# dstance panels and inverter

robocop
Registered Users Posts:

**97**✭✭
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

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## Comments

3,854✭✭✭✭✭✭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.

33,327adminWhat 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 Vmp-array / Imp-array 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 Vmp-array ~ 100 VDC max, possibly more? (are you in Curaçao, Caribbean Sea?).

For a Vpanel input of 600 volts, a Vmp-array 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. -Bill

97✭✭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

234✭✭✭97✭✭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

97✭✭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

33,327admin- 5,500 Watts * 1/0.85 AC inverter eff * 1/42.0 volts batt cutoff = 154 Amps (pretty much worst case)

From a 250 AH battery, the typical maximum current you can draw (reliably over time/state of charge) is around C/5 discharge rate (5 hour rate):- 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)

Using the NEC code (relatively conservative):https://lugsdirect.com/WireCurrentAmpacitiesNEC-Table-301-16.htm

6 AWG is "good" for ~55 to 75 Amps using the North American Electrical code

4 AWG is "good" for 70-95 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/voltage-drop-calculator.html?material=copper&wiresize=0.1608&voltage=48&phase=dc&noofconductor=1&distance=2&distanceunit=feet&eres=50&x=0&y=0

Voltage drop:

0.0098Voltage drop percentage:

0.020%Voltage at the end:

47.9902

And 10 feet (3m) @ 150 Amps @ 2 AWG:

https://www.calculator.net/voltage-drop-calculator.html?material=copper&wiresize=0.5127&voltage=48&phase=dc&noofconductor=1&distance=10&distanceunit=feet&eres=150&x=54&y=18

Voltage drop:

0.47Voltage drop percentage:

0.98%Voltage at the end:

47.53

2 AWG is a bit small for 150 amps (NEC 95-130 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/voltage-drop-calculator.html?material=copper&wiresize=1.296&voltage=48&phase=dc&noofconductor=1&distance=2&distanceunit=feet&eres=50&x=30&y=12

Voltage drop:

0.079Voltage drop percentage:

0.16%Voltage at the end:

47.921So, your numbers (as I guess at them), look fine.

-Bill

97✭✭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

33,327adminThen 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/how-to-make-series-and-parallel-connection/

To parallel battery strings, use this website's suggestion:

http://www.smartgauge.co.uk/batt_con.html

A DIY solar setup--The battery bus (one way to parallel):

http://2manytoyz.com/battbank.html

-Bill