12 volt buck/boost unit

As an ET with 40+ years in the 12 volt field I would really be interested in what needs exactly 12 volts. Component tolerances alone would likely allow some change,.

Any device placed in the line is going to contribute to "inefficiency" in some way. It's not a big deal.

Victron makes some good dc-dc converters.

If you are plugged-in and can offer the device at least a 1-volt Delta T, a bucker may work especially one of the better ones like a DROK. I use these all the time and build small circuits. But remember, there is going to be noticeable "droop" between no load and full load - even three amperes. So the device output needs to be tweaked under load. I build circuits with a Drop Out voltage of .8 another way is to boost then drop. Two converters. Side by side. Use the booster to obtain just enough Delta T then a good DROK bucker to tweak down to the tenth of a volt. The double conversion isn't all that inefficient either. I would recommend something like a 12.4 to 14.4 boost then a 14.4 to 12.00 buck. But the buck must be tweaked under load of whatever Hungarian Movie Actress sensitive device you are powering.

If you put a meter on that 12 volt "wall wart" you will likely discover that it is 13.5 to 14 volts.

Visit an electronics store web site.. Many good stores carry Buck/Boost units, basically these are switching power supplies with an inverter front end. but you dont' need to know that.

Some can take as low as 2 or 3 volts, or as high as 30 or 40, and do not mind if the input voltage varies from too low to too high or the other way around.

And the output is dead on whatever you select. plus or minus... NOTHING.

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subcamper wrote:

DC-DC Converter 10-18VDC in 12VDC out

That's a great site- particularly http://www.powerstream.com/powerhumor.htm

:)
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We used one of these at work when we were doing some automotive testing of our equipment that required close to 12V:

DC-DC Converter 10-18VDC in 12VDC out

If you don't want to do soldering to a module, you can get a "finished" unit:

DC-DC Converter Unit

Steve

I wonder how a big chunk of those 4A DC you will lose with inverter and wall wart. 1-1.5A total losses of the wart and inverter. Mostly in the wart.

Unless you are on a mid-small solar, living fulltime with no generator - which I think you are not - you will hardly notice daily 10 AH loss, or whatever long you have to run that appliance.

But, if you really need to save energy, get one of Meanwell DC supply units. 5-6% loss VS 30-40% of your regular AC-DC wart. Cleaner DC too. Cheap warts often output poorly filtered voltage.

What he said... Just curious what requires exactly 12v ? Unless you are going directly into electronics POST onboard regulator, and that output voltage is a regulated 12v, you have a delta of several volts at least. The next lower common regulated board voltage is 9v

For that you would need a regulator. If using 120V power, a regulated power supply.

Care to share what device you are powering that is so critical on voltage? You do know that a wall wart for 12V will have an unloaded voltage of 13V->16V?