Adding batteries to existing solar system

Swan_Valley

Our PV Inverters & Battery systems are mounted in the garage below the bungalow. It seems to stay above freezing, even if it is frosty  (-5C) outside. The GivEnergy monitoring at https://beta.givenergy.cloud/ allows quite comprehensive data on all aspects of the system, even though it only gives a "snapshot" update every 5 minutes.

From checking a cold day last month, the battery temp only changed between 11 & 19 degrees C.

EVandPV

mickyduck55 said:

QrizB said:

mickyduck55 said:

... the freezing temperatures in my garage where the batteries are housed reduced the charge rate significantly.

It's generally advised that you should never charge lithium iron phosphate (LiFePO4) batteries of they are below freezing,as it's saod to damage them permanently.

LiFePO4 batteries intended for cold weather use are often equipped with electric heaters to reduce the risk of this happening.

Hi my garage is not usually below freezing it is attached to my house but is significantly colder than inside.  My sons batteries that are inside charge at a much higher rate than mine.. typically if it is cold they start of with a low charge rate and it ramps up over the charging period.  I guess this is the BMS doing its job of protecting them from harm...

Yeah the cell temperature increases with charging, I've seen mine increase as much as 10°C during charging.

Pulpdiction

Thinking about adding one of these Givenergy batteries, but also wanted to add some additional panels.  I have 3.5kw system installed already.  So if I added a new string, separate from my existing panels could both feed the battery without interfering with the FIT payments?  Anyone looked into this?  

Just to be clear I know I won't get FIT payments on new panels and would have thought I would need a second meter?

Exiled_Tyke

Pulpdiction said:

Thinking about adding one of these Givenergy batteries, but also wanted to add some additional panels.  I have 3.5kw system installed already.  So if I added a new string, separate from my existing panels could both feed the battery without interfering with the FIT payments?  Anyone looked into this?  

Just to be clear I know I won't get FIT payments on new panels and would have thought I would need a second meter?

That seems to match what I did.  When I got my battery (Solax) I put up just two additional panels which share one microinverter.  Both sets of panels feed the battery.  The new panels have their own meter but I only really use that to check that they are generating ok. The actual readings are pretty redundant. And of course my FIT arrangements remain unchanged using the original generation meter. 

Incidentally I talked to my installer about the question of pro-rata payments from extending the system.  (e.g. add two panels to a 10 panel system and then claim 10/12 of new production).  They had no experience of anyone doing this and wouldn't suggest trying it. Even if a FIT provider advised it to be ok, if they changed their mind then it would be too late: the system would have been altered and FIT payments lost. Best to keep any additions entirely independent. 

michaels

Exiled_Tyke said:

Pulpdiction said:

Thinking about adding one of these Givenergy batteries, but also wanted to add some additional panels.  I have 3.5kw system installed already.  So if I added a new string, separate from my existing panels could both feed the battery without interfering with the FIT payments?  Anyone looked into this?  

Just to be clear I know I won't get FIT payments on new panels and would have thought I would need a second meter?

That seems to match what I did.  When I got my battery (Solax) I put up just two additional panels which share one microinverter.  Both sets of panels feed the battery.  The new panels have their own meter but I only really use that to check that they are generating ok. The actual readings are pretty redundant. And of course my FIT arrangements remain unchanged using the original generation meter. 

Incidentally I talked to my installer about the question of pro-rata payments from extending the system.  (e.g. add two panels to a 10 panel system and then claim 10/12 of new production).  They had no experience of anyone doing this and wouldn't suggest trying it. Even if a FIT provider advised it to be ok, if they changed their mind then it would be too late: the system would have been altered and FIT payments lost. Best to keep any additions entirely independent. 

Do the FIT panels have to feed the battery after the inverter and generation meter - thus two way losses?

Exiled_Tyke

michaels said:

Exiled_Tyke said:

Pulpdiction said:

Thinking about adding one of these Givenergy batteries, but also wanted to add some additional panels.  I have 3.5kw system installed already.  So if I added a new string, separate from my existing panels could both feed the battery without interfering with the FIT payments?  Anyone looked into this?  

Just to be clear I know I won't get FIT payments on new panels and would have thought I would need a second meter?

That seems to match what I did.  When I got my battery (Solax) I put up just two additional panels which share one microinverter.  Both sets of panels feed the battery.  The new panels have their own meter but I only really use that to check that they are generating ok. The actual readings are pretty redundant. And of course my FIT arrangements remain unchanged using the original generation meter. 

Incidentally I talked to my installer about the question of pro-rata payments from extending the system.  (e.g. add two panels to a 10 panel system and then claim 10/12 of new production).  They had no experience of anyone doing this and wouldn't suggest trying it. Even if a FIT provider advised it to be ok, if they changed their mind then it would be too late: the system would have been altered and FIT payments lost. Best to keep any additions entirely independent. 

