BMS Com Fault.

[Vic.chrissy]

Hi Guys my first posting .
We buying a house which have solar ,
We had it surveyed the other day and the Growatt panel says BMS Com fault .
the owner of the house had died and the people selling it don’t know anything regarding the solar .
Not knowing how long the fauit had happen and it be some time before we complete on the sale ,
my question is will this fault cause damage to the batteries?

 

[SeaGal]

Welcome. IMHO, the status of the batteries will largely depend on what state of charge they are in as it would appear from that fault that they are no longer being charged. LiFePO4 batteries should not be discharged below 2.5V per cell. Can you check what type of battery pack is attached / how many if more than one and whether there is any indication regarding their current state of charge (SOC) or even better, voltage? Then we can advise in more depth.

If the house is being sold as having a solar installation, then it would be reasonable to ask for the asking price to be reduced accordingly as, being in the UK, you will have put an offer in "subject-to-survey" and, presumably, not yet exchanged? If the solar is just a bonus, then I doubt the executors would offer any reduction.

 

[Vic.chrissy]

Welcome. IMHO, the status of the batteries will largely depend on what state of charge they are in as it would appear from that fault that they are no longer being charged. LiFePO4 batteries should not be discharged below 2.5V per cell. Can you check what type of battery pack is attached / how many if more than one and whether there is any indication regarding their current state of charge (SOC) or even better, voltage? Then we can advise in more depth.

If the house is being sold as having a solar installation, then it would be reasonable to ask for the asking price to be reduced accordingly as, being in the UK, you will have put an offer in "subject-to-survey" and, presumably, not yet exchanged? If the solar is just a bonus, then I doubt the executors would offer any reduction.

I made a few more enquiries to day to find out roughly how much it would cost to replace the batteries if they where shot and been told that I couldn’t just replace the batteries I would need to replace everything as only Growatt batteries would fit that system,
I was a bit surprised as I would had thought I could just replace the batteries
That system I been told is is no longer available.
It just gets worst .

 

[SeaGal]

been told that I couldn’t just replace the batteries I would need to replace everything as only Growatt batteries would fit that system,

I don't believe that is correct. It sounds as though the company you contacted just want to make more £££.

I was a bit surprised as I would had thought I could just replace the batteries

I too would expect that is possible. Let us know the exact model of the Growatt and of the batteries and I'd be surprised if they are as proprietary as you have been told. Although I don't have a Growatt, there are many on here, both in the UK and abroad that do, so hopefully someone can help you move forward with this.

In the meantime, do come back with any more details about battery SOC or voltage as I mentioned before.

It just gets worst

Don't get disheartened - buying a house is stressful enough without receiving (likely) misinformation.

 

[DIYrich]

Certain models of growatt use a high voltage battery. They are also cheap. Easy to replace a growatt inverter and its battery with a new inverter and battery. Check the voltage of the panels, and make sure a new inverter can handle that voltage. You don't have to stay with growatt. Make your offer based upon no solar, and the panels are a bonus.

 

[SeaGal]

Certain models of growatt use a high voltage battery.

Good point. From the picture it looks like this one...

http://www.stealthenergy.co.uk/download/Growatt-SP2000_Datesheet.pdf

...if so, it's 48V, but no idea about the BMS to inverter comms.

Fascinated why there's a label saying "knock here" on the inverter by the status button... is that where Growatt are anticipating having a faulty contact that needs knocking back into position!

 

[DIYrich]

BTW: Might be able to charge in Voltage mode, and disconnect comms.

 

[Vic.chrissy]

This may help ,
Been in touch with Growatt service and they basically said replace the lot, but then they would say that .

 

[SeaGal]

How many panels are installed on the house? I'm assuming you don't have more details about them (age or power, for example).

Either way, it looks like you will have a number of options when/if you complete on the sale (e.g. resurrect battery / replace battery / replace inverter and battery).

All I'd say at this stage, with the limited data we have, is that a 2000W inverter is not that powerful these days, so even with a full charge of battery it will only power 2/3 of a kettle, or a microwave on its own, but not (say) a microwave and an air-fryer simultaneously. So maybe replacing the inverter and battery would be a good option anyway.

