Solar and battery system – battery nowhere near stated capacity and installer does not want to know

cm4ever

kgrins said:

Anyway, since the 4th (Monday overnight - I only set the battery to charge from Flux on Sunday evening), the inverter logs show the battery taking on average around 3.4 kWh to charge from 11% to 99% for a calculated full capacity of 4 kWh rather than 10 kWh.

I have invested in the console cable for the battery system and have previously put an IP camera up in the loft to watch it and can leave my laptop up there to remote into it to get the battery system's console. When the inverter thinks it is at 100%, the battery system says likewise with all of the indicator LEDs on both batteries full lit, and logging into the console says the same.

That's the bit that speaks volumes to me.

Just some thoughts: -
Maybe faulty BMS firmware
Maybe 'fake/knock-off' battery packs/unit
Maybe used/recon battery cells

I know you said you didn't pay on a credit card, but did you take out any sort of loan? I'm just wondering if there's any sort of angle/leverage that could be used there if available to add a bit of pressure on your installers?

Sorry you may have said, but have you tried to reach out to the battery storage manufacturer, sometimes surprising they can be helpful even though you're a 3rd party to them i.e. the end customer and not the distributor/installer....

1961Nick

I don't know if this is of any help, but looking at the spec of the 5.1kWh Pytes 48R100 battery I noticed that the operating voltage range & nominal voltage is considerably higher than other systems - Pylontechs 48v, Pytes 51.2v.

is it possible that the the wrong battery system has been selected on the inverter or the wrong parameters have been set for the Pytes? Worth a check?

MeteredOut

1961Nick said:

I don't know if this is of any help, but looking at the spec of the 5.1kWh Pytes 48R100 battery I noticed that the operating voltage range & nominal voltage is considerably higher than other systems - Pylontechs 48v, Pytes 51.2v.

is it possible that the the wrong battery system has been selected on the inverter or the wrong parameters have been set for the Pytes? Worth a check?

That's why i suggested looking into inverter/battery incomparability/setup issue.

OP, you could also try this more general FB solar group, where there are a lot of knowledgeable people:

https://www.facebook.com/groups/2197329430289466

kgrins

1961Nick said:

I don't know if this is of any help, but looking at the spec of the 5.1kWh Pytes 48R100 battery I noticed that the operating voltage range & nominal voltage is considerably higher than other systems - Pylontechs 48v, Pytes 51.2v.

is it possible that the the wrong battery system has been selected on the inverter or the wrong parameters have been set for the Pytes? Worth a check?

Yes, already done that. Pytes is set in the Inverter and Afore on the master battery (Pytes insist that the slave battery should be left as it in terms of DIP switches).

Initially the installer had left it at:

Lithium	Pytes
VBatMax	61.0 V
VBatMin	40.0 V
IChargeMax	77.04 A
IDChargeMax	78.0 A

Whereas Pytes give Min and Max as 47.5V-57.6V.

Did this way back in August but it made no difference.

I have now put the old laptop back in the loft so I can RDP into to.

SOC % is currently at 10% but using the console to do so shows the batteries as

PYTES>bat 1

Battery  Volt     Curr     Tempr    Base State   Volt. State  Curr. State  Temp. State  Coulomb
0        3289     0        9000     Idle         Normal       Normal       Normal         0%         90 mAH
1        3289     0        9000     Idle         Normal       Normal       Normal         1%       1358 mAH
2        3290     0        9000     Idle         Normal       Normal       Normal         1%       1910 mAH
3        3289     0        9000     Idle         Normal       Normal       Normal         0%         90 mAH
4        3290     0        9000     Idle         Normal       Normal       Normal         1%       1574 mAH
5        3290     0        10000    Idle         Normal       Normal       Normal         1%       1742 mAH
6        3289     0        10000    Idle         Normal       Normal       Normal         1%       1199 mAH
7        3290     0        10000    Idle         Normal       Normal       Normal         1%       1358 mAH
8        3289     0        10000    Idle         Normal       Normal       Normal         1%       1213 mAH
9        3289     0        10000    Idle         Normal       Normal       Normal         1%       1787 mAH
10       3289     0        9000     Idle         Normal       Normal       Normal         1%       1170 mAH
11       3289     0        9000     Idle         Normal       Normal       Normal         0%         90 mAH
12       3289     0        9000     Idle         Normal       Normal       Normal         1%       1246 mAH
13       3289     0        9000     Idle         Normal       Normal       Normal         1%       1848 mAH
14       3290     0        9000     Idle         Normal       Normal       Normal         1%       1358 mAH
15       3289     0        9000     Idle         Normal       Normal       Normal         1%       1246 mAH
Command completed successfully
$$
PYTES>bat 2

