Book/manual on 12v electrics (1 Viewer)

[Dave K]

I have a few jobs I want to carry out on the van that involve 12 volt electrics, just wondered if anyone can recommend any reading material that would help me learn about the various components, I came across this Haynes manual
https://haynes.com/en-gb/automotive-electrical-haynes-techbook-usa
but I'm a bit unsure about how helpful it would be, I'm basically looking to gain enough information to be competent to carry out these tasks.
Dave

 

[hilldweller]

I'm basically looking to gain enough information to be competent to carry out these tasks.
Dave

You've already joined the best manual in the world. Between FUN and Google you'll be able achieve anything.

 

[Dave K]

You've already joined the best manual in the world. Between FUN and Google you'll be able achieve anything.

I fear I will be forever asking questions though Brian!
And sometimes there are very differing views and it's a job to know what's right or wrong, just my opinion of course!

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[hilldweller]

And sometimes there are very differing views and it's a job to know what's right or wrong, just my opinion of course!

Regretfully you are correct.

Sometimes there is no right and wrong, just varying opinions, just as I've witnessed in batteries. They all work and for all intents and purposed work much the same. Provided the charger matches the battery type.

So what would you like to do to your MH ? Let's see how confusing it might become.

 

[Dave K]

Regretfully you are correct.

Sometimes there is no right and wrong, just varying opinions, just as I've witnessed in batteries. They all work and for all intents and purposed work much the same. Provided the charger matches the battery type.

So what would you like to do to your MH ? Let's see how confusing it might become.

Fit an inverter, add a snipe 2 satellite, an additional solar panel and add a mobile wifi aerial which needs a 12 v supply

 

[maxi77]

This is a taster for what is one of the best 12 volt guide. It was written for boaties but applies just as well to vans. The full version is widely available in the the UK

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[Geo]

This is a taster for what is one of the best 12 volt guide. It was written for boaties but applies just as well to vans. The full version is widely available in the the UK

Good job im not hungry

 

[nicholsong]

A few coments.

I have owned a boat for 30 years and a MH for 8 years so I have some experience of dealing with 12v electrics.

The Haynes manual will help with the 'motor-side' of the MH but not much with the 'Habitation-side'

Dave(OP) does not say what his knowledge is of domestic(230v) electrics. Even supposing that is good he still needs to learn some basic principles of the differences, e.g. voltage drop over defined cable lengths for different size cables - this being more critical than for 230v., and then the effect on operation of a unit subject to a reduced voltage - some more sensitive than others.

The other knowledge needed, especially for anyone wanting to spend time away from 230v charging supplies, is the battery(ies) capacity, discharge rate under different loadings, according to use of appliances for different periods, and then the rates of replenishing the battery charge from different sources available, engine alternator, on-board charger from 230v supply, solar panels, stand alone/in-built generators, Efoy(bit too complex for this discussion)

Then we have to deal with the set-up, including wiring diagrams and where the cables run in each MH or Boat. I have been very surprised at the lack of information provided by manufacturers of both. I do not know of a yacht builder who provides this, but am told it is because they contract this out and each contractor might do his own thing.

However I would have thought that a MH converter would have a wiring diagram to issue to his employees, but it does not get published for the owners in my experience, unless anybody has one for their MH. Our N+B Owner's Manual is very good but still info short.

Maybe there are reasons why MHs do not have one; firstly manufacturers think owners cannot distiguich between the symbols for fuses, capacitors, relays etc. and could make a DIY mistake; secondly, that it encourages owners to go back to their dealers - but do the dealers have the wiring diagrams and cable layout? I personally doubt it.

For Dave(OP) I am sorry if have made this topic too complicated for your needs, but over time of the ownership of the MH, several of them might be relevant, as they have been for a lot of us.

As has been said there is advice on this Forum, but there are also others where some real experts post but are not members on here.

One other excellent source is many useful articles that have been publishe over the years by Clive Mott in Motorhome Monthly. However, unless they are online I expect they will charge for each.

geoff

 

[Alistair33]

A few coments.
, Efoy(bit too complex for this discussion)

geoff

Damm and there was me thinking it was the simplest thing out, if of course you remember to feed it as it's so quiet you forget all about it !

