Wiring setup critique : 240V, 24V, 12V

[Paddy_N_Murphy]

Spurned on by the thread about making a homemade panel, I have wondered if anyone here would mind me seeking advice on a Wiring installation on a .......................


Horse Lorry....

(I am a frustrated sailor landlocked in the North, with a wife who rides !)

Think of it like a boat if it makes you feel better !
Essentially the same scenario though eh? The Engine & Engine batteries are the Golden Egg and to be preserved at all times from draining, the rest is fripperies and toys ?

Judging by the sparks given off when we tried to 'review' the existing system and the odd flat battery we have had for no reason, I am assuming Ray Charles and Stevie Wonder put it together.

Anyway - My Plans / Hopes are :

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 (Lorry Engine / Lorry Living) 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??!)

I KNOW a better job can be done, and a better spread of bits and pieces could be used, but it will escalate to Hundreds and Hundreds unless I do it myself with all of these bits and pieces I have 'collected'.

 

[gasdave]

(I am a frustrated sailor landlocked in the North, with a wife who rides !)

I am in no way going to offer advice on your project (although I did fully re-wire a horse trailor this year) but I AM going to offer my extreme sympathies as I am in an identical domestic situation

Why do horses "need to be checked" every day?! Especially when the weather's great for sailing!

 

[pvb]

Why do horses "need to be checked" every day?!

You should try keeping a horse at home - my wife's horse gets "checked" about every hour!

 

[pvb]

Thoughts, Opinions, (cares??!)

It would be better to wire the charger direct to the 2 battery banks (ie not via the split charge diode). You haven't specified which charger you're looking at, but most have 2 or more isolated outputs.

 

[Paddy_N_Murphy]

It would be better to wire the charger direct to the 2 battery banks (ie not via the split charge diode). You haven't specified which charger you're looking at, but most have 2 or more isolated outputs.

The Charger is a 'general' Charger (actually bought through the classifieds here ironically) rather than a fancy Sterling type 4 phase charger....

I am not sure how you mean to wire to both Battery banks? Surely it is / would through the Split Diode?

 

[pvb]

Yes, that charger only has a single output, so you can't wire it direct to the 2 banks.

The reason to avoid wiring through the diode is because of the voltage drop inherent in diode splitters. If you haven't bought the diode yet, consider using a VSR (voltage sensitive relay) instead - these don't result in any voltage drop but still isolate the 2 banks when they're not being charged.

 

[gasdave]

Having said I would not comment on your diagram ...........

I would suggest connecting your charger to both batteries as PVB describes but using a VSR across the batteries to balance the charging instead of a diode.

 

[Paddy_N_Murphy]

I have bought the Diode set up, but It can go back I guess.

But a VSR is £100 plus ?

To Clarify, I suspect the Lorry, sorry BOAT, will almost never be plugged in to the mains - so most / all charging will be via the Alternator.
The Mains is as much to do with being able to easily jump start her.

 

[pvb]

But a VSR is £100 plus ?

£69 here.

 

[Paddy_N_Murphy]

Thanks for that one.

Lots to read there.

So - other than swapping out the Diode unit.
Comments?

I will still wire in the Charger on the 'Lorry' side of the fence, and I assume when it is active, it will trickle though the VSR to the Leisure side ?

 

[pvb]

I will still wire in the Charger on the 'Lorry' side of the fence, and I assume when it is active, it will trickle though the VSR to the Leisure side ?

Yes, the VSR is the only link between the engine batteries and the domestic batteries. Whenever the engine batteries are being charged (either by the mains charger or by running the engine), the VSR will close and also feed charge to the domestic batteries.

 

[caiman]

Are both sets of batteries wired up to give 12v?
Cheers

 

[Paddy_N_Murphy]

Are both sets of batteries wired up to give 12v?
Cheers

No, not quite. Two banks of batteries- each of 2 x 12v in series to be 24v per bank, hence the need to use the 12v dropper for the fridge

 

[pvb]

No, not quite. Two banks of batteries- each of 2 x 12v in series to be 24v per bank, hence the need to use the 12v dropper for the fridge

Your diagram shows them wired in parallel, ie 12v.

 

[Paddy_N_Murphy]

Proper Doh! Moment.

I can confirm they are / will be 12 + 12 to make 24v.

Apologies for the poor posting at the moment, I am on my iFail !

 

[pvb]

If you decide to buy a VSR, make sure it's a 24v version.

 

[ProDave]

Only 2 comments:

Wiring a "horse box" is exactly the same as wiring a (motor) caravan. It is covered under ieee wiring regs and must comply with those. So don't forget the important things like you MUST have an RCD in the consumer unit, and the vehicle chassis must be bonded to incoming mains earth from the hookup. Also you must use stranded wire, not the solid wire used for fixed house installations.

My only other point is the 12V fridge. That appears to be the only 12V load. You are proposing a 24V to 12V regulator for that.

Would it not be simpler to connect the fridge to just a 12V battery directly (assuming your 24V battery stack is two 12V batteries in series) If you are worried about discharging one battery quicker than the other, I would ballance that by using 12V lighting and 12V water pump running from the other 12V battery. Might need to do some sums on expected loads to see if that would work.

 

[Paddy_N_Murphy]

Thanks all - and sorry for sending you off on the wrong Tack with the 12v Parallel thing !
Back at a Laptop now, and yes - I would be wanting the 24v VSR for sure.

Thank you for the comments on the Regs / advise on the 'correct' procedure for the wiring with regards to Regs.
There are several Buzz bar mounted RCD / MCD's that I shall recycle for various component switching - and as mentioned will have a 'proper' sparky take care of the Mains to the Charger side of things.

Originally (the first review of the darn thing) we thought as their was one 'Leisure' Battery and Two 'Lorry Batteries' it was wrongly assumed the Lorry was 24v everything else was 12V, and the Leisure seemed to be a one way drain - no charge ability. I bought a Waeco 24 to 13.8v Battery Charger from fleabay for a song, and thought this was the (only) obvious fix needed. Oh, how wrong I obviously was !

So I have 24v to 12v dropper anyway in my box of bits, so to use that for the Fridge is a given. I am also warned off by reading everywhere that tapping of a single Battery to get 12v is a BAD thing. Your suggestion though did remind me - I do also have a Water Pump to wire in , but that is already a 24v so that too will come off the common 24v Buzz bar and across to ground.

cheers for all comments so far

 

[Paddy_N_Murphy]

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

Should I pack it up and send back for a VSR ? or would it be 'good enough' in reality ?


Revised Diagram too !

[/IMG]

 

[Paddy_N_Murphy]

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....