12v transformer problems

[Ricesnaps1971]

Just bought a new Abbey van (1995). Came without s leisure battery, but has a kt12sm transformer. My understanding was it should rum the 12v equipment without a battery attached. It doesn't. It switches on and indicates it is on (the on off rocker switch lights up).

I haven't checked the fuse and I have a leisure battery on the way.

Does this sound fatal and in need of replacing? If so, do I have to replace with the same model or is there a cheaper option that's easy to fit and if so what?

 

[bertieboy1]

Hello Ricesnaps,
Trying to disentangle your post to decide what your problem is.So far I've gathered the problem is no 12 volt equipment works.
From what you've said if the switch lights up then 12 volts must be present - if the switch is connected to the 12 volt side (or secondary ) of the transformer.
It could be the switch is on the primary side of the transformer in which case when it lights up only confirms mains voltage is present and the transformer is switched on.
Simple things such as 12 volts lights should work without the battery connected however other things such as televisions may not work without the battery connected.
First thing to do before trying to source replacement bits is check the fuse is intact (not ruptured) and if you feel able get a voltmeter and check that 12 volts is present on the output of your power unit.

 

[WoodlandsCamper]

Doesn't a 1995 van need a battery in circuit? That's 20 years old and before the more modern design of joint charger/power supply.

 

[Ricesnaps1971]

Thank you. Firstly, correct, no 12v things working at all - no lights, no water pump...

Have checked one inline fuse as it's fine but have a feeling there are others.

It is possible the rocker switch indicates mains power and not full working order

The manual does say the 12v system should work without a battery present, but I have one coming anyway

 

[ProfJohnL]

I can't claim I know for certain, but from what I have seen of pictures of the kt12sm unit, it looks like it is just the power supply. It was usually installed along with a power distribution system PMS4 , so a problem with the 12v systems could be due to either product.

The switch with the neon will only show that mains power is connected and switched on it does not show the state of the dc output. The manufacturer was Plug In Systems Ltd, of Wetherby Hull, but they no longer exist, but an ex employee does offer a repair see,

http://www.expluginsteve.co.uk/
or possibly
http://www.apuljackengineering.co.uk/
who I know do work with a range of makes.

(Note a transformer only converts 230ac to 12vac - a power supply does that and all the other things necessary to produce usable 12vdc or in this case 13.8Vdc)

The first thing to do is check all the fuses, then if you have the necessary skills and equipment you can start to probe the 12V system to see if the ks12 is producing power or not.

If you are not confident with doing this then I'm sorry but you have no choice but to call in an expert to check it out for you. Just remember that although you are unlikely to get as shock from 12V systems, they can still cause fires if they are not wired correctly.

If anything does need replacing, there are other power supplies available such as Zig - who have recently moved to Nuneaton as part of the Carver Group Ltd companies. http://www.zig-electronics.co.uk/index1.htm

 

[Gafferbill]

Are there 6 red 10 amp 12 volt blade fuses present on the control panel just below the red illuminated rocker switch?

 

[Woodentop]

I can't claim I know for certain, but from what I have seen of pictures of the kt12sm unit, it looks like it is just the power supply. It was usually installed along with a power distribution system PMS4 , so a problem with the 12v systems could be due to either product.

The switch with the neon will only show that mains power is connected and switched on it does not show the state of the dc output. The manufacturer was Plug In Systems Ltd, of Wetherby Hull, but they no longer exist, but an ex employee does offer a repair see,

http://www.expluginsteve.co.uk/
or possibly
http://www.apuljackengineering.co.uk/
who I know do work with a range of makes.

(Note a transformer only converts 230ac to 12vac - a power supply does that and all the other things necessary to produce usable 12vdc or in this case 13.8Vdc)

The first thing to do is check all the fuses, then if you have the necessary skills and equipment you can start to probe the 12V system to see if the ks12 is producing power or not.

If you are not confident with doing this then I'm sorry but you have no choice but to call in an expert to check it out for you. Just remember that although you are unlikely to get as shock from 12V systems, they can still cause fires if they are not wired correctly.

If anything does need replacing, there are other power supplies available such as Zig - who have recently moved to Nuneaton as part of the Carver Group Ltd companies. http://www.zig-electronics.co.uk/index1.htm

Not quite Prof.
Plug-in Systems - and the electrical wholesaler of which they were part but who's name escapes me at this instant - were taken over by Bonus Electrical (also in Hull) some years ago, so I would guess starting there would be the best bet.

 

[bertieboy1]

Woodlands Camper.
Caravan age doesn't mean anything in this case,our 2013 Bailley manual says a battery must be connected before running anything on 12 volts.
Battery eliminator circuits (basically a capacitor ) have been around for years,It's all down to economics.

 

[ProfJohnL]

...

Not quite Prof.
Plug-in Systems - and the electrical wholesaler of which they were part but who's name escapes me at this instant - were taken over by Bonus Electrical (also in Hull) some years ago, so I would guess starting there would be the best bet.

Hello Woodentop,
Whilst I can't tell if Plug In systems were taken over as you describe, what I can tell is that Bonus Electrical don't list any caravanning systems on their web site, so it looks as though the Plug In brand and its products are no longer produced, and the absence of details about a 'service/repairs department' at Bonus makes me suspect this is now just a retailer and the Plug in products are no longer supported.

