Growatt SPF5000ES Offgrid 9kw DIY Solar Project

[Pink7]

14 minutes ago, lom said:

^ Yes, any supported battery that doesn't have BMS communication but I guess you have BMS comms.

 

^^ BMS continuously tells inverter about the SOC so the inverter will know when it is at 100%. If BMS wants to balance batteries then it can request a lower voltage from the inverter.

No I do not have any communication between BMS and Inverter. Im reading myself up on this issue I have and see other with some of same issue.

 

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[lom]

28 minutes ago, Pink7 said:

No I do not have any communication between BMS and Inverter.

That explains it but why don't you let the BMS manage the battery? It does that so much better than an inverter.

 

[Pink7]

5 minutes ago, lom said:

That explains it but why don't you let the BMS manage the battery? It does that so much better than an inverter.

 

Well the BMS does manage the battery in normal situation. Just to be clear so no misunderstanding: communication vs no communication in this case is related to use com port on Inverter with a compatible BMS and battery not just voltage per cell as ordinary BMS setup ( as I have) Here is more on the issue

 

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[Pink7]

Today my units started charge as normal after i change: 05 Battery type from "Use2" (who Growatt want its user to use) to "Use" who much user say better to use. Use2 have a complicated way to try manage parts of the charge... This is a quite common issue for Growatt and some similare inverters. Create issues like Inverter not start to charge or stop to charge. Who wants details on this just google: "Growatt - Odd behavior"

 

 

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[Pink7]

Today I got the highest watt value since my build went up 11 months or so ago: 7624Watt. I also noticed the current to be 20A on the one inverter  who also highest i seen. My Growatt 500ESP are supposed to have limit on 22A from earlier 18A.

 

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[Pink7]

Got a advice and help to check my BMS settings today since my inverters sometimes not complete the charge: Found out that i should not use same max charge current settings on inverter and BMS. So I adjusted some down on inverter and some up on BMS charge current limit ( My system log show some: charge over current protection) So lets hope that solved that issue. It should because times in log corresponded with my issues.

 

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[Pink7]

Today its 1 years since i got my solar setup up and working. My solar production for that year is 9,435 KWH so that should be around  B38.7K saved on electric bill if 1 unit is B4.1. My average bill is  B1xx per month. 13% of the cost of the setup back after first 12 months. If use same rates ROI  will take 7.5-8 year.

 

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[Pink7]

Used some more air con than normally last days and Im getting some short on battery storage..

 

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[Crossy]

7 hours ago, Pink7 said:

Used some more air con than normally last days and Im getting some short on battery storage..

 

Do you really need an excuse to get more storage? 

[Muhendis]

3 minutes ago, Crossy said:

 

Do you really need an excuse to get more storage? 

It may not be so simple although I hope it is.

There may also be a need to increase charging capabilities too

and whilst your about it have a look at whether or not the batteries are getting fully charged.

 

Another thought has occured to me, as they accassionaly do.

Last year the batteries presumably handled their loading OK but this year they don't

I would be inclined to check installed battery capacities first.

 

[Pink7]

1 hour ago, Crossy said:

 

Do you really need an excuse to get more storage? 

It took me not even a minute to tell wife maybe we should ad another battery, from 2 to 3..

 

Edit: Let me ad she was not so enthusiastic about that..

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[Pink7]

51 minutes ago, Muhendis said:

It may not be so simple although I hope it is.

There may also be a need to increase charging capabilities too

and whilst your about it have a look at whether or not the batteries are getting fully charged.

 

Another thought has occured to me, as they accassionaly do.

Last year the batteries presumably handled their loading OK but this year they don't

I would be inclined to check installed battery capacities first.

 

I must use some time to check this more in details.. But look like aircons used more electric last days ( they both cleaned a week ago) It might just been extra hot last days and we used more power than we used to do. I tried to compare back same time last year but Growatt stat do not store data that long.

 

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[Muhendis]

5 minutes ago, Pink7 said:

and we used more power than we used to do.

Air cons are great energy consumers. 

 

[Crossy]

5 hours ago, Muhendis said:

Air cons are great energy consumers. 

 

Particularly when your Thai grand-daughter has this as her Facebore picture.

 

 

Yes, she lives up to her logo!

[Pink7]

2 hours ago, Muhendis said:

It may not be so simple although I hope it is.

There may also be a need to increase charging capabilities too

and whilst your about it have a look at whether or not the batteries are getting fully charged.

 

Another thought has occured to me, as they accassionaly do.

Last year the batteries presumably handled their loading OK but this year they don't

I would be inclined to check installed battery capacities first.

 

Batteries are getting charged and usually full at lunch time so i have more charge capacity. It this current time both batteries are charge at 40A or so each.

 

Regarding more batteries i guess there is not much point to ad batteries with more than 280A as the others batteries are 280A?

 

Pink

[Muhendis]

27 minutes ago, Pink7 said:

i guess there is not much point to ad batteries with more than 280A as the others batteries are 280A?

Quite so.

If you have a big battery in parallel with a small battery of the same voltage, The small battery will become discharge sooner than the big one and unless they are isolated from each other with a huge diode the big battery will spend some of its energy maintaining the charge in the small battery. 

Since you say your batteries are full by lunchtime I'm guessing that has always been the case so your batteries are not capacity challenged except that they are struggling with your load.

Option 1.

Turn off/down air con. 

Option 2.

Turn off wife and get more batteries.

[BritManToo]

1 hour ago, Pink7 said:

Batteries are getting charged and usually full at lunch time so i have more charge capacity. It this current time both batteries are charge at 40A or so each.

 

Regarding more batteries i guess there is not much point to ad batteries with more than 280A as the others batteries are 280A?

 

Pink

1. Run your aircon at full blast between mid-day and end of solar production to cool the house when it's free power.

or

2. Add grid-tie inverters to wind the meter back after your batteries are full.

 

I do No. 2,

added a couple of new panels and a 1000w grid-tie inverter.

[Pink7]

2 hours ago, BritManToo said:

1. Run your aircon at full blast between mid-day and end of solar production to cool the house when it's free power.

or

2. Add grid-tie inverters to wind the meter back after your batteries are full.

 

I do No. 2,

added a couple of new panels and a 1000w grid-tie inverter.

I use to have a stra6tegy same as your alt1..but usually forgotten..but today Im back on that .

 

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