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

Forum|Forum|1 year ago
January 7, 2025
79 replies
2855 views

Wondered if anyone can answer my query

Im an existing FIT payment receiver (solar panels installed with single string inverter 11 years ago) so receive a decent FIT payment.

Recently had installed a EcoFlow 3.6kw inverter with 10kw battery storage, the generation meter was changed to a bidirectional meter as instructed and followed the correct schematic.

However the meter is showing a negative number and I can’t seem to work out what the solar panels are generating apart from what shows in the EcoFlow app

We charge the batteries up at night using an off peak rate and then any solar during the day tops the batteries up.

am I correct in thinking there should be another meter of sort between the solar panels and inverter just to monitor the generation from The solar panels?

installers seem to think by summer it will change to a positive but that’s no good to me right now when I’ve generated about 30kw of solar

Best answer by BPLightlog

Actually, the NET meter is normally the correct one to use. It calculates the difference between any import from the grid and your generation. During winter and acknowledging losses in the system, if you are significantly charging overnight and then discharging during the day, it can show negative at this time of year.
You might just double check with your FIT provider as to which reading they will accept. As I mentioned, normally it’s the NET reading but some want the EXP reading.
There will be no other meter just for generation on a set up like yours (mine is the same)

Show previous replies

S

SpeckleD

Rank 1

Hi everyone,

After much angst dealing with uncooperative Installer and FIT provider, and tremendous help from Alex, his diagnosis of my problem was correct. The electricians wired the bi-directional meter in the same way as the previous generation meter which is entirely wrong. The wiring is 180 degrees different hence my meter was counting backwards and the net reading was an increasing minus. They’ve been today to fit me a new meter starting at zero and it appears to be counting upwards this time - hooray!

I’ve requested a letter of explanation and apology from the Installers and will use that to try to convince my FIT supplier to credit me with the negative final figure (that should be a positive).

In researching all this I’m having second thoughts about topping up my battery overnight on a cheaper tariff as this will increase my Export meter potentially wiping out my Import figure leaving me with no FIT generation/£p. I can’t do anything until July when my present fixed tariff expires but I am going to have to calculate whether the gain on using cheaper priced fuel downloaded to my battery overnight compensates for the loss in FIT revenue if I end up with a minus NET figure again.

Thanks to everyone who chipped in to help (even OVO - and I’m not even with them) but especially Alex who spent time on the telephone with me going over the possibilities. Your help very much appreciated Alex.

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)

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.

S

ScottyWigan

Newcomer

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

BPLightlog

Super User

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.

Bring me Sunshine ~ E&E {Solar PV, Battery Storage, Hybrid EV, ASHP and Home Assistant automation}

S

ScottyWigan

Newcomer

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.

S

ScottyWigan

Newcomer

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.

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

BPLightlog

Super User

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.

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?

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

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

Bring me Sunshine ~ E&E {Solar PV, Battery Storage, Hybrid EV, ASHP and Home Assistant automation}

K

kanulondon

Newcomer

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.

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?

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

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

B

Brimar23

Newcomer

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 .

S

ScottyWigan

Newcomer

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.

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?

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

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

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.

K

kanulondon

Newcomer

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

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

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