6.7Kwh 8S2P system what is better approach

[talk2abs]

Hi People, i just got a delivery of system below

1. Growatt SPF 5000 ES (5kva) (1pc)
2. Solar Panel details (420W (+3), Max Imp 12.28A, Max vmp 34.20V, Short circuit 13.06A (+3), Open Voc 40.28V (+3)) (16pcs) (fuse at 20A)3. Felicity Battery 10KVA
3. LPBA48200-H (1pc)hope that help to advise on the right configuration to maximize the system.

I'm wondering what will be best configuration to maximize the use of this system, i did watched a video of 2S2P (4 solar panel) system and that looks good, but how do i expand that to 16 Panels ?, any diagram or video of how to wired it would be helpful, thank yo so much, a Newbie here

 

[OffGridForGood]

1. Growatt SPF 5000 ES (5kva) (1pc)

ES - not the US model?
you better check, the ES model is European Standard ie 230 volt 50 hz hot to N is 230 volt. I belive this has been discussed extensively on this forum - do a search to check and confirm.

Solar Panel details (420W (+3),

not sure what the (+3) means, did you buy just three solar PV panels? But the thread title says 8s 2P = 16 panels I suspect.
you need to check the inverter PV input voltage and current maximums. Find out the max number of series PV you could use, allowing for coldest temp ever, and check the PV max input current your inverter can handle.
Most of the AIO inverters will have two PV inputs, so you may want to split between them, or if it can handle all 16 on one input you have the other as a spare.

 

[timselectric]

8s2p is what you want to do.
As long as it doesn't get very cold in your area.

 

[talk2abs]

8s2p is what you want to do.
As long as it doesn't get very cold in your area.

Thank you so much, can you point me to how this would be setup?, how so i wire 8S2P ?, sorry about the confusion about (+3), i was just writing out what was written on the panel

 

[talk2abs]

ES - not the US model?
you better check, the ES model is European Standard ie 230 volt 50 hz hot to N is 230 volt. I belive this has been discussed extensively on this forum - do a search to check and confirm.


not sure what the (+3) means, did you buy just three solar PV panels? But the thread title says 8s 2P = 16 panels I suspect.
you need to check the inverter PV input voltage and current maximums. Find out the max number of series PV you could use, allowing for coldest temp ever, and check the PV max input current your inverter can handle.
Most of the AIO inverters will have two PV inputs, so you may want to split between them, or if it can handle all 16 on one input you have the other as a spare.

Sorry about the +3, i was just writing out what was written on the panel, the location is west Africa it gets really hot there

 

[timselectric]

8s2p
8s means that you wire 8 panels into a series string.
Then you connect 2 strings in parallel.

 

[OffGridForGood]

Sorry about the +3, i was just writing out what was written on the panel,

+/- 3%
LOL okay the rating of 420 Watts is plus or minus 3% tolerance. got it, thanks for clearing that up!

the location is west Africa it gets really hot there

I thought you were in San Francisco - ie it may be cold during winter, - but not if the actual location for this set up is in warmer location like Africa.
(I doubt San Fran actually gets any really cold weather either, but not sure of the extremes) LOL.

 

[talk2abs]

+/- 3%
LOL okay the rating of 420 Watts is plus or minus 3% tolerance. got it, thanks for clearing that up!

I thought you were in San Francisco - ie it may be cold during winter, - but not if the actual location for this set up is in warmer location like Africa.
(I doubt San Fran actually gets any really cold weather either, but not sure of the extremes) LOL.

Yes i'm based out in SF, i got project back in west africa

 

[OffGridForGood]

Yes i'm based out in SF, i got project back in west africa

okay makes sense,
something to watch out for will be high temperatures for the inverters and batteries.
The heat will have some impact on PV panels - ie lower output.
LFP cells on the other had will not last long if they are exposed to 40 Celsius temperatures, just mention it so you know.
Some inverters are better with high temps than others, check before you buy.

 

[talk2abs]

i'm still having issues with the 8s2p, the voltage will exceed the inverter 450V, i have order another same inverter, would that help ?

What options do i have here?

 

[OffGridForGood]

i'm still having issues with the 8s2p, the voltage will exceed the inverter 450V, i have order another same inverter, would that help ?

