12 power adaptor.

[bag 'o' bones]

A lot of equipment these days is low volatge and use A/C to D/C adaptors so they can be plugged into the wall.

 

So my question is does anyone make a D/C - D/C 12 volt adjustable adaptor so that lower than 12volt equipment can be run straight off the 12 volt supply?

 

I know that I can use a a normal 230 volt adaptor from my inverter supply but it does seem a bit silly to step the voltage up and then back down again especially in that it wastes such a lot of valuable battery capacity through heating effects.

 

I've had a look on the net and checked this sites search facility so i'm guessing that such a thing does not exsist?

[Bones]

A lot of equipment these days is low volatge and use A/C to D/C adaptors so they can be plugged into the wall.

 

So my question is does anyone make a D/C - D/C 12 volt adjustable adaptor so that lower than 12volt equipment can be run straight off the 12 volt supply?

 

I know that I can use a a normal 230 volt adaptor from my inverter supply but it does seem a bit silly to step the voltage up and then back down again especially in that it wastes such a lot of valuable battery capacity through heating effects.

 

I've had a look on the net and checked this sites search facility so i'm guessing that such a thing does not exsist?

 

 

Try Maplins.

 

I purchased a 12volt adaptor that is adjustable down to 1.5 volts, and another adaptor that goes up to 24volts.

[twocvbloke]

If you mean a 12v-12v DC conditioner, yes, there are such things, if you have a search of the forums it might come up with links to them...

 

As for the title, "12 power" reminds me of Sulu's line from Star Trek: The Motion Picture, which was just that, "12 power?!" (in astonishment at the mysterious cloud object they were approaching)...

[PeterF]

Confirm that Maplins do such devices and I have 2 in use on the boat, one set at 12V for soemthing that did not like the 14.8V when engine was running and the other set at 9V for an alarm clock that was off a PP3 battery.

 

See attached link for the unit I have. Only downside is these are only 1.5A output. Aso, you may have to cut the cigarette type plug off and change to whatever you have. But they are good for small DC appliances.

 

PeterF.

 

Maplin DC to DC regulator

[Nickhlx]

Confirm that Maplins do such devices and I have 2 in use on the boat, one set at 12V for soemthing that did not like the 14.8V when engine was running and the other set at 9V for an alarm clock that was off a PP3 battery.

 

See attached link for the unit I have. Only downside is these are only 1.5A output. Aso, you may have to cut the cigarette type plug off and change to whatever you have. But they are good for small DC appliances.

 

PeterF.

 

Maplin DC to DC regulator

 

 

The Maplin box described above is a adjustable voltage regulator which needs 3 to 4 volts to provide regulation, hence the "12 volt" output option needing 16 Volts on the input side to provide a regulated 12 volts out.

 

What the OP I think was asking is about the availability of something that gives 12V out for say 9 to 16 volts in....

 

The device that does this is called a " Buck-Boost " regulator - e.g. the input can be between at least 9 to 16 volts and the output may well be variable as well, depending on model. Various current rating models exist too.... They have more electronics within so naturally cost more.

 

The cheaper type ( Maplin ) may well be OK if you can tolerate reduced output at 12 volts - they just won't let the output rise above 12 volts ( within their capabilities) Keep the load light to minimise this effect.

 

For the techies amongst us, only today have I finished a similar box - based on a LM317T, it has up to 2 amps output at 12.0 volts, but does need approx 14.4 volts to achieve that rating. The LM317T is only rated as 1.5 amps but this is a minimum and the two I have tested could give up to 2.2 amps. At 1 amp load, the voltage headroom needed was approx 1.6 volts.

 

 

Nick

[bag 'o' bones]

Confirm that Maplins do such devices and I have 2 in use on the boat, one set at 12V for soemthing that did not like the 14.8V when engine was running and the other set at 9V for an alarm clock that was off a PP3 battery.

 

See attached link for the unit I have. Only downside is these are only 1.5A output. Aso, you may have to cut the cigarette type plug off and change to whatever you have. But they are good for small DC appliances.

 

PeterF.

 

Maplin DC to DC regulator

 

Thats the one.

 

I see should have typed in 12 volt regulator rather than 12 volt adaptor.

[PeterF]

The Maplin box described above is a adjustable voltage regulator which needs 3 to 4 volts to provide regulation, hence the "12 volt" output option needing 16 Volts on the input side to provide a regulated 12 volts out.

 

What the OP I think was asking is about the availability of something that gives 12V out for say 9 to 16 volts in....

