Replacing existing Inverter

[Iansolar2]

I recently had installed a 2.6KW set of West facing panels along with 2 Fox ESS 5KWh batteries and a 3.7KW inverter.

Additionally I have an existing 2.16KW solar panel set split as 2 strings (East and South). They were installed in 2011 under the old FIT scheme so can’t be connected directly to the new system under the FIT rules. The inverter is a 3KW Aurora One which has done well, but is now 14 yrs old and the power output seems to be dropping. Although the original panels are wired separately, on sunny days excess power from both sets of panels charge the batteries.

Hence I am looking to replace the original inverter with a Fox model that will integrate with the new battery / inverter Apps etc. As I need 2 strings, I am thinking about a Fox ESS F3000-G2 3kW single phase inverter.
I would therefore welcome comments on whether this is the best option to go with and if there are any alternatives.

[Dave Foster]

The Fox F series is a very good dependable solar only inverter, sadly because of your FiT installation having a bigger hybrid inverter (such as a KH) that can handle all of your strings in a single inverter would be ruled out.

The F series is likely to be more efficient than your Aurora one, but it sounds like your panels nearing 14 years old will be holding the generation back.

The F series will generate it’s own statistics when fitted with a datalogger but if you haven’t already got this you should connect CT2 from your new hybrid so it can monitor the generation from the solar only inverter and the majority of the stats will be in a single screen in the Fox app.

There are a quite a few users on here that have a similar setup - I think most wish they could have a single larger inverter to handle all the strings but needs must.

[Iansolar2]

Thanks for the info. Also, do you know if changing the inverter needs to be reported to the DNO or FiT provider?

[Dave Foster]

Thanks for the info. Also, do you know if changing the inverter needs to be reported to the DNO or FiT provider?

You shouldn’t need to notify your Fit provider as most contracts state unless you are changing the agreed output ratings you don’t need to - but despite this being Ofgem’s guidance as each contract is different you should double check your specific contract terms.

On the DNO if you have G98 you will already have notified them when the system was installed, but as this is a new make/model of inverter (even though the same size) you are expected to notify them when there is a material change, they will need details to check it is compliant and listed in the ENA database.