FoxESS Community - Owners & Installers Forum

Hello we have added two batteries to our existing system H1-3.0-E-G2 (Fox ESS), However they dont seem to be adding any extra power and the system is not showing any faults. any ideas would be appreciated we are new to this system so our knowledge is limited regards

Can you provide a bit more information please,

What model of batteries do you have (HV,ECS,EP,EQ etc..)

How many batteries did you have originally and how many extra batteries have you fitted.

Did you ensure the existing batteries were at 50% when you added the new ones ?

If you open the app, click ‘Device’ at the bottom then click on Battery, click the ‘Info’ tab approx half way down the page, then click ‘Detailed Parameters’ what do you have showing for ‘Voltage’

thank you

the batteries are EQ4800

We had one master and one slave batterie and we have added 2 more slave batteries

we didnt ensure batteries at 50% as we were only advised when we bought the system that we can just add batteries at any time we have only found out about this since fitting the new ones

the voltage is 182.2 volts

your help is most appreciated

Thanks, the good news is that the combined battery voltage is showing correctly and confirms that you have 4 EQ4800 batteries.

The capacity problem will happen as a result of the soc mismatch when you added the extra batteries - the master (BMS) can maintain the balance of a pack of batteries when they are close in soc, but when you have a big difference you will be limited by the size of that difference.

For example if the existing batteries were at 75% when you added the new ones (which are shipped with approx 50% soc) then when the pack discharges the new 2 batteries will hit minsoc 25% earlier than the existing; and likewise when the pack is charged the 2 existing batteries will be full (which terminates the charge) before the new ones.

If you constantly charge and discharge the batteries to 100% and then back to 10% they will eventually train themselves over time to harmonise their SoC but it can take many, many weeks of this to achieve balance.

In the meantime if you continue to charge the batteries as regularly as you can from grid - if you are on a low tariff charge them every night and try and use as much of the battery as possible.

It is possible Fox can assist with some special software that allows the batteries to harmonise quicker, if you raise a service request in your app click ‘Me’, ‘Contact Us’, ‘Support’ and explain you have added 2 new batteries and the pack may not have been at 50% and ask if there is anything they can do.
At a minimum ask if they can load the latest firmware version onto all batteries which will help.

That’s great thank you for your help