Seeking Advice for PV Setup

[Sotech]

Hi Everyone,

I have this situation, can you please give me your advice how do I go about with the setup?
panels configuration, how many in series, parallel or combination. for a save setup.

My plan is to make two strings of 7 panels in series, each string, gives a Voc 287.28V ,10.82A and the 2 strings in parallel, to give 287.28v, 21.64A .
Is this the best approach given what is available? See attached product specifications for more information.

1) Panel 14 pieces, 370W each.
2) Hybrid Solar Inverter rated power 5500W, Maximum PV power 6000W
3) Battery 12v, 200AH, 4 pieces
4) DC Breaker, 2pieces 2pole 125A, 500VDC
5) AV Breaker, 1 piece 20A, 220-240V
5) Surge protection device, 1 piece Uc 500VDC

.

 

[timselectric]

My plan is to make two strings of 7 panels in series, each string, gives a Voc 287.28V ,10.82A and the 2 strings in parallel, to give 287.28v, 21.64A .

Your numbers are good. But your SCC says that the minimum operating voltage is 360v ( maybe a typo ). Which is the voltage required to wake up the SCC. That seems very high for an operating range of 120v to 450v.
If it were me, I would go with 9/or 10s2p.

3) Battery 12v, 200AH, 4 pieces

What type of batteries?
It's not recommended to put BMS controlled batteries in series.

5) AV Breaker, 1 piece 20A, 220-240V

Assuming "AC" breaker.
The rated output of the inverter is 22a. I would recommend a 25a breaker, to avoid nuisance tripping.

 

[littleharbor2]

Definitely look into that minimum operating voltage spec. Given the MPPT range of 120 to 450vdc it surely looks like a typo, if not, it severely limits you configuration possibilities.

 

[BenQ]

I went to Sohigh’s website and saw a very similar solar kit to what you’re working with. Have you tried talking to them about the “minimum operating voltage: 360v?” They seem to be selling a kit with 12 panels of instead of 14 so I looked at their 10 kw kit and I see that they recommend putting 10 panels at 30.78v in series for a total of 307.8v which is under the “minimum operating voltage: 360v” but well within the mppt range like your configuration. Just upgrade your “AV breaker” to a 25a AC breaker as @timselectric suggested and you should be good to go!

 

[Sotech]

.

Your numbers are good. But your SCC says that the minimum operating voltage is 360v ( maybe a typo ). Which is the voltage required to wake up the SCC. That seems very high for an operating range of 120v to 450v.
If it were me, I would go with 9/or 10s2p.

What type of batteries?
It's not recommended to put BMS controlled batteries in series.

Assuming "AC" breaker.
The rated output of the inverter is 22a. I would recommend a 25a breaker, to avoid nuisance tripping.

Exactly, this is where I have issue, the SCC of 360V. is the 9 or 10S, 2P to makeup for the 360V?
Thanks for the battery info, I will cross check.

 

[timselectric]

Exactly, this is where I have issue, the SCC of 360V. is the 9 or 10S, 2P to makeup for the 360V?

If needed.
But I would anyway, just to get into the sweet spot of production.

 

[Sotech]

I went to Sohigh’s website and saw a very similar solar kit to what you’re working with. Have you tried talking to them about the “minimum operating voltage: 360v?” They seem to be selling a kit with 12 panels of instead of 14 so I looked at their 10 kw kit and I see that they recommend putting 10 panels at 30.78v in series for a total of 307.8v which is under the “minimum operating voltage: 360v” but well within the mppt range like your configuration. Just upgrade your “AV breaker” to a 25a AC breaker as @timselectric suggested and you should be good to go!

yab, I chatted with someone from Sohigh and he did confirmed my setup 7 panel series x the 2 series in parallel, cause my conflict was the 360v startup constraint. I just wanted to get second expert opinion if I am on track with this setup. Thank you so much. As for the 25A load side, I will go with that, thanks @timselectric and thank you BenQ.

 

[Sotech]

If needed.
But I would anyway, just to get into the sweet spot of production.

This is worth considering, thanks Tim.

 

[Sotech]

Hi Everyone,

I have this situation, can you please give me your advice how do I go about with the setup?
panels configuration, how many in series, parallel or combination. for a save setup.

My plan is to make two strings of 7 panels in series, each string, gives a Voc 287.28V ,10.82A and the 2 strings in parallel, to give 287.28v, 21.64A .
Is this the best approach given what is available? See attached product specifications for more information.
View attachment 159533
1) Panel 14 pieces, 370W each.
2) Hybrid Solar Inverter rated power 5500W, Maximum PV power 6000W
3) Battery 12v, 200AH, 4 pieces
4) DC Breaker, 2pieces 2pole 125A, 500VDC
5) AV Breaker, 1 piece 20A, 220-240V
5) Surge protection device, 1 piece Uc 500VDC

.

Hi Guys,

@timselectric, @BenQ @littleharbor2 and Everyone in the house,
Finally, all is set for instillation, and just a little follow up concern I have please. Giving that I have roughly PV power of 5000W (from the 14 pieces of solar panels @370W / piece), I'm wondering if the batteries are insufficient (time wise) for such power, on average of 5hrs sunshine, which is typical here in my area during our Dry Season. We do get about 6-10 hrs of sunshine a day for straight 30 or 60 days or even more days during our dry season. With this amount of power possible to generate, I am concern about the battery's health. Is the 7penels string x 2 strings in parallel a good fit? The charge current is about 100 AH from the MPPT Charge Controller photo attached, (considering over charging)? What would be your expert opinion, because I have only these 4 batteries? Currently, we get roughly 2hrs sunshine because we are in the Raining Season here. Thank you so very Gentlemen.

