# Wiring Diagrams For Horseboxes? Help.24v, then 12v, then 240v



## andy_duncan (6 October 2010)

Heeeelp Please.

I must of come over feeling feint one day as I have agreed to help SWMBO a Horsebox. 
Took a Mech with us and I bought on the Condition of Lorry, not fripperies or Paint colours.
It has a Coachbuild body and setup - I believe !

Anyway it is a 1997 Iveco Cargo Lorry (6sp) etc running 24v on the 'Lorry' side, and the usual 12v for the Living. 
I have put in a Bluetooth Stereo Speakers, a Twin Camera system etc and had a 2nd Hand Eberspacher Heater fitted.
Downside is I have discovered the 2 x Lorry Batteries were on their knees, ditto the Living Battery.

So having discovered (we believe) the 24v side NEVER charges the 12v and being confused by that I have a dropper charger .... long story short, even with both12v and 24v isolator I have wiggly amps running around the Lorry! 
I have found a plethora of RCD's in a an area above the Fridge. 
Sooo, tomorrow I will have it to the workshops at my Yard, and we shall start to poke around. 

The point of this post / thread? 
I am desperately looking the internet for a "Typical" Installation and Wiring Diagram - DIY Motorhomes, Horseboxes, Even Boats, but not really any luck.

Anyone got anything they can share with me?
Cheers


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## perfect11s (6 October 2010)

not got a diagram  but on mine  ive not conected anything to the lorry itself apart from a built in charger so avoiding   running the starter bateries down,   I have a  12v leisure batery for lights pump and heater etc  this charges off the mains hook up or the built in generator... through a 3 stage 18 amp charger..  I would  keep things simple and would say its a bad idea  to try to charge your living batery of the lorry bateries  because you never realy  run the lorry long enough to put much in with it running  best to hook up to the mains at home and go with the batery fully charged if you want TVs etc  then have a second back up batery if you want any info how to do things your welcome to pm me...


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## andy_duncan (6 October 2010)

Interesting - you say the Lorry "doesn't" charge the Living Battery at all through the engine / driving?

It seems that there has been methodology to the installation and some labelling but I am a wondering on how much has been bolted on / spliced in over the years.

I am not to stripping a lot back if need be, but we shall persevere to 'investigate' and see what does what.

What alarms me the most is that I was seeing sparks connecting up tonight the Drop Charger when I had the Isolater on the lorry batteries and the isolator on living both pulled !!

I am wondering if I have another bleedin battery somewhere too !! (behind the Fridge perhaps?)


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## perfect11s (6 October 2010)

andy_duncan said:



			Interesting - you say the Lorry "doesn't" charge the Living Battery at all through the engine / driving?

It seems that there has been methodology to the installation and some labelling but I am a wondering on how much has been bolted on / spliced in over the years.

I am not to stripping a lot back if need be, but we shall persevere to 'investigate' and see what does what.

What alarms me the most is that I was seeing sparks connecting up tonight the Drop Charger when I had the Isolater on the lorry batteries and the isolator on living both pulled !!

I am wondering if I have another bleedin battery somewhere too !! (behind the Fridge perhaps?)
		
Click to expand...

 yes  if you can work out what does what  that is a good way forward however  dont assume the builder knew what he was doing it the first place!!! some are a totaly wierd bodge or unnessarly complicated  and yes someone may have added all sorts over the years to overcome "faults"


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## andy_duncan (7 October 2010)

mmm, in case anyone is bothered.....
in the cold light of Day and with further poking around I have deduced :

Whilst there is 2x 12v to make a 'Lorry' 24V system, and a single 12V to make a Living System, there is also a 24v to 12v dropper in there somewhere so there is in fact 2 x 12v Living Systems coursing their way through the Lorry !!

At least I have found a form of Wiring Harness between the three * 





[/quote]

I am going to put on some Rubber boots before I investigate further !


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## perfect11s (7 October 2010)

andy_duncan said:



			mmm, in case anyone is bothered.....
in the cold light of Day and with further poking around I have deduced :

Whilst there is 2x 12v to make a 'Lorry' 24V system, and a single 12V to make a Living System, there is also a 24v to 12v dropper in there somewhere so there is in fact 2 x 12v Living Systems coursing their way through the Lorry !!o

At least I have found a form of Wiring Harness between the three * 





Click to expand...

