maximum distance from PV array to Charge Controller

[shumbaman]

I have a 3KW PV Array of 12 panels arranged 3 in series and 4 sets in parallel.

 

The panel specs are:

 

Vmp 30.7V

Imp   8.15A

Voc   37.4V

Isc     8.63A

 

I have an Axpert 5KVA inverter with inbuilt MPPT charge controller.

 

Using 16 mm sq stranded (flexible) cable to connect the PV array to the Inverter what is the max length this cable can be?.

 

Is the rigid cable (ie fewer but thicker strands) a better option?

 

What is the end result if the voltage drop is more than 2%.? 

 

Will the MPPT charge controller not just compensate for the voltage drop?

 

Thanks in anticipation

 

 

 

 

 

[Wetkit]

Ok, so you have 3 panels in a string. 30.7V * 3 = 92.1V

That is still at 8.15Amps.

Now the 4 strings in total at max power will be around 8.15 * 4 = 32.6 Amps.

A 4mm cable should be able to manage 32Amp easy, so 16mm will be no problem.

16mm single core is good enough for 72Amps.

 

Even at 2% volt drop you still way above your battery voltage, so there should be no real issues.

[shumbaman]

Thanks Wetkit...so what is the max distance I can position the PV from the inverter? I need 60+ meters/

[Wetkit]

Is there no way you can bring the inv and batteries closer to the PV?

Running 230V AC over 60m is no problem, but 60m with 16mm cable is going to cost you $$$.

[Eugene]

http://photovoltaic-software.com/DC_AC_drop_voltage_energy_losses_calculator.php

 

92V - 32A - Copper 16mm2 - 60M one run = Voltage Drop = 5.52V = 6%

 

20M = 2% voltage drop

[shumbaman]

If I try to position the PV Array closer I run into all sorts of problems with shading.

 

I am aware of the cost but just have to accept it if I want full benefit from the PV Array. If I position the batteries and inverter closer to the PV I then have to run an AC armoured cable to the DB box and that is also expensive.

 

I already have 30 mts of 16 mm so all I need to get is another 30 mts.

 

I just need to know that it will work ok. I think it will but just looking for confirmation.

[shumbaman]

Thanks we agree on the calculations. The inverter specifies a PV Array MPPT Voltage range of 60-115 Vdc so I am assuming that the voltage drop of 6% resulting in an output of 87vdc will be fine. Do you agree?