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Please check my math (Zoom F8 power consumption)
Old 6 days ago
  #1
Gear Addict
 
🎧 5 years
Please check my math (Zoom F8 power consumption)

Can someone please check my math?

- According to the manual my Zoom F8 uses 12 Watts of power. I am assuming (!) that this is just the recorder with no mics attached.

If input voltage is 12 volts, then it is drawing 1 amp = 1000mA. Watts = volts x amps. Right?

- The P48 spec gives maximum power draw at 10mA.

So if you max things out, then a Zoom F8 with 8 microphones plugged in all drawing the maximum of 10mA will draw 1080 mA. Correct? If you are powering the F8 with a lithium-ion battery of for example 5000 mA/hr, then it would be able to power this for about 5000 / 1080 = 4.6 hours.

Is my math correct or am I getting something wrong here?

Regards, Christine
Old 6 days ago
  #2
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jimjazzdad's Avatar
 
🎧 10 years
Quote:
Originally Posted by connloyalist ➑️
Can someone please check my math?

- According to the manual my Zoom F8 uses 12 Watts of power. I am assuming (!) that this is just the recorder with no mics attached.

If input voltage is 12 volts, then it is drawing 1 amp = 1000mA. Watts = volts x amps. Right?

- The P48 spec gives maximum power draw at 10mA.

So if you max things out, then a Zoom F8 with 8 microphones plugged in all drawing the maximum of 10mA will draw 1080 mA. Correct? If you are powering the F8 with a lithium-ion battery of for example 5000 mA/hr, then it would be able to power this for about 5000 / 1080 = 4.6 hours.

Is my math correct or am I getting something wrong here?

Regards, Christine
Sounds about right to me Christine. I like to include a 'fudge factor' of 10% or so, assuming the battery may not attain full charge as it ages/cycles, so I would say "4 and a bit hours"...
Old 6 days ago | Show parent
  #3
Gear Addict
 
🎧 5 years
Quote:
Originally Posted by jimjazzdad ➑️
Sounds about right to me Christine. I like to include a 'fudge factor' of 10% or so, assuming the battery may not attain full charge as it ages/cycles, so I would say "4 and a bit hours"...
Thank you

Regards, Christine
Old 5 days ago
  #4
Gear Maniac
 
🎧 10 years
I would suggest to always use Wh when calculating battery capacity.

1 channel P48 maxed out is 48 V x 10mA = 0.48W
8 channels will draw 3,84W.

One F8 with & 8 mics will draw 12+3.84= 15.84W

One litium-ion cell is usually 3.6 V.
5000 mAh x 3.6 V = 18Wh.

18/ 15.84 = 1.13636….

Your powerbank will power your F8 with 8 mics for just over one hour!
Old 5 days ago | Show parent
  #5
Gear Addict
 
🎧 5 years
Quote:
Originally Posted by ljudatervinning ➑️
I would suggest to always use Wh when calculating battery capacity.

1 channel P48 maxed out is 48 V x 10mA = 0.48W
8 channels will draw 3,84W.

One F8 with & 8 mics will draw 12+3.84= 15.84W

One litium-ion cell is usually 3.6 V.
5000 mAh x 3.6 V = 18Wh.

18/ 15.84 = 1.13636….

Your powerbank will power your F8 with 8 mics for just over one hour!
Interesting, thank you. One of the reasons for this exercise is that I am thinking about changing the way I power my F8.

At the moment I use a "Power Gorilla", 21000 mAh battery putting out 12 volts that I plug into the 12v plug in the back, where the AC adapter normally goes. Using your math that would last just over 4Β½ hours at max. The new version of the power gorilla is spec'd at 24000 mAh and 88Wh, which boils down to 3.66 volts. Assuming my older version is also 3.6 volts as you suggest that would make it 76 Wh.

Last Saturday I was using four mics with phantom power for about 2 hours. Don't know how much power those mics draw. The Power Gorilla has a display with six bars to indicate how much power is left. In those two hours I used up one bar.

