Ninian Posted December 10, 2013 Share Posted December 10, 2013 Hi, If you are using your leisure battery for the 12+ supply does the 12- have to return to the leisure battery or can it just go to the chassis which is probably the engine battery, or does it matter. Thanks. Link to comment Share on other sites More sharing options...
Dr Dave Posted December 10, 2013 Share Posted December 10, 2013 Both engine and leisure batteries should have the negative connection connected to chassis with suitable size cable. This ensures that the chassis can be used for the negative 'return path' if necessary to the leisure battery. Link to comment Share on other sites More sharing options...
spospe Posted December 10, 2013 Share Posted December 10, 2013 I am not 100% sure what you are asking here, but on the basis that you mean the 12 volt negative terminal of fitted equipment, such as lights, water pump etc, then this connection can go to the chassis. The above assumes that the leisure battery has its negative terminal connected to the chassis. Link to comment Share on other sites More sharing options...
Tracker Posted December 10, 2013 Share Posted December 10, 2013 Does this help? Most 12 volt electrical items are double cabled from the leisure battery with both + and - because they are built into wood, or what passes as wood these days and wood does not conduct. The leisure battery itself is fed negative from a chassis connection and positive from a relay linked to the starter battery and alternator output. You can wire anything new with a + direct, but suitably fused, from the leisure battery + side and either wire the - back to the battery - side or to any convenient point on the steel chassis / bodywork as long as you get a good connection to paint less steel. Link to comment Share on other sites More sharing options...
lennyhb Posted December 10, 2013 Share Posted December 10, 2013 Leisure batteries are not always earthed (most are) to the chassis if wiring in new equipment I would run an earth cable back to the battery. If you look at existing equipment I expect you will it is wired with a return to the neg side of the battery usually via the charger. Edit: As Rich says wired with two wires as that is the easiest way as everything is mounted in timber, don't want any more holes in the floor (to access chassis) than necessary. Link to comment Share on other sites More sharing options...
Derek Uzzell Posted December 10, 2013 Share Posted December 10, 2013 There's a basic wiring schematic here http://deepredmotorhome.com/electrics.php The installation includes a Sterling B2B charger, but it's still relevant. (This is a useful website, not just for people who might be contemplating a self-build motorhome.) Link to comment Share on other sites More sharing options...
hallii Posted December 10, 2013 Share Posted December 10, 2013 I suggest that for technical reasons (possible high resistance earth path) that two batteries are best connected + to + and - to - with cable. The current in a circuit is always the same at any point in it. Steel rusts, connections go high resistance. Just my thoughts, of course it is cheaper to go to the chassis, copper cable is expensive. H Link to comment Share on other sites More sharing options...
sshortcircuit Posted December 10, 2013 Share Posted December 10, 2013 hallii - 2013-12-10 7:32 PM I suggest that for technical reasons (possible high resistance earth path) that two batteries are best connected + to + and - to - with cable. The current in a circuit is always the same at any point in it. Steel rusts, connections go high resistance. Just my thoughts, of course it is cheaper to go to the chassis, copper cable is expensive. H Does that mean your batteries are connected in parallel and your leisure battery is now being used as a starter battery which it may not have been intended? And what size of cable connecting? Link to comment Share on other sites More sharing options...
Derek Uzzell Posted December 11, 2013 Share Posted December 11, 2013 hallii - 2013-12-10 7:32 PM I suggest that for technical reasons (possible high resistance earth path) that two batteries are best connected + to + and - to - with cable. The current in a circuit is always the same at any point in it. Steel rusts, connections go high resistance. Just my thoughts, of course it is cheaper to go to the chassis, copper cable is expensive. H I think you may be advising on how best to connect multiple batteries in parallel, but (like previous posters) I'm pretty sure that's not what Ninian was inquiring about. Link to comment Share on other sites More sharing options...
hallii Posted December 11, 2013 Share Posted December 11, 2013 Ah! I have not understood properly. No, you shouldn't use a "Leisure Battery" as a starter battery (although recent topics question whether there is actually any real difference). Whatever method is used, make sure the connections are clean, tight, and a smear of something like silicone grease is used. I have always used Vaseline, and it works fine. H Link to comment Share on other sites More sharing options...
Ninian Posted December 11, 2013 Author Share Posted December 11, 2013 Hi, Thanks for the replies, possibly i've misled some of you, my query was if you wire in a new socket and the 12v+ comes from the leisure battery do you have to put the return back to the - side of the battery or just to the van chassis . Thanks, Link to comment Share on other sites More sharing options...
Tracker Posted December 11, 2013 Share Posted December 11, 2013 Ninian - 2013-12-11 11:36 AM Hi, Thanks for the replies, possibly i've misled some of you, my query was if you wire in a new socket and the 12v+ comes from the leisure battery do you have to put the return back to the - side of the battery or just to the van chassis . Thanks, Yes! Either is fine! Often depends on the cable to hand, the difficulty of routing the cable, and the proximity of an earthing point! Link to comment Share on other sites More sharing options...
sshortcircuit Posted December 11, 2013 Share Posted December 11, 2013 Ninian - 2013-12-11 11:36 AM Hi, Thanks for the replies, possibly i've misled some of you, my query was if you wire in a new socket and the 12v+ comes from the leisure battery do you have to put the return back to the - side of the battery or just to the van chassis . Thanks, The negative can be taken back to the leisure battery or if the leisure battery has been earthed to the chassis, then to the chassis. Ensure cable is correct rating for what you are going to power and that an in-line fuse is fitted as near to the battery as possible with a rating less than the current carrying capacity of the cable you are using. Link to comment Share on other sites More sharing options...
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