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[hilldweller]

Fit an inverter, add a snipe 2 satellite, an additional solar panel and add a mobile wifi aerial which needs a 12 v supply

Inverter is pretty easy. Choose the appropriate size and wire direct to hab battery with suitable cable and a fuse next to the batt +.

Snipe. Never done a sat dish, have done an aerial ( which sticks inside to more difficult ). Choose a good place, decide if you are using sikaflex or sikaflex and screws. Drill hole for cable, run cable and make sure they are leak-proof. Find 12V feed. There is an art in routing cables through a MH, you get to know it intimately, but basically the wardrobe and cupboards give plenty of scope.

WiFi booster. Most people stick them on with suckers when needed. 12V from a cigar socket, but if you feel the need to hard wire it's just the same as the Snipe.

You NEED a multimeter just to be sure you connect the right way because German vans use BLUE as +12V. I know this well and I still wired one socket up the wrong way running on autopilot.

There, sorted.

 

[Dave K]

Inverter is pretty easy. Choose the appropriate size and wire direct to hab battery with suitable cable and a fuse next to the batt +.

Snipe. Never done a sat dish, have done an aerial ( which sticks inside to more difficult ). Choose a good place, decide if you are using sikaflex or sikaflex and screws. Drill hole for cable, run cable and make sure they are leak-proof. Find 12V feed. There is an art in routing cables through a MH, you get to know it intimately, but basically the wardrobe and cupboards give plenty of scope.

WiFi booster. Most people stick them on with suckers when needed. 12V from a cigar socket, but if you feel the need to hard wire it's just the same as the Snipe.

You NEED a multimeter just to be sure you connect the right way because German vans use BLUE as +12V. I know this well and I still wired one socket up the wrong way running on autopilot.

There, sorted.

Thanks Brian, somebody kindly gave me some info regarding an inverter so I'm sorted there, hardest part for me is knowing where to take the 12v power from when fitting the snipe and wifi, I would imagine it will be a case of finding a circuit that will have more than enough current to power it and connecting into that, although I'm sure it's not that simple.

 

[hilldweller]

knowing where to take the 12v power from

WIFi is easy, it takes so little either a light circuit or a cigar ( or DIN type ) socket will do.

Snipe, I've no idea of current but worst case go direct to battery. Fuse next to batt + of course. Cigar/Din sockets are usually speced to 16A so worth a try.

If either goes wrong all it should do is blow a fuse harmlessly. You could come unstuck if some prat has wired the circuit unfused or some other prat ( his cousin ) had stuck a big fuse in. If you can identify the fuse, by pulling it, you'll know for sure.

It's not rocket science. Be very tidy, keep cables protected from chaffing, keep notes, take photographs before you ever disconnect wires.

Be careful around the battery. Drop a spanner or screwdriver across the battery terminals and it gets very very exciting. Sensible people would remove the battery -ve connector whilst working on the MH, old hands aren't that sensible.

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[hilldweller]

It's not rocket science..

Cables. Because they are flexed every bump you go over do not use domestic house wiring cables, they will fracture. Make sure you get good quality flexible cables.

Splicing in a cable. Chock blocks / strip connectors with cable protectors ( under the clamp screw ) are good, just make sure no bare wire is outside the plastic and wrap of insulating tape is added protection. Fasten the cables so they can't flop about, especially at joints as even flex will eventually fail -- most people have had vacuum/iron cables fail where they flex entering the vacuum/iron.

A soldered joint is not necessarily best. Fine for electricity but the hard solder against soft copper is an edge that is prone to failure due to vibration, if you do solder stop that area flexing with tape or glue.

 

[Dave K]

Cables. Because they are flexed every bump you go over do not use domestic house wiring cables, they will fracture. Make sure you get good quality flexible cables.

Splicing in a cable. Chock blocks / strip connectors with cable protectors ( under the clamp screw ) are good, just make sure no bare wire is outside the plastic and wrap of insulating tape is added protection. Fasten the cables so they can't flop about, especially at joints as even flex will eventually fail -- most people have had vacuum/iron cables fail where they flex entering the vacuum/iron.

A soldered joint is not necessarily best. Fine for electricity but the hard solder against soft copper is an edge that is prone to failure due to vibration, if you do solder stop that area flexing with tape or glue.

Great info Brian, thank you, regarding splicing in to existing, would it be ok to do that or would wiring extra items onto an existing circuit cause a drop in performance of the original items that were wired, and would i fuse the new cable? and finally would I have to wire into a circuit that was a higher amp circuit than what I was fitting? Hopefully that makes some sort of sense!

