Battery Isolator.

Nov 16, 2015
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When leaving our caravan in storage, a Coachman VIP 560 2013, the battery will discharge , with everything switched off due to the power still being fed to the radio, fridge and the Power main control. So the only way to totally isolate is to pull the 20 amp main battery fuse or lift off the battery terminal.

I have purchased one of these. And will fit it next week, has anyone else fitted one and if so what problems.
s-l1600.jpg
 
Jan 19, 2002
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A helpful illustration on this link

www.autoelectricsupplies.co.uk/product/147/category/30

fitted in place of the negative, with the present earth connector clamped to the end.
Is your radio security coded and do you have the code? Does any caravan alarm need to remain connected?
Seems like a good idea and you can even remove the green screw altogether away from the caravan as additional security.
 
Nov 16, 2015
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Hi Rob, no Radio is not coded, The Caravan alarm , Sargent is fed from Main battery but not a problem, as it has its owne battery three month life.

Just fed up pulling the 20 amp blade fuse and arching so would prefer this type of isolater. .
 
Nov 16, 2015
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Why do they build a caravan with electrics, that do not isolate every thing. . Not everyone uses their caravan every month , and have the knowledge to disconnect batteries. :angry:
 
Oct 8, 2006
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Just get a keyswitch as fitted to operate the supply to a motor mover. Pretty well all dealers sell them and they cost well less than a tenner. They are rated to switch 100A so won't be a problem - like this:-
battery-isolator-switch-removeable-key.html


Google is your friend?
 
Nov 16, 2015
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Woodentop said:
Just get a keyswitch as fitted to operate the supply to a motor mover. Pretty well all dealers sell them and they cost well less than a tenner. They are rated to switch 100A so won't be a problem - like this:-
battery-isolator-switch-removeable-key.html


Google is your friend?

Thanks WT, I did wonder if that would be a better option, but wondered about making the cable connections , crimped or soldered.
 
Sep 26, 2018
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Always Crimp... Aircraft industry use crimps exclusively because solder makes the end of the cable hard, and subject to breaking under vibration. Use a good quality crimp tool (at least a ratchet one) and the right sized crimp
 
Sep 29, 2016
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Hi Hutch,

I used to fit the type Woodentop linked to for additional security on vehicles(years ago).

It never caused any problems and the one you have purchased will be great for the job.

It so happens that I am thinking of doing the same to my caravan, I will probably get the type in WT's link, only because I can buy them with 2 keys for £3.00 from China.

I will stash 1 key in the caravan somewhere, just in case I forget to bring master isolator key with me (or I lose it :blink:).
 
Oct 3, 2013
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Many years ago when I was a new apprentice crimp connections were just introduced.Some of the old boys at the time were debating whether crimps were a good or bad thing.The concensus was they were not good as you could not tell when the connection was too hot whereas with a solder connection the solder would melt thereby telling you the connection was too hot and therefore coming loose.
I don't agree with the reasons given for favouring crimped connections although I favour them - crimped connections can also loosen through vibration.
 
Mar 14, 2005
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In electrical and electronic systems, frequently it's poor connections that can cause a myriad of problems. Connector-less construction is an ideal goal for designers, but in some cases its inevitable that some form of connection is required. Caravans are no exception to this, and it seems almost obligatory for wiring harnesses to be terminated with a connector of some kind sometimes to meet legislative requirements for means of disconnection, or principally to simplify and speed up the assembly.

Which type of connection should be used has no universal answer its horses for courses and the choice of connection or termination method will depend on several factors, which will include, legislation or trade practice, the scale of current it is expected to withstand, the quality if contact required, speed of assembly, cost of parts, and reliability, resistance to environmental conditions (Including chemical ingress and attack, pressure differences, Oxidisation, Thermal cycling, electrolytic of dissimilar metals and ++++) spark containment ... etc

Taking a lead (no pun intended) from the car manufacturers who of course are very well experienced with 12V dc and high current applications, the vast majority of connectors are crimped.

As with so many things the strength of any system is determined by the weakest link, and whilst crimping does generally provide a good termination method for 12V dc systems, its only as good as the crimping. Poor crimping will be as unreliable as any other poorly or badly specified job.

Working with crimps is not too hard or expensive for cable up to 2.5mm2 csa, but going beyond that can be difficult unless you have a professional crimping tool for the job, and I'd suspect that caravan wiring will need at least 6mm2 csa.

