Power Supply on the Go 2
Over the last few months I have revised my power supply concept several times and am now on a path that works excellently for me. In this article I will not only describe the current concept but also the path to it.
When using my power banks the following things bothered me:
Miller ML-102 with one to four 18650 batteries
- As soon as you have to charge several batteries overnight in a hotel you are not spared getting up during the night to swap batteries
- 18650 batteries have a relatively low capacity of 3400 mAh; with my old smartphone this was not a big deal but the G4 has a standard battery of 3000 mAh. Due to the power losses when converting from the 3.7V of the battery to the 5V USB port to the 3.7V and the large capacity of the battery one battery was slightly less than one full charge.
Anker 20100 mAh power bank
- Charging the power bank simply takes what feels like an eternity due to the huge capacity.
- The large batteries weigh relatively much
Since my LG G4 smartphone has a replaceable battery I considered replacing it with a larger one. After a short search I found a replacement battery with 9800 mAh. With this battery I don’t need any charging option at all on weekend trips with intensive use. However this comes with the disadvantage that charging the phone now takes a good six hours.
So that the whole thing could continue to prove practical the charging time also had to be shortened.
Thus a long test series of the charging currents of various USB power adapters was in order. Let me say upfront that I only found one power adapter that actually delivered the specified output. However not only the power adapters have an influence on the actual output but also the USB cables. Up to 50% less measured output was possible depending on the cable. I achieved the highest output with USB cables from the power bank provider Anker and only used those for testing the chargers.
| Charger | Specified output (at 5V) | Measured output (at 5V) | Weight | Weight/Output |
| LG G4 standard charger | 1,8A | 1,8A | 81g | 45 |
| OnePlus One standard charger | 2,4A | 1,6A | 41g | 25,63 |
| China Dual Port | 2,4A | 0,6A | 46g | 76,66 |
| EasyAcc 24W Dual Port | 2,4A | 2A | 89g | 44,5 |
The weight divided by output column shows how many grams you would have to invest to get 1A of output and can thus roughly compare the devices. Only the EasyAcc charger delivers the same output on both ports. When sharing the charger with two people the value would thus have to be divided by two again - ergo 22.25 g per 1A per port.
Since my LG G4 also supports QualmColm QuickCharge version 2.0 I tested another power adapter for this.
| Charger | Specified output (at 5V) | Measured output (at 5V) | Weight | Weight/Output |
| BEZ Quick Charge 3.0 travel charger | 3,1A* | 2,9A* | 47g | 16,21 |
* The charger jumps from the 5V QuickCharge profile 5V*2.9A (14.5W) to the 9V profile since it is supported by the phone; from this point on it continues charging with 9V*1.9A (17.1 W).
This charger fully charges the 9600 mAh battery in a good 3 hours. Thus not only the search for the USB cable but also the search for the charger was successfully completed.
To charge my flashlight on the go without a power bank I also bought a USB OTG adapter. With this adapter USB devices can be charged from the phone. Thus from now on my smartphone also acts as a power bank for the flashlight. I can also take the previous battery charged with me on longer trips as a power bank substitute.
Electronics previously (frequently used setup with 9800 mAh capacity)
| LG G4 without battery | 114g |
| Battery (3000 mAh) | 37g |
| Battery charger standard | 81g |
| USB cable long | 47g |
| Miller ML102 charger | 36g |
| 18650 battery (3200 mAh) | 50g |
| 18650 battery (3200 mAh) | 50g |
| Total | 415g |
Electronics new with 9800 mAh capacity
| LG G4 without battery | 114g |
| New battery/phone cover | 156g |
| Battery charger | 47g |
| USB cable long | 47g |
| USB OTG adapter | <1g |
| Total | 365g |
Thus I have the same capacity with fewer parts and less weight and save myself many individual charging cycles. A lot of weight can still be saved with the USB cable; nevertheless I have learned to appreciate the length of 1.8 m since further use of the smartphone while charging is not significantly restricted.
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