What options do i have here?

your panel PV spec shows VOC 40.28
if you put 8 panels in series + - + - + - + - + - + - + - + - the the total max voltage will be 8x 40.28 = 322.24 volts (and we assume it will never be cold at the location in West Africa. (note: in colder temperatures the voltage from the panels increases.

so with your 450v max inverter you will not exceed this.

 

[zanydroid]

8s = 8* 40.28 = 322.24V

The wiring diagram is problematic. Why is the battery connected like that to the panels? The DC+/- from panels should go straight into MPPT.

 

[talk2abs]

your panel PV spec shows VOC 40.28
if you put 8 panels in series + - + - + - + - + - + - + - + - the the total max voltage will be 8x 40.28 = 322.24 volts (and we assume it will never be cold at the location in West Africa. (note: in colder temperatures the voltage from the panels increases.

so with your 450v max inverter you will not exceed this.

i think this is where i'm getting it wrong, i have 16 panels not 8, which mean a total of 14 panels will be in series right and or maybe i dont understand what series means the battery connection was just for illustration i think i got that wrong

 

[OffGridForGood]

i think this is where i'm getting wrong, i have 16 panel not 8, which mean 14 panels will be in series right or maybe i dont understand what series means the battery connection was just for illustration i think i got that wrong

You are mis-understanding the connections between the PV panels.
you will have two groups of 8 panels
in each group the pos of panel one connects to the neg of panel two, the pos of panel two connects to the neg of panel three - continue to panel eight.
Now you are left with a neg cable at panel one, and a pos cable at panel 8 (all the other panel cables are connected,
Repeat with a second row of 8 panels.
now you have two rows, and at one end two neg cables, and at the other end two pos cables.
the two negs will connect together and run to the Growatt NEG PV input,
the two pos will connect together and run to the Growatt POS PV input.
The battery will connect to the Growatt battery connection terminals (pos to pos, Neg to Neg)


Edit: Here is a simple set up Will explains all the basics for setting up a solar off grid system - even uses the Growatt Inverter as his example.

 

[talk2abs]

Thank you so much, just like the diagram i drew in paper right?, i think i understood it to that point, since there are two groups of 8 panels, how then is the total voltage equal 8x 40.28 = 322.24 and not 16x 40.28 ?, i think this was another confusion for me, if you can explain that, i would really help,

 

[OffGridForGood]

Thank you so much, just like the diagram i drew in paper right?,

No, the diagram has the PV connected directly to the batteries - Do Not Do This!
The Growatt is an All-In-One machine, this means it is an inverter (can change DC to AC electricity) but it is also a Solar Charge Controller, and an Automatic Transfer Switch 'all built into one box'.
If you connect those PV panels, with 322vDC directly to a 48v Battery pack - Wow that would be a BAD DAY - BOOM.
The PV panels will connect to the Growatt - the Growatt will transform the 322v x 24Amps (7700Watts) down to a suitable voltage near the battery voltage of about 48 volts but now at 161 Amps for safely charging the batteries.

i think i understood it to that point, since there are two groups of 8 panels, how then is the total voltage equal 8x 40.28 = 322.24 and not 16x 40.28 ?, i think this was another confusion for me, if you can explain that, i would really help,

Gladly - the PV panels are each rated at about 40v and 12 Amps and a total of 40x12 = 480 Watts (actual will vary with sun, angle etc)
If you connect two panels in SERIES (panel 1 neg connects to panel 2 pos) the voltages ADD, and the amperage remains constant - in this example with just two panels you end up with 80v and 12 Amps. 80 x 12 is now 960Watts or double the first example.
Connecting all 8 panels neg to pos to neg to pos to neg ....x 8 you will be left with one pos on panel 1, and on neg on panel 8 - in this example you will now have 320volts and still have 12 Amps. 320x12 = 3840Watts

Now lets see what parallel PV panels do:
Two PV panels pos to pos connected, and neg to neg connected. The voltage remains the same as each panel 40v in our example. But now the currents add - that is the amperage of 12A from Panel 1 will add to the amperage from panel 2 and now we will measure 40v and 24Amps =960W
notice there is no free ride, two identical PV panels of 480W combine to make 960W in parallel or series, the difference is at what voltage and what amperage they make the 960 Watts.
Higher voltages are easier for the inverter and the cables to carry than higher amperages.