Soldering is another practical solution, but as with all methods it does need to be done correctly to ensure good contact and a secure termination of the cable.
 
Sep 26, 2018
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You need to use the appropriate sized cable for the job. The load and the distance from the battery/bus bars are the critical factor. 6mm2CSA is overkill for most applications, that's what you would use for something drawing peak load of 25-30A over a distance of 5-10m. I have used that size for a macerating electric toilet on the boat, but LED lighting on the other hand would be much smaller.
 
Mar 14, 2005
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Guzzilazz said:
You need to use the appropriate sized cable for the job. The load and the distance from the battery/bus bars are the critical factor. 6mm2CSA is overkill for most applications, that's what you would use for something drawing peak load of 25-30A over a distance of 5-10m. I have used that size for a macerating electric toilet on the boat, but LED lighting on the other hand would be much smaller.

Thank you for your comment. I mentioned 6mm2csa to emphasise the fact that trying to close a crimp on such a large cable really needs the proper tool, and it unlikely a DIY person would have one to hand. I do agree that its more likely caravan battery wiring would be 2.5 or possible 4mm2csa, but even 4mm is likely to be difficult without the proper tool.

Cable sizing is of course important for any power application, but its proportionally more critical for extra low voltage systems like 12V, as the load currents can be quite large, and will produce a more significant voltage drop and power loss even on modest runs of cable if they are under size.

In general the size of cable already installed by the caravan manufacturer should be man enough for the job

In this particular case, the OP wished to interrupt the battery feed (and supply) cable. And whilst LED lamps don't draw much current, because they and other appliances (heater fan/pump, radio or televisions, even fridge controls tend to be used for long times, they will noticeably deplete the charge in a battery. When the caravans power supply is switched on, modern ones are capable of producing 16 to 20A of charge current, which, both the switch and the wiring, must be able to handle. In theory the cars alternator could conceivably also produce similar if not greater charge rates under the correct conditions.
 
Aug 11, 2018
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On my caravan there is a 16 fuse fuse box, top fuses live all the time, bottom ones live only when isolator on, and two for supply from car.

I had a problem every time the isolator was switched off/on or the car plugged in/out the radio would auto go to default demo mode, so I actually moved radio to powered all the time, then it would remain off. This would depend on radio make.

However it should be easy enough to swap a high current user from always powered to only powered when the main switch is on.

I leave caravan plugged in 24/7 but use a timer so only powered for one hour a day, this seems to work, another option would be a smart charger.
 
Sep 26, 2018
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ProfJohnL said:
Thank you for your comment. I mentioned 6mm2csa to emphasise the fact that trying to close a crimp on such a large cable really needs the proper tool, and it unlikely a DIY person would have one to hand. I do agree that its more likely caravan battery wiring would be 2.5 or possible 4mm2csa, but even 4mm is likely to be difficult without the proper tool.

A ratchet crimper will handle up to Yellow Crimps (6mmCSA max). I did 8 on 6mm last Saturday... My crimper is now about 10 years old, and cost me about £16 from Machine Mart...
 
Oct 12, 2016
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I'd stick with plan A. Simple mechanical fitting, no crimps or soldering, just make sure you have a good firm connection when you fit the device in that it is fully pushed down on the battery post before tightening, same applies to fitting the displaced cable onto the device. The £3 Chinese isolators are cheap and cheerful. I wouldn't bother, all you'll do is incur more work, mounting the switch and making off the cable ends. You'll also be able to easily move it to your next 'van.
 
Nov 16, 2015
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The connector arrived in the post today, ideal for what I require a well made item grips the battery post well and a good contact area from the screw, Just a couple of turns and totally disconnects the power. As I have no access to crimps from work this is ideal.
 
Nov 11, 2009
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EH52ARH said:
The connector arrived in the post today, ideal for what I require a well made item grips the battery post well and a good contact area from the screw, Just a couple of turns and totally disconnects the power. As I have no access to crimps from work this is ideal.

Hutch was that the one shown at the start of this thread on Page 1. Green round top?
 
Nov 16, 2015
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otherclive said:
EH52ARH said:
The connector arrived in the post today, ideal for what I require a well made item grips the battery post well and a good contact area from the screw, Just a couple of turns and totally disconnects the power. As I have no access to crimps from work this is ideal.

Hutch was that the one shown at the start of this thread on Page 1. Green round top?

Yes it was, it fits on the negative terminal, good quality, it seems.
 

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