12V DC to 9V DC Voltage regulator @ 3A

M

MrMackie

New Member
Hi All,

Just noticed this website and what a ripper it is! But enough plugging as im sure you get plenty of that from all the newbies that join :-)

I have a device that currently runs off a 9Vdc (9VDC @3Amp) plugpack which is pluged into the Mains power to operate, as supplied with the unit.

However i would like to use the device while traveling to pass the time during long trips either in a car, bus or plane and need a battery power pack to run it.

I can purchase a Li-ion battery pack for a reasonable price but only at 12V (9600ma) and dont want to blow up my device by just pluggin the 12V into the input, so need to make a step down regulator.

Can anyone recomend an easy AND reliable circuit i can built (im handy with the iron, but not @ designing circuits), and the components that go along with it. Even a sketch on paper would be helpful.

Cheers in advance!

MM
 
MrMackie said:
Hi All,

Can anyone recomend an easy AND reliable circuit i can built (im handy with the iron, but not @ designing circuits), and the components that go along with it. Even a sketch on paper would be helpful.
Click to expand...

You could use 4 or 5 silicon power diodes in series which would give you a fairly constant voltage drop of around 3 volts (give or take).
 
The problem with diodes is that the battery pack is a nominal 12v- it will be quite a bit higher than that when charged. Don't forget you will also be needing a charger.
If you aren't concerned about efficiency, just use a 12v regulator.
If you want to maximize battery life, you'll need a switched DC/DC converter.
9600mAH (assuming you dropped the H) should give you about 3 hours if you are really drawing 3 amps, using a regulator. More like 4 hours if you use a DC/DC.
 
Thanks for the reply's so far.

The battery im looking at comes with a charger so thats a bonus. Approx 3 hours useable time would be fine.
Regarding the switched DC-DC convertor, are these able to be made in kit form, or best to just buy one?
Efficiency in my application would be a good thing if possible.

Has anyone used one of these switched DC-DC convertors before?
 
You must log in or register to reply here.
Back
Top