I am going to put on some Rubber boots before I investigate further ![/QUOTE] OOOOHHHH
that looks like fun!!!


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## sallybush (7 October 2010)

That looks like a proper bodge job...240v MCB's on 12/24v DC wiring.  And they haven't even bothered using an small consumer unit type enclosure.

From your description of whats in the lorry, I would be tempted to strip everything out and start a fresh.

Try www.sbmcc.co.uk/forum for some pointers, you only get a handful of free posts so use them wisely.  There are members on there with 24v trucks powering 12v leisure systems.  And a basic split charge system is always worth putting in, the lorry won't need much of a run to charge the batteries unless you are only driving for a few miles.  A normal alternator puts out 60-90amps and trucks plenty more.


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## andy_duncan (7 October 2010)

Thanks - and Yes, I think I will be tackling it that way - pull it and rewire it. A bit of Fun on the Drive, the problems ensuring you have EVERY bit you need by the time you start the Job.

We kinda figured it out, and I just need to find out where the Dropper is located.

I am certain the Two Main truck Batteries also have a take off to a 12v dropper that is Permanently Live - even when I throw the Isolator. That Living Battery I have (all three are replaced only last week *groan* ) is an Afterthought I think. 

I want to get that out and changed and bring in the Secondary / Living Bank straight as a 12v Circuit.


240v => Charge the 24v Batteries > Charge the 12V Batteries > Runs the 240v side of the Fridge, and powers everything.
24v (i.e. engine running) => Charges through the Alternator firstly the 24V bank of Batteries and then the 12V & Powers the Fridge at 12V and Living Lights etc.
24V Isolated => Living / Fridge / Stereo / Lights Run from the 12V battery but CAN NOT drag down the 24V systems.

This, my friends, is why I am wondering if anyone has a good example of a wiring Diagram for me to crib from or at least put the bones of a system together with.....


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## perfect11s (8 October 2010)

On mine which is a self build on a 04 atego I wired it using automotive electrical bits from durite they have a very good range of stuff like cable and fuse holders they do chargers and droppers ..and yes as other poster said it would be best to strip out the junk and mains stuff  I think you need to work out what you will be doing with the lorry ,if  its going to do 100s of miles a week and you are going to be away for days then its worth using the lorry alternator to charge the leisure battery, remember if its been well discharged it  will take about 12 hours  charge to  get it back to fully charged (about 500miles driving) you could charge faster  ie high amps but it will shorten battery life and not give the best capacity... I strongly belive  in simple is best   a good charger and a well fused system the minimum of add ons so if it goes wrong its simple to fix and to wire up ..I sat down and did my own wiring diagram once id worked out what it needed,  lights,pump,heater, radio, tv on 12v and then i have a small 2 way mains consumer unit which feeds the chargers , fridge and a socket,some caravan places sell a kit for a mains hook up with all the bits for about £100... www.durite.co.uk


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## andy_duncan (8 October 2010)

Brilliant.
To be Honest the amount of Use the Living will get is probably not half as much as some of you, unlikely to be any overnighting in truth.
I am simply looking at what there is and I know it is a bit of a dury rig right know and for a few hours tinkering and a few items / cables I can make it a much tidier job with some redundancy.

You mention charging the Leisure battery, and a good Charger. 
I 'plan' to wire into the 24v Side a 24v/12-14v Charger and use that to drop down and charge the Leisure battery. Perhaps through a split charge relay.

Today (don't tell the boss) I will be mainly sketching out the Existing Wiring as I understand it, and a New Wiring Harness I plan to put in and making a shopping list of bits and pieces.
Cheers


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## steadyeddy (18 October 2010)

andy_duncan said:



			Brilliant.
To be Honest the amount of Use the Living will get is probably not half as much as some of you, unlikely to be any overnighting in truth.
I am simply looking at what there is and I know it is a bit of a dury rig right know and for a few hours tinkering and a few items / cables I can make it a much tidier job with some redundancy.

You mention charging the Leisure battery, and a good Charger. 
I 'plan' to wire into the 24v Side a 24v/12-14v Charger and use that to drop down and charge the Leisure battery. Perhaps through a split charge relay.

