How thick should the wires be?

Discussion in 'Tech/Mech General' started by irnbru, Oct 18, 2016.

  1. irnbru

    irnbru Funster Life Member

    Joined:
    Jun 27, 2013
    Messages:
    5,330
    Likes Received:
    9,690
    Location:
    Glasgow
    Hi all you knowledgeable lot. Alan is wiring up a battery bank of 4 batteries. How thick of diameter should these wires be bearing in mind at a later date I may want to add a 2k inverter....or should it be moms I order in. A bit confused and I like to run things past funsters first.

    Thx
     
  2. andy63

    andy63 Funster

    Joined:
    Jan 19, 2014
    Messages:
    1,847
    Likes Received:
    6,441
    Location:
    south shields
    35mm square should do..if cable runs are not excessive...:)
     
    • Like Like x 2
  3. TheBig1

    TheBig1 Funster Life Member

    Joined:
    Nov 27, 2011
    Messages:
    7,212
    Likes Received:
    9,592
    Location:
    Dorset
    35mm sq is about right,as using undersized cable will introduce resistance between the batteries
     
    • Like Like x 2
  4. andy63

    andy63 Funster

    Joined:
    Jan 19, 2014
    Messages:
    1,847
    Likes Received:
    6,441
    Location:
    south shields
    Well I've just had a look on line... they suggest double that ie 70mm square for a 2kw inverter... that''s with load at up to 2 m distance... I'll look again:)
     
    • Like Like x 1
  5. andy63

    andy63 Funster

    Joined:
    Jan 19, 2014
    Messages:
    1,847
    Likes Received:
    6,441
    Location:
    south shields
    Interesting and confusing read lol

    I have never had an inverter so don't know what the possible surge currents etc can be... the advice on wire size always seems to be follow the manufacturers recommendations. .
    So 35mm square cable is capable of 200A dc.. and I'm sure capabe of a higher surge current so that's what I would use unless told differently..
    Andy.
     
    • Like Like x 2
  6. Gromett

    Gromett Funster

    Joined:
    Feb 27, 2011
    Messages:
    7,928
    Likes Received:
    13,977
    Location:
    UK
    I wouldn't want an inverter mounted 2 meters from my battery especially the high power ones. The close to the battery the better.

    Losses in cables are I²R so (current x current) x the resistance. The thinner the cable the cable the higher the resistance, the longer the cable the higher the resistance.

    You can't affect the current used, so you need to reduce the resistance as much as possible by either using bigger cables or shorter lengths or both.
     
    • Like Like x 2
    • Thanks Thanks x 1
    • Useful Useful x 1
  7. Gromett

    Gromett Funster

    Joined:
    Feb 27, 2011
    Messages:
    7,928
    Likes Received:
    13,977
    Location:
    UK
    The other thing to think about when choosing cable size. What type of terminals are on the device. If it is the screw type there might not be a big enough hole to fit the larger cable into. If it is a bolt then some crimp terminals might be too big to fit without touching each other.
     
    • Like Like x 2
    • Useful Useful x 1
  8. Abacist

    Abacist Funster

    Joined:
    Oct 15, 2013
    Messages:
    1,198
    Likes Received:
    1,233
    Location:
    Devon
    I used 70mm2 multicore welding cable with crimped and taped ends that were all bolted down to the battery terminals and the same cable to my 1500w inverter that can draw up to 3000w and obviously a big fuse between the batteries and the inverter. The cables between the battery terminals are no more than 1 foot long and the 2 lengths to the inverter is no more than 15 inches. I only have 2 180amp hour batteries linked together which made life a bit easier.
     
    • Like Like x 2
  9. oldflemo

    oldflemo Funster

    Joined:
    May 7, 2013
    Messages:
    2,165
    Likes Received:
    634
    Location:
    Redcar- N.Yorkshire
    Get intelligent ones Sandra thick ones are never much good!
     
