Log in

View Full Version here: : Quality of power to astro cameras.


DIYman
16-04-2021, 10:41 PM
I hope someone can assist with knowledge of electronics.

I am getting a power supply built to run a CMOS camera. (To convert 240V to 12 V.) The guy building the unit asked just how "clean" does the 12 V need to be. If I say "the cleanest possible" it is going to cost me big time.



So I ask what is a sensible value I can stipulate that will not cause issues for the camera?



(PS. I want to move from using my existing battery bank as it is inconvenient and requires monitoring.)

peter_4059
16-04-2021, 10:56 PM
Did the camera come with a power supply from the vendor?

JA
17-04-2021, 11:06 AM
That's not necessarily an easy question to answer exactly, but I would have thought a commercially available regulated linear power supply at your voltage should provide sufficiently clean DC so as not to cause any issue. Maybe you could use a switch-mode supply, but if you are fussy then you'd need to measure it first to be sure which is the best, BUT that all begs the question of whether you will notice. Certainly if the AC component in the DC is too high you will get all sorts of strange effects, certainly with video (and also in any audio application).

Getting back to the theme of Peter's question (hello Peter): why not use the camera's designated supply from the manufacturer? If you feel this isn't good enough perhaps and that could be improved upon, then that depends upon what your objectives are. Will you be powering ONLY the camera with this supply? Which camera? What are the voltage /current requirements for the camera. Some of this can be gleaned from the power supply provided with or recommended for use with the camera by the manufacturer. Also if you had the power supply it could be measured for the cleanliness of its DC output on an oscilloscope and other gear and then you could go crazy and design (or buy) a better supply, with more capacitance, better regulators, inductors, shielding, etc.......

The real question is will it make a difference? Perhaps you could go some way to answer this by looking for reports of others using your camera and the standard manufacturer's power supply reporting any issues related to cleanliness of the DC supply.

Also note that 12 V is not always what it seems in battery/automotive applications. It might be 12V nominal as in the case of a car battery/electronics which is typically 13.5-14V DC. Point of the story is to know what your device is and what it needs to feed it.

Best
JA

peter_4059
17-04-2021, 11:22 AM
I was thinking the label on the supply might reveal the type of supply and capacity they recommend.

In my case I always use the power supply that came with the camera for the camera and a GME 13.8V regulated power supply for everything else however I suspect the GME would be fine for the camera also.

JA
17-04-2021, 11:48 AM
Hi Peter,

I wasn't questioning your suggestion (just saying Hi :D and acknowledging):thumbsup:, I was also trying to relate the importance of your question to DIYman as it's central to the issue in terms of just that: some of the specs - Voltage, current, power .... and then if he did have the supply he could have it measured for "cleanliness" of the DC on an oscilloscope and redesign / improve it as he saw fit.

Best
JA

peter_4059
17-04-2021, 01:28 PM
Sorry JA - I wasn't trying to have a go at your suggestion - just expanding on my original post that if the camera came with a power supply it might provide some information on the device such as the voltage, current rating and potentially type of power supply it was. There may even be a part number that can reveal more info with a google search. :thumbsup:

Peter

JA
17-04-2021, 01:37 PM
^100% Peter :thumbsup:

Best
JA

AdamJL
17-04-2021, 03:58 PM
either of these will do it fine

https://www.jaycar.com.au/12v-dc-5a-desktop-power-supply-2-5mm-dc-plug/p/MP3242

https://www.jaycar.com.au/12vdc-7-5a-switchmode-power-supply-mains-to-cigarette-lighter-socket/p/MP3575

The second one just needs a cigarette lighter adapter.

Rerouter
17-04-2021, 04:24 PM
work on 12V +- 1V max, with atleast some output filtering, most of the astro gear runs the margins thin with only 14-15V max regulators with no reverse polarity protection (WHY!) but a normal switchmode converter will be clean enough for it,

Just beware transformer power packs with no DC regulator, most of them will raise in voltage when unloaded e.g. 12V @ 10A rating, sometimes up to 17-21V with no load, and your gear will not appreciate it.

Personally I have been slowly modding my gear to handle 10-32V but I understand stuff in warrenty needs to be treated differently,

lazjen
17-04-2021, 08:49 PM
For some of these newer CMOS cameras, you may run into issues if your power supply starts dropping below 12V. I've just experienced this myself with the new ASI2600 when the power dropped to around 11.8V (it might have been slightly lower, but I didn't immediately check the voltage at the time).

AdamJL
18-04-2021, 10:11 AM
what power supply was that, Chris?

lazjen
18-04-2021, 12:11 PM
Actually, the power supply was ok (I think it was a 15A Jaycar one from memory). The issue was I had a cable that was inadequate for the amps I was drawing through when I added the ASI2600 (and some other stuff) into the mix. As the cable heated, the voltage dropped, causing chaos with the ASI2600.

Removing that cable and reworking the setup for the power routing - the problem went away.