I am thinking about buying a Hawk Woods DV-SQNR which hooks up to the hirose connector on the F8, puts out 12 volts and takes NP-F batteries. To my knowledge NP-F batteries are less than 12 volts, so there must be some kind of voltage step-up going on there, no idea how that works. Anyway, those NP-F batteries are smaller than the power gorilla so I am trying to figure out what to expect.

Doing a search for NP-F970, here (https://electronics.sony.com/imaging...ories/p/npf970) I read that it is 6300 mAh and 45Wh. Doing the math with 45 Wh / 15.84 Wh = just over 2 hours 45 minutes. So one battery would last a concert, but to be on the safe side perhaps better to swap batteries during the intermission.

Regards, Christine
Old 5 days ago | Show parent
  #6
Lives for gear
 
🎧 5 years
Quote:
Originally Posted by connloyalist ➑️
...
Last Saturday I was using four mics with phantom power for about 2 hours. Don't know how much power those mics draw. ... To my knowledge NP-F batteries are less than 12 volts, so there must be some kind of voltage step-up going on there, no idea how that works. ...
Yes, NP-F batteries are nominally 7.4 volts.

I have a friend with whom I've worked several concerts that used a Zoom F8 for a couple of years before getting a Sound Devices MixPre 10 II. I'll ask details of his battery consumption. My impression is that the 12w consumption figure for the Zoom F8 is overstated, and was likely closer to 6w when we were running four Line Audio condenser mics. The Line Audio mics are 3mA each. Also, it's quite rare to have a phantom-powered mic that uses more than 6mA, and the CAD M179 famously used 8mA.

Many times the phantom current load spec isn't published. That's the case with my Aston Starlight mics, and the Rode NT55's that I routinely use (along with stereo ribbon mics) for concerts.

As you can see from this PDF [link below] the second page shows that using 2450mAh AA NiHM batteries (qty 8, 1.2v each) that the Zoom F8 runs for 6 hours, which means that its consumption is 3.92 watts continuous, while capturing 8 channels; phantom off.

You caught me at a time that I'm testing my Zoom F6 with a 38Wh NP-F battery. I'm at 8hrs-41min so far, and the battery indicator finally turned yellow.

https://d1aeri3ty3izns.cloudfront.ne...oad_429415.pdf
Old 5 days ago
  #7
Gear Maniac
 
🎧 10 years
Maybe you can use a V-mount battery with a d-tap to hirose cable?
Old 4 days ago | Show parent
  #8
Gear Addict
 
🎧 5 years
Thank you for your insights, this is an interesting discussion.

Quote:
Originally Posted by MediaGary
My impression is that the 12w consumption figure for the Zoom F8 is overstated, and was likely closer to 6w when we were running four Line Audio condenser mics. The Line Audio mics are 3mA each. Also, it's quite rare to have a phantom-powered mic that uses more than 6mA, and the CAD M179 famously used 8mA.
I got the 12W number from the F8 manual, but have no way to verify it. I agree that when you run the numbers with AA batteries the 12W figure doesn't add up to what is seen in the real world. Looking at the numbers in your PDF and running that through the small spreadsheet I made with the 6W figure does indeed sound a lot more plausible.

I am aware that most mics don't use 10mA I took that as a worst case scenario. Are most mics around 2 ~ 4mA or so?

Quote:
Originally Posted by ljudatervinning ➑️
Maybe you can use a V-mount battery with a d-tap to hirose cable?
Yes, apparently many people do that without problems. The catch, as I understand it, is that while the nominal voltage of a V-mount battery is 14.4 volts, apparently the voltage of a fully charged V mount battery can be 16.8 volts which exceeds the maximum of 16 volts at the F8's hirose input. Probably this is why in the F8n Zoom increased the voltage range here to 18 volts.

