FoxESS Community - Owners & Installers Forum

We are installers of Fox products and like a lot of other companies experiencing customer concerns on battery logic in low ambient conditions.

The new range of batteries includes a built in heater to protect the battery and allow charging and discharging at low ambient temperatures <0C. This is great but what is the power consumption of the heater? Can you provide any data on the expected reduction in efficiency, cost and output at low ambient?

We obviously factor battery degradation in to our ROI calculations for our customers but not the reduction in efficiency or output in low ambient. The heater is a parasitic loss and should be included in the calculations. The BMS will manage the battery at ambient <10C. As stated by Fox this will result in the battery not fully charging or discharging. What is the expected reduction in efficiency and output under these operating conditions?

Hope you can help
Kind regards
Matt

So as the battery cools down to single figures the internal resistance increases and the bms reduces the charge/discharge amps to protect the battery. This can be very noticeable on smaller battery setups as the voltage is also lower so a lower amps over volts means less kW in and out of the battery in terms of peak power throughput.
The capacity doesn't change all that much when cold it just takes a lot longer to charge.

The heater modules in the newer batteries is rate at 200w from memory so being able to keep the battery warm at around 15c should keep the performance stable for the cost of a few kWh daily.