# Is 4mm2 wire big enough for 260 watt solar panels



## kencocamper (May 1, 2005)

Hi all,
just bought 2x160watt kyocera solar panels, a steca 20amp charge controller and 4mm2 solar cable, I am now wondering if the wire is strong enough and would it lose any power over a 4.5 metre run from the solar panels to the charge controller?, the run from the batteries to c/cont is only 1 metre which I think is probably OK?. Can anybody advice please
many thanks
Ken


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## Trance (Mar 2, 2007)

4mm2 wire would take approx 39 amps.

Gregg


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## kencocamper (May 1, 2005)

Hi Gregg,
thanks for that, so does that mean it would carry say 15amps on a 4.5metre run without any power loss
Ken


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## wakk44 (Jun 15, 2006)

hi Ken,
Your 2 160watt solar panels together wired in parallel are capable of producing a hefty current of around 20A.So I would think a 20A voltage regulator is on the limit,personally I would use a 30A regulator,I would also be inclined use 6mm cable in this situation to prevent voltage drop along a 4.5mt run.

There are not many solar panel set ups in m/homes capable of producing 20A,you must have an unusually high 12v power consumption and a large battery capacity to warrant this installation.

Steve

edit:just read the heading-260 watt panels,assuming that is 2x130 and not 2x160,then they could generate approx.15A wired together,in which case the 20A regulator would be ok and also 4mm cable sufficient.


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## kencocamper (May 1, 2005)

*re-4mm2 wire for solar*

Hi Steve,
when I ordered the panels I asked for a 30watt controller and the supplier said that the maximum I would get from the panels was 15amps and a 20 amp c/cont would be ample and 4mm wire so I went along with this as I thought he should know best but I now have my doubts, I dont have a really high power use but we often winter in Spain for several months without EHU so I have installed 4x100ah batteries to get me through the rainy days and the solar panels to recharge the batteries when the sun comes out (hopefully)
Ken


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## wakk44 (Jun 15, 2006)

hi Ken,
I think we must have crossed.I have edited my 1st post because I misread the original heading,in my opinion your installation will be adequate.

Steve


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## kencocamper (May 1, 2005)

Hi Steve,
thanks for that, I had better crack on with the wiring then or I will never get to Spain, I see you are in Mansfield, I'm just up the road in Sutton
many thanks
Ken


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## sallytrafic (Jan 17, 2006)

Around 11mV per Amp per metre

So for 20A and 4.5m 

that is about 1 volt dropped which is significant

with 6mm cable is would be just over half a volt.


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## kencocamper (May 1, 2005)

Hi Frank,
thanks for that, I dont have enough 4mm wire for the job anyway so I will get some 6mm for the long run, no point in losing power for the sake of a few pence extra on wire
many thanks
Ken


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## sallytrafic (Jan 17, 2006)

kencocamper said:


> Hi Frank,
> thanks for that, I dont have enough 4mm wire for the job anyway so I will get some 6mm for the long run, no point in losing power for the sake of a few pence extra on wire
> many thanks
> Ken


Yes you only buy copper once; losses are for ever.


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