Re: Separate power for mount - why?


Dale Ghent
 

My own experience with running everything off a single, common power source has not given me any issues that could be attributable to doing that. I get the feeling that there are two main reasons behind this advice, though:

One is that it's given with the aim of avoiding some (common? maybe at some point?) electrical issues with certain gear configurations - current leaks, noise, stuff like that. Stuff that's also hard to identify and quantify if you're not an EE or know what to look for. But this, I feel, is largely a situational thing and not something that affects every setup out there.

The other is around battery chemistries where there can be a large-enough voltage drop when the current draw suddenly increases - such as when a mount starts slewing. This voltage drop can be large enough to knock other equipment offline, cause them to reset, or even lockout into a safe mode. It's not great for gear and their own voltage regulation circuits. But, chemistries such as LFP don't tend to suffer from such precipitous voltage drops under load so you might be ok there if you're running everything off of a single LFP battery. These kinds of batteries didn't really exist, at least commercially, 10, 15 years ago.

On Jan 10, 2022, at 12:55, ap@captivephotons.com <ap@CaptivePhotons.com> wrote:

First, I take all advice from AP seriously, and use a separate power supply for my mount now (AP1100AE).

After my first attempt at night at a dark site, I need to redo my battery planning. I ran dead before midnight with a Group 27 Lead Acid battery. It was a bit premature due to a fallacy in the SOC indication I was using, but on further measurements I was way under sized and would have been completely dead before morning. So a big 200ah LiFePO4 is on the way.

But that brings up the mount. I have a Group 24 FLA for it, and that is more than adequate with its miniscule draw. But it is about 50 pounds I lug around to the dark site. I might replace it as well, say a 50ah LiFePO4, much lighter and smaller. But expensive if not needed.

So here is the question: The recommendation is to have a separate DC power supply, due to noise from cameras, etc.

Is the recommendation based on trying to prevent damage to the CP4 or mount?


Or is the recommendation because it may create anomalies in tracking/guiding?

Bottom line: Is there any reason not to give it a try off the same big battery, and so long as tracking is its usual near perfect self, not bother hauling (or buying) the separate battery? If there's a risk of damage, obviously I'll keep two.

I'm well aware in terms of investment the cost of another LiFePO4 battery is negligible, it is more about one more piece of "stuff" to haul out, back, etc. The last trip I spent more time packing and unpacking than imaging. Working to streamline other aspects also, but this one came up when I was debating whether to go ahead and order a second LiFePO4 battery or not.

Linwood


Join main@ap-gto.groups.io to automatically receive all group messages.