There is no specific time limit for expanding a battery system, however we recommend expanding systems as early in their life as possible, and we do not recommend expanding the system beyond 2 years from the commissioning date.
The main consideration is that of battery degradation. Batteries will degrade over time – this degradation will average (with normal usage) around 2% per year – however, this is not a guarantee and this can vary depending on throughput.
Any additional batteries added later would align to the state of health of the batteries already installed. A battery SoH of 96% would reduce the throughput capacity of the new battery to 96%, so would lose a small amount of capacity immediately.
Adding New Batteries
Additional batteries can only be added by suitably qualified technicians. Self-installation by end users is not permitted and may invalidate the warranty.
Before adding the additional batteries, please follow these steps:
- Ensure the SoC of the existing batteries is around 50% – the new batteries will have an SoC of approximately 50% and this will help reduce cell imbalance. You can force charge or force discharge the batteries accordingly.
- Fully power down the system following our shutdown procedure. Ensure the system is fully deenergised and isolated.
- For ECS batteries, remove the master battery and add the new slave(s) to the top of the stack. Add the master battery back to the stack and reenergise.
- For EP batteries – if you are expanding from a single battery to two or more batteries, you will require an EP junction box. Connect the new battery into the junction box input using the cables provided. Connect the batteries together using the provided data patch cable and relocate the link in/link out RJ45 connectors accordingly. Reenergise the system at this point following the restart procedure.
- We would recommend upgrading the firmware following expansion, especially if there has been a significant time delay between the original install and the expansion. You can request a firmware update from the Fox Service Team, or those with Agent Account access can update through their Fox Cloud account.
