I have a working knowledge of electronics and circuits but am a little lacking when it comes to design. I can follow the diagrams but designing was never my game.

I am wanting to supply a clean and (relatively ) consistant 12v DC @10amps (or better) to my DC TV and some other DC appliances in my motorhome. There is a TV, Security DVR, Modem Router and a NAS unit. It of course feeds from a battery bank and charges from solar. There is more than enough voltage and current from the 1300ah bank. My concerns are the fluctuations in the voltage from the solar. It can be as high as 14.4v.

Currently the items run from 2 x 12v variable power adapters for a car. These are 5 amps but can only run one thing at a time.

I worked once with a unit that provided a stable 12v 20amp with input up to 16v. I cant remember where I got it from or even the name.

I would very much appreciate if anyone had or would consider drawing a diagram for something like this. I would prefer something with a reasonable current rating, 10amp min. I would also like to be able to pull 9v out of it as well but can handle living without this.

All thoughts would be very much appreciated.

Please and Thank you Mal

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    \$\begingroup\$ Please draw a diagram or an overview. It's difficult to follow what you aim for. \$\endgroup\$ – winny Nov 7 '16 at 8:49
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    \$\begingroup\$ The unit of voltage is "Volt", and is abbreviated "V" (capital V). For current, the unit is "Ampere", and is abbreviated "A" (capital A, not small a, not amp). \$\endgroup\$ – Marcus Müller Nov 7 '16 at 9:13
  • \$\begingroup\$ By "diagram" do you mean schematics? \$\endgroup\$ – Lundin Nov 7 '16 at 9:27
  • \$\begingroup\$ Use @ before the username or the user will not be notified. Yes, I mean a schematic. \$\endgroup\$ – winny Dec 9 '16 at 7:38

Actually it starts with the question if you need a stabilizer. Many appliances rated for 12V DC are build to be used in cars, motor homes, etc. The maximum voltage of a fully charged lead-acid car battery is 14.4V. If you look in the manuals of your appliances you can find if you can use the apparatus from a car battery. If this is the case then 14.4V does not pose a problem.

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  • \$\begingroup\$ Isn't it the very same problem that many modern tech companies are trying to solve, and are solving with a workforce of hundreds of seasoned engineers? Like Solar City? Sunpower, Solarbridge, etc. Solar variability, low light, high light, uneven solarization of different panels, 90+ % efficiency, reliability, lightening protection, etc, etc. ? Is there anything where a DIY can compete at the LDO/PowerFET level? I don't think so. \$\endgroup\$ – Ale..chenski Nov 7 '16 at 18:35

IF you really need 12V (see what Decapod said) you want a 12V LDO (low dropout) regulator OR a boost buck module that takes Vin from below to above 12V and gives 12V out. Forr the latter see ebay. For the former, consider the following (or again see ebay):

This shows a P Channel MOSFET and controller inside a single IC but you cam implement that with basic discrete components.

enter image description here http://www.richtek.com/selection-guide/img/ldo-pmos.png

You can achieve this with an eg LM358 opamp and a suitable P Channel MOSFET - see below.


Vdo - the "dropout voltage" ( - minimum Vin-Vout at max current is lomited only by the MOSFET Rdson (on resistance). At Rdson = 10 milliOhms Vdo = 0.1V at 10A.

Any of these parts, in stock at Digikey & available in 1's will readily meet the need.

DMP3010 30V 17A 8 milliOhm $0.62/1 !!!

IDP068P03 30V 70A 6.8 mOhm at 70A :-} $0.85/1 What Is the world comming to !!!? :-)

To this, apparently ! :-)

IPB180P04P4L02ATMA1 (!!!) 40V 180A, 2.4 mOhm at 100A {!!!!!!} $US 2.20/1 Would not even need a heatsink at 10A :-).

The lead assignment also makes hand soldering a doddle


ggg sss

enter image description here

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