Putting a 12v plug on a 240v device - can it work?

[docus]

Hello,

 

I've had an idea and I was wondering if I could run it past some wiser heads to see if it'll work!

 

I have a hi-fi that runs on 240v. However, the lead has a powerpack on it that transforms the voltage to 12v exactly, which then goes into the back of the hi-fi. If I snip the lead and solder on a regular 12v cigarette lighter plug, instead of the 240v plug and powerpack, would the hi-fi work?

 

Any tips appreciated!

[rover220]

Hello,

 

I've had an idea and I was wondering if I could run it past some wiser heads to see if it'll work!

 

I have a hi-fi that runs on 240v. However, the lead has a powerpack on it that transforms the voltage to 12v exactly, which then goes into the back of the hi-fi. If I snip the lead and solder on a regular 12v cigarette lighter plug, instead of the 240v plug and powerpack, would the hi-fi work?

 

Any tips appreciated!

 

the "powerpack" will be a voltage regulator that keeps the output at 12v. if you take this out of the equation, you could end up supplying the hi-fi with anything from 10-15ish volts. it would probably be fine with this but may no like it for long term use.

[chris w]

Hello,

 

I've had an idea and I was wondering if I could run it past some wiser heads to see if it'll work!

 

I have a hi-fi that runs on 240v. However, the lead has a powerpack on it that transforms the voltage to 12v exactly, which then goes into the back of the hi-fi. If I snip the lead and solder on a regular 12v cigarette lighter plug, instead of the 240v plug and powerpack, would the hi-fi work?

 

Any tips appreciated!

The simple answer is YES - assuming you get the polarity correct (ie: you know which lead is positive and negative). The less simple answer is "maybe". This is because the actual 12v on a boat can be as high as 15v and as low as, say, 11.5v so it depends on whether your HiFi has internal voltage regulators. It may be a suck-it-and-see exercise, but beware that 15v might (though not likely) blow the appliance. Personally, I have run lots of items in this way with no ill-effects so far, including radios, hi-fi's and TV's.

 

Chris

[benjamino]

I have recently had a similar situation with a hard drive (a Drobo actually) - it uses a 12v power brick to run on 240v. Being sensitive equipment I wanted to make sure I fed it with a stable 12v so I bought the Amperor 12v Stabiliser which has a standard 12v coaxial type plug which is the same as on the end of the power brick lead. If you have the same connection (there are 3 different types available with the Amperor unit) you could probably do the same.

[docus]

Thanks for the replies! I was quite surprised to see the actual voltage coming from the powerpack was exactly 12v. I'll give it a try and see how it goes!

 

What about appliances that take e.g. 13v (like my digital radio)? What would the chances of that working with the above method be? How far from dead on 12v can it be before it damages it?

[alan_fincher]

the "powerpack" will be a voltage regulator that keeps the output at 12v. if you take this out of the equation, you could end up supplying the hi-fi with anything from 10-15ish volts. it would probably be fine with this but may no like it for long term use.

Yes, I agree with Rover.

 

The problem is that TVs, radios, stereos, etc, where a separate supply gives "12 volts DC" often actually means "12 Volts DC, and no more".

 

A well charged lead acid battery can supply well over this, maybe 13 volts if literally just taken off charge, and if you try and connect to your boat batteries whilst the engine is actually running you could "see" voltages approaching 15 volts.

 

Some equipment is fine with this, other may "expire" over time, (bear in mind that 15 volts is a full 25% over a stated requirement of 12 volts).

 

What you really need is a DC to DC converter that will take the power from your boat, (day 10 volts through 15), and turn it to a reliable 12 volts.

 

Look at companies like Maplin, most are inexpensive, often around the £20 mark, depending on power rating, or whether there are any offers on.

 

This approach does not have to be limited to nominal 12 volt equipment. We use two laptops on board, both requiring 19 volts DC input. Maplin do DC to DC converters for Laptops, supporting a whole range of voltages and power. Ours cost £20, works well with both laptops, and has removed another of the lingering requirements for a small 240 volt inverter. In fact I don't think I used the inverter once whilst we were away last week. All power we used was without any requirement for "mains", I think.

 

Alan

 

What about appliances that take e.g. 13v (like my digital radio)? What would the chances of that working with the above method be? How far from dead on 12v can it be before it damages it?

If a proper converter can be had for £20, why take risks seeing which equipment will blow, and which will not ?

