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

If you are not charging from the grid, then you shouldn’t have much reduction in your generation reading. There is a + and - effect when you use surplus solar to charge the batteries but unless there is a huge amount of surplus, it would work out mostly balanced - I say mostly as you never get as much out of the batteries as you put in due to the losses (around 10%).

If you think that the negative effect on your net meter (and therefore generation reading) is significantly higher than it should be, you might want to get the cabling checked out as the grid only part of your supply to the property should not go through the net meter.

Thanks. Another respondent has similarly commented that the cabling might be wrongly connected as my negative net reading is climbing each day in this sunny weather. Have put in an urgent request to the Installer to revisit and check the wiring. Same reader sent me a schematic of the difference between the old generation meter and the bi-directional meter.  Hopefully that diagnosis is the correct one, but then I have the problem of convincing my FIT provider that the negative net reading is actually a positive one!

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.

Hey, no worries! Glad we could help!

If you need us for basically anything else, feel free to swing by anytime. We’ll be more than happy to see you again. :)

Hey ​@David49 

Thanks for coming back with that update!

I’m glad they were able to get to the bottom of that for you. Do keep us updated on how you get on getting some credit back if they can.

As Blastoise mentioned, feel free to pop back anytime.😊

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.