Today (don't tell the boss) I will be mainly sketching out the Existing Wiring as I understand it, and a New Wiring Harness I plan to put in and making a shopping list of bits and pieces.
Cheers
		
Click to expand...



there is some good products on the market for split charge 24v-12v etc .

pm me if you want !


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## Mike007 (18 October 2010)

Not sure you will find a satisfactory 24 to 12 volt charger that will be powerfull enough. I would pull 12 volts off the earthed battery of the 24 volt pair,Put it through a durite 12volt split charger suitably fused (at both ends as there are two potential supplies).Isolator switches should be on the earth cable.Use decent heavy cable and proper crimps not the cheapo Blue /red/  yellow ones.


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## andy_duncan (19 October 2010)

Wow - forgot I had this thread running - thanks.

I have been collecting bits and bobs so now I am planning to wire :

240v to a Consumer unit with two outlets in reality: 240v Sockets / 3 Way Fridge and a 24V Battery Charger capable of boost Charge permanently wired to the Lorry Batteries

From the Lorry Batteries Loop on the right side of the Isolate I have a 24 -12V Charger (MOBITRONIC voltage converter Ref. No. 812-2412G ) dropping down to the Leisur Battery via  relay on the Ignition so it only pulls in on the Engine running and can't possibly drain down the Lorry when at standstill.

From the Leisure, I think the Best bet it is to pull out the existing, re-lable and re-wire

Fingers crossed? 

All comments welcomed - the design is still in the umm design stage !


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## cundlegreen (19 October 2010)

Ihave the whole manual for a DAF 45 on disc.  PM me with what exactly you want to see re wiring, and I'll try to get it to you


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## perfect11s (19 October 2010)

andy_duncan said:



			Wow - forgot I had this thread running - thanks.

I have been collecting bits and bobs so now I am planning to wire :

240v to a Consumer unit with two outlets in reality: 240v Sockets / 3 Way Fridge and a 24V Battery Charger capable of boost Charge permanently wired to the Lorry Batteries

From the Lorry Batteries Loop on the right side of the Isolate I have a 24 -12V Charger (MOBITRONIC voltage converter Ref. No. 812-2412G ) dropping down to the Leisur Battery via  relay on the Ignition so it only pulls in on the Engine running and can't possibly drain down the Lorry when at standstill.

From the Leisure, I think the Best bet it is to pull out the existing, re-lable and re-wire

Fingers crossed? 

All comments welcomed - the design is still in the umm design stage !
		
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 Yes
sounds Ok   to me however my design would  differ depending  on if you have mains power where you park the lorry or not,  I guess  from what you are saying there isnt  so you have to use the lorry's alternator for charging the leisure batery/s  maybe adding a good solar panel say about 80w  for charging would help,  Im fortunate mine is at home so I can leave it hooked up to the  mains  and  two chargers constanty charge and maintain  the starter bateries and the one for the living...


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## andy_duncan (19 October 2010)

cundlegreen said:



			Ihave the whole manual for a DAF 45 on disc.  PM me with what exactly you want to see re wiring, and I'll try to get it to you
		
Click to expand...



Thanks I will (although it is a Iveco Cargo we have!) 
I dare say the principles are similar !


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## andy_duncan (19 October 2010)

'Perfect' where the lorry is parked it won't be 'plugged in' to the mains but we could run a lead out to it - and this is part of my thinking :

a) if doing a rewire, lets do one that makes sense, and covers all eventualities.
b) By using a Charger hardwired in to the the Lorry via a Consumer unit  / Hookup it allows my dearest to start the Lorry with zero technical knowledge, and generally Electricity is readily available either at the Yard, or in a Field at an event (we even have a portable Gennie that came with the lorry  )

as for topping up the Leisure off the alternator it seems daft not to in my opinion. 
I will look at that Solar option too.

Like I say we have kicked it about a bit at work on the whiteboard in my office, and I only have one or two queries left !
Once I rip in to it I think all will be sorted and a nice coloured wiring loom installed (i.e separate colours for the 240V, 24v, 12v and earths)

Have a tip to Abu Dhabi this weekend so it will have to be next weekend I do it !


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## perfect11s (19 October 2010)

Mike007 said:



			Not sure you will find a satisfactory 24 to 12 volt charger that will be powerfull enough. I would pull 12 volts off the earthed battery of the 24 volt pair,Put it through a durite 12volt split charger suitably fused (at both ends as there are two potential supplies).Isolator switches should be on the earth cable.Use decent heavy cable and proper crimps not the cheapo Blue /red/  yellow ones.
		
