Anderson plug

Thanks Rod I have Googled without success. I have 2 options for connecting my van to the car. One is a 7pin plug which does blinkers, stop tail, earth brakes and accessories(fridge and battery charging). The other is to use a separate wire for the fridge and battery charging. To use a separate wire I need to mount an Anderson plug externally.

The rubber caps don't help - in my experience they just trap the sand and water around the connectors and they corrode much faster.

Water just flowing through does no harm in my view.

Jaycar sell the plug covers. Believe it or not they cost the same as the plugs. Why am I surprised!!??

ta

Thanks Rick, that sure shows how not to do it!!!!

thanks drivesafe and well done to understand my rather convoluted explanation - you obviously know what I'm talking about. I'll go in search of the covers now.

Hi again Aandy, sounds like you are going to be running some new cable to the back of your rig, if so here’s a little trick that might save you some money and time.

This is a quick and easy way to fit a new permanently powered power socket in the rear of your rig if you haven’t already got one.

50 amp Anderson plug terminals will accept up to 16mm2 cable but if you go back one cable size to 6B&S ( 13.5mm2 ), run the 6B&S from the engine bay to the Anderson plug, you can then use the anderson plug as the cable junction.

Strip about 18 mm of insulation off the two 6B&S cables and then get some 6mm auto twin cable and strip 18 mm of insulation of both of these cables and twist the red 6B&S and red 6mm together and fit them into the terminal, there’s just enough room to do it.

Do the same with the black cables and then just run the 6mm auto twin to where you want to mount the power socket.

Cheers.

thanks Ian.

Thanks Rob. I'll check ebay now but still wondering about the actual mounting of the plug. Saw a pic of one mounted sideways which was giving problems. I don't have a lot of space for mounting - the right angled bracket with the 7 pin round trailer plug seems the only place and sideways seems the only way to do it.

Aandy

I try to keep them straight.

Make sure the cables are soft and free.

Thanks Rocky. Part of my mounting problem is lack of access to the tow bar. It's one of those that only shows the tongue with the hitch slot hidden. Looks neat but not much room for additions. The advice that the plugs survive unprotected has been useful and I'll adapt a fitting to the existing 7pin socket bracket.

Quite true Derek and I made no specific statement about the type of power socket in the rear because there are a number of options, such as Cigarette lighter power sockets, which you have in your diagram, Hella type plugs, Anderson PowerPoles or even an 50 amp Anderson plugs, all of which can carry different currents, I still should have posted that if you carry out this addition, you should fit a suitably sized protection device, circuit breaker or fuse for what ever device you are intending to use on that circuit.

But Derek, you are the last person to be correcting anything relating to 12 volt applications and obviously you can’t comprehend information provided, even if you don’t like the manor in which it’s provided.

You continue to show how little you truly know about 12 volt wiring.

The average Cigarette lighter power socket handles 10 amps ( including those in your diagram ).

Hella Plugs can handle 20 amps.

Anderson PowerPoles can handle from 30 amps up.

50 amp Anderson plugs are obviously 50 amps.

Any of these connectors can be used but the circuits cable will only safely handle up to 25 amps so protect accordingly

As posted above, the protection installed in a circuit has to protect the devices connected to the circuit as well as the wiring and as you rightly pointed out, I should have posted the need for a protection device and anybody else should pick me up on this omission BUT as usual your supposed correction of my omission is no better than not putting anything there in the first place.

You have a 20 amp circuit breaker protecting a 10 amp device and again, if you had any real knowledge of 12 volt wiring you would know that Cigarette lighter power plugs and sockets are renowned for over heating and melting in an overloaded use and this is the very reason automotive manufactures only fit 10 amp fuses in this circuit.

Your 20 amp circuit breaker will easily protect the cable as 6mm automotive cable can safely handle 25 amps in such a short run, but any Cigarette lighter power plug and socket, if over loaded, would simply melt and your 20 amp circuit breaker would give absolutely no protection at all, unless of cause the melting plug or socket managed to contact an earth BEFORE it caught fire.

Now I have only covered the connection on the end of my proposed branch, if your planning to carry out the addition, when picking the protection device you will also have to take into account what you are planning to run off the addition.