Now lets consider your two strings of 8 panels - each string will make about 320 volts and about 12 amps.
When we parallel the two strings, the voltage remains 320 but the amperage will add and double to 24amps.

In this short 4 minute video Nate explains with some diagrams how parallel and series PV panel connections are done.

 

[timselectric]

FYI
The drawing is correct.
The solar panels are NOT connected to the batteries.
I think that everyone is seeing it wrong.

 

[talk2abs]

No, the diagram has the PV connected directly to the batteries - Do Not Do This!
The Growatt is an All-In-One machine, this means it is an inverter (can change DC to AC electricity) but it is also a Solar Charge Controller, and an Automatic Transfer Switch 'all built into one box'.
If you connect those PV panels, with 322vDC directly to a 48v Battery pack - Wow that would be a BAD DAY - BOOM.
The PV panels will connect to the Growatt - the Growatt will transform the 322v x 24Amps (7700Watts) down to a suitable voltage near the battery voltage of about 48 volts but now at 161 Amps for safely charging the batteries.


Gladly - the PV panels are each rated at about 40v and 12 Amps and a total of 40x12 = 480 Watts (actual will vary with sun, angle etc)
If you connect two panels in SERIES (panel 1 neg connects to panel 2 pos) the voltages ADD, and the amperage remains constant - in this example with just two panels you end up with 80v and 12 Amps. 80 x 12 is now 960Watts or double the first example.
Connecting all 8 panels neg to pos to neg to pos to neg ....x 8 you will be left with one pos on panel 1, and on neg on panel 8 - in this example you will now have 320volts and still have 12 Amps. 320x12 = 3840Watts

Now lets see what parallel PV panels do:
Two PV panels pos to pos connected, and neg to neg connected. The voltage remains the same as each panel 40v in our example. But now the currents add - that is the amperage of 12A from Panel 1 will add to the amperage from panel 2 and now we will measure 40v and 24Amps =960W
notice there is no free ride, two identical PV panels of 480W combine to make 960W in parallel or series, the difference is at what voltage and what amperage they make the 960 Watts.
Higher voltages are easier for the inverter and the cables to carry than higher amperages.

Now lets consider your two strings of 8 panels - each string will make about 320 volts and about 12 amps.
When we parallel the two strings, the voltage remains 320 but the amperage will add and double to 24amps.

In this short 4 minute video Nate explains with some diagrams how parallel and series PV panel connections are done.

Wow, thank you so much, this was exactly where i missed it now it make perfect sense, thank's a million for breaking it down "
Now lets consider your two strings of 8 panels - each string will make about 320 volts and about 12 amps.
When we parallel the two strings, the voltage remains 320 but the amperage will add and double to 24amps."

 

[talk2abs]

@OffGridForGood , @timselectric

Again, thanks a million for helping this newbies (lol), so i've got one more issue, while i was waiting for answer to the 8s2P strategy (now resolved) i'd read in other forum to buy another inverter so i ordered that same inverter (Growatt 5000 ES), now i'm not sure what to do with it, and there a no return or refund in that part of the world except if you want swap it with something else.

I've being reading about connecting inverters in parallel, but i have no clue what is the use or usecase for such, any video or when and how to do it would be appreciated.

So what is the benefit of a second inverter in my setup if i want to install it without affecting the current proposed setup? or should i just lock it up in storage until the installed become faulty ?

 

[timselectric]

@OffGridForGood , @timselectric

Again, thanks a million for helping this newbies (lol), so i've got one more issue, while i was waiting for answer to the 8s2P strategy (now resolved) i'd read in other forum to buy another inverter so i ordered that same inverter (Growatt 5000 ES), now i'm not sure what to do with it, and there a no return or refund in that part of the world except if you want swap it with something else.

I've being reading about connecting inverters in parallel, but i have no clue what is the use or usecase for such, any video or when and how to do it would be appreciated.

So what is the benefit of a second inverter in my setup if i want to install it without affecting the current proposed setup? or should i just lock it up in storage until the installed become faulty ?

You can connect them in parallel to double the output. And gain a second SCC for more panels.
Or just save it as a spare, if you don't need it right now.