Battery  Volt     Curr     Tempr    Base State   Volt. State  Curr. State  Temp. State  Coulomb
0        3290     0        9000     Idle         Normal       Normal       Normal        32%      32572 mAH
1        3291     0        9000     Idle         Normal       Normal       Normal        33%      32985 mAH
2        3291     0        9000     Idle         Normal       Normal       Normal        31%      31227 mAH
3        3292     0        9000     Idle         Normal       Normal       Normal        34%      33739 mAH
4        3291     0        9000     Idle         Normal       Normal       Normal        33%      33572 mAH
5        3291     0        9000     Idle         Normal       Normal       Normal        33%      33072 mAH
6        3292     0        9000     Idle         Normal       Normal       Normal        33%      33322 mAH
7        3291     0        9000     Idle         Normal       Normal       Normal        25%      24997 mAH
8        3291     0        9000     Idle         Normal       Normal       Normal        26%      26076 mAH
9        3291     0        9000     Idle         Normal       Normal       Normal        32%      32320 mAH
10       3291     0        9000     Idle         Normal       Normal       Normal        21%      21755 mAH
11       3291     0        9000     Idle         Normal       Normal       Normal        25%      25495 mAH
12       3290     0        9000     Idle         Normal       Normal       Normal        22%      22420 mAH
13       3291     0        9000     Idle         Normal       Normal       Normal        28%      27908 mAH
14       3291     0        9000     Idle         Normal       Normal       Normal        25%      25161 mAH
15       3291     0        9000     Idle         Normal       Normal       Normal        25%      25246 mAH
Way back in August they were well balanced, now they are not. I hope the BMS has protected the cells as Battery #1 looks poorly now.

Pytes health command, soh, says all is fine but I really have to see what they say tomorrow AM when they should be fully charged.

With Octopus Flux I wonder if I should not charge a bit during the day before peak kicks in?

Before peak the day rate is 28p a unit, during peak - and peak is 16:00 until 19:00 on the Flux tarrif - it is 40p. Charging has an overheat with not only the quoted Pytes 5% loss but the inverter must generate heat too converting mains to ~50V; Afore quote 97% efficiency. So a potential loss of 8% (95% * 97%) - still cheaper than 40p.

kgrins

cm4ever said:

kgrins said:

Anyway, since the 4th (Monday overnight - I only set the battery to charge from Flux on Sunday evening), the inverter logs show the battery taking on average around 3.4 kWh to charge from 11% to 99% for a calculated full capacity of 4 kWh rather than 10 kWh.

I have invested in the console cable for the battery system and have previously put an IP camera up in the loft to watch it and can leave my laptop up there to remote into it to get the battery system's console. When the inverter thinks it is at 100%, the battery system says likewise with all of the indicator LEDs on both batteries full lit, and logging into the console says the same.

That's the bit that speaks volumes to me.

Just some thoughts: -
Maybe faulty BMS firmware
Maybe 'fake/knock-off' battery packs/unit
Maybe used/recon battery cells

I know you said you didn't pay on a credit card, but did you take out any sort of loan? I'm just wondering if there's any sort of angle/leverage that could be used there if available to add a bit of pressure on your installers?

Sorry you may have said, but have you tried to reach out to the battery storage manufacturer, sometimes surprising they can be helpful even though you're a 3rd party to them i.e. the end customer and not the distributor/installer....

Well, I did try contacting Pytes a few months ago but never received a reply. Not sure if they have a distributor here or at least somewhere in Europe but the Chinese office wasn't helpful.

Of course, like the installers (and their lackeys in the regulator), Pytes and Afore may just do a finger pointing exercise.

Unsure whether there are any firmware updates. Back in February when the temps were so low ours and every other client of our installers with the same battery had it refusing to charge (as too cold), for that the installer was able to get a firmware update.

DIY fixing it would be great, but I also have to post in the consumer rights sub-forum (I almost finished what I want to say the other day) in case we do have to go to court.

kgrins

MeteredOut said:

1961Nick said:

I don't know if this is of any help, but looking at the spec of the 5.1kWh Pytes 48R100 battery I noticed that the operating voltage range & nominal voltage is considerably higher than other systems - Pylontechs 48v, Pytes 51.2v.

is it possible that the the wrong battery system has been selected on the inverter or the wrong parameters have been set for the Pytes? Worth a check?

