Enerwow Power Bank 40000mAh

Don't waste your time and money on this scam product! This 30W 40,000mAh power pack is at best a poorly functioning 22.5W 27,000mAh power pack in disguise and its total output capacity is 10% less than better quality units like the "Imuto 30W 27000mAh Power Bank"! I should have believed the negative reviews instead of wasting all of this effort only to end up adding yet another detailed negative review to the list! Of course it's possible I received a bad unit just like all the other folks who generated negative reviews about its performance. On the other hand, maybe we are the only ones that actually ran measured tests and discovered this product was really a scam. Details: The Enerwow power pack is labeled as 40,000mAh capacity which gives it a 148Wh power rating (the industry standard formula for lithium power packs is: Wh = Ah * 3.7V). But my unit really only stores 108Wh of input power (equivalent to 29,190mAh labeling, 27% less than 40,000mAh) and only produces 75.8Wh total output power (equivalent 20,486mAh labeling, almost 50% less than 40,000mAh). The average of the input and output power values is what is considered the fairest rating of a power pack and in this case it would be 91.9Wh which has an equivalent labeling of 24,837mAh. This means it is behaving like a power pack with a 25,000mAh capacity rating, not the 40,000mAh it claims to be! It only has a maximum steady output of 20W on the USB-C port when it is the only one used, not the steady 30W it claims to provide. To make things even worse it does most of its recharging at a 14W input and it takes over 6.5 hours to recharge this completely drained power pack! The measured output wattage and total power input/output capacity are at the very bottom range of a very poorly functioning 22.5V 27,000mAh power pack and its total output capacity is 10% less than better quality units like the ""Imuto 30W 27000mAh Power Bank" (see Imuto details bellow)! In fact, it performs closer to a properly working 20W 25,000mAh power pack! Note: This power pack would not be allowed as passenger airplane carry-on luggage (no power packs are allowed at all as checked luggage). The FAA regulations only allow carry-on lithium power packs with a capacity of 100Wh or less, the equivalent to a labeling of 27,027mAh or less. Even though this Enerwow power pack has 10% less output capacity than a quality 27,000mAh labeled power pack, it would not be allowed as carry-on because its labeling claims 40,000mAh capacity. Summary: This 30W 40,000mAh capacity power pack is at best a very poorly functioning 22.5W 27,000mAh power pack in disguise! I would not be surprised if the internal component was really an inexpensive factory-reject 22.5W 27,000mAh power unit with a throttled down input wattage that fools unsuspecting owners by taking as long to recharge as a typical 40,000mAh unit. Most owners would be so happy with the price they paid that they wouldn't even notice how poorly it functions when charging devices. When compared with the Enerwow "Product Description" claims, this product is a scam that relies on customers not noticing the difference! Test Equipment: I used a "Kowsi KWS-066C Digital " USB Power Multimeter to measure the total input/output Watt-Hour power capacity and real-time Wattage of this power pack. After an initial full charging of the power pack to 100% and verifying the input wattage was down to 0W, I tested a complete discharge and recharge cycle. To drain the power pack (output) I used a Lenovo ChromeBook laptop with "Adaptive Charging" disabled and did as many laptop 10%->90% charging cycles as needed. To recharge the power pack (input) I used a 65W USB-C PD (Power Delivery) charger. To connect these two to the power pack I used a 100W rated USB-C PD-2.0 cable with the USB power meter in-line (the USB meter is rated at a maximum 195W). Note it is important to use an appropriate wattage-rated USB-C cable for testing that supports the PD-2.0 specification or else the cable's internal microchip may throttle the wattage throughput to a lower value (Yes, any USB-C cable that supports 25W or higher must have an internal "E-Mark microchip" that specifies its wattage rating or, if the chip is missing, typically only 24W will be the maximum power pushed into the cable!). Power Pack Nerdy Details: (Skip this section unless you are extremely nerdy or bored!) Watts (Wattage = Amperage x Voltage) are a measure of "electrical power" and Watt-Hours are used to measure electrical power capacity. Watt-Hours are used to measure the power capacity of systems like solar panels, storage battery systems, laptops, and electric vehicles. Watt-Hours, not Amp-Hours, are the only correct "measure" of power capacity for modern power packs which provide variable output voltage and amperage. For example, 10,000mWh of output power capacity can be generated by either "1,000mAh x 10V" or "2,000mAh x 5V". If you used a USB power meter to only measure the mAh output of a power pack and didn't factor in the voltage it was producing, you would incorrectly conclude the power pack that measured 2,000mAh had 2x more power capacity when in fact they both have the same power capacity. If instead you used the USB power meter to measure mWh you would see they both produced the same 10,000mWh of output power. The reason typical batteries are only labeled with their Amp-Hour capacity rather than also including their Watt-Hour capacity as a measure of their "electrical power" is because batteries of the same type all have the same constant voltage (e.g. 1.5V, 3.7V, 9V, etc.) and the only component that varies the power is the Amp-Hour. Amp-Hour labeling provides detailed technical information about a battery's measurable amperage but can also be used to compare the relative power capacity of batteries of the same voltage. For example, the relative power capacity of all 1.5V batteries can be compared by simply comparing their labeled mAh capacity rating. However, if you want to compare the power capacity between different battery types, for example a 1.5V vs a 9V battery, you cannot just use their labeled Amp-Hour capacity for comparison. You need to multiply their Amp-Hour capacity by their respective voltage to get their true Watt-Hour capacity for a proper comparison. Likewise, modern power packs are not constant voltage/amperage power sources (though they may internally be made up of battery cells) and Watt-Hours is the only correct true measure of their power capacity. Nevertheless, the