B2B cable runs

Discussion in 'Tech/Mech General' started by bungy, Nov 26, 2012.

  1. bungy

    bungy Funster

    Joined:
    Jan 24, 2010
    Messages:
    2,246
    Likes Received:
    4,127
    Location:
    Welsh marches
    Im going to be fitting a Sterling B2B charger, and to do so i need to do some rejigging of where things are

    Currently the batteries are under the bed at the back, and they will be moving forward under a bench seat so the B2B, starter and leisure batteries are all close together - as im led to believe this works best with a B2B

    but i now need a run from the leisure batteries to the back where the 12v distribution is. I can do a run under the van through existing 'holes' and have enough 35mm cable to do that (its a 4.5m run)

    before i set too work - is there any reason why running the 12v under the van is not a good idea i.e. should i go 'through', or is the run too long etc
     
  2. Gromett

    Gromett Funster

    Joined:
    Feb 27, 2011
    Messages:
    7,941
    Likes Received:
    14,012
    Location:
    UK
    I personally chose to run the cable internally to avoid potential problems.

    It is a balance. If you have to run the cable internally across well trafficed areas then underneath "may" be better.

    However so long as it is fused at battery end on the engine side and at both ends on the leisure side it should be safe enough underneath.
     
  3. hilldweller

    hilldweller Funster Life Member

    Joined:
    Dec 5, 2008
    Messages:
    26,447
    Likes Received:
    25,130
    Location:
    Macclesfield
    I can think of no reason to move the batteries as long as you use thick cable.
     
  4. Gromett

    Gromett Funster

    Joined:
    Feb 27, 2011
    Messages:
    7,941
    Likes Received:
    14,012
    Location:
    UK
    I think moving the batteries is a good move. Reduces voltage drop.
     
    • Like Like x 1
  5. hilldweller

    hilldweller Funster Life Member

    Joined:
    Dec 5, 2008
    Messages:
    26,447
    Likes Received:
    25,130
    Location:
    Macclesfield
    What about the voltage drop from new location back to distribution point in original location.

    If he is running a big inverter that is a bigger load than the B2B.
     
  6. Gromett

    Gromett Funster

    Joined:
    Feb 27, 2011
    Messages:
    7,941
    Likes Received:
    14,012
    Location:
    UK
    The charge current is higher than the current to the distribution block and as you know it is the square of the current that is the most important part of the equation. Beefing up the cable to the distribution box can't hurt.

    As for an inverter this should always be wired into the battery anyway if it is of reasonable size.

    My personal rules are any cable transferring over 5amps 12v DC be as short as possible even if it means moving batteries or devices. I also oversize cables as much as possible.
     
    • Like Like x 1
  7. haganap

    haganap Funster Life Member

    Joined:
    Dec 5, 2007
    Messages:
    11,069
    Likes Received:
    13,678
    Location:
    Heavan
    Oh the fun and games have started with out me have they :Wink:

    I personally would move the batteries as its the right thing to do. I would also look to re route the wiring inside, its not as hard as you might actually think, just means taking a few cupboards apart. :Laughing:

    One thing I didn't mention when I sent you to buy this piece of kit I forgot to mention you need one of these

    http://www.ebay.co.uk/itm/NASA-BATT...tEquipment_Accessories_SM&hash=item337e04d675

    far better for you than a scooter, you can sit and watch things go up and down all day, siwtch a light on and bang you know how many amps your using :Rofl1::Rofl1:

    About £90 notes for one look forward to seeing all the finished work on Friday :thumb:
     
    • Like Like x 2
  8. bungy

    bungy Funster

    Joined:
    Jan 24, 2010
    Messages:
    2,246
    Likes Received:
    4,127
    Location:
    Welsh marches
    well... thought id get things moving...but had a snag on the way which ill regail you with on friday...some minor bodywork has been needed in a corner:cry:

    ill have to go out and underneath at one point anyway as the door is in the way, and it just so happens that there are holes in all the right places for going underneath - path of least resistance and all that!!

