Math Help Needed for Mixed Panel Arrays!

[Ceefiveceefive]

Good Afternoon!

This is a question for any individual who is willing to help me arrange my mixed solar panels into the best possible configuration.

DISCLAIMER!!!!! I already know that mixing panels of different brands, voltages, and amps is not ideal. I am looking for the best possible scenario using the panels that I currently have, not what would be ideal if I purchased more panels. I will optimize my system when I can afford to as soon as possible. I'm only using a few panels and need to increase the solar coming in to charge my batteries.

With that said, I'll start with my inverter specs. Picture is attached. I have an all-in-one Hybrid LV 6048.

I have 1 combiner box that allows up to 6 strings.

Panels:
Five 335 watt
Two 270 watt
Four 250 watt
Three 240 watt

The amps & voltages of all are in the photos.

Thank you for any math wiz that can help me arrange these in the best possible scenario!

 

[sunshine_eggo]

Math doesn't work miracles. You have redefined the worst case. You're mixing 120, 72 and 60 cell panels in odd numbers. This is pretty much insane.

The 335W panels are horrible choices for your MPPT.

Their Voc is too high to be 2S, but their Vmp is too low for 48V in 1S.

Their current is also so low, they will cripple any of the other panels if placed in series with them.

There are no reasonable combinations of panels that will allow you to use all of them.

if you absolutely don't care that your array is jacked up:

Strings 1-4:
335W in series with 250W
87.7 Vmp, 5.85 Imp per string, 513W potential

in parallel with

String 5:
3S 240W
87.7 Vmp, 7.89 Imp, 692W potential

in parallel with

String 6:
335 in series with 270W
87.7Vmp , 5.85 Imp, 513Wpotential

Total: 3,257W (assuming I haven't made a 4th math error somewhere)

Definitely recommend blocking diodes on each string.

EDIT: Corrected a math error. Note that one of the 270W panels won't be used.

EDIT: Ouch... another error. I used panels you didn't have.

Again, definitely recommend blocking diodes on each string.

 

[Ceefiveceefive]

Math doesn't work miracles. You have redefined the worst case. You're mixing 120, 72 and 60 cell panels in odd numbers. This is pretty much insane.

The 335W panels are horrible choices for your MPPT.

Their Voc is too high to be 2S, but their Vmp is too low for 48V in 1S.

Their current is also so low, they will cripple any of the other panels if placed in series with them.

There are no reasonable combinations of panels that will allow you to use all of them.

if you absolutely don't care that your array is jacked up:

Strings 1-4:
335W in series with 250W
92.8 Vmp, 5.85 Imp per string, 543W potential

in parallel with

String 5:
3S 240W
90.9 Vmp, 7.89 Imp, 717W potential

in parallel with

String 6:
2S 270 + 1S 250
101.3Vmp, 7.60 Imp, 770W potential

HOWEVER, the 90.9Vmp is the worst case limiter, so:

Strings 1-4, 90.9*5.85 = 532W EA
String 5, 717W
String 6, 90.9*7.6 = 691W

Total: 3,536W (assuming I haven't made a math error somwhere)

Definitely recommend blocking diodes on each string.

Thanks! And yes, I'm looking at the jacked up version as this is all I have to work with.

 

[Ceefiveceefive]

Math doesn't work miracles. You have redefined the worst case. You're mixing 120, 72 and 60 cell panels in odd numbers. This is pretty much insane.

The 335W panels are horrible choices for your MPPT.

Their Voc is too high to be 2S, but their Vmp is too low for 48V in 1S.

Their current is also so low, they will cripple any of the other panels if placed in series with them.

There are no reasonable combinations of panels that will allow you to use all of them.

if you absolutely don't care that your array is jacked up:

Strings 1-4:
335W in series with 250W
87.7 Vmp, 5.85 Imp per string, 513W potential

in parallel with

String 5:
3S 240W
87.7 Vmp, 7.89 Imp, 692W potential

in parallel with

String 6:
2S 270 + 1S 250
87.7Vmp , 7.60 Imp, 667W potential

Total: 3411W (assuming I haven't made a math error somwhere)

Definitely recommend blocking diodes on each string.

EDIT: Corrected a math error. Note that one of the 335W panels won't be used.

Again, definitely recommend blocking diodes on each string.

What would be the next best case scenario with leaving a few out?

 

[sunshine_eggo]

Bump. Corrected a couple errors.

 

[Ceefiveceefive]

Math doesn't work miracles. You have redefined the worst case. You're mixing 120, 72 and 60 cell panels in odd numbers. This is pretty much insane.

The 335W panels are horrible choices for your MPPT.

Their Voc is too high to be 2S, but their Vmp is too low for 48V in 1S.

Their current is also so low, they will cripple any of the other panels if placed in series with them.

There are no reasonable combinations of panels that will allow you to use all of them.

if you absolutely don't care that your array is jacked up:

Strings 1-4:
335W in series with 250W
87.7 Vmp, 5.85 Imp per string, 513W potential

in parallel with

String 5:
3S 240W
87.7 Vmp, 7.89 Imp, 692W potential

in parallel with

String 6:
335 in series with 270W
87.7Vmp , 5.85 Imp, 513Wpotential

Total: 3,257W (assuming I haven't made a 4th math error somewhere)

Definitely recommend blocking diodes on each string.

EDIT: Corrected a math error. Note that one of the 270W panels won't be used.

EDIT: Ouch... another error. I used panels you didn't have.

Again, definitely recommend blocking diodes on each string.

A friend of mine is willing to lend me another combiner box that is the same as the one I already have.

Would adding 6 additional strings from another box help improve this mess?

 

[sunshine_eggo]

A friend of mine is willing to lend me another combiner box that is the same as the one I already have.