    • Funny Funny x 7
  10. funflair

    funflair Funster Life Member

    Joined:
    Dec 11, 2013
    Messages:
    4,459
    Likes Received:
    4,705
    Location:
    Guisborough
    I used 10mm dia or 50mm square on ours but again less than 2 metres from batteries.
    IMG_0881.JPG

    And no I dont have big hands, the 10mm is the copper conductor diameter.

    Martin
     
    • Like Like x 3
    • Useful Useful x 1
  11. andy63

    andy63 Funster

    Joined:
    Jan 19, 2014
    Messages:
    1,847
    Likes Received:
    6,441
    Location:
    south shields
    That's fair size cable... if it's 10mm diam (is that overall or just the copper core ) it would make it about 78.5mm square...
    Andy
    I should read more closely. .. it's the cu conductor as you said:whistle:
     
    • Like Like x 1
  12. irnbru

    irnbru Funster Life Member

    Joined:
    Jun 27, 2013
    Messages:
    5,330
    Likes Received:
    9,690
    Location:
    Glasgow
    Thx I will get Alan to read the thread after dinner.

    What I can tell you is the battery bank is all 4 batteries going under the seat so no long wires (says me) :rolleyes:

    The future inverter would be around there too.
     
    • Informative Informative x 1
  13. Camping Gaza

    Camping Gaza Funster

    Joined:
    May 7, 2016
    Messages:
    106
    Likes Received:
    93
    Location:
    London
    What about weight issues on just one side of the van, Is this something to consider?
     
  14. irnbru

    irnbru Funster Life Member

    Joined:
    Jun 27, 2013
    Messages:
    5,330
    Likes Received:
    9,690
    Location:
    Glasgow
    Shouldn't be as the cooker and fridge are on other side.
     
  15. gus-lopez

    gus-lopez Funster

    Joined:
    Aug 18, 2014
    Messages:
    4,368
    Likes Received:
    7,938
    Location:
    Lorca,Murcia,Spain
    I bought jump leads from Wilko's when I needed some in the UK. 2m in length & some as your photo's. £10 (y)
    home here I use welding cable
     
  16. rupert

    rupert Funster

    Joined:
    Nov 23, 2014
    Messages:
    114
    Likes Received:
    82
    Location:
    leeds
    hi and thanks all, for your input. the cable size sandra is talking about is for linking the 4 batteries together. i thought these cables would not need to be as heavy as the load cable to the inverter, as this is shared by the 2 longest cables ,as per the diagram.
    or have i got it all wrong..........again
    batt_new_2.gif

    also i'm intending to box in the bank of batteries to stop them moving around. do they need air to be able to circulate around them to prevent over heating
    thanks alan /rupert
     
    • Like Like x 1
  17. funflair

    funflair Funster Life Member

    Joined:
    Dec 11, 2013
    Messages:
    4,459
    Likes Received:
    4,705
    Location:
    Guisborough
    You are right Andy, I was thinking it was 50mm sq but it is good chunky stuff.

    Martin
     
    • Like Like x 2
  18. movan

    movan Funster Life Member

    Joined:
    Dec 2, 2009
    Messages:
    12,850
    Likes Received:
    22,426
    Location:
    Moving around
    Gosh Sandra ... respect woman... I wouldn't have a clue what you are talking about!!! Hope it sorted for you.
     
    • Funny Funny x 1
  19. andy63

    andy63 Funster

    Joined:
    Jan 19, 2014
    Messages:
    1,847
    Likes Received:
    6,441
    Location:
    south shields
    Don't worry joy... nor has she..that's Sandra I mean.. @irnbru
    Andy
     
    • Funny Funny x 3
  20. irnbru

    irnbru Funster Life Member

    Joined:
    Jun 27, 2013
    Messages:
    5,330
    Likes Received:
    9,690
    Location:
    Glasgow
    I dont @movan I just want to make sure its done the best way possible and thats where the funsters come in. :)2 heads better than one and all that ...
     
    • Funny Funny x 1
Loading...

Share This Page