Solar charger cable

PSL
PSL Forum Participant Posts: 7
edited June 2016 in Caravans #1

Hi.  I am new to caravaning and have purchased a 100w folding solar panel with only 3 metres of cable which I need to extend or replace with longer cables.  Could you help me with what cable i need?   I am confused by what all the ratings etc and sizes mean.
 Thank you.   I apologize if this is a silly question.  

Comments

  • AndyNYorks
    AndyNYorks Forum Participant Posts: 144
    100 Comments
    edited June 2016 #2

    I replaced mine with a length of lawn mower cable but this was from the output side of the controller. The maximum output being 14v and 10 amp. The lawn mower cable is therefore Ok. This may not be the case for a direct link from the solar panel itself.

  • Boff
    Boff Forum Participant Posts: 1,742
    1000 Comments
    edited June 2016 #3

    I did exactly what Andy did and used a cable I had salvaged from a scrap flymo.  If you want the proper stuff if you google solar cable you will see what you need.  Most solar panels are connected with MC4 connectors.  If this is the case with yours and
    you don't want to go the scrap flymo route.  if you look on eBay etc you can buy lengths of cable that terminate with a male and female mc4 at either end.  Simply buy a length twice the length you need, cut in half conect to SP and connect cut ends to controller
    via some sort of plug assuming it isn't going to be plugged in permenently.  It is also worth spending £1 on a mc4 connection tool. 

  • PSL
    PSL Forum Participant Posts: 7
    edited June 2016 #4

    Thank You.  I am green.   I dont have flymo cable but do have a hook up cable spare.   Do you think this would work?   I know I can't use the earth.   

     

  • Nuggy
    Nuggy Forum Participant Posts: 512
    edited June 2016 #5

    I bought a second hand SP and it was fitted with a good length of orange Hookup cable. Mine works fine. I assume the thicker the cable the less the resistence, so that is a plus point.

  • PSL
    PSL Forum Participant Posts: 7
    edited June 2016 #6

    Thank you.  I'll give it a go.  

     

  • ChrisRogers
    ChrisRogers Forum Participant Posts: 435
    edited June 2016 #7
  • MartinL
    MartinL Forum Participant Posts: 23
    edited June 2016 #8

    The 100W panel will produce a maximum of 5-7 amps.  It is important to keep the voltage drop to a minimum otherwise the Solar controller will not see the actual battery voltage. Therefore its smart charge capability may be impared. For example if the recommended fully charged voltage for the battery is 14.2 volts and you have a loss of 0.3v on the cable at 5 Amps then the battery voltage will actually only reach 13.9v and not be fully charged.  

    The current rating on cable sold for 240v mains allows for some voltage drop - however on mains equipment a voltage drop of a a few volts is irrelevant in most cases.

    I have an 80W panel and use 2.5mm (Conductor cross sectional area) cable. This can be solar rubber cable which can be used inside or outside the van or 2.5mm 13A mains flex which can be used inside the van.  Do not use solid core building wiring cable as this can fracture if used in a mobile environment.  A lawnmower cable is probably less than 2.5mm but a hook-cable should be ok.  Note you can get Rubber flex of various sizes, by the metre,  from City Electrical Factors who have many stores.

     

  • PSL
    PSL Forum Participant Posts: 7
    edited June 2016 #9

    Thank you.  I have been looking for that spare old cable but think it was victim for the dump.    I will look at the cables reccomended .  The extentions reccomended look ok but Im thinking it will probably be better to replace the cables with a longer one
    so no joining and tidyer.   The solar cable seems expensive.  Is it only single core so I would need to use 2 or is it double  Thank you for the explanation.  

     

  • Boff
    Boff Forum Participant Posts: 1,742
    1000 Comments
    edited June 2016 #10

    Proper solar cable is only single core I'm afraid.  Thinking about my flymo lead was connected from the solar panel to the controler. A solar panel outputs a higher voltage to the controller, which then converts the voltage to the charging voltage so any
    drop along the cable is accounted for.  

    Really the regulator should be placed as close to the battery as possible. 

    Nobody has asked what you want to use the panel for.  If it is just for the odd night then if it keeps the battery topped up rather than fully charged it probably won't matter. If you want to go off grid for weeks on end then getting the most from your system
    becomes more critical. 

  • PSL
    PSL Forum Participant Posts: 7
    edited June 2016 #11

    You have all been so useful with the replies.   Martin L and Boff for giving clear explanations.  I have found twin core solar cable now which fully explains which size I need on the website but I couldnt have done it without your advice.   I am going for
    6 mtrs of twincore 4mm solar suitable  here

    http://www.sunstore.co.uk/4mm-Outdoor-Solar-Cable-2-Core-1m.html

  • Boff
    Boff Forum Participant Posts: 1,742
    1000 Comments
    edited June 2016 #12

    Let us know how you get on.  It is always interesting to read new perspectives. 

  • MartinL
    MartinL Forum Participant Posts: 23
    edited June 2016 #13

    The 4mm should be more than adequate.  I bought my caravan solar system from Sunstore in early May and found them very helpful and the products I looked at were good quality.  

  • PSL
    PSL Forum Participant Posts: 7
    edited June 2016 #14

    Thank you for the review on Sunstore.  It is next day courier delivery so will order next week as I am camping this weekend.   

     

  • Nuggy
    Nuggy Forum Participant Posts: 512
    edited June 2016 #15

    If you might possibly have it on the ground, as many do when camping with friends, still consider a length of chain to deter a passing opportunist thief. I padlock mine to a corner steady. 

  • PSL
    PSL Forum Participant Posts: 7
    edited June 2016 #16

    Thank you.   I already do to the y rame of the hitch.   I figured the corner steady could be wound up to release chain but thinking on.   There is a loop.   Good strong motor cycle chain.    Good advice.