typical retail consumer thinks of power packs as if they were big "smart batteries" and they are accustomed to thinking about battery power capacity in Amp-Hours, not Watt-Hours. The power pack manufactures make it easy for consumers to use Amp-Hours in evaluating the total power capacity of their products by adopting an industry standard Amp-Hour rating system. All power pack manufactures label the power capacity of their products using this Amp-Hour rating system and typically only specify the true Watt-Hour capacity of their product in the fine print of their technical specifications. Since 3.7V is the industry accepted standard for the constant voltage of a lithium battery, they make believe their power pack behaves like a big 3.7V lithium battery. They then calculate what labeled Amp-Hour value would make a constant 3.7V battery have the same total Watt-Hours as their variable voltage/amperage power pack. The labeling formula is "Ah = Wh / 3.7V" and for example a 100Wh power pack would be labeled as 27,027mAh (27,027mAh = 100,000mWh / 3.7V). A benefit of using a 3.7V based Amp-Hour capacity formula is that the labeled power pack mAh capacity can now be directly compared to the labeled mAh capacity of standard rechargeable 3.7V lithium cellphone batteries. In theory this makes it very easy to evaluate how many times a fully charged power pack can recharge your cellphone. However there is a difference in the Watt-Hours required to charge a power pack (input) and the Watt-Hours a power pack can provide as output. There typically is a normal 30% loss of power output due to expected heat and electrical inefficiency in inexpensive low quality power packs. The fair rating would be to label the mAh capacity of a power pack as the average of these two numbers but many manufactures instead label their product much closer to the higher input capacity number so that their product advertising stands out. This means the effective power input capacity required to fully charge a completely drained power pack is typically 115% of its rated power capacity and its effective total power output capacity is often less than 85% (the worst case typically being 70%). This smaller effective output capacity needs to be factored in when evaluating how many times a power pack can recharge a cellphone. It is important to realize the labeled power pack mAh value will always be significantly greater than the total mAh that would ever be measured by a USB power meter because the minimum USB system voltage is typically 5V, not 3.7V, and the power pack will be varying the voltage to much higher levels while the variable amperage electric current is flowing. Unlike batteries, this labeled mAh value is not the real total "measurable" mAh of the power pack; it is only a number to be used in comparing the relative total power capacity of power packs and cellphones. But it can also be used to calculate the corresponding true rated Watt-Hour capacity of a power pack by using the formula "Wh = Ah x 3.7V". For example this Enerwow 40,000mAh labeled power pack does not state its Watt-Hour capacity anywhere at all (a clue it might be a shifty product), but nevertheless we know it should have a rated 148Wh of total power capacity (148,000mWh = 40,000mAh x 3.7V). This 148Wh rating can be verified by using a USB power meter to measure the total output Watt-Hours required to fully drain the power pack and how many input Watt-Hours are required to fully recharge the power pack. Test Result Details: The measured Enerwow total output power capacity is 75.8Wh (equivalent to a 20,486mAh labeling), which is only ~50% of the claimed 148Wh rating. If it really did have the 148Wh capacity rating, a 50% lower output of 75.8Wh is significantly lower than the expected normal 15% lower output of 125.8Wh. The worst problem was that, though the maximum single port UBC-C output wattage would start at 30W, it would quickly drop to a steady output of only 20W and so it takes a longer time to recharge a large power capacity device like a laptop. Recharging the drained Enerwow to 100% only took 108Wh of input power which is the equivalent of a 29,190mAh labeling. 108Wh is 27% less than the 148Wh capacity rating it claims to have and dramatically less than the 15% higher recharge input of 170.2Wh that would have been required for a 148Wh fair-averaged capacity rating. It took longer than expected to recharge because, though it began recharging at 20W, it very quickly only used a maximum of 14W input. It took 5.5 hours for the drained power pack to reach 80% full. It takes a total of more than 6.5 hours to fully recharge the power pack. The correlated significantly lower 75.8Wh output and 108Wh input power capacities means the Enerwow really does have the standard 30% power loss inefficiency (75.8Wh-output ≈ 108Wh-input x 70%). The average of its input and output capacity values would give it a fair capacity rating of 91.9Wh which has the equivalent labeling of 24,837mAh. This means this power pack is functioning more like a power pack rated at 25,000mAh capacity, not the 40,000mAh it claims to be! Test Conclusion: The maximum steady output wattage and total Watt-Hour input/output capacity of this 30W 40,000mAh power pack is similar to either a poorly functioning 22.5W 27,000mAH power pack or a properly functioning 20W 25,000mAh power pack! Imuto 30W 27000mAh: My old heavy and bulky power pack is a "Imuto 30W 27000mAh Power Bank" and I wanted a lighter and smaller unit that had at least 40% more capacity. The Enerwow claims 40,000mAh capacity (48% more), weighs almost 30% less, and is a physically smaller size. But the 40,000mAh Enerwow power pack only produces a steady 20W output and ends up having 10% less total output capacity than the 27000mAh Imuto! The 27,000mAh Imuto is explicitly labeled right on the unit as having 99.9Wh capacity. My unit has a measured output capacity of 85Wh (equivalent to 22,973mAh) and a recharge input capacity of 118Wh (equivalent to 31,892mAh labeling) which is a 28% inefficiency loss. Its labeled 27,000mAh capacity rating is very close to the average of these two values (27,433mAh) and its output is 85% of its labeled rating. It has a maximum consistent output of 30W on the USB-C port when it is the only one used. It recharges using 30W input and only reduces the input to 14W when above 90% full and then finally a trickle-recharge to protect the power pack battery life. Because the Imuto is labeled as only 99.9Wh power capacity, the FAA allows it on commercial airplanes.