Ninian Posted December 15, 2018 Share Posted December 15, 2018 Hi, I want to fit a 12v cigarette socket in the back of the van. I have two batteries which are in parallel. How do I connect the cables at the batteries. Thanks. Link to comment Share on other sites More sharing options...
witzend Posted December 15, 2018 Share Posted December 15, 2018 Use the -negative & +positive on the same battery don't forget to fit a inline fuse nr battery Link to comment Share on other sites More sharing options...
Ninian Posted December 15, 2018 Author Share Posted December 15, 2018 Hi, Thanks for the reply, I wasn't sure by connecting to the one battery if it would upset the load balance on the other battery. Thanks Link to comment Share on other sites More sharing options...
Alanb Posted December 15, 2018 Share Posted December 15, 2018 If your habitation batteries have two main positive cables connected to one battery, and two or three main negative cables on the other battery, then your batteries have been connected so as to be balanced as far as possible. (I mention 3 negative cables because the return negative cable to the starter battery could be connected at this point.) If the above applies, to avoid a clutter of cables at one point, you could connect your socket to the positive via a fuse, and negative terminals having only one cable attached. This would also preserve any battery balancing. May I suggest that as regards cable size, that instead of using the absolute minimum of 1.0 sq mm (commonly denoted as 1mm ) you use a considerably larger cable size. While you may not intending to draw much power now, what about future uses? Alan Link to comment Share on other sites More sharing options...
Derek Uzzell Posted December 16, 2018 Share Posted December 16, 2018 The WRONG and CORRECT ways of parallel-connecting a pair of leisure batteries are shown in the attached diagram. Ninian’s Auto-Trail Dakota is a 2014 model, but (obviously) I don’t know how its two batteries havre been linked. This YouTube video-clip shows the task being DIYed but it’s not easy to decide how the cabling has been arranged (the WRONG way if I had to guess) Link to comment Share on other sites More sharing options...
StuartO Posted December 16, 2018 Share Posted December 16, 2018 Ninian - 2018-12-15 2:53 PM Hi, I want to fit a 12v cigarette socket in the back of the van. I have two batteries which are in parallel. How do I connect the cables at the batteries. Thanks. It depends what you want to use the 12v socket for. If you want the full current potential of a 12v socket (for example to power a cigarette lighter or to run a 12v compressor to inflate tyres) then you will need to run a separate cable pair of suitable large size from the battery as described above. But I'm guessing that you have much lighter use in mind, such as charging phone or running a small bedside fan, in which case you should be able to connect to an internal lighting circuit as a fused spur, as I did. If you use a dedicated usb socket outlet instead of a 12v cigar-type socket you probably don't even need to fuse the spur because they draw only 1 or 2 amps. Link to comment Share on other sites More sharing options...
Alanb Posted December 16, 2018 Share Posted December 16, 2018 Please note that if connecting directly to the batteries, any battery current monitoring facility will be bypassed. Alan Link to comment Share on other sites More sharing options...
Derek Uzzell Posted December 16, 2018 Share Posted December 16, 2018 There is a number of on-line entries about adding a 12V socket to a leisure vehicle https://tinyurl.com/yapoangl A potential advantage of Stuart’s suggestion to ‘spur’ off an existing 12V circuit (rather than directly connect to the leisure batteries) is that there would (probably) be an existing switch that would turn off the added-on socket when it was not being used. As Stuart says, how the extra socket is best fitted will depend on what it is to be used for. Link to comment Share on other sites More sharing options...
colin Posted December 16, 2018 Share Posted December 16, 2018 StuartO - 2018-12-16 8:43 AM Ninian - 2018-12-15 2:53 PM Hi, I want to fit a 12v cigarette socket in the back of the van. I have two batteries which are in parallel. How do I connect the cables at the batteries. Thanks. It depends what you want to use the 12v socket for. If you want the full current potential of a 12v socket (for example to power a cigarette lighter or to run a 12v compressor to inflate tyres) then you will need to run a separate cable pair of suitable large size from the battery as described above. But I'm guessing that you have much lighter use in mind, such as charging phone or running a small bedside fan, in which case you should be able to connect to an internal lighting circuit as a fused spur, as I did. If you use a dedicated usb socket outlet instead of a 12v cigar-type socket you probably don't even need to fuse the spur because they draw only 1 or 2 amps. I've done similar to Stuarts suggestion, couple of sockets taken off the existing circuits, you will need to know what power you need and what power the circuit is capable of handling. Link to comment Share on other sites More sharing options...
aandncaravan Posted December 17, 2018 Share Posted December 17, 2018 Sorry to disagree with most of the above, but the power distribution unit is there to distribute all the power safely and with control so that ALL power fed to any appliances, should run from that point. Never directly from the battery. WHY? Because the builder of the vehicle goes to a lot of trouble to give you 'One Touch power Off'. Shutting down the display above the door also disconnects all devices and appliances from the 12v (with a few exceptions). The Power controller has built in safety fusing with ALL the power distribution fuses in a single location. It has been established over many, many years that having the fusing in a single place is a good idea, for obvious reasons. The Sargent, Schaudt, BCA, etc Power controller also monitors the battery voltage and shuts down the power when the voltage drops below a set level. These days most modern units are using a setting of 11volts or above to disconnect the battery to prevent damage. Some of these units now have dedicated fused circuits specifically for Alarms to be wired to. These circuits are given priority to be 'kept alive' for as long as possible, but ultimately preventing battery damage. This has been done because so many so-called Alarm/Tracker installers continue to power the Alarm from the Starter battery when a Starter battery isn't designed to discharge low over weeks. The habitation battery bank (controlled by the Power Controller/distribution box is both designed for this and additionally has more than twice the capacity. These Power controllers are becoming more sophisticated, the best already give an estimate on battery usage and the power still available. These are only accurate if all power into, and drawn from, the battery goes through the Power controller. They won't know about any power you take from the battery so can show the battery as having more capacity than is actually available. Taking a feed from an existing circuit is the next best thing to taking a new feed directly from the box (note both Stuart and Colin's excellent comments above) but when the best Controllers have spare distribution points, along with fuses dedicated to the purpose, it makes sense to use them. That is what the Motorhome Builder wants to be done. Doing it any other way makes it harder (and usually more expensive) for any subsequent buyers to work out what each new fuse and bit of wire does. Although our 'Wire your Camper Yourself' web page is not aimed at the OP's particular request, it demonstrates why things are now done the way the are : http://www.aandncaravanservices.co.uk/wiring-your-camper.php I know magazine 'experts' usually advocate taking power from the battery, but when you consider their approach is 20 years out of date and so completely at odds with the Builder, it all allows you to judge just how expert they are. We would guess that next to Damp, electrics are a motorhomes most expensive running cost, so would therefore suggest that when looking at any prospective purchase, you quickly walk away from one that has a lot of fuses and cables coming off the habitation battery. It should be neat and simple. Anything that resembles a plate of spaghetti shows the previous owner didn't follow what the motorhome builder started, probably because they didn't have a clue. That is always going to bring expense and unreliability. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.