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Are my batteries dead or my inverter settings incorrect???


Dani
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Please help.😪🤗

This morning in grey jhb i noticed that my batteries were in the low 40 volts - like 42 volts.

I dont expect this when I am running a 48v system and it has moved to bypass because the solar energy does not suffice to power the load.

Here is my system.

Axpert 5kva/5kw inverter

4x 100ah AGM omnipower batteries in series to get 48v (I know this is under specced for the system but ...)

I think the bulk and float charging for these batteries were not set correctly originally - see below.

https://sinetechstore.co.za/shop/batteries/lead-acid-batteries/opr120-12-omnipower-12v-120ah-opr-deep-cycle-rechargeable-agm-gel-hybrid-vrla-battery/

12 x canadian solar 400w poly

My inverter settings are as follows.

1: SOL

2:20A

3:APL

4:Sds

5:USE

6:LFE

7:TFE

8:n/a

9:50hz

10: na/

11: 20A

12:48V

13: 52V

16: CSO changed to SNU after seeing the horrible low voltages this morning

17: NA

18: 60F

19:TEP

20: LON

21:  N/A

22:AOF

23: BYE

24: N/A

25: FDS

26: 58.4V this spent a year at 56.4 the inverter default

27: 55.2V this spent a year at 54 the inverter default

28: PAL

29: 42.0V

30: ONE dont know what this is

31: SBE

32: 60

33: EEN

34: 58.4V

35: 60

36: 120

37: 30D

38: DIS

39: ADS

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Thanks @iops 42V is the default setting on the Axpert, from what I have read on this forum changing that setting messes with the other programs maybe @Chris Hobson or other Axpert experts can confirm?

The batteries are not being used overnight the system goes to bypass and tops the batteries up at the start of the night.

The next morning the batteries do run down a bit when the visible solar energy is insufficient to run the load but that should cut out at 48V (setting 12).

What I don't understand is how they got down to the low 40's after hitting 48 they should have gone back to bypass with the sun topping up the batteries, worst case if there is insufficient sun to recharge the batteries they should have stayed at 48?

Could the inverter still be drawing power from the batteries even though it is on bypass??

 

 

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7 hours ago, Dani said:

38 views but not a single bite? 

For the record the batteries are behaving today? 

How did you use the batteries? Did you cycle them daily/only for loadshedding?

My guess is that if you cycled them daily to 42V for a year, I won’t be surprised if they are dead. I’m assuming that 42V on AGM is a very low SoC. My understanding is that AGMs never be drained to less than 50% SoC? That said, I don’t know lead acids myself at all.

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18 minutes ago, Dani said:

But 50w won't take it from 49v to 42v?? It seemed like the inverter was drawing much more than that. Not for the load and not for standby. Can the current be going towards the panels? In reverse?? 

If you couldn’t properly charge the batteries due to rainy days or so, you might well. I’m not sure what the self-consumption of those Axperts are, I’m guessing 50W. You could have also had loadshedding in between the sun’s availability for which the batteries could’ve run down all the way to 42V.

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On 2020/09/03 at 5:13 AM, Dani said:

This morning in grey jhb i noticed that my batteries were in the low 40 volts - like 42 volts.

As others have noted, that's really low. Very bad for lead acid.

Quote

4x 100ah AGM omnipower batteries in series to get 48v (I know this is under specced for the system but ...)

They will be working hard, depending on your typical loads. This will wear them out much faster.

Quote

12 x canadian solar 400w poly

I should do the usual: is this on a 145 V absolute max solar charge controller?

Are you running 3S or 2S if that's the case? Or 6S if it's a 450 V absolute max model?

Quote

My inverter settings are as follows.

25: FDS

You may as well turn this on (FEn). I can't see a reason to ever have it off (and off is the default). But this is no biggie.

Quote

26: 58.4V this spent a year at 56.4 the inverter default

27: 55.2V this spent a year at 54 the inverter default

Yes, this won't have helped matters. In conjunction with other problems, it has probably contributed to extra degradation of the battery.

Quote

28: PAL

This can cause unusual problems. You should change it to SnG. See FAQ #3.