Do the FIT panels have to feed the battery after the inverter and generation meter - thus two way losses?

I don't know whether they 'have to' but mine do. So FIT panels feed the  inverter  then to the generation meter. If the battery is not full already then on to the  separate battery inverter and on to the battery.   

michaels

Exiled_Tyke said:

michaels said:

Exiled_Tyke said:

Pulpdiction said:

Thinking about adding one of these Givenergy batteries, but also wanted to add some additional panels.  I have 3.5kw system installed already.  So if I added a new string, separate from my existing panels could both feed the battery without interfering with the FIT payments?  Anyone looked into this?  

Just to be clear I know I won't get FIT payments on new panels and would have thought I would need a second meter?

That seems to match what I did.  When I got my battery (Solax) I put up just two additional panels which share one microinverter.  Both sets of panels feed the battery.  The new panels have their own meter but I only really use that to check that they are generating ok. The actual readings are pretty redundant. And of course my FIT arrangements remain unchanged using the original generation meter. 

Incidentally I talked to my installer about the question of pro-rata payments from extending the system.  (e.g. add two panels to a 10 panel system and then claim 10/12 of new production).  They had no experience of anyone doing this and wouldn't suggest trying it. Even if a FIT provider advised it to be ok, if they changed their mind then it would be too late: the system would have been altered and FIT payments lost. Best to keep any additions entirely independent. 

Do the FIT panels have to feed the battery after the inverter and generation meter - thus two way losses?

I don't know whether they 'have to' but mine do. So FIT panels feed the  inverter  then to the generation meter. If the battery is not full already then on to the  separate battery inverter and on to the battery.   

I was thinking if you only had the FIT panels you could potentially fill them before the inverter/export meter to avoid the inverter round trip losses - but then I guess you lose and battery losses from your FIT output - swings and roundabouts.

Pulpdiction

Just had a quote from EON for a Givenergy 8.2kw battery (3kw ac inverter) installed for £5,400 inc vat, but they offer 36 months interest free credit.  The person I spoke to seemed very interested to know if I had a smart meter, I said no and they said "and you don't want one" implying that if I did have a smart meter it would impact my FIT payments, but I thought the deemed fit was unaffected by smart meter?

Also one of the main reasons for getting this is to charge it cheaper using off peak, albeit that I would need to move to a provider who has that facility, like Octopus go, but their web site is basically implying they don't want new customers due to the price cap and uncertainty.  Not sure what to do about that.....

Coastalwatch

Pulpdiction said:

Just had a quote from EON for a Givenergy 8.2kw battery (3kw ac inverter) installed for £5,400 inc vat, but they offer 36 months interest free credit.  The person I spoke to seemed very interested to know if I had a smart meter, I said no and they said "and you don't want one" implying that if I did have a smart meter it would impact my FIT payments, but I thought the deemed fit was unaffected by smart meter?

Also one of the main reasons for getting this is to charge it cheaper using off peak, albeit that I would need to move to a provider who has that facility, like Octopus go, but their web site is basically implying they don't want new customers due to the price cap and uncertainty.  Not sure what to do about that.....

Hi PD,

Added a link below to a website which sells the items you are seeking to having installed. Their costs are minus VAT but will give an idea of basic cost minus installation bearing in mind there will few addtional adds ons such as a dongle plus Isolators, ac and dc. Oh, is the quote part of a package to be installled with PV thus attracting merely 5% vat or added independently in which case 20% vat?

Regarding FIT payments, I went onto a Smart meter some 15 months ago and still receiving our deemed FIT and Export.

Sorry can't make any suggestions about Octopus other going back for a quotation letting them know you would like a smart meter fitted with the intention of hooking up to their Go tariff as you are having a storage battery fitted.

https://www.itstechnologies.shop/collections/givenergy-battery-storage

Edit. No idea of your location but if you live in Suffolk or North Essex my installer may supply a quote failing that if you go on the Givenergy website they list all their qualified installers on it!

https://www.givenergy.co.uk/localstore

Pulpdiction

Thanks Coastalwatch, yes this would be stand alone hence the 20% VAT, unfortunately.  To be honest I don't want to part with the best part of £5k in one go in cash as having building work on the house, so the ability to speak payments appears, although I could do that on a credit card.  Realise I am paying a premium of sorts, but I will go back and ask for a discount off the quote based on another quote I had from a local installer - who quoted me £5k inc VAT for a similar system but they weren't sure when they could do it or when they could do a site survey etc and it all just seemed a bit difficult.  They were trying to upsell me to a Tesla power wall.

I am based in the midlands so unlikely your installer would be interested.

I think I just need to call Octopus and see what's what.