Regards, C.
Old 4 days ago
  #9
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jimjazzdad's Avatar
 
🎧 10 years
Amps and watts are pretty much interchangeable in calculating power requirements (at least in DC powered circuits). Batteries are almost always specified in amp-hours (Ah) so I find it easier to calculate in A or mA x time, but the actual voltage must always be used - i.e. not a 'nominal' voltage like 12 or 18 VDC that may be printed above the power connector.
Old 4 days ago | Show parent
  #10
Lives for gear
 
🎧 5 years
Quote:
Originally Posted by connloyalist ➑️
...
I am aware that most mics don't use 10mA I took that as a worst case scenario. Are most mics around 2 ~ 4mA or so?
...
Here are some sample specs:
AKG C414 XLII 4.5mA
Neumann TLM 103 3mA
Neumann KM184 3.2mA
Neumann U 87 Ai 0.8mA
AT 4033 3.2mA

What mics do you have?
Old 4 days ago | Show parent
  #11
Gear Addict
 
🎧 5 years
Quote:
Originally Posted by MediaGary ➑️
Here are some sample specs:
AKG C414 XLII 4.5mA
Neumann TLM 103 3mA
Neumann KM184 3.2mA
Neumann U 87 Ai 0.8mA
AT 4033 3.2mA

What mics do you have?
Nothing really fancy here, but the mics I use most frequently in no particular order:

Advanced Audio CM1084 (with either cardioid or omni caps)
Sennheiser MKH406T
Sennheiser MKH416T
Audio Technica AT4081 (P48 ribbon mic, usually as a side mic in an MS pair)

Occasionally: Sennheiser MKH816T

Off topic: on the wish list is a pair om MKH106's (either P48 or T). But these seem to be few and far between on eBay. More generally I am considering a pair of "dedicated" SDC omni's, but that is for a different thread.

Regards, Christine
Old 4 days ago | Show parent
  #12
Lives for gear
 
🎧 5 years
Quote:
Originally Posted by connloyalist ➑️
... Nothing really fancy ...
Curiosity got the better of me:

Advanced Audio CM1084 -no spec found
Sennheiser MKH406T -6mA
Sennheiser MKH416T - 2mA
Audio Technica AT4081 -3mA
Sennheiser MKH816T - 2.3mA (x2)
Old 3 days ago
  #13
Lives for gear
 
🎧 10 years
Why don't you put a current meter in serious with the battery, plug all the mics you want to use and set the recorder to record, take an actual current reading. The reading should answer your question definitely. Ultimately, you should do a dry run with the battery you want to use.
Old 3 days ago | Show parent
  #14
Gear Addict
 
🎧 5 years
Quote:
Originally Posted by dseetoo ➑️
Why don't you put a current meter in serious with the battery, plug all the mics you want to use and set the recorder to record, take an actual current reading. The reading should answer your question definitely. Ultimately, you should do a dry run with the battery you want to use.
I have thought of that but I don't think I have a current meter, nor would I know how to hook that up. What I did try is to put a meter between the wall socket and the adapter for the Zoom F8. My thinking was that it would read a bit high due to the loss in the adapter. I didn't have any mics attached then, but the actual reading was 0. My assumption is that because of the 220 volts to 12 volts conversion the watts is too low to measure?

Regards, C.
Old 2 days ago | Show parent
  #15
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jimjazzdad's Avatar
 
🎧 10 years
Quote:
Originally Posted by dseetoo ➑️
Ultimately, you should do a dry run with the battery you want to use.
^^^
This Christine. Easy to do (just takes time) and you will know exactly what to expect with your set up.
Old 2 days ago | Show parent
  #16
Lives for gear
 
🎧 10 years
Quote:
Originally Posted by connloyalist ➑️
I have thought of that but I don't think I have a current meter, nor would I know how to hook that up. What I did try is to put a meter between the wall socket and the adapter for the Zoom F8. My thinking was that it would read a bit high due to the loss in the adapter. I didn't have any mics attached then, but the actual reading was 0. My assumption is that because of the 220 volts to 12 volts conversion the watts is too low to measure?

Regards, C.
Most of AC power current meter are not sensitive enough to accurately measure such a small power consumption. You need a digital multimeter to do a DC current measurement on the battery. To do that, you need to break the battery connection and insert the meter to bridge the break so the current can flow through the meter to show the reading.

An indirect way to figure out the power consumption of the recorder is to install a known capacity battery, such as a fully charged rechargeable AA battery and run it till the unit shuts down, with however many microphones you care to plug them in. Using the run time duration, battery voltage and current capacity, you can get a rough idea. Frankly, if a set of rechargeable lasts more than two hours, you are golden. Just make sure you fully charge the battery before you take them to the gig.
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