Description
Sometimes I need a camera in some places where there is no easy power supply, so I have to run with a battery. I usually use a UPS, like the one we use for ower computers, but this machine converts from a 12v battery to 220v output, and then, the Yi Home Camera transformer convert from 220v to 5v.
So I thought using a power bank (those which we use to recharge our mobile in a emergency) to avoid even the transformer. I bought the bigger I found, Xiaomi Power Bank 2C 20.000mAh.
Theoretical calculations
The power supply of the Yi Camera is 5v 2.0A. In the Yi Home Camera 2 is noted 4.0W(MAX).
If the camera consumes 4 watts for 24h it involve 96Wh
The battery is rated at 20.000 mAh and 5v, that is 100Wh.
With these data, and assuming that the camera is always at max consumption, (4W) it should last: 100/96 = 25h, a bit more than a day. That assuming:
- The battery could be fully discharged. False, Li-polymer battery can be discharged 80% as much
- The camera consumes 4W all the time. False, I have tested the camera with a consumption-meter for a full week and it consumes 2.4W in average.
So now the calculations are: (80%100Wh)/(2.5w24h) = 80/60 = 32h
Let’s check.
In Practice
Now my test. I full charged the power bank, set it to low current output mode (according to power bank user guide this funcion is for small devices, fitness bands, watches, bluetooth headsets and other small gadgets), and place the camera in my cottage. I set it up recording continiously (not only when motion is detected) at 1080p @25fps (max quality) and disabled all other stuff like gesture recognition o baby crying recognition. The camera was with no WiFi connection (perhaps it was searching for WiFi all the time and that is a battery consuming operation). It started recording August 19, 2018 at 20:56h, and the last slice of recording was at August 21, 2018 at 06:37h.
So, my Yi Home Camera 2 connected to a Xiaomi Power Bank 2C as power supply continuosly recording last 33 hours and 41 minutes.
Wow!!! Only a 4,3% of deviation between theory and reality.
Next tests:
- With WiFi connection linked, not always searching.
- With motion detection only recording. I suposse it will increase autonomy because of not writing continiously to the sd card. On the other hand motion detector is a CPU consuming operation…
Anyway if you got here, perhaps you have to have a look to Blink cameras and this Blink cameras with AA batteries but be aware of region lock before purchasing one.
Great post. Any luck with the WiFi recording?
Hi Adam,
Thank you for your comment.
I haven’t test the battery with a WiFi link established and neither with » record only when motion detector» instead of «always recording»
Buenas tomás!
Did you tested how long it records with only motion detector enabled? Im interested in getting close to 48h with that setup.
What is the power comsuption with ir leds on?
For your calcs you forgot that a battery with 20.000mah is rated for 74Wh (rated at 3.7v), not for the output that can vary as 5v 9v or 12v and new models up to 20v.
Espero tu respuesta!
Hi Galleta!
I think I tested with only motion detection enabled, and I think the results were quite similar, but I don’t have the data. I will test again if you are interested.
Regarding the voltage, think that the camera doesn’t has a fixed voltage, it doesn’t fluctuate. The different voltages of the battery are designed for mobile phone charge (aka Qualcom Quick Charge). The camera does not use of that.
PD: Take a look at Blink cameras, they last a lot with motion detection. I suppose the don’t analize the picture to check motion, instead they use a traditional IR motion detection, and when motion is detected, camera is powerd on.
Ty tomas.
You miss understand me, you said «The battery is rated at 20.000 mAh and 5v, that is 100Wh.» Battery is rated at 20.000 mah always at 3.7v, output can vary from 5v to more voltage but the capacity is reduced with more voltage, so it is 74W not 100W (battery sticker says 74W too) . Also all xiaomi batteries has a little more capacity that they advertise, in fact that batterty has 23500 mAh (87W), feel free to test it yourself or check some youtube videos testing it.
About blink cameras, there are a lot of brands with pir sensor much cheaper, they last up to a year with an AA battery, depending on the activity, but the PIR sensor cannot record further than 5m, has problems if the subject stays more than x seconds on camera because it doesnt keep recording it and it doesn’t work behind a glass, so i dont like it, its useless for me.
If you could repeat the measure with the pir sensor will be great.
Great blog, sorry i miss your answer in time.
Great info Sr Galleta. Thanks
I have no camera with PIR sensor to test
I mean if you could test how many time last the xiomi yi home camera with IR leds on (on night all the time, like in a box) or at least what is the amps it draw with IR leds on and off.
I will test it