Why have I got a regulated dc power supply XM19v?

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NealB

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On the motor boat, there's a Maplin's regulated dc power supply XM19v.

It's plugged into the 240v mains, and the 12v output from an old style mains charger is fed to it. The power is then fed from the regulated supply to the 2 x 110AH domestic batteries.

What's the regulated supply for?

My ignorance of things electrical is profound, so please answer in layman's terms, if possible.

Many thanks.
 
Not 19 volts !! check the part number in the Maplin catalogue.

It is a power supply unit with 240volt mains input and a regulated 13.8 volt DC output with a max rating of 10 amps.

"ideally suited for powering CB radios, communications transceivers and other devices that require a 13.8V supply."​

I do not understand why the 12volt output from an old style battery charger should be connected to it, or why it is connected to a large battery bank.
Perhaps someone was trying to use it and the battery charger in parallel to charge the battery bank. Connecting the output of a large battery charger to it could be detrimental to it. In any case it is not designed as a battery charger.

It seems completely out of place on the boat. It is intended to power the type of equipment mentioned directly from the mains without the use of a battery. (Just what one would use to run the VHF at home or the marina office etc)

Sorry. Maybe someone else will check the Maplin catalogue also and have some other views.
 
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as Vic suggests below, I think the 19v, rather confusingly, is part of the model number, rather than the output voltage.
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Your Bio says you are a lecturer in accounting. Should have been a diplomat I think! ;)
 
Thanks Vic, I think you're onto something (though I'm not sure what!).

You're right: the output from the regulator is 13.8V.

I've now moved a few things in the engine bay, so I can see more clearly what's going on.

The regulator looks very similar to this unit:

http://www.maplin.co.uk/module.aspx?moduleno=231

I guess mine is a superceded model.

The 12v output from the charger, is fed to the two big terminals on the front of the regulator, and then two other wires go straight from the same terminals to the battery bank.

It's definitely got me confused!

VicS said:
Not 19 volts !! check the part number in the Maplin catalogue.

It is a power supply unit with 240volt mains input and a regulated 13.8 volt DC output with a max rating of 10 amps.

"ideally suited for powering CB radios, communications transceivers and other devices that require a 13.8V supply."​

I do not understand why the 12volt output from an old style battery charger should be connected to it, or why it is connected to a large battery bank.
Perhaps someone was trying to use it and the battery charger in parallel to charge the battery bank. Connecting the output of a large battery charger to it could be detrimental to it. In any case it is not designed as a battery charger.

It seems completely out of place on the boat. It is intended to power the type of equipment mentioned directly from the mains without the use of a battery. (Just what one would use to run the VHF at home or the marina office etc)

Sorry. Maybe someone else will check the Maplin catalogue also and have some other views.
Click to expand...
 
The regulator looks very similar to this unit:
Click to expand...
Make no mistake its not a regulator as such. It is a mains driven power supply unit with an output controlled to 13.8 Volts and not designed to regulate a supply fed to it from another source, although to some extent it may do so.

The XV19A is listed in the link you gave. It is a current item in the catalogue.
 
VicS said:
Make no mistake its not a regulator as such. It is a mains driven power supply unit with an output controlled to 13.8 Volts and not designed to regulate a supply fed to it from another source, although to some extent it may do so.QUOTE]

Thanks... I understand that bit.

It seems to me that it just sits there using mains power for no real reason.

I'm going to be brave, and remove it (Oi!!don't laugh!! It's alright for you teccie types - for me, this is advanced electrical engineering).
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Could it be that a previous owner thought that he could use the Maplins power supply to drive the domestic electrics whilst at the same time using the charger to top up the batteries ?

Suggest you remove it without delay !

John
 
RestlessL said:
Could it be that a previous owner thought that he could use the Maplins power supply to drive the domestic electrics whilst at the same time using the charger to top up the batteries ?

John
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Could well be..... I know he had just finished some sort of electrical evening classes.

The unit has now been removed!
 
If the powersupply is connected to the domestic batteries then its been fitted so that anything connected to the batteries can be used without draining the batteries when you have a 240v mains supply when in a marina etc.

so if you have a 12volt fridge it would be powered from the powersupply rather than the batteries and it would also top the batteries up if a bit low but the battery charger would be used if the batteries need a lot of charge!
 
gibbo26 said:
If the powersupply is connected to the domestic batteries then its been fitted so that anything connected to the batteries can be used without draining the batteries when you have a 240v mains supply when in a marina etc.

so if you have a 12volt fridge it would be powered from the powersupply rather than the batteries and it would also top the batteries up if a bit low but the battery charger would be used if the batteries need a lot of charge!
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Would it work in that way, though?