Again, with Cigarette lighter power plugs and sockets, the devices designed to use this type of connection rarely have a current requirement of more than 10 amps for the very reason I posted above, because auto makers don’t provide more than 10 amps to these sockets.

Sockets are to be fused at the socket with the appropriate fuse.

Take note the sockets are not drawn in or connected in the diagram as part of the circuit but only an indication of 12v sockets.

20A breaker is to protect the cable only.

So just to clarify the important safety principles that Derek and Drivesafe are applying here.

When deciding what size fuse to put in a circuit -

Never put in a fuse larger than the current carrying capacity of the THINNEST wire connecting to the circuit. Also apply an appropriate safety factor (i.e. reduce fuse size) since a 50 amp fuse won't blow for several minutes when carrying 50 amps.

Example 1 - If you have a 50 amp fuse at the battery feeding a 6G (13mmsq - 75 amp rated) cable and at the end of it you split it into several 10G (5mmsq - 40 amp rated) circuits, then EACH of these circuits needs to have a smaller fuse - say 30 amps.

Example 2 - say you have an 80 amp fuse at the battery and 4G wire (21sqmm - 95 amp rated) running to an Anderson Connector at the back. If you plug in a trailer with the usual 6mm OD auto wire (8G - 8sqmm - 55 amp rated) to the trailer battery you have a safety hazard. The trailer wiring is only protected by the 80 amp fuse at the battery but the trailer wiring is only rated at 55 amps. So to retain safety you need to install a 40 amp fuse inside the vehicle or very close to the trailer plug.

Derek, on the other thread, I agreed with the moderator not to pursue the thread any further.

You are having a dig when ever you can, fine go ahead and my post above, was intended to take the Mickey out of you as well.

I won’t both doing anything more than state the obvious from here on in with out the rhetoric because quite bluntly you just don’t get it.

I initially was posting about using the Anderson as a junction, I wasn’t going into what the circuit would be used for but you rightly pointed out that there should be some form of protection there.

I have covered the reason why your diagram appears to be wrong, now I have some questions for you.

1 Why never, never, never use the plug as a junction when by using the plug as the junction you can run the cable, uninterrupted from the front circuit breaker all the way to the rear of the vehicle, as each additional break will just add more resistance into the circuit and there is no electrical reason why you can’t use the plug as a junction?

2 If, as you say, the circuit breaker is not going to the Cigarette lighter sockets and it certainly looks like thats what it’s for, why would you even both to put anything there at all.

3. Why have you now suddenly stated using 16mm2 cable now because until I posted the the correct size the other day, you were telling everybody to use the much thinner 8B&S.

Cheers.

Derek / DriveSafe,

I have very little knowledge so please forgive any ignorance in these questions.

In the diagram above it shows the plug going to the rear socket for the trailer as being earthed to the chasis. I have read many times that dual battery systems should definitely not do this, I think because of voltage drop problems.

The diagram is labelled single battery but I would have thought voltage drop would still be an issue. Is an earth bolt appropriate?

and why is a battery isolater required on a single battery system? What is it being isolated from?

I am also very interested in seeing Derek's answer to Q1 above as I am about to do this but will now hold off.

And re Q3, DriveSafe is being a bit harsh if he is implying that Derek is not allowed to learn anything from this forum, although if that is the case perhaps Derek better edit some previous threads to correct anything he may have erronously suggested as I am sure many people like myself do go trawling the old threads for info before we post questions in case they have already been answered.

Hi Disco

There is also a earth wire all the way back to the battery. The reason for this is to properly earth the 12V outlets in the rear of the vehicle.

If you don't require these sockets there is no need for this and simply run twin core to the rear Anderson plug.

The isolator is there to prevent the engine cranking off the trailer battery which can cause damage to wiring and plugs.

If you use the plug as a junction how close would you be able to get a fuse or breaker to the plug to protect that circuit. I would ideally need to be inside the car out of the dust and dirt which means that the section of wire between the plug and the breaker is unprotected except for the heavier breaker under the bonnet. If you are charging 300 a/h of battery capacity in your trailer as many of us do then the breaker will need to be around (LOOSELY USED TERM) 50 amps which is too high for the take off wire. If using good quality connectors the resistance is very low and won't effect your circuit.

You are never too old to learn and new products come out all the time so updating of articles and my web site happens all the time.