I would still suggest the OP's best option would be to contact the independent ex employee who seem to specialise in recovering these products.

eproducts

 

[pmb]

I'm with prof on this. I replaced the charger circuit board in my ESM unit and got a replacement from expluginsteve. Could you confirm it is an PMS4 as the prof thinks? . There is an inline fuse somewhere near the output of the unit. Is there a voltmeter in the van and can you confirm if there is a 3 position switch to select 12v from car or caravan? Mine is a 99 model and was tripping the rcd. Look on the explugin website as it has some good info and Steve is very helpful if you ring him.
There is a fuse on the board as well but you need to drill the rivets out to check it. It the end it depends on if you feel ok maybe changing the board/ fault finding. I would have thought the lights should work without a leisure battery (may go and try it on mine).
I did have a thread about it at the time but can't find it with a search.This is the unit with the cover off. (and the mains input leads to the board disconnected)

http://s300.photobucket.com/user/pmbond/media/P1100067_zpsipedyx8r.jpg.html?sort=3&o=0
edit: had a further look and if it is a kt12 then it could be a standalone charger and not contained within an ESM or similar unit.

 

[gary]

Deleted

 

[gary]

In 1993, the KT12SM is possibly the first in the way of 13.8v switch mode power supplies and as such perfectly capable of providing a smooth 12v supply up to 12amps without need of a battery.
Plug in Systems used different suppliers so cannot be certain, however, if it's a standalone charger in silver/grey box or possibly black box? check on the same end and opposite corner to on/off switch for a small 15A fuse holder.

As a replacement though, I'd suggest Amperor and one of PinS suppliers for a direct more modern replacement at a good price.

http://www.amperorassociates.co.uk/c-battery_chargers/BatteryC-3_18A.html

 

[Gafferbill]

My caravan is a 1995 Swift and it was originally fitted with the same power supply/charger as the OP's caravan.
It failed at about 15 years old and I replaced it with the Amperor 18 amp model as shown in Gary's link.
This has been a brilliant piece of kit and was supplied direct from Amperor at a much lower price than is often asked for inferior equipment.
It an easy DIY job to fit......even the mountings are the same as the old unit.
Amperor are temporary out of stock at present according to their website.

 

[gary]

As it happens Bill and should it be needed, I've got one in stock

 

[Ricesnaps1971]

Thanks for all the advice - I will try and reply to each one directly in the next few days.

By way of an update,I have now fitted a leisure battery and all the 12v systems are working when the switch is on "caravan", yet nothing still works with it in the middle setting (the manual suggests the middle setting is for 12v without drawing from the battery). There is a meter on the panel on the wall (which again I believe indicates the charge level of the battery) and this has constantly been in the green since I fitted the battery (although I haven't done much more than switched the lights on every now and then and fun the water pump)

 

[ProfJohnL]

Hi Ricesnaps,

At least that's some good news, so it looks most likely, either a faulty power supply, or possibly a missed blown fuse between the PSU and the three way switch.

 

[WoodlandsCamper]

By way of an update,I have now fitted a leisure battery and all the 12v systems are working when the switch is on "caravan", yet nothing still works with it in the middle setting (the manual suggests the middle setting is for 12v without drawing from the battery).

When we've had 3 way switches on previous vans the middle position was 'off'. The extremities were for 'internal' (ie from battery or charger) and 'external' (12v from the car whilst engine running).

 

[pmb]

When we've had 3 way switches on previous vans the middle position was 'off'. The extremities were for 'internal' (ie from battery or charger) and 'external' (12v from the car whilst engine running).

That is what I thought BUT having read my manual this morning it does say that when the switch is in the centre position 12v is available provided the charger is on. I intend to try this next time I am in the van.

 

[bertieboy1]

Ricesnaps,
Where is the 12 volts coming from - the battery,the power supply unit or the battery/power supply unit.Check this by connecting a voltmeter across the battery then switch on the power supply unit, the voltage should go up.If it doesn't then the power supply unit isn't working and it's the battery alone that is supplying the 12 volt system.If left like this the battery will become flat and unable to supply the load.
Under correct operating conditions the power supply unit should supply the 12 volt system and also charge the battery at the same time.

 

[gary]

On PinS car/van switches, the middle position is for battery charger only while on hook up, and while hooked up to car for charging the battery.

So if nothing works while on hook up and middle switch position selected it does not sound good! Another simple test for it working or not is switch charger off, then with switch set on van, switch a light on and while watching light, switch charger back on, now if you see the light distinctly brighten then chargers working.

 

[Pd43016]

Hi there, just seen the post, I was recommended a firm, apuljack engineering for anything electrical. I am not technical but i am toltd they know their stuff, and nake sense from a money perspective. Http://www.apuljackengineering.co.uk/product_repair.html, or ebay http://www.ebay.co.uk/itm/Caravan-Motorhome-PS276-AE276-Mains-Power-Supply-Transformer-Charger-/231858386792?hash=item35fbd63768%3Ag%3AlcwAAOSwFNZW0FAh

They have replacement units and you tube videos showing how to fit them. https://m.youtube.com/watch?v=r_SY8zUpqiwhy