[benjamino]

Looking at some options on maplin, depending on the power requirements on your device you could look at this or this - the other laptop type power supplies that can handle higher currents tend to start at 15v output so would probably be too high. I went for the Amperor 12v stabilizer as it outputs 12v but supports higher currents.

[Chris Pink]

Thanks for the replies! I was quite surprised to see the actual voltage coming from the powerpack was exactly 12v. I'll give it a try and see how it goes!

 

What about appliances that take e.g. 13v (like my digital radio)? What would the chances of that working with the above method be? How far from dead on 12v can it be before it damages it?

 

I also power anything that looks like it might go from the 12V, after all modern electronics are in general tolerent of voltage differences, although in recent discussions other forum members report damage to flat screen tvs.

 

As for the hifi, it will almost certainly sound better if run from DC rather than a power supply. A lot of midi systems with mains leads have a transformer inside and can be adapted to 12V if you know what you're doing.

 

As chris w says polarity polarity polarity - it is so easy to fry 12V electrics by getting it wrong.

[johnandcharlie]

I've got a Philips stereo that runs off an external 13 volt supply in my van. I bought a plug and lead from Maplins so I didn't have to cut the supplied cable (if it goes wrong it's always been run off the supplied power supply!). It's been running direct from the 12 volt supply since about February this year. Being 13 volt, it's nearly always running on a bit less than this. I run my 12 volt battery charger through a cheap lighter socket regulated supply.

[GrahamK]

benjamino recommended the amperor unit. I have two of theses units running the PC and TV on Jannock. The advantage of these 'seemingly' expensive units is that they deliver 12V regulated output when the input varies from 10V to more than 15V. This means that my TV no longer switches off when the loo is flushed or the fridge cuts in.

Graham

nb seamlessTVviewing

www.jannock.org.uk

[docus]

Thanks to everyone for the advice! I went to Maplin today and bought one of the converters kindly recommended - I tested it in my car's cigarette lighter socket and it worked well, so hopefully it'll work on the boat too. This is going to open up a whole new world of electronic appliances on the boat for me - so much for 'getting away from it all'!

[chris w]

This means that my TV no longer switches off when the loo is flushed or the fridge cuts in.........

Graham

nb seamlessTVviewing

www.jannock.org.uk

Graham

 

You are curing the symptoms but not solving the issue. If the TV literally switches off when the loo is flushed or the fridge cuts in, then either your batteries are not charged enough (ie: overall low voltage) or the cables to the TV are not large enough and the voltage at the TV is not sufficient, exacerbated by the loo's flushing etc.

 

This was happening to a boater in my marina when cruising (ie: TV kept switching off). On my suggestion he bought an alternator controller, which I fitted for him, and he reported back that the next cruise was the first one ever that the TV had behaved itself. Ergo, his batteries had not been charging sufficiiently.

 

Chris

[Guest]

I remember Gibbo warning that running such appliances directly off the boat batteries without a regulator could be risky, not necessarily because of the 14+ volts, but because of the spikes present in such a system. I would trust Gibbo's opinion and have never risked running our (12V) T.V.'s etc in this manner despite the temptation.

Edited November 4, 2008 by Guest

[The Meerkatat]

I have recently had a similar situation with a hard drive (a Drobo actually) - it uses a 12v power brick to run on 240v. Being sensitive equipment I wanted to make sure I fed it with a stable 12v so I bought the Amperor 12v Stabiliser which has a standard 12v coaxial type plug which is the same as on the end of the power brick lead. If you have the same connection (there are 3 different types available with the Amperor unit) you could probably do the same.

 

 

Likewise Banjamino, I wasn't using the Amperor stabiliser for a hard drive but I was using it for my Mikomi LCD TV that has a the 4 pin connection, which I believ they call their S3U edition - Top service and the tech team were quick to get back to me enquirey

[alan_fincher]

Likewise Banjamino, I wasn't using the Amperor stabiliser for a hard drive but I was using it for my Mikomi LCD TV that has a the 4 pin connection, which I believ they call their S3U edition - Top service and the tech team were quick to get back to me enquirey

Welcome to the forum!

 

Interesting first post on a thread that has lain dormant for half a year.....

 

You wouldn't happen to work for Amperor, would you ?

[david and julie]

You wouldn't happen to work for Amperor, would you ?

I couldn't answer the above, save to say that I've also spoken to the guys at Amperor several times and have always found them really helpful and pleasant too - I definately don't work there.