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 Not such a good idea as one batery gets overcharged and the other under  and the leisure batery has to have a lower resistance than the batery you are drawing off  and  will rarely get a decent charge as horse boxes dont do many miles  I work on ambulances, security vans and PSVs
most have secondary battery systems  with quite sofisticated  charging systems  even then there is often battery problems unless they  have a hook up from the mains supply  to charge the batterys when  the vehicle is parked.. however durite do a very good 24v to 12 volt automatic charger that gives a regulated 20amp output and has a voltage sensor so it only starts charging when the alternator is operating and the 24volt system is ok...


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## andy_duncan (19 October 2010)

perfect11s said:



			Not such a good idea as one batery gets overcharged and the other under  and the leisure batery has to have a lower resistance than the batery you are drawing off  and  will rarely get a decent charge as horse boxes dont do many miles  I work on ambulances, security vans and PSVs
most have secondary battery systems  with quite sofisticated  charging systems  even then there is often battery problems unless they  have a hook up from the mains supply  to charge the batterys when  the vehicle is parked.. however durite do a very good 24v to 12 volt automatic charger that gives a regulated 20amp output and has a voltage sensor so it only starts charging when the alternator is operating and the 24volt system is ok...
		
Click to expand...

This is also my understand - the Don't connect one of the two Lorry Batteries across to the Leisure. All sorts of misbalance an potentially dangerous scenarios.

I have seen the Duarite solutions and yes it is certainly a slick bit of kit but costs about £250 !
I got the 24 to 12v Charger unit I mentioned for £13 off fleabay


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## andy_duncan (2 November 2010)

Just a quick update (in case anyone is still following !!) 

SO everytime I look to get in and on to this Wiring job it is two step forward one back. 
I have got all my bits and pieces all collected through Fleabay, and the whiteboard in my ofice at work has had the entire engineering dept re-scribe possible arrangements and I went armed with my Mark6 wiring Diagram.


After reflooring the living, hanging new blinds I rewired some of the Drains off the Lorry onto the Living to discover Aaaahh the Lights inside are 24v so Mark6 won't work.

Head in hands on Sunday Lunchtime I accepted Man-defeat and saught to seek professional help on Monday from a really friendly Lorry builder a few miles away.

Chatting about my plans, discoveries and Aims seems I was not too far from the right roads, but I thought to getting a pro installation.

UNTIL, he thinks it would take him  couple of days at least (at £35 an hour)Thats a grand I don't want to throw at it and a couple of mates - one a sparky - reckon we can give it another go.

SO Mark 8 is currently getting drafted on the Whiteboard.
24v Lorry, separate to the 24v Living, with a 12v Dropper circuit for the Fridge, and a 240V Charge built in to charge / jump both sides from a Mains connection.


Rome wasn't built in a Day !


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## Gucci_b (2 November 2010)

On my horsebox (the same make as yours) I have 2 lorry batteries in the skirt box outside the horsebox, and a leisure battery inside the horsebox under the bench seating. I have two battery isolators, so when the horsebox is running i can turn the leisure battery isolator on to re-charge the leisure battery for the t.v/d.v.d player... works well for me as when we are parked up or at the yard we can watch the t.v without worrying about the lorry batteries draining.


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## andy_duncan (3 November 2010)

Yep - you have a cross between our Mark6 and Mark8 ! 

Speaking to the pro, I will be going down a similar route to yours.

Currently the 24v powers Truck and 'some' living, and the 12v 'some'

I suspect that the 12V was a late addition and looking at some of the switchgear, stuff has been robbed out of it (the CCTV for example - I know it was in it at some point).

I have fitted heavy duty Isolator on the truck side 24V and a mickey mouse one on the 12V living side.
It runs , starts, stops fine. The chaos begins of you start to use lights etc - I had to jump it yesterday in Monday for example after little 'lights' etc over the weekend. Frustrating !!

So, I shall take the 12V living, add a second to it, fit it under the bench seat inside, and run the 24v Living from it, and a dropper from that to the 12v Living.

The truck Batteries in the skirts will run only the Truck. Full Stop !


