dstance panels and inverter
robocop
Registered Users Posts: 118 ✭✭
Hi
like to know the type of wire to connect between solar panels to inverter.
Do have 8pcs 500w each panels 12 pcs 250ah batteries and a 5.5kw rated hybrid inverter.
The distance panel to inverter is about 135 feet using mc4 connects.
system voltage is 48v
Awaiting your reply and thanks
Bob
like to know the type of wire to connect between solar panels to inverter.
Do have 8pcs 500w each panels 12 pcs 250ah batteries and a 5.5kw rated hybrid inverter.
The distance panel to inverter is about 135 feet using mc4 connects.
system voltage is 48v
Awaiting your reply and thanks
Bob
Comments

Well it depends on the voltage allowable by the inverter, higher voltages results in lower current therefore smaller conductors, how are the panels configured, what are the specs of both the panels and inverters charger? Assuming the hybrid inverter has a MPPT charger builtin.1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS
Second system 1890W 3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.
5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding. 
Bob,
What are you using for the connection from the solar array to the battery bank (MPPT charge controller or GT Inverter or what)?
Basically, need to know the Vmparray / Imparray configuration (x series * y parallel connections). What is the Vmp/Imp of the panel?
For example, a 150 Vpanel max input MPPT controller, you can run Vmparray ~ 100 VDC max, possibly more? (are you in Curaçao, Caribbean Sea?).
For a Vpanel input of 600 volts, a Vmparray of 400 volts or so is possible... Higher the voltage, lower the current, smaller diameter wire you have to use...
Bill
PS: I have closed your other discussion... Keep everything in one location. BillNear San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset 
hi Bill
panel vmp is 58.95 imp is 10.87 voc 48.63
inverter : max panel array is 4000w pv array mppt voltage is 130vd max pv array open circuit voltage is 145vd
inverter is MUST hybrid 5.5kw and I do live in curacao.
What about the inter panel connections ? Should I use less panel? And what will the thickness be for 35 meter lengt
I do have 12pcs 250ah batteries to form 48v and 750 ah
Thanks for you attention and have a nice day
Bob

Here are some specifications I see for your unitMax Voc =145VDCPV array voltage 64130VDCMax current 80AI think you have your panel voltage backwards. Voc is always higher than Vmp. Are they Voc=58.95 and Vmp=48.63? Something else is not right. If the panel is 500W, then 500W/48.63V = 10.28A (Imp). Is your amperage actually Isc=10.87?If the Voc is 58.95, that means you can only have two panels in series to get a Voc of ~118 VDC. Three panels in series would be >176VDC which would exceed the 145V limit of your box.It's doable to wire these panels in series/parallel, but your unit is limited to 4000W, meaning four strings of 2 panels (2S4P). So 8 total is maximum. Because your working voltage is rather high (118VDC) you can get by with using 10 gauge solar wire. In my own system, I'm going 125' with 10 gauge at 120VDC, and I measure virtually no voltage drop.Now each of your batteries is 12V? A 250AH 12V battery is very large? I'm guessing that each battery must weigh about 65kg? To wire them for 48V you need to wire them in a 4S3P configuration. You'll need to read up on how to proper wire up three strings so they do not become unbalanced. Assuming each string needs about 25amps to charge, you are looking at 25A x 3 x 52+ volts = 3900Watts, so the panels are in the right ballpark.I'm interested in hearing about how one of these Chinese allinone units actually performs out in the realworld. Please keep us posted on how things turn out?System 1) 15 Renogy 300w + 4 250W Astronergy panels, Midnight 200 CC, 8 Trojan L16 bat., Schneider XW6848 NA inverter, ACDelco 6000w gen.System 2) 8 YingLi 250W panels, Midnight 200CC, three 8V Rolls batteries, Schneider Conext 4024 inverter (workshop)

Hi Bill
Checked with the manufacturer and the label was wrongly printed so you are right
You will hear from me when system is working
thnks and regards
bob

Hi Bill
Another question about cables
Intent using 16mm/ 6awg between each string of batteries ( 4x 12v/250ah) .
each length of cable will be about 8 9 inhes long.
To interconnect to each string will used 4 awg and from the batteries to the inverter 48v will use 2awg as lengt of 3 meter.
Plse let me know if ok
HAve a nice saterday
Bob

The maximum continuous current from a 5.5 kWatt AC inverter on a 48 volt battery bank would be:
 5,500 Watts * 1/0.85 AC inverter eff * 1/42.0 volts batt cutoff = 154 Amps (pretty much worst case)
 250 AH * 1/5 hour rate = 50 Amps typical max current draw (2x that for a few second surge like starting a well pump)
 3x parallel strings * 50 amps = 150 Amps max continuous (math check)
https://lugsdirect.com/WireCurrentAmpacitiesNECTable30116.htm
6 AWG is "good" for ~55 to 75 Amps using the North American Electrical code
4 AWG is "good" for 7095 Amps... (are you using battery to battery at 6 AWG, and each "string of batteries" at 4 AWG?)
Using a voltage drop calculator... I would suggest around ~2 volts maximum drop (48 volt bus, i.e., 46 volt battery under load  2 volt drop = 44 volts at load) on all the wiring... For example, 2 feet (one way) of 4 AWG @ 50 Amps:
https://www.calculator.net/voltagedropcalculator.html?material=copper&wiresize=0.1608&voltage=48&phase=dc&noofconductor=1&distance=2&distanceunit=feet&eres=50&x=0&y=0
Voltage drop: 0.0098
Voltage drop percentage: 0.020%
Voltage at the end: 47.9902
And 10 feet (3m) @ 150 Amps @ 2 AWG:
https://www.calculator.net/voltagedropcalculator.html?material=copper&wiresize=0.5127&voltage=48&phase=dc&noofconductor=1&distance=10&distanceunit=feet&eres=150&x=54&y=18
Voltage drop: 0.47
Voltage drop percentage: 0.98%
Voltage at the end: 47.53
2 AWG is a bit small for 150 amps (NEC 95130 Amps)But with exposed cable (not in conduit), I am sure it will not overheat...
2 feet @ 6 AWG @ 48 volts @ 50 amps (battery interconnect):
https://www.calculator.net/voltagedropcalculator.html?material=copper&wiresize=1.296&voltage=48&phase=dc&noofconductor=1&distance=2&distanceunit=feet&eres=50&x=30&y=12
Voltage drop: 0.079
Voltage drop percentage: 0.16%
Voltage at the end: 47.921
So, your numbers (as I guess at them), look fine.
BillNear San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset 
Hi bill
I do have cables awaiting for the las 4 batteries.
concern 12 batteries of 12v 250ah
making 1 string of 4 batt in parrallel/series connecting to another ai 24v 250ah connecting to another string of same
batt parrallel/series to form 48v 500ah and then again to a third string of same batt in parrallel to form 48v 1000ah.
Can you give me in picture how to connect to see if I do have it ok?
Awaiting your reply
Regards
Bob

Personally, I like to run 4x 12 volt batteries in series for 48 volts as a string. 48 volts @ 250 AH capacity per string.
Then take the 3 (?) strings of 48 volts, and connect in parallel. 48 volts @ 750 AH total for bank.
I am not sure your battery connections... Series connections add Voltage (only).
Parallel strings add Amp*Hour (only).
https://engineeringengineashar.wordpress.com/2015/08/23/howtomakeseriesandparallelconnection/
To parallel battery strings, use this website's suggestion:
http://www.smartgauge.co.uk/batt_con.html
A DIY solar setupThe battery bus (one way to parallel):
http://2manytoyz.com/battbank.html
BillNear San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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