Existing Solar PV system needs to install battery

[bhups]

Hello,

I have an existing Solar PV system which I would like to add a battery to.

I live in the UK and my existing set up was installed with the government Feed-in-Tarriff.
Due to this reason I am unable to change the existing setup without it affecting my feed-in-tarriff.

I am on an Economy 7 tariff with my energy company so I am on about half-rate electricity between the hours of around 00:30 - 07:30

My current inverter is a very old Aurora Power-One PVI-3.6-TL-OUTD.

I would like to install a battery system of about 5-10 KWh and am maybe looking towards this (as it was recommended on this site on another post)

Aolithium 51.2V 100Ah Server Rack Lithium Battery(2 Slot), LiFePO4 Battery for Solar, RV, Off-Grid.

With 6000+ life cycles & 20-Year lifetime, built-in BMS & LED monitor, this 2 slot LiFePO4 battery (51.2V/100Ah) is the best choice if you want to build a huge off-grid solar power system at a more afforable price. It is designed for backup power application, such as home storage systems...

aolithium.co.uk

I would also like to install another inverter to help me charge the battery during the night half-rate period or during the day while I have excess solar generation.
This inverter should also provide energy back to the home when the solar generation is not so high (e.g. shaded days or winter times).

Please could someone advise if something like this would be possible for me to do and if so, I would be very greatful for some advice on carrying out this operation.

(Existing setup - This is in my out-house/garage)

 

[bhups]

Hello,

Sorry if my post was not helpful to help others help me with my query.

Maybe I can change my wordings for my request for help.

Please would it be possible to recommend me an inverter which i could use with LiFePO4 batteries such as the following:

Aolithium 51.2V 100Ah Server Rack Lithium Battery(2 Slot), LiFePO4 Battery for Solar, RV, Off-Grid.

With 6000+ life cycles & 20-Year lifetime, built-in BMS & LED monitor, this 2 slot LiFePO4 battery (51.2V/100Ah) is the best choice if you want to build a huge off-grid solar power system at a more afforable price. It is designed for backup power application, such as home storage systems...

aolithium.co.uk

US5000-Pylon Technologies Co., Ltd.

This inverter will be seperate to my existing solar PV system, but should be able to monitor the PV generation and household useage and charge/discharge accordingly.

I was watching these two videos and it is almost the same way of set up that i would like
e.g. CT clamps and some sort of modbus meter to measure the in and out currents, and also a wireless transmitting device like the LoRa device so I can have the inverter away from the mains power location.

My power consumption peaks to around 4-6KWh at times and so would like for the inverter and batteries to be able to handle this.

Thank you very much in advance!

 

[bugone]

I've recently added a battery to my micro inverter solar install. Are you intending to DIY this?

I used a Solis 5g RAI AC Coupled and a PylonTech US5000 battery.

Solar PV & battery Storage components – ITS Technologies

.I.T.S. Technologies is a supplier of an extensive range of renewable & energy saving technologies for both domestic and commercial

www.itstechnologies.shop

My installation (showing the inverter side as well)

I wouldn't worry too much about trying to cover peak loads. Storing your excess and covering 95% of use will make a drastic difference, and then using the grid for the peaks.

 

[bhups]

I have been looking around and going through a couple of options and have thought about going with either of these inverters due to the power they are able to output via the battery.
(Unfortunately I'm not sure if these hybrid inverters (or any hybrid inverter) require PV connection for it to work.)

• S6-EH1P(3-6)K-L-EU (5K)
  Datasheet: https://www.ginlong.com/uploads/file/Datasheet_S6-EH1P(3-6)K-L-EU_GBR_V2,2_2022_11.pdf
• X1-FIT G4 (X1-FIT-5.0-W)
  Datasheet: https://kb.solaxpower.com/image/684...22-11-11/82f7f61003a4e0952a546e3befe6d6cb.pdf

Would I be right to think that the X1-FIT G4 will not be compatible with the Aolithium 2 Slot 51.2V 100Ah Server Rack LiFePO4 Battery with Rack?

 

[FVScimitar]

Yes your correct Solax is High Voltage HV for batteries using solax T5.8 LFP 115volts
Master and Slave for two batteries is 230 volts idle. Pylontech batteries are 52v for LV
Low Voltage. You need to know what battery system you are requiring to use in conjunction compatible inverter whether for batteries alone or Hybrid inverter which will also do Solar and batteries.

Read up on DC and AC coupled battery systems. If you have no desire to have Solar PV array no need for Hybrid inverter just for a battery system as Hybrid inverter is more expensive.

Therefor an AC Coupled battery system is slightly cheaper if you can utilise TOU (Time Of Use) tariff like Octopus Go if you have EV vehicle for that tariff or E7 all have different tariff prices per kWh.

 

[bhups]

Thank you for your message.

I am looking for an inverter which can help pull up to 5kw.
Unfortunately the AC coupled inverters I can find are mostly just limited to 3kw.

 

[bugone]

If you're going to DIY it, it's a lot easier staying within the G98 limit.

 

[houseofancients]

Thank you for your message.