    its on my amazon wish list:BigGrin:, weve got one in the house, one of them owl things, and i had such fun working out what was what...kinda scary on somethings, like how many cuppas are made in a day and how much it costs over a week etc!!


    wont be finished...but it will all be in place ready to finish

    need to pick your brains about the split relay circuit...and what to do with it
     
  9. hilldweller

    hilldweller Funster Life Member

    Joined:
    Dec 5, 2008
    Messages:
    26,447
    Likes Received:
    25,130
    Location:
    Macclesfield
    I have no idea, I'll have to take your word for this.

    No so, for accurate charging of the batteries we are interested in voltage drop not power loss. Assuming of course we are not going to have glowing cables.

    So if he has a big inverter you advise him to re-locate this to the new battery location.
     
  10. bungy

    bungy Funster

    Joined:
    Jan 24, 2010
    Messages:
    2,246
    Likes Received:
    4,127
    Location:
    Welsh marches
    just to confirm...I dont have an inverter so not an issue. (yet:Blush:)

    but if (when:Doh:) i was to put one in, then it would probably go in the front locker anyway so all should be well :thumb:
     
    • Like Like x 1
  11. haganap

    haganap Funster Life Member

    Joined:
    Dec 5, 2007
    Messages:
    11,069
    Likes Received:
    13,678
    Location:
    Heavan
    mmm, that's interesting, I have a very nice Izzy power 1200w inverter for sale. Can dry hair. :thumb:
     
  12. bungy

    bungy Funster

    Joined:
    Jan 24, 2010
    Messages:
    2,246
    Likes Received:
    4,127
    Location:
    Welsh marches
    i just knew that was coming!:Rofl1:
     
  13. Gromett

    Gromett Funster

    Joined:
    Feb 27, 2011
    Messages:
    7,941
    Likes Received:
    14,012
    Location:
    UK
    In every case I have looked at the charge current will always be higher than the draw.


    correct. I was in solar panel mode and thinking about the power lost in cables rather than going into the battery. The voltage drop is directly proportional to both the current and the length of the cable (for a given size of cable)

    Absolutely... Reduce the length of the low voltage DC cable and increase the length of the 240V Ac cable. The higher the voltage the lower the losses in the cable.. Common sense.
     
  14. jonandshell

    jonandshell Funster

    Joined:
    Dec 12, 2010
    Messages:
    5,261
    Likes Received:
    7,881
    Location:
    West Norfolk
    No Comment!

    Bloody electron-spotters!:BigGrin:
     
    • Like Like x 2
  15. pappajohn

    pappajohn Funster Life Member

    Joined:
    Aug 26, 2007
    Messages:
    29,474
    Likes Received:
    16,939
    Location:
    YO11 2BD

    it's very clever the things an inverter can do, never seen one double up as a hair drier though.

    and how would you know it dries hair, surely not first hand experience mate ? :Rofl1:
     
    • Like Like x 2
  16. edgy

    edgy Funster

    Joined:
    Jan 25, 2011
    Messages:
    347
    Likes Received:
    421
    Location:
    bolton lancs
    I Have got an idea! Simples you buy Shirleys eleccy bike [used once] carefully:Wink:. Sit clare on it and tow her backwards to church stretton .Now the clever bit if you disconnect the wiring off the battery on the bike and revarse the wires and then connect to your now redundant towing socket this should put a load of charge in your van batteries . If it works you will save a fortune on B2B and cos your a mate and all that i will do you a good deal on the bike:thumb:. Of course if that fails you will always have the spare battery of the bike to light your gas barbecue. Hope this Helps:Smile::Smile:
     
    • Like Like x 2
  17. bungy

    bungy Funster

    Joined:
    Jan 24, 2010
    Messages:
    2,246
    Likes Received:
    4,127
    Location:
    Welsh marches
    you know...im not entirely sure if your being serious or not:Laughing:
     
    • Like Like x 1
Loading...

Share This Page