That's why i suggested looking into inverter/battery incomparability/setup issue.

OP, you could also try this more general FB solar group, where there are a lot of knowledgeable people:

https://www.facebook.com/groups/2197329430289466

Reasonably sure that the settings are now correct but changing anything on the inverter is user hostile in the extreme: imagine the worse single line central heating timer box but with 100s of settings. Even with Afore's PDF of the layout it is a pain.

Right, hadn't considered facebook for forums/groups but have now requested access to that. Seems to be end-users and installers so if nothing else if we go to court we would need an expert statement so maybe someone there can produce those (for a fee)?

hardergamer

I can see a problem with your battery state readout, you said it has 10% SOC with the first battery showing around that 1% at 90-1500mah, but going by the voltage they are at around 60-65% SOC, this shows you are only using the top 40% of the first battery, and a little more on the second one, 10% SOC should by around 2.65V each cell (16 cells = 48v nominal, 58.4v HOT, 40v empty), yours are at 3.29v (52v).

LiFePO4 cell range is normally 2.5v to 3.65V (2.5v 0% SOC 3.65v 100% SOC)

This is either the BMS programming or BMS telling the inverter it is empty too early, or the inverter is misreading the batteries' BMS, or it is programmed for Lithium Ion MCN,MCA or LA, not Lithium phosphate LiFePO4, and going by this each battery is around 5kwh.

My guess is the AIO/inverter is programmed for the wrong battery chemistry, probably Lithium Ion MCN ,MCA etc, as its cell voltage range is mostly 3v 0% to 4.15v 100%.  

kgrins

hardergamer said:

I can see a problem with your battery state readout, you said it has 10% SOC with the first battery showing around that 1% at 90-1500mah, but going by the voltage they are at around 60-65% SOC, this shows you are only using the top 40% of the first battery, and a little more on the second one, 10% SOC should by around 2.65V each cell (16 cells = 48v nominal, 58.4v HOT, 40v empty), yours are at 3.29v (52v).

LiFePO4 cell range is normally 2.5v to 3.65V (2.5v 0% SOC 3.65v 100% SOC)

This is either the BMS programming or BMS telling the inverter it is empty too early, or the inverter is misreading the batteries' BMS, or it is programmed for Lithium Ion MCN,MCA or LA, not Lithium phosphate LiFePO4, and going by this each battery is around 5kwh.

My guess is the AIO/inverter is programmed for the wrong battery chemistry, probably Lithium Ion MCN ,MCA etc, as its cell voltage range is mostly 3v 0% to 4.15v 100%.  

Thanks for that.

Getting the settings of the inverter is "nasty" as it's all on that single line display. However, I am pretty sure it is set to Lithium and that is what Pytes seem to suggest. Don't think the inverter distinguishes between Lithium and Li-ion and LiFePO4

Having said that, Pytes USA (but nowhere else) have a bunch of installation guides including ones for Afore:

https://www.pytesusa.com/Download-Center/

and inside it says to set the battery to Afore. This is after setting the Pytes DIP switches to Afore. They (Pytes USA) also say to set both min and max voltage to 56V rather 475.V / 57.5V which Pytes are rated at, or the 61.0V / 40.0V the installers had set them at.

Might setting minV to 56 make it so that the battery never gets drained at all, though?

I guess in a roundabout way I am asking: does the BMS tell the inverter it's percentage, or does the inverter "guess" from the voltages? As the inverter settings being wrong is far more likely IMO than the BMS not knowing what cells it has. Well assuming Pytes have some competence. Wonder if Pytes have any firmware? I know the installers had to change the firmware shortly after installing as they were set to now charge unless over 15°C or so (pretty unlikely in an cold loft as a huge percentage of UK attics are - I had asked the sales, "surveyor", and during installation and been told that a cold roof space would be fine...)

I posted the question on Pytes NL's FB back as they contact box Pytes.com has never responded to.

This suggests to me that Pytes' DIP switches can change quite a bit in terms of compatibility. I would hope that the BMS handles charging and the reports what it has to inverter rather than the inverter driving things directly.

Currently, I am testing the two batteries one after one. Bat #1 showed going from 10% to 100% in about 1.7kWh which is about a third of the expected. Bat #2 currently on it's own. I intend to join the two after they both individually think they are 99/100% full.

Somewhat reluctant to go with Pytes USA's suggestions as it is a lot of changes at once - making it hard to revert things later.