Would adding 6 additional strings from another box help improve this mess?

Generally speaking, adding complexity to a shit stew doesn't make it better.

You already have six strings. Are you proposing to add another 6 strings?

 

[Ceefiveceefive]

Generally speaking, adding complexity to a shit stew doesn't make it better.

You already have six strings. Are you proposing to add another 6 strings?

Yes, the inverter has 2 separate built in charge controllers. The additional 6 strings would operate on the other charge controller. The total would be 12 strings divided between 2 charge controllers.

 

[sunshine_eggo]

Yes, the inverter has 2 separate built in charge controllers. The additional 6 strings would operate on the other charge controller. The total would be 12 strings divided between 2 charge controllers.

does the combiner box you have include blocking diodes?

My only suggestion is that you don't create such a Frankenarray on the 2nd MPPT

 

[Ceefiveceefive]

does the combiner box you have include blocking diodes?

My only suggestion is that you don't create such a Frankenarray on the 2nd MPPT

Im not sure. I have the Mid Nite Solar MNPV6. Specs attached.

 

[sunshine_eggo]

I have the MNPV6 as well. No. It does not include blocking diodes. It simply provides rails for the breakers. If you are being offered a free one, take it.

 

[Nan_wpg]

Math doesn't work miracles. You have redefined the worst case. You're mixing 120, 72 and 60 cell panels in odd numbers. This is pretty much insane.

The 335W panels are horrible choices for your MPPT.

Their Voc is too high to be 2S, but their Vmp is too low for 48V in 1S.

Their current is also so low, they will cripple any of the other panels if placed in series with them.

There are no reasonable combinations of panels that will allow you to use all of them.

if you absolutely don't care that your array is jacked up:

Strings 1-4:
335W in series with 250W
87.7 Vmp, 5.85 Imp per string, 513W potential

in parallel with

String 5:
3S 240W
87.7 Vmp, 7.89 Imp, 692W potential

in parallel with

String 6:
335 in series with 270W
87.7Vmp , 5.85 Imp, 513Wpotential

Total: 3,257W (assuming I haven't made a 4th math error somewhere)

Definitely recommend blocking diodes on each string.

EDIT: Corrected a math error. Note that one of the 270W panels won't be used.

EDIT: Ouch... another error. I used panels you didn't have.

Again, definitely recommend blocking diodes on each string.

I thought all modern new panels have all the blocking/bypass diodes in them??

 

[sunshine_eggo]

bypass yes. blocking no.

 

[Ceefiveceefive]

bypass yes. blocking no.

Are these the kind you would suggest?

 

[sunshine_eggo]

You would need 1 blocking diode per string, which would require the diode be rated for more than string Voc including temperature effects.

Google found this:

https://powerwerx.com/mc4-diode-reverse-current-protection?gclid=CjwKCAiA-dCcBhBQEiwAeWidtbUlYJw2B-WUvZ2YiJHyKXL7OBb_PUyric601yjv0_ShFi98xYbJixoCdZgQAvD_BwE

Looks like it meets the specs. Just plug one in each series string.

 

[Ceefiveceefive]

You would need 1 blocking diode per string, which would require the diode be rated for more than string Voc including temperature effects.

Google found this:

https://powerwerx.com/mc4-diode-reverse-current-protection?gclid=CjwKCAiA-dCcBhBQEiwAeWidtbUlYJw2B-WUvZ2YiJHyKXL7OBb_PUyric601yjv0_ShFi98xYbJixoCdZgQAvD_BwE

Looks like it meets the specs. Just plug one in each series string.

Thanks!

 

[Ceefiveceefive]

Math doesn't work miracles. You have redefined the worst case. You're mixing 120, 72 and 60 cell panels in odd numbers. This is pretty much insane.

The 335W panels are horrible choices for your MPPT.

Their Voc is too high to be 2S, but their Vmp is too low for 48V in 1S.

Their current is also so low, they will cripple any of the other panels if placed in series with them.

There are no reasonable combinations of panels that will allow you to use all of them.

if you absolutely don't care that your array is jacked up:

Strings 1-4:
335W in series with 250W
87.7 Vmp, 5.85 Imp per string, 513W potential

in parallel with

String 5:
3S 240W
87.7 Vmp, 7.89 Imp, 692W potential

in parallel with

String 6:
335 in series with 270W
87.7Vmp , 5.85 Imp, 513Wpotential

Total: 3,257W (assuming I haven't made a 4th math error somewhere)

Definitely recommend blocking diodes on each string.

EDIT: Corrected a math error. Note that one of the 270W panels won't be used.

EDIT: Ouch... another error. I used panels you didn't have.

Again, definitely recommend blocking diodes on each string.

Greeting again!

I got all the panels lined up in the configurations suggested and am just about ready to attach everything.

I have the proper blocking diodes on each positive end of all strings. I am now ready to attach all strings in parallel and power my system.

Question 1: I have 14 sets of the 2-to-1 Mc4 connectors (picture attached). What is the recommended way to attach what I have? At the panels? At the combiner box?

Question 2: If I run out of time tomorrow to get the paralleling finished, will leaving each string separate in just series temporarily affect the setup adversely?

Thanks for all the suggestions!

 

[Nan_wpg]

bypass yes. blocking no.

What is the purpose of blockers? I thought the charge controller prevents battery backfeeding?

 

[Bud Martin]

What is the purpose of blockers? I thought the charge controller prevents battery backfeeding?

The blocking diodes are used when combining many strings of panel in parallel, for example the 4 to 1 Combiner box.

 

[Hedges]

Their Voc is too high to be 2S, but their Vmp is too low for 48V in 1S.

Inverter label says min solar voltage 40V, max 145V.
This isn't just buck, so might open up more possibilities.

1S for the SunPower, 2s for all the others?