Several portable, rechargeable lithium-ion (Li-Ion) cell phone power banks were compared with standard 6-V gel lead-acid batteries as alternative power sources for operating mosquito surveillance equipment. In laboratory trials, ToughTested® (TT)16000 and 24000, Goal Zero Venture™ 70, and Griffin Survivor® units either met or exceeded that of sealed 6-V batteries when operating the Centers for Disease Control and Prevention (CDC) suction light traps (with incandescent light on) for an average of 24 h. No significant difference was found when continually operating traps powered by either the TT16000 or Goal Zero Venture 70 units compared with 6-V batteries (at approximately 57 h). The TT24000 unit was the only Li-Ion power bank that exceeded this threshold at an average of approximately 73 h. In field studies, there was no significant difference in species diversity or abundance of mosquitoes among the above 4 power sources when operating CDC light traps for 24 h compared with 6-V batteries. Our results indicate that portable Li-Ion cell phone power banks ≥10,050 mAh may be suitable replacements for 6-V gel lead-acid batteries when operating these light traps, especially if weight and size constraints influence the extent of mosquito surveillance during deployments.

The Centers for Disease Control and Prevention (CDC) miniature light trap is the standard surveillance tool used within the Department of Defense for mosquitoes, sand flies, and other flying insects. For nearly 60 years the method of powering these traps has remained unchanged despite the invention of lighter, more efficient types of batteries and charging devices (Sudia and Chamberlain 1962). Sealed 6-V lead-acid batteries for powering CDC traps are used in Role II–IV preventive medicine units and represent a large portion of weight in Entomology medical equipment sets (MES). For example, 10 CDC miniature light traps with 22 6-V batteries and 7 battery chargers are authorized in these sets. Each battery weighs 1.9 kg, for a total of 40.9 kg (90 lb). Moreover, the single battery chargers for these units add an additional 0.7 kg and are designed to be plugged into a 120-V US wall outlet that may not always be available in contingency operations. Therefore, batteries and chargers can take up an entire storage chest and represent a significant amount of weight in equipment sets. Commercial, off-the-shelf chargeable lithium-ion (Li-Ion) cell phone power banks could considerably reduce the amount of weight and space needed by the Entomology MES. Lighter, smaller power sources would also be preferable in military contingency operations, as this would make it easier for Service Members to carry and deploy the CDC light trap. Moreover, Li-Ion rechargeable cell phone power banks are commercially available in a wide variety of sizes and voltages that may serve as an alternate power source to sealed 6-V lead-acid batteries for operating mosquito vector surveillance traps. The purpose of this project was to determine if portable Li-Ion cell phone power banks could operate CDC miniature light traps as an alternative to standard 6-V gel lead-acid batteries for mosquito surveillance.

The following 7 commercially available Li-Ion cell phone power banks were evaluated: Griffin Survivor Power Bank® (Griffin Technology, Corona, CA), Goal Zero Venture™ 30 and 70 (Goal Zero, Bluffdale, UT), Powerfilm® Lightsaver Mini and Powerfilm® Lightsaver Max (Powerfilm Solar, Inc., Ames, IA), and ToughTested® (TT)16000 and 24000 (Mizco International, Avenel, NJ) (Fig. 1). These power sources were evaluated to determine operational longevity (on a single charge) when continuously operating a 6-V CDC miniature light trap (John W. Hock Company, Gainesville, FL [National Stock Number 3740-01-457-5527]) with incandescent light on in laboratory studies. Standard commercially available USB to alligator clip connectors were used to connect a trap to a power source. Data were compared with a standard sealed 6-V gel lead-acid battery (Power Sonic®, Model PS-6100 F1; Power Sonic Corp., Reno, NV). The Powerfilm Mini and Max units featured roll-up solar panels, while the TT16000 and 24000 units possessed a flat solar panel on one side of the unit. Powerfilm solar panels were rolled up and those of the TT units were completely covered by a thick piece of cardboard to prevent possible bias in accidentally charging the unit during evaluations. Relative costs of all power sources, based on manufacturer list prices in 2021, are provided in Table 1. All cell phone power banks used a generic USB charger cord available for Android cell phones, with the exception of TT24000 for which a heavy-duty USB recharging cord was provided by the manufacturer. Lithium-ion units were charged using an Anker 60-W 10-port USB wall charger (http://anker.com) with the exception of the Powerfilm Lightsaver Max, which required a 2.4-A port source (Model B2E027; Belkin International, Inc., Playa Vista, CA). The 6-V gel lead-acid batteries were charged with a Johnson Controls 6-V Dynasty charger (John W. Hock Company).