Battery 12v, 200AH, 4 pieces

 

[timselectric]

Best answer is
Time will tell
I would plan for future capacity expansion.
Almost everyone could use more capacity.

 

[Sotech]

I do agree with you for future expansion. My main concern is whether the current volume of PV power (5000W) is safely proportional to the 4 batteries capacity (12v, 200Ah x4 ), without over current/ overcharging the battery, or should I consider reducing the PV power for safe charge? Thank you again.

Best answer is
Time will tell
I would plan for future capacity expansion.
Almost everyone could use more capacity

 

[Dinobot248]

I think your batteries (10kwh) are too small but it is a good starting point. You can always add more.

I didn't see above anything about how much electricity you use (also I could have missed it).

 

[timselectric]

I do agree with you for future expansion. My main concern is whether the current volume of PV power (5000W) is safely proportional to the 4 batteries capacity (12v, 200Ah x4 ), without over current/ overcharging the battery, or should I consider reducing the PV power for safe charge? Thank you again.

The max charging you are now capable of is around a .5 C rate. Minus any loads that are being fed at the time. It shouldn't be any concern.

 

[Sotech]

Great!! @timselectric, @Dinobot248

Thank you guys for the advice. I'll keep you updated.

Cheers!!,​

 

[Sotech]

I think your batteries (10kwh) are too small but it is a good starting point. You can always add more.

I didn't see above anything about how much electricity you use (also I could have missed it).

Here is an estimate of the load:

• Air Condition = 6A @220v (12KBTU)
• Refrigerator = 3A @220v
• Television x 2 pieces = 360w @220v
• Fan 4 pieces, 90x4 = 360w @220
• Led lights (all) = 553w @220
• Other items (laptops, piano, children's toys, etc) =320w @220v
• Total load = 3213w @220v, 14.6A

 

[Dinobot248]

Using a very simple scenario and many assumptions, this is what I I could come up in 2 minutes.


Assumptions are
Solar is collected 8 of 24 hours (1/3 of day)
You want to replace 100% of your electricity with the battery during the other 16 hours
Total house load is 3200

Total house load runs on average 20% of the time. 0.2 x 16 x 3200 = 10,240 or 10kwh

Battery reserve takes away 10%
Efficiency loss from converting DC to AC is 10%
Net battery capacity is 8kwh (10x 80%)

Assume every day is the same. Sun shines exactly 8 hours, you use exactly 10kwh, you want 100% replacement of electricity during 16 hours when there is no solar, etc


In this simple scenario,
You need 10kwh and your battery can provide 8kwh

Again, there are a lot of assumptions. Change some of them and it will work, change others and it will not work.

 

[MisterSandals]

My main concern is whether the current volume of PV power (5000W) is safely proportional to the 4 batteries capacity (12v, 200Ah x4 ), without over current/ overcharging the battery, or should I consider reducing the PV power for safe charge?

If you are concerned about too high charge current, you can spread the charging out during the day instead of mostly when the sun is at its highest point.

You can point one string east-ish to start charging earlier and one string pointing west-ish to charge later in the day. Theoretically halving your charge current but doubling the time charging.

 

[Sotech]

This is pretty much the design of the roof on which the panels are going to be mounted east to west (sun rise to sun set), hence, 7s 2p.
Thanks a lot.

If you are concerned about too high charge current, you can spread the charging out during the day instead of mostly when the sun is at its highest point.

You can point one string east-ish to start charging earlier and one string pointing west-ish to charge later in the day. Theoretically halving your charge current but doubling the time charging

 

[Sotech]

Using a very simple scenario and many assumptions, this is what I I could come up in 2 minutes.


Assumptions are
Solar is collected 8 of 24 hours (1/3 of day)
You want to replace 100% of your electricity with the battery during the other 16 hours
Total house load is 3200

Total house load runs on average 20% of the time. 0.2 x 16 x 3200 = 10,240 or 10kwh

Battery reserve takes away 10%
Efficiency loss from converting DC to AC is 10%
Net battery capacity is 8kwh (10x 80%)

Assume every day is the same. Sun shines exactly 8 hours, you use exactly 10kwh, you want 100% replacement of electricity during 16 hours when there is no solar, etc


In this simple scenario,
You need 10kwh and your battery can provide 8kwh

Again, there are a lot of assumptions. Change some of them and it will work, change others and it will not work.

Got it! Thanks Bro.

 

[BenQ]

Hi Guys,

@timselectric, @BenQ @littleharbor2 and Everyone in the house,
Finally, all is set for instillation, and just a little follow up concern I have please. Giving that I have roughly PV power of 5000W (from the 14 pieces of solar panels @370W / piece), I'm wondering if the batteries are insufficient (time wise) for such power, on average of 5hrs sunshine, which is typical here in my area during our Dry Season. We do get about 6-10 hrs of sunshine a day for straight 30 or 60 days or even more days during our dry season. With this amount of power possible to generate, I am concern about the battery's health. Is the 7penels string x 2 strings in parallel a good fit? The charge current is about 100 AH from the MPPT Charge Controller photo attached, (considering over charging)? What would be your expert opinion, because I have only these 4 batteries? Currently, we get roughly 2hrs sunshine because we are in the Raining Season here. Thank you so very Gentlemen.

Glad to hear that you’re continuing your build. If you got the Gel batteries that sohighsolar sells then just remember to set your charging parameters for that specific battery type. If you go with lithium ion batteries you’ll probably need to set the parameters manually and remember that lithium iron phosphate batteries have a different charging profile than lithium ion and flooded lead acid/gel batteries. Otherwise, run heavy loads while the sun is shining and you should have plenty of battery capacity to last the night! Good luck!