Quote

29: 42.0V

This is the biggie; it's mainly a big issue in South Africa where there is often load shedding. 42 V is a "disaster - never go below" voltage, for 1-3 times in the life of the battery. But with regular load shedding, it's way too low. Yes, changing this value will affect the estimated SOC, but for reasonable battery life with regular load shedding, this needs to increase to around 48 V, or perhaps as low as 46 V. See FAQ 2 re the interaction between these settings. This will of course affect run time. As others have noted, regular discharging to 42 V will ruin a lead acid battery in short order. Of course, when Eskom is available, the battery should start re-charging at 48 V because of setting 12. But I think it's the regular long load sheds that have degraded the battery.

Quote

30: ONE dont know what this is

It's not important.

Quote

34: 58.4V

I think this is again a default value. Oddly, your battery seems to need a lowish 57.6 V for equalisation; usually equalisation voltage is higher then absorb voltage.

8 hours ago, Dani said:

But 50w won't take it from 49v to 42v??

It will eventually. And more quickly the more degraded the battery becomes.

11 hours ago, Dani said:

What I don't understand is how they got down to the low 40's after hitting 48 they should have gone back to bypass with the sun topping up the batteries, worst case if there is insufficient sun to recharge the batteries they should have stayed at 48?

True. If there is Eskom or sun.

Edit: I should also have mentioned the premature float bugs. These will also cause your battery to degrade. You may be able to run patched firmware to fix this.

Edited by Coulomb
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Thanks @Coulomb for the detailed response.

8 hours ago, Coulomb said:

I should do the usual: is this on a 145 V absolute max solar charge controller?

Are you running 3S or 2S if that's the case? Or 6S if it's a 450 V absolute max model?

You right the wiring is a problem - I only found out when I started monitoring the system closely that they are in sets of 3, my installer needs to come back to rectify but now he is playing hard to get. I may need to get someone else to rewire.

 

8 hours ago, Coulomb said:

change it to SnG

will do.

8 hours ago, Coulomb said:

42 V is a "disaster - never go below

Will make 45V but this could be too late to save them...

8 hours ago, Coulomb said:

your battery seems to need a lowish 57.6 V for equalisation

can you please explain how you go 57.6V I got 56.4 (14.1x4) attached is the data sheet.

8 hours ago, Coulomb said:

Will try patch it - dunno how yet but assume USB?

I have lots to learn...

Thanks again!

OmniPower-OPR120-Datasheet.pdf

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1 hour ago, Dani said:

Thanks @Coulomb for the detailed response.

You right the wiring is a problem - I only found out when I started monitoring the system closely that they are in sets of 3, my installer needs to come back to rectify but now he is playing hard to get. I may need to get someone else to rewire.

Ok, good.

1 hour ago, Dani said:

Will make 45V but this could be too late to save them...

Sadly, yes.

1 hour ago, Dani said:

can you please explain how you go 57.6V I got 56.4 (14.1x4) attached is the data sheet.

Oops, my bad. Yes, 57.6 V.

1 hour ago, Dani said:

Will try patch it - dunno how yet but assume USB?

Actually, you can't use the USB port of the inverter, unless it's one with the removable display. The usual way is to plug the provided RJ-45 to D9 cable into the inverter, and plug a compatible USB to serial adapter into that, and that plugs into USB on your Windows computer. See the index (in the first post) of this topic for details on the USB to serial adapter, and the firmware uploading instructions. It can be a bit daunting the first time.

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On 2020/09/04 at 2:55 PM, Dani said:

My installer needs to come back to rectify this

My current wiring is 10mm. how thick must the wiring be from the panels to the inverter to sustain 6 sets of 2 panels. Canadian solar 400w. My maths is that 10mm is just on the border for the amps? But I could be totally wrong

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Just to add, with same batteries (8 of them), last night I saw the attached on the Victron Venus GX connect 😭

And yes, I was cycling the batteries to 80% SOC every evening, but that being said, as per the battery brochure they should have lasted couple of thousand cycles with such discharge.
I guess that is not the case. Overall, from what I see, these batteries are for backup application only and nothing else :(

victron.jpeg

Edited by Bobby Kaucic
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