Fig. 1.

Various lithium-ion (Li-Ion) cell phone power banks used to evaluate the operational effectiveness of Centers for Disease Control and Prevention (CDC) miniature light traps for mosquito surveillance (scale in inches).

Fig. 1.

Various lithium-ion (Li-Ion) cell phone power banks used to evaluate the operational effectiveness of Centers for Disease Control and Prevention (CDC) miniature light traps for mosquito surveillance (scale in inches).

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Table 1.

Mean ± SE continuous operating and charging time of several lithium-ion (Li-Ion) cell phone power banks when operating a Centers for Disease Control and Prevention (CDC) miniature light trap with incandescent light on compared with a standard sealed 6-V gel lead-acid battery in laboratory evaluations. Retail cost and mean weight of power sources are also presented.

Mean ± SE continuous operating and charging time of several lithium-ion (Li-Ion) cell phone power banks when operating a Centers for Disease Control and Prevention (CDC) miniature light trap with incandescent light on compared with a standard sealed 6-V gel lead-acid battery in laboratory evaluations. Retail cost and mean weight of power sources are also presented.
Mean ± SE continuous operating and charging time of several lithium-ion (Li-Ion) cell phone power banks when operating a Centers for Disease Control and Prevention (CDC) miniature light trap with incandescent light on compared with a standard sealed 6-V gel lead-acid battery in laboratory evaluations. Retail cost and mean weight of power sources are also presented.

Continuous operating time, voltage during operation, as well as trap intake and output air velocity were recorded for all power sources. Voltage was measured at 4-h intervals until light out using a voltage meter (Milwaukee Tool, Brookfield, WI). Intake and output air velocity was measured by placing an anemometer (Kestrel 3000; Kestrel, Boothwyn, PA) approximately 2.5 cm above and 5 cm below the trap (slightly off center) and recorded at the time voltage was measured.

Field trials

Lithium-ion power bank units that met or exceeded the continuous operating time of the 6-V battery (57 h) were evaluated in operational field studies (Table 1). The CDC miniature light traps suspended 1.5 m from shepherd's hooks were placed at 50-m intervals along a linear transect in a heavily forested bottomland freshwater swamp on the grounds of the Naval Air Station, Jacksonville, FL (30.2001430, −81.6877297). Traps were not visible to one another. Incandescent lights were turned on during operation and 1.5 kg of dry ice pellets in a 2.0-liter Igloo container was suspended above each trap with a tube inserted from the bottom of the container into the air intake of the trap. Evaluations were conducted from June 15 through July 22, 2020. Trap contents were collected at 24-h intervals. The solar panels of both TT units were covered as indicated earlier for the laboratory trials. Intake and output air velocity of traps was measured at the time of deployment in the field using the same methods mentioned in laboratory trials at the time of set out and pick up of mosquito collections. All mosquitoes from traps were identified to the species level using the taxonomic key of Darsie and Morris (2003). Study design followed a 5 × 5 Latin square. Three rotational repetitions were performed with initial random assignment of each trap and location at the start of a rotation.