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## Mike007 (3 November 2010)

andy_duncan said:



			This is also my understand - the Don't connect one of the two Lorry Batteries across to the Leisure. All sorts of misbalance an potentially dangerous scenarios.

I have seen the Duarite solutions and yes it is certainly a slick bit of kit but costs about £250 !
I got the 24 to 12v Charger unit I mentioned for £13 off fleabay 

Click to expand...

Providing you use a split charger it can be done, Yes there are certain variables. The battery internal resistance varies with the state of charge and I,m sure we all understand the significance of that.However on the grand scale of things it is not really a problem. Its not rocket science ,and I would definately know if it were


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## andy_duncan (11 November 2010)

Critique my Plan below. (if anyone is still reading this thread)
:hehe:

So I have a plan to use as follows :

IP rated 240v Inlet hard wired in feeding a Consumer Unit.
Consumer Unit feeding a 240v / 24v Charger Booster, the 240V Fridge Circuit, and any Aux 240V Sockets.

The Lorry Alternator and above Charger are in turn is connected to the two Battery Banks (now both will be 24V) Via a Split Charge Diode|http://www.the12voltshop.co.uk/Shop/split-charge-diode-70a-ste-d70a2.html (the bit I am concerned about TBH.)

From there, One split goes straight back to the Lorry Batteries via an Isolator (currently on +ve, I will hopefully swap to the -Ve)

That should have the Lorry isolated from all other Drains than the lorry itself, yet charge all Batteries whilst driven, and giving the ability to charge all batteries if hooked to the Mains via the Shore Supply. BUT better still, by switching the Charger to 'Boost' giving an 18A output, I can jump the Lorry from the Mains or the Generator we have so the OH could easily get going again if stranded rather than worrying about Jump leads / Sparks etc..

OK - moving over to the other side of the Lorry - the Leisure Batteries are isolated too, and power 24V supply to the Diesel Cab Heater, the General 24V Lighting, and a 12V Dropper to Power the Tri-Source Fridge (240V/12V/LPG).

Thoughts, Opinions, (cares??!)


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## OWLIE185 (11 November 2010)

How do you intend earthing the 240 volt consumer unit within the lorry?


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## andy_duncan (11 November 2010)

OWLIE185 said:



			How do you intend earthing the 240 volt consumer unit within the lorry?
		
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Ummm, ask my Electrician friend... the AC/ 240v side is not my strong point I admit.

I am open to suggestions and only assumed using a Caravan Consumer like this :
http://cgi.ebay.co.uk/ws/eBayISAPI....72741&ssPageName=STRK:MEWNX:IT#ht_1048wt_1029


would be a sensible way to go from a 240V feed into the lorry and route to various items.
I am open all ears....

What about the Split Diode arrangement? 
Sorry - original link to the Diode above is rubbish. here it is:

http://www.the12voltshop.co.uk/Shop/split-charge-diode-70a-ste-d70a2.html


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## andy_duncan (12 November 2010)

So, 

as it happens I have had a delivery of bits this morning, including the :

Sterling Pro Split D unit :
http://sterling-power.com/products-diodes.htm 


Others have advised I should use a VSR (Voltage Sensing Relay) instead.
Should I pack it up and send back for a VSR ? or would it  be 'good enough' in reality  ?

Revised Diagram too !


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## andy_duncan (30 November 2010)

Bump 


Job done. Picked maybe the worst day fo the Year for it on Saturday with snow around, but Dad and I ripped it out, and started a fresh - got it all fired in and Jbs a  good un.

Plugged it in to the Mains and you could see the charger pulling 15A dropping down to 2A overnight.
All good except for one oversight of mine buying 12v Switchpanel : http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=140467295337#ht_500wt_922 not a 24v Switchpanel - so the bulbs behind the switches get dammed hot, but I will change that as soon as I find a good replacement.

The most important thing is that I have separate the living from the Lorry so I feel satisfied that if SWMBO goes off for an evening and uses the indoor lights, the lorry WILL still start !!

Cheers for the inputs....


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## Mike007 (30 November 2010)

The important thing is have you fused,EVERY potential power source ?People forget that secondary batterys also apply a voltage to the system charging them so the system must be fused at BOTH ends.


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## andy_duncan (30 November 2010)

Oh - then potentially no I haven't .

Every Source? How and where? just and Inline fuse ? Amperage?

(damnit, I thought I signed of the project....)


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