In my ignorance, I'd have thought it'd need a changeover switch to select power from either the battery bank or from the power supply.
 
It's a 10 amp model, rated at 7 amps only for continuous use. There's a caveat about using them in well ventilated areas.

It's very difficult to see what its role on the boat could be, apart from providing a power source to some small electrical device such as a sound system.

There's an interesting typo on the Maplin page, where they state that the output voltage is "138V".

Better off the boat, than on, despite another erroneous bit in the spec.
Weight 3A: 195kg
5A: 29kg
7A: 38kg
10A: 525kg
 
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sarabande said:
It's a 10 amp model, rated at 7 amps only for continuous use. There's a caveat about using them in well ventilated areas.

It's very difficult to see what its role on the boat could be, apart from providing a power source to some small electrical device such as a sound system.
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Whilst I agree that there is no place for this power supply on the boat, I do have one at home. It comes in handy when I want to test or configure new kit before installing on the boat.

John
 
NealB said:
On the motor boat, there's a Maplin's regulated dc power supply XM19v.

It's plugged into the 240v mains, and the 12v output from an old style mains charger is fed to it. The power is then fed from the regulated supply to the 2 x 110AH domestic batteries.

What's the regulated supply for?

My ignorance of things electrical is profound, so please answer in layman's terms, if possible.

Many thanks.
Click to expand...


I am more concerned that the 12V DC supply from an old charger is plugged into the 240 Volt input of the regulated supply. A recipe for disaster if both switched on at once.


I can see the thought process for using the regulated supply when alongside instead of an elcheepo battery charger. Somone has told him about galvanic action and internal loops in old chargers resulting in damage to legs and props and then in tech he has learnt how solid state controlled regulated supplies have the output insulated from the mains so galvanic action reduced!!!!

Sound thinking but may be not the best solution. Are you sure the 12VDC of the old charger went to the 240 AC input, can't understand why the fire engine is still in the fire station!
 
Bilgediver said:
Are you sure the 12VDC of the old charger went to the 240 AC input, can't understand why the fire engine is still in the fire station!
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My understanding of the OP's post is that the dc outputs of the power supply and battery charger were connected together. With just the power supply connected and the Battery Isolator switch set to OFF this could be used to power some of the domestics. However, this depends on throwing the right combination of switch.

A better solution would be to replace both power supply and charger with a decent multi-stage marine charger, which will provide power for the boat as well as the batteries.

John
 
Bilgediver said:
I am more concerned that the 12V DC supply from an old charger is plugged into the 240 Volt input of the regulated supply. A recipe for disaster if both switched on at once.


I can see the thought process for using the regulated supply when alongside instead of an elcheepo battery charger. Somone has told him about galvanic action and internal loops in old chargers resulting in damage to legs and props and then in tech he has learnt how solid state controlled regulated supplies have the output insulated from the mains so galvanic action reduced!!!!

Sound thinking but may be not the best solution. Are you sure the 12VDC of the old charger went to the 240 AC input, can't understand why the fire engine is still in the fire station!
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Sorry, not quite clear enough in my description.

It's the 12v side of the charger and the regulator that were connected (the regulator has gone now).

Your warning about galvanic action is well made - though, when last checked (early June 2009), rudders, shafts, props etc were all fine.
 
RestlessL said:
My understanding of the OP's post is that the dc outputs of the power supply and battery charger were connected together. With just the power supply connected and the Battery Isolator switch set to OFF this could be used to power some of the domestics. However, this depends on throwing the right combination of switch.

A better solution would be to replace both power supply and charger with a decent multi-stage marine charger, which will provide power for the boat as well as the batteries.

John
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Yes! That's exactly what I meant about the way it was connected.

You've also answered my question about how the system was meant to work - thank you.

You're right: a decent modern charger is on the imminet shopping list. Any recommendations?
 
RestlessL said:
My understanding of the OP's post is that the dc outputs of the power supply and battery charger were connected together. With just the power supply connected and the Battery Isolator switch set to OFF this could be used to power some of the domestics. However, this depends on throwing the right combination of switch.
.

John
Click to expand...


I suspected this was what he meant to say however needed to get him to confirm so.....Never assume!

The regulated supply would work fine on its own as a standby power source when in port however a daft way to go as it would not ramp up the amps if there was a demand or the batteries needed a good charge.

I also vote for the Sterling which when I last looked was around 130 squids...Sent one to brother in law for fittibg on his river boat and wife has had no cause for complaint since as now batteries always in tip top condition. He reckons best birthday present in ages:D
 
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