Regards

Derek.

Hi Disco Stew, I was unaware that I had told Derek he couldn’t learn from the net, be it my posts or anybody else's, the problem is that his has made himself out to be an expert to get people take notice of him and don’t get me wrong, it’s always a case of buyer beware and to this end I have said nothing to interfere with his ability to urn a quid and I don’t care what he does to sell things as long as it doesn’t endanger others.

I too should have just stuck to the facts and left it at that.

Now to the location of the circuit breaker or fuse, as in this case, where the cable is already protected against dead short, there is no reason why the 10 amp circuit breaker or fuse can not be located in a readily accessible location inside the vehicle, because the overload, not the dead short, but overload can only be caused by the device and/or the cigarette lighter power socket, which are still on the circuit after the protective device so everything is protected correctly.

As to the cable running from the plug to the 10 amp circuit breaker, this section of cable only has to be protected from a dead short as there is nothing between it and the 10 amp circuit breaker that would create an overload and not a short and even 6mm auto cable can tolerate 300 or 400 amps for a second or two and if you are using a good quality automotive circuit breaker at both batteries, this kind of load will trip both circuit breakers in well under a second an so everything is correctly protected.

Your right, your never too old to learn or to accept your mistakes honestly.

Cheers.

Thanks for both of your responses, I have learnt much.

Derek, your diagram does not match your text. I admit I am a novice but I can read a basic circuit diagram and there is clearly no earth wire from the rear socket to the battery.

The answer re the isolator also makes sense for a dual battery system. My question was borne from the label on the diagram that it is a "single vehicle battery system". A pedant would point out to me that the label is right because there is only one vehicle but from your answer it is clearly a diagram that only makes sense for a dual battery system and hence the label is quite misleading, hence my confusion. May I politely suggest in the interest of effective communications that diagrams be used only where they are applicable to the problem being discussed. I personally wouldn't post a diagram unless I understood it all fully and made sure it was applicable.

Regarding the use of the socket as a junction point, it appears both answers highlight some good practice but DriveSafe's answer certainly also highlights the needs for us to think about what the circuit is for and to design it accordingly rather than just blindly following a good practice without understanding why it exists. I know now that fuse placement is about placing the fuse as close as possible to potential causes of faults and have finally realised why sometimes people suggest putting a fuse at both ends. In this case it does seem pointless to put it at the junction.

My apologies about my comment re Q3. I had noticed that a diagram referred to by Derek in another post (the one that got all controversial) still refers to 6B&S as being 16mm2, which I think is established as incorrect. I know we can't go back to every post we ever made amd fix em up but if you make a reference to something that you now realise has a mistake it is only fair to highlight that mistake when making the reference rather than propogate the mistake further. I shall pull my head in a bit :)

Cheers
Paul

Hi Mike, I beg to differ with you on the earth because even as you posted, things like the rear window demistor are earthed through the body, they are done by the manufacturer who has the knowledge of know where they can successfully pick up a good earth return.

In the vast majority of cases, doing a bit of snooping first and yes you are likely to get a good earth return BUT if you don’t get it right, then there is now way of knowing until the customer comes back complaining that their batteries just never seem to be fully charged or don’t charge at all.

The problem is that there is no way to adequately check that you have a good high current earth return before you do an installation so for the sake of a few extra dollars and the fact that you have to run a positive anyway, most installers will run positive and negative cables BUT, there is no reason why you can’t still try to take advantage of the potentially good earth return through the body by also fitting earth straps.

As to the Myth about not being able to charge a battery to more than 70%, I whole heartedly agree with but again there is actually some credence to this myth.

I have had a number of customers that have had problems with neither of the batteries ever being fully charged and having to constantly put a battery charger on their batteries to get them fully charged.

In every instance, between long trips, the vehicle has been the town shopping trolly and has not done enough driving between starts to get the batteries charged up properly.

On one occasion, when I was trying to workout why this particular customer’s batteries were always flat, I asked him how often he drove the vehicle and he replied “Every day, to and from his work” so that didn’t help and then just out of curiosity I asked him how long he drove for going to and from work and his reply was “ About 1 to 1 and 1/2 minutes” he drove 1 and a half blocks from his home to his Pub.

Cheers.