Data analysis

All mean mosquito and physical measurement data were initially subjected to a Wilk–Shapiro goodness-of-fit test (Shapiro and Wilk 1965) where they were determined to be not normally distributed. A 2-way Kruskal–Wallis test was used to determine differences between power sources (Kruskal and Wallis 1952). Mean continuous trap operation time, intake and output air velocity of traps, number of mosquitoes, pooled species, as well as the top 4 most abundant species collected were subjected to the Tukey HSD multiple comparison test to determine differences between power sources (Tukey 1953). Also, a Shannon–Weaver diversity index (Magurran 2004) was calculated as a measurement of species diversity related to abundance and species richness between power sources. All analyses were performed using R software (R Core Team 2013). Differences within data sets between power sources were considered significant at P ≤ 0.05.

Laboratory trials

Continuous operational run times varied between power sources but generally increased with battery capacity (Table 1). The Powerfilm Mini operated <5 h while Goal Zero Venture 30 averaged just below 24 h of continuous operation. On the average, TT16000 and 24000, Goal Zero Venture 70, Griffin Survivor Power Bank, and Powerfilm Max units exceeded 24 h of operating time necessary to operate CDC suction light traps (with incandescent light on). However, mean continuous operation time of Goal Zero Venture 70 and TT16000 units were not significantly different from that recorded for the 6-V gel lead-acid battery. The TT24000 unit significantly provided the greatest mean continuous run time of CDC suction light traps until light out at 73 h compared with the sealed 6-V gel lead-acid battery (57 h). Voltage levels were constant for all Li-Ion cell phone power banks during operation and abruptly ended at the time of battery depletion associated with light out. Voltage of the 6-V batteries slowly dissipated over time (Fig. 2) and the trap fan continued to operate slowly when the light was out. Interestingly, intake fan velocity significantly varied between most cell phone sources in laboratory tests (χ2 = 109.91, df = 54, P < 0.001). Intake fan velocity in pair-wise comparisons between Goal Zero Venture 70, Griffin, and TT16000, as well as between TT16000 and TT24000 units were not significantly different (P > 0.05). However, outtake velocity was significantly different between all power sources (χ2 = 107.19, n = 54, P < 0.001) and the 6-V battery but not between power banks. Mean recharge time of power sources is presented in Table 1; all Li-Ion power banks required less time than 6-V batteries.

Fig. 2.

Relative mean continuous operation time of 4 lithium-ion (Li-Ion) cell phone power banks compared with a sealed 6-V gel lead-acid battery (as standard) when continuously operating a Centers for Disease Control and Prevention (CDC) miniature light trap, with incandescent light on, in laboratory tests. Note: the 6-V gel battery will run approximately 57 h until light out.

Fig. 2.

Relative mean continuous operation time of 4 lithium-ion (Li-Ion) cell phone power banks compared with a sealed 6-V gel lead-acid battery (as standard) when continuously operating a Centers for Disease Control and Prevention (CDC) miniature light trap, with incandescent light on, in laboratory tests. Note: the 6-V gel battery will run approximately 57 h until light out.

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Field trials

Based on the earlier laboratory trials, Griffin Survivor Power Bank, Goal Zero Venture 70, Powerfilm Max, as well as TT16000 and 24000 units were evaluated against the 6-V gel battery in field trials because they met the commonly accepted timeframe (24 h) for mosquito surveillance. Unfortunately, the Powerfilm Max proved to be unreliable as it often turned off before the 24-h collection pickup period, for unexplained reasons. This occurred during early testing, and the power source was removed from further evaluation. No significant differences (n = 4, F = 0.57, P = 0.69; Fig. 3) in species diversity or mosquito abundance in traps (Table 2) were observed between the 4 remaining Li-Ion sources or 6-V batteries.

Fig. 3.

Shannon–Weaver diversity indices comparing total mosquito species obtained from Centers for Disease Control and Prevention (CDC) suction light traps powered by 4 lithium-ion (Li-Ion) cell phone power bank sources and a sealed 6-V gel lead-acid battery in field studies on Naval Air Station, Jacksonville, FL, 2020.

