Question about Power Output - Using TalentCell (PB120B1 - 38400mAh)

SHagler

I have an ASIAIR Plus that I am using with the following setup:

Skywatcher Star Adventurer GTI - GoTo mount - Connected to ASIAIR 12v Power
Canon 600D DSLR - Connected to ASIAIR 12v Power - Via StepDown Dummy Battery
ZWO Electronic Autofocuser - Connected to ASIAIR 12v Power
ZWO ASI120mm-mini Camera (guiding) - Connected to ASIAIR USB

The ASIAIR is powered via a TalentCell 12V Lithium Ion Battery (PB120B1) - 38400mAh / 142.08Wh with output spec-ed at 12V (12.6V-9V) / 6A Max

The good news -- Everything powers up and runs nicely. I have run this setup for 6-8 hours with zero power issues and it appears that the battery pack uses less than half of its capacity (based on 4 segment LED). Frankly, I was pleasantly surprised that everything worked well and that it appears that the battery could potentially last through 2 nights of imaging.

When looking at the power section of the app, I see that it "idles" at 0.4-0.5A Input Current and 4.5-5.5W Output Power. With guide camera cycling (1 sec) and slewing to a new target (with both Alt and Dec motors running), I see the power output go up to about 8W (again, via ASIAIR App). The Power Input only seems to get to about 0.7A

The questions:

Given that everything is pulling 12v, why does the ASIAIR App show power output between 4-8W? I would have thought that the measure here would have been in amps.
Assuming that Input Current is correlated to the output needs, does this indicate that I am likely running 0.4A on low side and 0.7A on high side to all devices?
The heart of my post is I am trying to determine how to calculate the true expected need of this setup and the likely number of hours that this battery should provide.

Everything works well right now...trying to understand how a different component (like dew strap or cooled camera) would impact everything.

Thanks to this community for sharing knowledge and experience.

w7ay

SHagler why does the ASIAIR App show power output between 4-8W? I would have thought that the measure here would have been in amps.

Power is measured in units of Watts [W], and electric current is measured in units of Amperes [A].

https://en.wikipedia.org/wiki/International_System_of_Units

For direct current (DC), power (in Watts) is equal to current (in Ampres) multiplied by voltage (in Volts). 12 Volts at 4 Amperes would correspond to a power of 48 Watts, for example.

For batteries, electrical energy is often measured in Watt-hours [Wh] instead of Joules (which is equivalent to Watt-seconds). So a 100 Wh battery will support a system drawing 10 Watts of power for up to 10 hours.

Chen