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

No worries David, I could feel your pain in the post and thought it best to speak to discuss our respective journeys! 

I have calculated that when all is said and done I am seeing 89% of the yield reported on the inverter. My Sunsynk consumes 1.2kw per day, that’ll always be covered by Solar generation in ANY weather but in my new hybrid setup, that amounts to £300 lost Fit Payments for keeping it on standby

I think in the winter it maybe worth charging but I wouldn’t charge to 100%, maybe 80% I noticed charging to 100% causes more losses. I also used to ‘top up’ the battery when I got cheaper slots of 7p charging open up with Octopus. To be clear, to anyone NOT on an old FIT scheme, top up and charge all you want. You don’t need to have a generation meter I believe, so it really doesn’t matter. But for FIT folks with Hybrid Meter you need to sip grid power

My advice actually would be to keep your existing inverter, if you get batteries, run them with a dedicated AC coupled inverter on a different circuit entirely. So any charging/discharging of the batteries would have NO impact on the generation meter whatsoever. It takes up more space yes, but not that much more. 

Kanulondon (aka Alex)

Sorry to keep this thread going.I'm still a bit confused by this. I'm the same as other users ,on old fit payments from solar installed 12 years ago,just had inverter replaced with hybrid and a battery plus new bidirectional meter.On fit I get paid for everything I generate from solar but now your saying if I charge the battery from the grid that gets taken off my solar generated figure..is this correct? But not the rest of my grid use for the house? Thanks in advance.

If you have a bi-directional (net) meter, it is most usually wired to record generation used directly by the house and also any that is diverted to batteries (which you would expect as that has been generated as well).

However, if you charge the batteries from the grid, this will be seen as imported and deducted from the total reading as that part was not generated. Hence the Import, Export and Net readings.

The problem with this is that if you use significant grid charging , especially during winter months, as the battery is probably only 80-90% efficient, it will significantly reduce your Net readings during that period.

You can see from earlier posts that some have had things rewired so that the meter only shows generation direct and ignores any used by the batteries. 

Per the reply by from BPLightlog

The current setup you have is not 100% optimal from a FIT viewpoint. It’s not terrible by any stretch but you are definitely not maximising your payment if you have the new inverter charged on the same circuit that feeds PV to the house.

To get your head around it, manually read the meter and measure generation against whatever your inverter says it’s generated. The two numbers will be off, this will obviously be affected by variables such as ‘time of day’, ‘battery soc’, etc . If the battery isn’t fully drained to say 10% or whatever then the excess solar maybe hidden from the meter until it’s discharged as AC instead of stored as DC

In these sunnier months, do ensure your battery charging schedule is set to not charge AC to 100% overnight

I’ve decided to reconfigure my setup to ensure my AC charging goes via a different circuit so I can truly have the best of both worlds. Charge my batteries with cheap grid 7p AC and ensure every KW generated is shown on the bi directional meter as it used to be

KL

Thanks for your replies. Ive seen earlier comments about bidirectional meter being wired wrong. I think mine must be with regards to bplightlogs statement that charging battery would go on import. Ive had my hybrid inverter and battery with bidirectional meter around 2 weeks my exp=22.8....imp=134.8.....net= -112...do u agree this meter is wired wrong.

It seems my solar generation is on import when I think your saying it should be export,  do you agree.. thx again.

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.

Very interesting, I’m just about to purchase a battery solution, I’m also on the original FIT tariff so I wouldn’t want to lose any generation at 74p per KWh looks like running an AC coupled inverter would be the prudent route for me to take.

Hi, hoping people can still view this. My problem is same as the above. Lets say in day I generate 10kw on my solar @20p[£2] but use it all, so at night I fill my 10kw battery on cheap tariff ,so 10kw@8p[80p], but that also registers on my bidirectional meter and takes 10kw off...so over the day my net reading is 0, so i lose my £2 i generated plus its cost me 80p,so im paying for it twice. Surely thats not right, i thought you got money on fit payments on everything generated. Could net reading off the meter not be for if you get SEG payments.But even that cant be right.. Thx Scott

Unfortunately for FIT generation, it doesn’t include anything supplied via the batteries, hence the net generation meter and your calculations.

If you read several posts earlier in this thread, you will see that there is a suggestion about having things rewired so that the battery doesn’t pass through the generation meter. It’s either that or being very careful what you charge and reuse.

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

 

 

 

 

Can i ask if this issue has been resolved in your favour...I hope so. 

Thanks for your super quick reply. Is it easy to have battery not pass thru meter and is it allowed? And would i still be able to charge the battery from solar generation and from grid?

 Thanks once again

Did you not get things changed/updated as you were intending earlier? Or has that not made any difference?

If you can get a reply from ​@kanulondon that might be the best help as they seem to have got their system sorted now

Good to see this thread is still helping people… I am fully sorted now and compliant. However it cost me a few hundred pounds as I have effectively had to re-install a simple string inverter and that’s on the end of my new bi directional meter...(in hindsight I didn’t need to change the meter had it all been wired correctly!)

What I had before (sub optimal if on FIT!)

Circuit A (Consumer Board) <> Bi Directional Meter <> AC/DC Inverter <> Batteries + Solar Panels

A quick mock up of what I have now (optimal if on FIT)

Circuit A (Consumer Board) <> Bi Directional Meter <> String Inverter with Solar Panels

Circuit B (Consumer Board) <> AC/DC Inverter (runs in AC) <> Battery Bank

As you can see the bi directional meter never sees any demand, only export of the energy. If there is surplus from the panels, my Inverter will detect and charge the batteries. I now charge the batteries at night with careless abandon to 80% as it will NEVER affect my FIT as it did before

KL

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

 

 

 

 

Can i ask if this issue has been resolved in your favour...I hope so. 

Unfortunately it hasn’t, the issue is now with OFGEM who will adjudicate on my complaint. EonNext are still relying on the paragraph in the guidance which I highlighted above to withhold FIT which clearly does not have any bearing on my problem. I am hoping that OFGEM will use some common sense which EonNext clearly lacks .

Yes my meter was wired correctly but its only now suns out less that i charged my battery on cheap night rate and realised it comes off your export.

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

 

 

 

 

Can i ask if this issue has been resolved in your favour...I hope so. 

Unfortunately it hasn’t, the issue is now with OFGEM who will adjudicate on my complaint. EonNext are still relying on the paragraph in the guidance which I highlighted above to withhold FIT which clearly does not have any bearing on my problem. I am hoping that OFGEM will use some common sense which EonNext clearly lacks .

This is really unfortunate ​@Brimar23  but in my opinion the issue is with your installer. It’s apparently that some newer installer though they may have the certs are NOT aware of older FIT schemes which have since been closed down. To be fair, these installers were likely at school when these older schemes were about.

Winter aside, a bi-directional setup simply doesn’t maximise your FIT generation. I asked whether in the future FIT generation could be calculated directly from the inverter but that will not be happening

I calculated with my sub optimal setup I would lose up to £500 (approx) of payments a year. As I have 10 years left, I didn’t want to leave that money on the table

KL