ComLife 9" Fan Low-Speed Run-time Measurements

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1

On 13, 14, 18 Oct 18, Amazon.com Lightening Deals offered the 18650-battery/USB-powered ComLife 9" Fan for $16.99. I am now in possession of two of these fans, and decided to measure battery-powered run-time performance. This test evaluated the fan's Low-speed operational mode with 18650 battery power only. Pre-test analysis of batteries used in the test is provided in Table 2. The run-time measurements are outline below in Table 1.

Table 1 - ComLife 9" Fan Run-Time Test
with Continuous Operation in Low Speed
Time
(hrs+min)		 Voltage 1
Fan 1 + Battery Pair 1 Fan 2 + Battery Pair 2
0+00 4.16 4.16
1+00 4.07 4.07
2+00 4.04 4.04
3+00 3.98 4.00
4+00 3.89 3.93
5+00 3.82 3.87
6+00 3.76 3.82
7+00 3.69 3.76
8+00 3.61 3.71
9+00 3.52 3.65
10+00 3.45 3.60
11+00 3.31 3.55
11+26 3.25 (End) 3.52
12+00 3.48
13+00 3.41
14+00 3.30
14+07 3.30 (End)
1. Measured using an Innova 3300 Multimeter (accuracy to ± 0.8% of reading).


The fans were turned on and left on for the duration of the test. Voltage measurements were made each hour with the Innova 3300 Multimeter. The battery covers were left off the fans for easy access. The fans were place on silicon hot pads to dampen minor occational cage vibrations. No noise eminated from the motors. The fans could be picked up and moved while running with no adverse effect.

Table 2 - Analysis of Batteries Used in the Test
Name Type Measured Capacity (mAh)1
Battery 1 Battery 2
Battery Pair 1 LiitoKala Lii-30Q
AKA Fake Samsung 30Q		 2963 2908
Battery Pair 2 Panasonic-Sanyo
NCR18650GA
3500 mAh 10A		 3325 3361
1. Using a LiitoKala Lii-500.



Table 3 - Test Batteries Recharged to 4.2 V After the Test
and Calculations of Estimated Current Draw
Name Type Charge Amount (mAh)1 Estimated Current Draw
(mAh/h = mA)
Battery 1 Battery 2
Battery Pair 1 LiitoKala Lii-30Q
AKA Fake Samsung 30Q		 2487 2505 (2487 + 2505) mAh/11.4 h ≈ 440 mA
Battery Pair 2 Panasonic-Sanyo
NCR18650GA
3500 mAh 10A		 2938 2918 (2938 + 2918) mAh/14.1 h ≈ 420 mA
  1. Using a LiitoKala Lii-500.

Note that the fan's built-in battery charger was not evaluated during this test. The fans were not tested using the USB cord and USB power supply. The fan built-in charging system was not tested. The batteries that came with the fans were not used in the test, but the results of analysis performed on them is listed in Table 4 below.

Table 4 - Analysis of the Batteries That Came with the Fans
(But Not Used in the Test)
Name Type Capacity (mAh)1
Internal Resistance (mΩ)2
Battery 1 Battery 2
Battery Pair 1 +LILENG 3.7V 22MA KPY8- 1442
34.6		 1629
31.6
Battery Pair 2 18650 3.7V 8.14 Wh
SZNS H140503EL 511674		 2224
51.0		 2226
47.6
1. Measured using a LiitoKala Lii-500.
2. Using a SM8124A 1 kHz Internal Resistance Meter


RESULTS:

  1. Both fans ran quietly for the duration.
  2. Fan 1 ran for over 11 hours in Low on a pair of fully charged Lii-30Q batteries (Table 1).
  3. Fan 2 ran for over 14 hours in Low on a pair of fully charged Panasonic - Sanyo NCR18650GA 3500 mAh batteries (Table 1).
  4. Both fans stopped operating when the voltage dropped to about 3.23 - 3.30 V. (Table 1)
  5. The estimated current draw of Fan 1 was 440 mA. (Table 3)
  6. The estimated current draw of Fan 2 was 420 mA (Table 3)
  7. The fans seemed to slow down as the battery voltage dropped.

CONCLUSIONS:

  1. I like this fan. It ran beautifully during the test.
  2. It moves a satisfying amount of air in Low.
  3. It is versatile since it can be powered with either 18650 batteries or a USB power supply.
  4. Because of the high operational voltage range of the motor, the fan stops with about 15% of capacity remaining in the batteries. On the positive side, however, one can use unprotected batteries without fear of over-draining them.
  5. For the price, it is a good buy. But its longevity is yet to be determined.