FoxESS Community - Owners & Installers Forum

Hi, new to solar panels and coming into winter for the first time.

Over the last few days I have noticed that my outdoor battery (ecs2900-2) is charging at 0.61kwh (up until now over 3kw, I have the 3.7kw inverter)

I had a look at the data sheet at it seems there is a derating when the battery temperature is at between 0 and 15c. Can this be the reason for such a drastic drop in the charging rate? Battery temp seems to be around 12-13c and we are still in autumn!

If it is, does it not render the battery almost useless over winter given that it doesnt charge under 0c?

If this is the root cause are there any solutions? Planning on building an insulated enclosure otherwise.

Thank you in advance.

Hi,

I made a video about this, up yes, on small battery setups that are lower voltage, you'll see large impact by the exterbal temp.

Thank you for your reply.

I watched the video and I saw the table with the temperatures. At 10c the battery can draw 15amps.
My battery is currently drawing 2amps at 15.2c, surely I should be expecting better performance than this? Is this temperature related or is something else happening here?

The newer the firmware, the more aggressive the charge profile.
Double check you've not got your charge and discharge amps set lower by mistake

Thanks I have been in touch with my installer, the firmware is up to date and all parameters appear to be normal. They have set my charge settings over the weekend as they believe it may be user error, will see what they say Monday.

do keep us posted

The problem with the battery charging is the temperature. FoxESS have changed the parameters on their latest firmware update as a “safety measure” but no one seems to know why.
If the battery temp is below 15 it will slow down the charge.
There are two solutions to this.
1. Build an insulated box around the battery which should keep the temp around 20 C but keep a good air gap around it. This worked for me.
2. Complain to FoxESS UK and they will offer you a replacement master unit which does not have the restriction, if it’s within the warranty period.
I opted for number 2 which has been fitted today but I am still keeping the insulated box around it as a precaution.

Did your installer replace the master or did you DIY and did you have to return the original master with the limitation back to Fox?

My original installer replaced the Master Unit only as that is the one that carries the software.
The old one was boxed up and I am waiting for FoxESS to come and collect it.

Did Fox collect the master or let you keep it?

FoxESS have now picked up my old Battery Master Unit and my new one is behaving as it should.