Upgrading from 4 to 12 panels, best configuration?

[mlsadler]

Hello Members am new on this forum but i need assistance, i had a solar system set up with four(4) 280W solarworld panels but am upgrading and have bought new eight(8) 290W solarworld panels and my panel total number is now 12 panels but of different wattages with a victron MPPT 150V 85A, am wondering what is the best panel array that will give me the lowest voltage drop working with a 48V battery bank system.
Thanks

[Yet another Yeti]

There are newer and older versions available of this Victron string inverter .

How many DC-inputs are available ?

The one , that seems newer has 3 inputs .

The guess is , that formerly there were 2 panels in a string and these 2 strings attached to different inputs .

The victon does only accept 145/150 Volts-DC according to it s datasheed ,
and therefore in a voltage range of 25-45 Volts of each PVpanel ,
only up to three modules on a string would fit .

The input voltage to start charging an attached battery needs to be 5 Volts over the battery s voltage .
If the battery has 48 V , the panels need to deliver 53 V , and this is achieved by already two panels
running in Standard Test Conditions and Normal Operating Conditions between 30 and 36 Volts .


The best combination for the version with 3 inputs would be 2 similar modules in a row and then two of these rows
in parallel , which would be perfect in colder climates , since the temperatures do not reach
values , that pull down the Voltages of the PVs to lesser than battery voltage values .

Input 1 : 2*2 280 W , 2*10 A
Input 2 : 2*2 290 W , 2*10 A
Input 3 : 2*2 290 W , 2*10 A

As I understand the datasheet correctly , there are 30 Amps allowed each input , and 3*20 Amps is 60 Amps .


One could also join all three 2*2 strings and attach these to one input .


Asynchronic Setup for Voltages in the 25-45 V range in hotter climates :
Input 1 : 1*3 280 W, 10 A
Input 2 : 1*1 280 W + 2*290 W , 10 A
Input 3 : 2*3 290 W , 20 A


For the Amps and Voltages see the datasheets for your pvpanels ,
which should be downloadable as .PDF s .

[mlsadler]

There is only one dc input for PV and its + and -

[mlsadler]

Here are the panel ratings

280W Voc = 39.0V , Vmpp = 31.8V, Isc = 9.45A, Impp = 8.93A

289W Voc = 39.6V , Vmpp = 31.9V, Isc = 9.75A, Impp = 9.20A

Hope that can help

[Mike90250]

1.) Two panels in series and 6 series joined to one cable make a parallel to attach to the inverter .

2.) Three panels in series and 4 series joined to one cable make a parallel to attach to the inverter .
......

BAD ADVICE. You can only safely parallel 2 panels. You are speaking from a place of ignorance.

3 or more panels (or parallel strings) need to be paralleled with a Solar Combiner Box with fuses or circuit breakers that can isolate a bad string and prevent a fire.

Mr Jr Member Yeti. Listen closely. Bad or Dangerous advice will not be tolerated on this forum. Our suggestion is to refrain from blurting out "good ideas" when
you really have no idea. I really don't care about your ego. I do care about some neophyte that may follow your bad advice and die in a fire caused by your bad advice,

[mlsadler]

Hello Mike90250

Thanks for the advise so would you advise me to do 2 panels in series and 6 parallel connections for the 12 panels?

Regards

[Yet another Yeti]

BAD ADVICE. You can only safely parallel 2 panels. You are speaking from a place of ignorance.

3 or more panels (or parallel strings) need to be paralleled with a Solar Combiner Box with fuses or circuit breakers that can isolate a bad string and prevent a fire.

Mr Jr Member Yeti. Listen closely. Bad or Dangerous advice will not be tolerated on this forum. Our suggestion is to refrain from blurting out "good ideas" when
you really have no idea. I really don't care about your ego. I do care about some neophyte that may follow your bad advice and die in a fire caused by your bad advice,

Since when ? At the time of the release of this apparent old charge inverter , solar combiner boxes were apparently not invented , yet .

MODERATOR: He/She has been warned previously about running amok at the keyboard without any clue as to the accuracy of the output.

All postings by Yeti are suspect as to safety and accuracy.

It appears , that this current over-protections were introduced somewhere around year 2010 .

SO, if you have an old car without seatbelts, you should not use belts ever ? more bad information from yeti

Do you think, that the installation of a "simple" battery charging inverter somewhere will result in unrecoverable losses ?
Usual purposes for such kind of installations are small sheds and barns for chickens , or colony gardens ,
but since gipsy-like living-conditions become more and more common , also for trailer dwellers .

Inverters are waste parts , that unfortunately die after a while ; usual living-time for an inverter is considered 10 years .

So , the TStarter should probably take into consideration to shift the inverter .


Nevertheless , calculating 4*280w panels as rounded 1kW , and assuming 100Ah batteries in series

[Yet another Yeti]

a 12 Volts would make a battery of 4,8 kWh .

1 kW solar would supply at 2/3rd STC and 1/5th charging losses around 550 Watts into the battery ,
and at sunny days should fill it in around 8 hours having been deep cycled emptied .

That there is the apparent need to add so much more Wattpower , indicates , that there is something
not right with the sunshine conditions .

When adding so much more solar Watts , the TS should probably add a second 4*12 V battery in parallel .

[littleharbor]

Looks like Mr.Yeti didn't comprehend the warning. Whatever he's talking about here sounds like gibberish.

Time for a time out?

[SunEagle]

Since when ? At the time of the release of this apparent old charge inverter , solar combiner boxes were apparently not invented , yet .

It appears , that this current over-protections were introduced somewhere around year 2010 .

......


Nevertheless , calculating 4*280w panels as rounded 1kW , and assuming 100Ah batteries in series

It doesn't matter what the rules were before 2010. You now have to follow the latest regulations for your area even if you do not agree with them. So please stop posting stuff that can be considered dangerous or does not follow the electric code.

[Mike90250]

If the panel numbers are right:

Here are the panel ratings
280W Voc = 39.0V , Vmpp = 31.8V, Isc = 9.45A, Impp = 8.93A
289W Voc = 39.6V , Vmpp = 31.9V, Isc = 9.75A, Impp = 9.20A

I would run 3 panels in series if you are concerned about copper wire cost. That will save a bit on cable expenses

If you are in a area with hot days, I would run 3 in series. Panel voltage drops with increase in heat. Vmpp of 63V cannot be relied upon to allow a MPPT controller to fully charge a battery,
fully charging and EQ a 48V battery needs up to 65 volts.

And you need a Solar PV combiner with breakers or fuses, That's going to be a bit more money, but if you use breakers, you now have an easy diagnostic way to measure each string of panels for troubleshooting if needed

[mlsadler]

Hello Mike

Thank you so much for that advise

regards