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Gear / Technical Help => Remote Power => Topic started by: willndmb on March 08, 2017, 12:42:45 PM

I asked a similar question yrs back and was given a formula to figure out approx run times based on draw, but I can't find the thread :)
If anyone can tell me what the approx run time would be for say a 10,000 mAh battery pack w/1A and 2A USB outs. (I assume if I was using both at once the run time is just cut in half since both devices would be exactly the same)
This is what the manual say...
Power
Power Supply (rated)
3.6V DC (battery pack), 5.3V DC (compact power adapter)
Power Consumption
2.7W (SP mode, AF on, LCD normal brightness)
CA110 Compact Power Adapter
Power Supply: 1=240V AC, 50/60 Hz
Rated Output/Consumption: 5.3V DC, 1.5A / 17VA (100V)  23VA (240V)
BP709 Battery Pack
Lithium Ion
Rated Voltage: 3.6V DC
Capacity: 920mAh (typical) 3.3Wh/895 mAH (minimum)
THE POWER BANK WOULD BE RUN INTO THE "CA110 COMPACT POWER ADAPTER" JACK
using this cable http://www.ebay.com/itm/CA110USBCABLEforCanonHFR20R21R26R27R38R205R307R306/121460300558?pt=Camera_Cables_Cords&hash=item1c47991b0e basically as a replacement for the wall plug/charger
Huge Thanks

Found it http://taperssection.com/index.php?topic=166875.msg2081127#msg2081127
5.3/5 = 1.06 or 1060 mAh
1A battery min required
(My current battery) 10400/1060 = 9.8 hrs
9.8/2 (using both outs at once) = 4.4 hrs
Sweeeeeet that I can run two camcorders off a pocket size battery for a whole show without issue

You have to be careful as most Chinese made batteries advertise total CELL mAh capacity (they take the total number of cells and add the mAh number together  4 cells at 2500mAh = 10000mAh) to get as big of a number as possible  this is a marketing tactic. In addition to being misleading on the true capacity the CELL capacity does not take into account the energy lost when converting from one voltage to another (i.e. via DCDC converter). A good cheap DCDC design can be about 85% efficient
Most LiIon batteries use 3.7v cells so 10000 mAh or 10Ah at 3.7v ~ 37Wh x 0.85 ~ 31.45Wh of usable capacity
So if you are running a 5v load at 1A then you can expect a little over 6 hours on this battery
If you run a 5v 2A load then 3 hours or so

You have to be careful as most Chinese made batteries advertise total CELL mAh capacity (they take the total number of cells and add the mAh number together  4 cells at 2500mAh = 10000mAh) to get as big of a number as possible  this is a marketing tactic. In addition to being misleading on the true capacity the CELL capacity does not take into account the energy lost when converting from one voltage to another (i.e. via DCDC converter). A good cheap DCDC design can be about 85% efficient
Most LiIon batteries use 3.7v cells so 10000 mAh or 10Ah at 3.7v ~ 37Wh x 0.85 ~ 31.45Wh of usable capacity
So if you are running a 5v load at 1A then you can expect a little over 6 hours on this battery
If you run a 5v 2A load then 3 hours or so
thanks
which battery are you referring to, any in particular?
The battery I currently have is a Rav Power from Amazon.
I was going to get a similar one (new version)