Fig. 3.

Shannon–Weaver diversity indices comparing total mosquito species obtained from Centers for Disease Control and Prevention (CDC) suction light traps powered by 4 lithium-ion (Li-Ion) cell phone power bank sources and a sealed 6-V gel lead-acid battery in field studies on Naval Air Station, Jacksonville, FL, 2020.

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Table 2.

Four of the most commonly collected mosquito species (and overall) mean ± SE in Centers for Disease Control and Prevention miniature light traps (with incandescent lamp on) and associated fan velocity parameters powered by various lithium-ion cell phone power banks compared with sealed 6-V gel lead-acid batteries on Naval Air Station, Jacksonville, FL, 2020.1

Four of the most commonly collected mosquito species (and overall) mean ± SE in Centers for Disease Control and Prevention miniature light traps (with incandescent lamp on) and associated fan velocity parameters powered by various lithium-ion cell phone power banks compared with sealed 6-V gel lead-acid batteries on Naval Air Station, Jacksonville, FL, 2020.1
Four of the most commonly collected mosquito species (and overall) mean ± SE in Centers for Disease Control and Prevention miniature light traps (with incandescent lamp on) and associated fan velocity parameters powered by various lithium-ion cell phone power banks compared with sealed 6-V gel lead-acid batteries on Naval Air Station, Jacksonville, FL, 2020.1

Our results indicate that the following portable Li-Ion cell phone power banks—Griffin Survivor Power Bank, Goal Zero Venture 70, as well as TT16000 and 24000 units—provided suitable replacements for sealed 6-V gel lead-acid batteries when operating a CDC miniature light trap with light on. This is especially important for military vector surveillance when weight and size limitations influence the capacity and extent of mosquito trapping during deployments. Indeed, the Li-Ion power sources we evaluated weighed 4 to 11 times less than a 6-V battery (Table 1). Depending on the need for ≥24-h continuous trap operation, TT16000 and Goal Zero Venture 70 were just as effective (statistically) as a 6-V sealed gel lead-acid battery when operated for approximately 57 h. Moreover, the most effective cell phone power bank was the TT24000 that operated continuously for approximately 73 h.

Interestingly, during field trials, we found no difference in trap fan intake or output velocity within and between power sources despite the differences earlier reported from laboratory trials. Ambient field conditions (i.e., wind currents) probably influenced this difference. We also examined whether TT16000 and 24000 solar units could recharge via ambient solar radiation while operating a CDC trap in the field. Placement of each unit in direct sunlight (approximately 14 h during August 2019) for 24 h resulted in neither unit replacing enough voltage, through solar radiation, to compensate for output voltage.

We should note that the long-term operational longevity of Li-Ion cell phone power banks for operating CDC light traps is currently unknown. As a baseline, our pattern of use for 6-V batteries has generally averaged about 3 years of field use. Although there are manufacturer differences regarding the electronics of each Li-Ion cell phone power banks, we found that power banks ≥10,050 mAh would provide at least 24 h of continuous operation of a CDC miniature light trap with incandescent light on during dawn/dusk mosquito surveillance activities.

The authors thank the professional staff of the Navy Entomology Center of Excellence for their logistical assistance with field collections. This study was funded in part by the Defense Health Program grant DP_67.2_17_I_17_J9_1704. The views expressed in this article are those of the authors and do not reflect the official policy or position of the Navy and Marine Corps Public Health Center, Navy Bureau of Medicine and Surgery, Department of Defense, or the US Government. The authors include a service member as well as employees of the US Government. This work was prepared as part of their official duties. Title 17, U.S.C., §105 provides that copyright protection under this title is not available for any work of the US Government. Title 17, U.S.C., §101 defines a US Government work as a work prepared by a military Service member or employee of the US Government as part of that person's official duties.

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