Hence, I'd agree with @DIYrich and...

Make your offer based upon no solar, and the panels are a bonus.

 

[Vic.chrissy]

How many panels are installed on the house? I'm assuming you don't have more details about them (age or power, for example).

Either way, it looks like you will have a number of options when/if you complete on the sale (e.g. resurrect battery / replace battery / replace inverter and battery).

All I'd say at this stage, with the limited data we have, is that a 2000W inverter is not that powerful these days, so even with a full charge of battery it will only power 2/3 of a kettle, or a microwave on its own, but not (say) a microwave and an air-fryer simultaneously. So maybe replacing the inverter and battery would be a good option anyway.

Hence, I'd agree with @DIYrich and...

The inverter is 4000w , it’s a sunny boy inverter ,
I think your looking at the Growatt box of tricks.
There 20 panels in all

 

[kommando]

Maybe this thread can be merged with this on the same subject

Understanding grid tie system

I like to understand how grid tie solar with batteries bank work . I thought that while the batteries have charge and the panels and working that any power used in the house would first come from the batteries and the panels and if any other power was needed or if the batteries where low ,it...

diysolarforum.com

Its one of those odd systems where a 2nd DC to battery inverter was added to a normal DC to AC inverter to add on a battery so the self use of the PV output could be increased. Now defunct due to either immersion diverters or full hybrid inverters.

If the battery can be recovered then fine, if not leave the Sunny Boy in place and dump the Growatt. That assumes the FIT is based on the SB and not the Growatt.

 

[SeaGal]

Maybe this thread can be merged with this on the same subject

Sounds like a good idea - I'm spending time answering questions with only 30% of the information on this thread - no mention of the Sunny Boy until today

 

[Vic.chrissy]

Sounds like a good idea - I'm spending time answering questions with only 30% of the information on this thread - no mention of the Sunny Boy until today

Sorry the sunny boy wasn’t mention in this posting , mostly because the post was to find out if the Growatt fault would damage the batteries,
The other post a different subject.
Wasn’t trying to miss lead anyone .

Still have no idea what the Growatt box do , if it a charger or regular input and output or what ever else ,
It seen it’s been miss taken as an inverter here .

 

[Vic.chrissy]

Maybe this thread can be merged with this on the same subject

Understanding grid tie system

I like to understand how grid tie solar with batteries bank work . I thought that while the batteries have charge and the panels and working that any power used in the house would first come from the batteries and the panels and if any other power was needed or if the batteries where low ,it...

diysolarforum.com

Its one of those odd systems where a 2nd DC to battery inverter was added to a normal DC to AC inverter to add on a battery so the self use of the PV output could be increased. Now defunct due to either immersion diverters or full hybrid inverters.

If the battery can be recovered then fine, if not leave the Sunny Boy in place and dump the Growatt. That assumes the FIT is based on the SB and not the Growatt.

Thanks for that , I have to try and get more what the FIT is basic on ,
Just received info from EDF ,need to read it , the FIT tariff may not be worth the hassle .

 

[SeaGal]

the FIT tariff may not be worth the hassle

It is a very generous scheme, especially from back in 2012 - from my experience it can take a long while / forms / proof of ownership from your conveyancer, but lasts 25 years and the payments will be back-dated to your completion date. Just make sure you take meter readings, import and export when you move in, ideally with photograph of meters. It will also be a selling point if you sell in the next 12 or so years.

 

[Vic.chrissy]

It is a very generous scheme, especially from back in 2012 - from my experience it can take a long while / forms / proof of ownership from your conveyancer, but lasts 25 years and the payments will be back-dated to your completion date. Just make sure you take meter readings, import and export when you move in, ideally with photograph of meters. It will also be a selling point if you sell in the next 12 or so years.

Very good info thanks ,
There already sent me a form ,
which I found part are confusing and I am awaiting reply to my question on some parts .
May have to come back some time in the future for help .