I have FIT with new battery and inverter, do I have the right meters?

Looks like a similar issue to ​@David49 

Absolutely no way you should be -112 in 2 weeks that does indeed feel like a generation number. That export seems to be your AC charging/standby 

Having seen the fitting instructions I can see how it can easily happen but no excuse and something you need remediated asap

KL

I agree. If in this weather you are having an increasing negative net figure then your bi-directional meter is wired incorrectly. My installers wired the new bi-directional meter in the same way as the one it replaced. This is wrong. The wiring is 180degrees different. See the wiring diagram on this link https://midsummerwholesale.co.uk/pdfs/emlite-NET-installer-notes.pdf. You will need your installers to replace the meter with a new one starting at zero. Photograph the reading the meter being removed and get the installers to confirm in writing the wiring was wrong. Then you have to persuade your FIT supplier that the negative reading is in fact a positive one. I’m still struggling with that one. Otherwise you have recourse to the installer to recompense you for the lost FIT earnings. Best of luck!

So just to confirm,  export should be the figure my solar panels produce. So can I ask what is the import figure? Is it the total ive used from the grid? Thx again all for your help. 

On a correctly wired Net meter, Export is the energy delivered to the house either Solar PV generation or via any batteries connected.

Import is any energy supplied to the system from another source (ie via grid or other external power source).

Net is the reading usually required by your provider

Once your meter is re-wired you then have the dliema what to do. You can just rely upon the generated power from the solar panels and claim your FIT allowance via the Net reading from your FIT provider, or come the darker shorter days use an off-peak tariff to charge your battery from the grid then use this power in the high tariff times to minimise your Electricity bill. This will increase your Import reading and may even wipe out your export reading resulting in a small net positive or even a net negative and thus no FIT payments in the winter time. In discussion with others I think I’ve decided to maintain my FIT generation and forego the ability to charge the battery from the grid - though that option remains open if I change my mind. This site is a worth a read https://www.moneysavingexpert.com/utilities/is-solar-battery-storage-worth-it/

Thanks for the help everyone.. my installer is gonna change the meter in a couple of days.

A very useful thread which I came across when researching my problem. I apologise for the length of this post but I have the same issue as ​@David49 with the negative NET reading. But my FIT provider (not OVO) has asked for all of my FIT payments  paid to me over the last 2 years (Over £3000) to be returned to them. I had a SolarEdge DC battery installed in August 2023 and an Emlite Bi-directional meter fitted at the same time. Neither my installer or me noticed that it was displaying a negative NET reading. Neither did my provider either. I informed my FIT provider of the changes to my system and as requested, sent them photographs of the new meter readings on installation. They didn't notice the negative NET reading either and approved the continuance of FIT payments.

In April this year, as part of the regular audit, they asked for photographs of the meter which I provided. It was after this that they contacted me and pointed out the negative NET reading and suggested that I get my installer to check the wiring. The installer came out and sorted out the wiring and also replaced the meter after talking to EMLITE. They advised to replace it just in case it started to count down after the wiring had been fixed. The new meter reads as it should. I should mention at this stage that the IMP and EXP readings were correct and are providing the correct NET albeit with the negative sign in front.

All was well until the end of July they demanded that I return my FIT payments. This is what they said ‘Ofgem has asked us to investigate your FIT details following the installation of your battery back in 2023. As you are aware, your old Bi Directional meter that was removed on the 21st May 2025 was producing a negative NET reading as it was wired incorrectly to the fit system. I'm afraid we are unable to make FIT payments based on a Negative NET value. From the 4/08/23 up until 21/05/25 you will not qualify for fit payments under the fit scheme. This means you have been over paid by -£3,128.96’.  

Clearly, I have probably have a legitimate claim against the installer  but I think that the FIT provider is wrong. My contention is that they approved the FIT payments back in August 2023 after viewing the photographs of the new meter displaying a negative NET reading and therefore it is their problem. Having challenged them about this, pointing out that they failed in their duties as a FIT Licensee, they offered me £50 for their mistake in approving the system!

The FIT provider is relying on a paragraph to support their contention in the OFGEM guidance (they sent it to me):

Clearly this paragraph relates to what was discussed earlier in this thread where batteries are charged from grid in winter months and can sometimes produce a negative NET reading. 

Going for the installer is my fall back position should I fail to achieve getting OFGEM and/or my FIT provider to understand the issue from my perspective.  I welcome any views or advice any of you can provide. Thanks for reading

Hi Brimar23,

As you know I had the same problem with incorrect wiring and in my case the installer reimbursed me. The difference between you and me is the duration of the error and the eye watering amount. What would I do? Firstly I would put the installer on notice that their error is potentially costing you £3k and that should your appeal to OFGEM and the FIT Utility company fail you will expect them to repay you - or pay your FIT provider direct. I would also write to OFGEM for as you say, that paragraph is directed at people who charge their battery from the grid and produce a negative result. It is unfair for the FIT provider to rely on that paragraph which clearly does not relate to your problem. If you have the App on your phone showing your positive generation up until the installation of the new meter starting at zero that is evidence of your genuine production. Your FIT provider is relying on the letter of the law and not the spirit but I have to say this was the same attitude I had with my provider. The only people I fear who can change their attitude is OFGEM. Best of luck! I hope this helps.

Hi David49

 Thank you for your reply. My fall back position will be the installer as I have photos of the meter producing Neg Net from day one but clearly neither he or I recognised the significance. Over the years he has been helpful but in the end I can’t afford to lose £3k. I have spoken with Emlite the meter manufacturer who have confirmed that despite being incorrectly wired, the neg Net reading can be relied upon as an accurate reading of Net generation. I checked the inverter app and it confirmed that during the period in question I generated  4.8mW but was only paid for 4.1mW (that figure was taken from the meter Net reading).   Conversion losses are dreadful unless something else is happening. I have complained to Ofgem.

Be careful with totals from any inverter log, they are not ‘calibrated’ and therefore not really accurate. They often only log measurements every few minutes and therefore can’t be relied on.