vital for ensuring that your system operates efficiently and safely. If you are using two or more batteries, we recommend utilizing a common busbar. In this case, we suggest using the 25mm standard cable from each battery to the busbar. From the busbar, use the appropriate size power cable, along with the correct size fuse isolator, to connect to the inverter.

Please take into account that these figures are accurate for the standard battery cable length of 1.5 metres, when making up your own battery power cables over this length please calculate your DC requirements for distance/ voltage / current capability / voltage drop and please ensure all interconnecting battery cable sizes are the same length as cables of differing lengths can cause battery unbalances. 

For example: voltage drop for a 51.2V nominal battery such as the W5.3 should be no more than 2%

Using the correct cable size is crucial for ensuring that your system operates efficiently and safely. If you have any questions or need assistance in selecting the right cables for your setup, please feel free to reach out to our customer support team. We’re here to help you every step of the way!