I am looking for an inverter which can help pull up to 5kw.
Unfortunately the AC coupled inverters I can find are mostly just limited to 3kw.

look at a sunsynk inverter , which is fully certified , and a true hybrid

 

[bhups]

I upload a visual idea of the set up i currently have and the possible new setup.

 

[houseofancients]

wouldnt it be easier to exchange your current inverter ?

 

[bhups]

wouldnt it be easier to exchange your current inverter ?

Unfortunately, any changes to the existing set up will void my Feed-in-Tariff which I have with the energy company for the energy I send back.

 

[12VoltInstalls]

Due to this reason I am unable to change the existing setup without it affecting my feed-in-tarriff

wouldnt it be easier to exchange your current inverter ?

So the simplest would be an AIO installation between loads and ‘grid’ feeding a subpanel. When battery is depleted grid pass-through would be seamless and transparent as well as providing the power required, albeit atypical in that solar input may not be incorporated to the AIO unless there are additional panels added exclusive to the AIO.

But it would seem to meet the criteria of not changing the existing system.

@houseofancients is that a sound assumption?

 

[houseofancients]

So the simplest would be an AIO installation between loads and ‘grid’ feeding a subpanel. When battery is depleted grid pass-through would be seamless and transparent as well as providing the power required, albeit atypical in that solar input may not be incorporated to the AIO unless there are additional panels added exclusive to the AIO.

But it would seem to meet the criteria of not changing the existing system.

@houseofancients is that a sound assumption?

yeah, missed the part of the OP that he cant change his system, which seems really odd, as stuff like inverters can break.
i think if the OP looks at his contract, i think the "not changing" part reflects to his total amount of power send back to the grid ( generation) can't change...
i give you PowerCo a call and verify this 100%..

"hey listen, my inverter seems broken, can i replace it" , have them confirm that by email, and he should be good

so ..

hence .. replace inverter with a proper hybrid and he should be done without too much hassle

 

[bhups]

From what I recall a while back, if something was to go wrong and needing to be replaced, it was needed to be done with a like for like or almost equivalent.

At present, all solar generated is sent directly back to the grid and every bit is accounted for by the installed meter.
The generation on this is what I submit every quartarly and get paid for it.

If I were to change to an AiO/Hybrid, would this not affect the currents going into the meter either it being AC backup/AC Grid?
I'm guessing I will not benefit from all the solar generation made.

 

[houseofancients]

From what I recall a while back, if something was to go wrong and needing to be replaced, it was needed to be done with a like for like or almost equivalent.

At present, all solar generated is sent directly back to the grid and every bit is accounted for by the installed meter.
The generation on this is what I submit every quartarly and get paid for it.

If I were to change to an AiO/Hybrid, would this not affect the currents going into the meter either it being AC backup/AC Grid?
I'm guessing I will not benefit from all the solar generation made.

how will you not benefit ?
it will mean less usage from the grid for you loads, which i am betting is a lot more expensive than what you are getting paid to send power back to them at whole sale prices

 

[rpdom]

how will you not benefit ?
it will mean less usage from the grid for you loads, which i am betting is a lot more expensive than what you are getting paid to send power back to them at whole sale prices

The original FIT rates were really high. I'm talking £0.80 per kWh, not the £0.04 of the basic SEG. Although with the current cost of power it may be worth losing the FIT and saving a fortune on bills.

 

[ShaneC]

yeah, missed the part of the OP that he cant change his system, which seems really odd, as stuff like inverters can break.
i think if the OP looks at his contract, i think the "not changing" part reflects to his total amount of power send back to the grid ( generation) can't change...
i give you PowerCo a call and verify this 100%..

"hey listen, my inverter seems broken, can i replace it" , have them confirm that by email, and he should be good

so ..

hence .. replace inverter with a proper hybrid and he should be done without too much hassle

Knowing the UK there will be an extremely limited selection of vastly overpriced "approved" inverters that can be used to replace the OP's existing inverter in this situation.

 

[bhups]

how will you not benefit ?
it will mean less usage from the grid for you loads, which i am betting is a lot more expensive than what you are getting paid to send power back to them at whole sale prices

When I mean not to benefit, I was thinking along the lines of:
1. Solar generated
2. Solar stored to battery
3. Excess solar pumped back to grid

I'm not sure where the meter would fit in if we have multiple AC lines going into the inverter. I am quite a n00b on this and basing my limited understanding off differernt documents

 

[12VoltInstalls]

were to change to an AiO/Hybrid, would this not affect the currents going into the meter either it being AC backup/AC Grid?
I'm guessing I will not benefit from all the solar generation made.

Not “change to” but add it in ‘behind’ the existing equipment with your battery to optimize your time of use versus time of billing. They won’t see any difference in your metering other than a reduction in your billable usage.

 

[12VoltInstalls]

not sure where the meter would fit in if we have multiple AC lines going into the inverter. I am quite a n00b on this and basing my limited understanding off differernt documents

You won’t have any changes to your existing system because in the above scenario everything will be ‘behind’ the consumer distribution just like your lights, toaster oven, vehicle charger, electric heater or whatever. There is nothing for them to regulate with a “0-second” transfer AIO that does not feed back to the grid, just your loads