Power supply for Camera, 12V-8V Conversion

Thread Starter

pete81

Joined Sep 28, 2021
3
Hello all,
First post here so hoping it's in the correct place.
Straight to it... I'm into astrophotography and wanting to use a single power supply that will control my setup - I'm sure that's a line from a film (Lord of the Rings in case you missed it).
So, I have a 12V supply to power my mount (it actually outputs 13.8V with plenty of current to spare, so power requirement is fine - link). I'm also running a 12V-5V Buck converter (link) and powering a Raspberry Pi mini PC via a USB cable. So far so good.
My issue is the camera power supply - I have a mains camera dummy battery which works and supplies 8.3V. In an attempt to use the PSU above, I tried a buck converter approach (link) using 2 in series, to reduce the 13.8V to 10.8V and then 10.8V to 7.8V, but couldn't get the first to output more than 5.7V so that approach wouldn't work. Perhaps a dud-first one, I never tried others and sent the order back.
I then purchased (two) 12V-8V step-down adapter (link) which should have worked with my camera, but the first one didn't even put out 1V so sent back and tried a second which worked for a night before giving up on me.
I'm therefore left with two options - use another 12V-5V USB buck as per the RPi, and then a USB camera power cable (link), or ask advice on adjustable buck converters which will do the job of the poor quality Amazon one. Hence my post here. Going from 13V-5V-8V seems a bit silly and adds extra components and cost, but is likely to work well, but I'm more interested in going for a 12V-8V converter that will do the job for me and work.
TLDR:
Looking for a means to convert 13.8V to 8.3V for a DSLR - recommendations appreciated as have been unsuccessful with duds to date!
Thanks in advance!
 

Thread Starter

pete81

Joined Sep 28, 2021
3
Hi Eric,
Thanks for your response. The rating of the USB cable is 2-4A at 5V, with the dummy battery quoting 7.4V at 2A. Using it with the Nevada PSU last night at 13V, there was little current drawn (<1A on the PSU display) so I would be pretty sure this is to be safe. Hence my thinking about buck converters which (from what I have seen and in my minimal understanding) can happily output 3A, so well within the limits of what I'm looking for.
HTH?
 

Thread Starter

pete81

Joined Sep 28, 2021
3
Bumping this for some help please.
I had assumed that a variable buck converter would take a voltage in and reduce it to a desired output, up to a maximum of V_out = V_in - 1.5V (ish), so by feeding 13V into a variable buck converter, I can get an output of up to 10V quite happily. My issue is the one that I tried wouldn't give an output of more than 5.7V.
I've used other bucks to give USB output and the 5V3A one that I have works a treat, so hopefully incorrectly assumed that the voltage out is more limited than I initially thought.

Can I ask if I am completely wrong about what a buck converter does or did I just get a 'dud' to start with?

Assuming the converter does what I think it is meant to, would anyone recommend a buck converter (eg https://www.amazon.co.uk/gp/product/B07DYP6L35) that will take 13V in and output a voltage that I can vary (specifically between 7-8V, noting obviously that it can supply sufficient current, where the url mentioned specs up to 3A).
Many thanks
 
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