 

The device that does this is called a " Buck-Boost " regulator - e.g. the input can be between at least 9 to 16 volts and the output may well be variable as well, depending on model. Various current rating models exist too.... They have more electronics within so naturally cost more.

 

The cheaper type ( Maplin ) may well be OK if you can tolerate reduced output at 12 volts - they just won't let the output rise above 12 volts ( within their capabilities) Keep the load light to minimise this effect.

 

For the techies amongst us, only today have I finished a similar box - based on a LM317T, it has up to 2 amps output at 12.0 volts, but does need approx 14.4 volts to achieve that rating. The LM317T is only rated as 1.5 amps but this is a minimum and the two I have tested could give up to 2.2 amps. At 1 amp load, the voltage headroom needed was approx 1.6 volts.

 

 

Nick

Nick,

 

Thanks for that, but the OP did specifically request an

 

"adjustable adaptor so that lower than 12volt equipment can be run straight off the 12 volt supply"

 

e.g a 9V (lower than 12V) piece of equipment can run off a 12V supply.

 

and the thank you note confirms this.

 

Peter.

[Nickhlx]

Nick,

 

Thanks for that, but the OP did specifically request an

 

"adjustable adaptor so that lower than 12volt equipment can be run straight off the 12 volt supply"

 

e.g a 9V (lower than 12V) piece of equipment can run off a 12V supply.

 

and the thank you note confirms this.

 

Peter.

 

Thank you for pointing that out - I was also partially replying to other replies and thought that it filled out the subject with more information that would also be of interest to those reading about regulation options for various devices on board.

 

Nick

[alan_fincher]

The search string "DC to DC Converter" is often useful for finding these, but note this includes devices that.....

 

1) Convert a nominal "12 volts" down to lower voltages (your requirement, I think).

2) Convert a nominal "12 volts" to voltages of maybe 12V up to 21V (typically to power laptops directly)

3) Convert 24 volts down to 12 volts (for example to allow a lorry to power equipment designed for cars, but useful to those having 24V domestic on a boat).

 

Maplin have devices that cover these, and many more requirements, but you need to read the packaging about suitability, and whether they can handle under-voltage as well as over-voltage on the input.

 

To ensure a steady 12 volts to a flat screen LCD TV, when input voltage may vary between (say) 10V and 15V, many people use the DC to DC converter by Amperor, although that typically has a higher price tag, (circa £40).

 

Alan

[bag 'o' bones]

The search string "DC to DC Converter" is often useful for finding these, but note this includes devices that.....

 

1) Convert a nominal "12 volts" down to lower voltages (your requirement, I think).

2) Convert a nominal "12 volts" to voltages of maybe 12V up to 21V (typically to power laptops directly)

3) Convert 24 volts down to 12 volts (for example to allow a lorry to power equipment designed for cars, but useful to those having 24V domestic on a boat).

 

Maplin have devices that cover these, and many more requirements, but you need to read the packaging about suitability, and whether they can handle under-voltage as well as over-voltage on the input.

 

To ensure a steady 12 volts to a flat screen LCD TV, when input voltage may vary between (say) 10V and 15V, many people use the DC to DC converter by Amperor, although that typically has a higher price tag, (circa £40).

 

Alan

 

I want it to power the Binatone walki-talkie set charger. I'm pretty sure it can handle a very dirty supply so no worries there. Will keep Amperor in mind though if i come across anything which turns out to be a bit finicky.

[chris w]

I want it to power the Binatone walki-talkie set charger. I'm pretty sure it can handle a very dirty supply so no worries there. Will keep Amperor in mind though if i come across anything which turns out to be a bit finicky.

Ah - it's a battery charger application......

 

You need to be very careful as the mains adaptor is not just a simple 240v to 9v adaptor when it is used to charge NiMH or NiCd batteries. It will contain what is known as a constant current circuit which ensures the charge current is set at a fixed value. For 2x walkie-talkies (ie 2 x 2 batteries in series) this will be around 160mA. These types of battery must be charged with a constant current NOT a constant voltage.

 

You CANNOT just plug a standard 12v/9v adaptor into the walkie talkies because you will fry the batteries. 240v/9v battery chargers of this type are NOT the same as standard 240v/9v converters. The latter is ONLY safe and OK to use for charging these batteries IF AND ONLY IF the constant current generator is in the walkie-talkie charging cradles, which personally I have never yet seen.

 

Chris

Edited February 3, 2009 by chris w