Re: Upgrading my equipment #iEXOS-100 #TECHNICAL #ASCOM #astrophotography


Jeff Snell
 

Thanks Vince!  I’ll give these a look.

Jeff


On Jul 18, 2020, at 9:31 PM, Vince White <vnwhite@...> wrote:


Hey Jeff,

I have a couple of quick comments on lightening your battery pack:

If you haven't actually measured the running wattage of all of your equipment, you might be surprised by how little something consumes versus the rated wattage of the AC-DC adapter.  Something like this is convenient to measure the running wattage of individual equipment, and generally handy around the house.  You might find that your total running wattage is lower than you think and that the 114AH battery may be oversized, certainly 70# is a lot to drag around.  Depending on your laptop and OS, you should be able to enable power-savings and significantly reduce its running power consumption. 

Also, I suspect that most, if not all, of your astro gear is DC powered.  Doing a conversation from the lead-acid 12VDC to 120VAC with an inverter, then back to DC via the individual AC-DC adapters is not very efficient.  Ideally you would just use the 12VDC of your battery straight to your devices (like the PMC-Eight) or do a 12VDC to DC conversion using boost or buck converters, which are very efficient (~90%).  The downside to buck converters is that if they fail, they tend to supply the full input voltage to the end device, which can be very bad, depending on how the electronics are designed.  A boost converter doesn't have the same issue, since it would either fail or just output 12VDC.  I'm currently using 3 small buck converters and I've built added overvoltage protection circuits (called a crowbar) to each of them, however, it was a fairly complicated process to do.  Some people risk using buck converters without overvoltage protection or double them up in series to tolerate a single failure.  You also might be able to find 12V versions of your current gear, for example, here's a 12VDC powered USB 3.0 hub you could power directly off of your battery.

-Vince

--
Mount: ES PMC-8 EXOS2-GT
Scopes: BRESSER 208mm f/3.9 Newt + ES HR Coma Corrector, Celestron C90 Mak, generic 50/191mm guide scope
Cameras:  Canon EOS RP, T7C (ZWO ASI120MC clone)
Misc: 2" Optolong L-eNhance filter, 2" Optolong UHC filter, Raspberry PI 4
Software: INDI + Kstars + EKOS, DeepSkyStacker, GIMP, Lightroom, Photoshop, SIRIL

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