14.8v @ 16 amps down to 12v @ 8 amps

[Builder_Of_Bots]

Hi, I am building a night vision monocular and need help getting from my 14.8v power source down to 12v @ 8 amps to power my low lux security camera (.0008 lux). The camera has a peak current draw of ~8amps. It is just a camera without any infrared lights. I will need to use this in about 2 hour intervals. As I couldn't find any 12v regulators that could handle 8 amps I thought that I could just put 6 or so of these https://www.sparkfun.com/products/12766 together. If that would work could somebody please show me how to wire them up? If not is there any other way to convert to 12v? Needs to be somewhat small because it will be going on an airsoft gun rail. Thanks for any help.

 

[cjdelphi]

I'm not sure there's enough give for a regular 7812, you'd need the LDO version, then on top of that you'd need to load balance them or 1 regulator will have a higher voltage and that will dump all it's current to the camera and the other regulators get cold

Say 0.1ohm on each 7812 out to limit total current for that reg..

 

[Tha fios agaibh]

Or you could put about 4 silicon diodes in series that would drop it from 14.8 to 12v.
Peak current is 8a, but you could probably get away with diodes or rectifiers rated 6a. Depending on your normal load.
I'd just use a 8a limiting fuse for protection.

 

[Builder_Of_Bots]

Or you could put about 4 silicon diodes in series that would drop it from 14.8 to 12v.
Peak current is 8a, but you could probably get away with diodes or rectifiers rated 6a. Depending on your normal load.
I'd just use a 8a limiting fuse for protection.

If I used three of these http://www.mouser.com/ProductDetail...wPN0G_irN0_kruXn-hn0Jl6ULl8umM4RQZRoCSdHw_wcB and the voltage came out at 11.5v would the camera operate on that? I need to add in the batteries changing voltage too. Fully charged it will be ~12.3v with 3 diodes and when it is running low ~11.5v with 3 diodes. Would it affect performance just .5v down from 12v? Thanks for your patience and help.

 

[Tha fios agaibh]

It's likely your camera will be fine Your power supply as is. Yes, its better to have the voltage higher than exactly 12v.
Unregulated power supplies will output a higher voltage than when hooked to the load of a circuit. For example a wall transformer may read 14.8v but will then drop to 12v when its loaded (hooked up) and drawing current.

A 12v car battery will measure around 12.5 and even higher (14.7v) with the car running and charging it.

Refer to the camera manual to see what voltage it should be.

Generally most electronics need slightly higher voltage over its nominal voltage.

 

[(*steve*)]

Generally most electronics need slightly higher voltage over its nominal voltage.

I would say "can cope with" rather than "require".

edit: and depending on what you're talking about, even that may not be true.

 

[Tha fios agaibh]

I would say "can cope with" rather than "require".

edit: and depending on what you're talking about, even that may not be true.

True, but notice I didn't say rated voltage.
Having the actual camera and ps specs would be useful here.

 

[Builder_Of_Bots]

Oops. I looked at the specs again before I tried anything and it said 8W instead of 8A. Stupid mistake on my part. I should have known though. 8 amps for a camera isn't exactly normal. I calculated it and it should be about 1.5A. Thanks for the help anyway. I will probably look at this in the future as my projects get bigger.

 

[Colin Mitchell]

8W is less than 1A.
Use 1A diodes.
Make sure the 14.8v does not rise. You can use a 5w 12v zener and 1A fuse. If it blows you know the 14.8v has risen. Just like Jesus.

 

[Builder_Of_Bots]

8W is less than 1A.
Use 1A diodes.
Make sure the 14.8v does not rise. You can use a 5w 12v zener and 1A fuse. If it blows you know the 14.8v has risen. Just like Jesus.

Amen brother.