 

[hilldweller]

Obviously if you wired a 16A Sat Dish ( surely not that much ) to the back of a cigar socket rated 16A, if you then had the sat running and plugged in another 16A the the fuse would pop.

If the cable you add is as thick as the one you are splicing to then the original fuse would be fine. If you used thin cable to your WiFi booster then it would need a small fuse in the +ve. Say 5A. You would not want to use a cable rated at less than 5A it would be just too fragile.

The fuse just stops the cable burning if shorted out. Just look at a fuse, it tells a story, you can see the thickness which will be thinner than the cable it protects, so the fuse pops before the cable burns.

There are loads of cases on here where "professionals" have done unspeakable work, I remember a tow bar with scrappy wiring in a lunch box. It's not hard to do a good job, don't rush it. Lots of cable ties, clips and neatness.

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[Dave K]

Obviously if you wired a 16A Sat Dish ( surely not that much ) to the back of a cigar socket rated 16A, if you then had the sat running and plugged in another 16A the the fuse would pop.

If the cable you add is as thick as the one you are splicing to then the original fuse would be fine. If you used thin cable to your WiFi booster then it would need a small fuse in the +ve. Say 5A. You would not want to use a cable rated at less than 5A it would be just too fragile.

The fuse just stops the cable burning if shorted out. Just look at a fuse, it tells a story, you can see the thickness which will be thinner than the cable it protects, so the fuse pops before the cable burns.

There are loads of cases on here where "professionals" have done unspeakable work, I remember a tow bar with scrappy wiring in a lunch box. It's not hard to do a good job, don't rush it. Lots of cable ties, clips and neatness.

Great info again, thank you very much Brian, I'm very conscientious which is why I want to try and do it myself

 

[maxi77]

In general I tend to fit an extra fuse panel and wire new services directly from that, this way I know it is all OK. As all my lights are now LEDs I do use lighting circuits to supply additional lighting.

Certainly the lack of wiring diagrammes and the tendency to hide wires in a way that maks it impossible to repair or replace. In boats much of the wiring tended to be run in conduit though you still get wiring glued in place under headlining. In one caravan I had one light fail no power at the switch and no way to trace the wire

 

[Dave K]

In general I tend to fit an extra fuse panel and wire new services directly from that, this way I know it is all OK. As all my lights are now LEDs I do use lighting circuits to supply additional lighting.

Certainly the lack of wiring diagrammes and the tendency to hide wires in a way that maks it impossible to repair or replace. In boats much of the wiring tended to be run in conduit though you still get wiring glued in place under headlining. In one caravan I had one light fail no power at the switch and no way to trace the wire

Thanks for that, so you would wire another fuse panel straight back to the battery and use that for additional wiring? Would I then have to work out cable sizing to the fuse panel depending on how far away it was from the battery

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[hilldweller]

Would I then have to work out cable sizing to the fuse panel depending on how far away it was from the battery

@scotjimland is the resident expert on cables, he helped someone a few days ago for solar. Another one on here that you can trust for an accurate answer.

 

[Dave K]

@scotjimland is the resident expert on cables, he helped someone a few days ago for solar. Another one on here that you can trust for an accurate answer.

Yes he kindly gave me some information regarding the inverter fitting etc.

 

[maxi77]

Thanks for that, so you would wire another fuse panel straight back to the battery and use that for additional wiring? Would I then have to work out cable sizing to the fuse panel depending on how far away it was from the battery

Yes but google will find you several tables that make it easy though I tend just to use 2.5 mm or 1.5 mm for he lower power items

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[Dave K]

So following on from this I now have the Motorhome wifi to fit, it has a box that needs wiring to the roof mounted aerial which is easy enough but it does need a power supply

I'm a bit limited to where I can house it because our overhead lockers above the settees aren't deep enough to have sufficient room to site the aerial satisfactorily so I'm left with the same locker as the status aerial, the wardrobe in the end bathroom or in the cupboard to the right of the microwave.

The 2 issues I have are the only power supplies in here are for lighting, is that sufficient or do I need to take it back to the battery, secondly I want to fit a snipe 2 satellite at some point so im also after some suggestions as to where to house it all, any help appreciated.
Dave.