Power bank- evaluation of Nitecore NB10000

A power bank, Nitecore NB 10000 at 150g provided 27h of cooking time with a blower stove which to my delight was about 57% of the advertised capacity of the power bank.

Introduction to the power bank evaluation

My past power banks. The traditional power banks that I use with my range of backpacking blower stoves have been those small tubular ones that use a single replaceable 18650 lithium-ion battery (shown photos below).

These have been very satisfactory considering their price. They provide for 2-3 hours of powerful cooking for a group of backpackers. However, they have no charge indicator and have irregularities in the percentage of the potential charge that they will receive during recharging. Typically, they achieve 40% of their advertised charging potential. But be assured that I still am delighted with the 2-3h of cooking they provide. This means that I usually carry three of these small power banks to cover such shortcomings.

Solar charging. I now have a backpacking solar panel that can directly run the blower stoves and charge batteries. Similarly, by my assessment, it only reaches 37% of its advertised charging power but it can easily run a blower stove directly or charge a battery to run a blower stove when the sun goes down. “So I am still delighted by this performance.”

It would be nice to be able to solar charge the battery while using it to run the stove (pass-through charging). However, this pass-through charging is not possible with these cheap and simple power banks.

Nitecore power bank

It occurred to me that a more powerful power bank such as the Nitecore NB 10000 at 150g, with pass-through charging, would make an almost infinite power source for this type of backpacking stove. With a similar weight to three lesser power banks, it might make an ideal, and worry-free power source for unlimited group cooking (and heating) on extended walks or ski trips. It also can be used to run LED lighting and charge other USB devices in remote areas.

The Nitecore power bank evaluation

Low expectations but great gratitude. I have grown to not be too optimistic about the performance of cheap electronic devices such as batteries or power banks or solar chargers. I don’t expect any to match the performance of the advertised values. Even though some may reach only reach 20-40% of the advertised value, “Let there be no grumbling,….. I have been delighted with the value proposition that each wonderful technology provides for our wilderness experiences.”

Inline energy meter. To my tinkerer’s tool kit, I have recently added a tiny inline power meter that measures run time (hh:mm), electrical potential (volts), current (amps) and cumulative current over time (mAh). The instantaneous current reading is quite variable with a steady fan load (0.17-0.23 amps). “Who knows why?”

Consequently, it was difficult to know just what current value to use in the calculation of power and energy usage. Luckily, the integrated recording of mAh by the inline meter appears to make an excellent surrogate for the direct amperage in the power and energy calculations.

The accumulated or integrated mAh value when recorded over long run times should provide a very accurate basis for the estimates of average current (mAh/total hours), power ( average current* average voltage [mwatts]) and energy used (mAh*average voltage[mwatt hours) from the power bank.

The tester/meter device conveniently has a reset button so that the accumulating mAh and run time can be zeroed and then automatically recorded for up to 100 hours without any supervision.

It gets even better. The recording stops and the readings are saved, when the circuit is broken or the power supply runs out. Then the recordings can be observed by repowering the meter with 5 volts (without a load). “Even if my calculations are screwed up, the run time duration will suffice. Aren’t we so lucky to have such cheap and wonderful technology at our fingertips?”

Results & Discussion

The fully charged power bank ran the fan for 27.15 hours and passed 5,560 mAh of current at an average of 5.085 volts (fluctuating between 5.08-5.09 Volts). According to the above calculations, this translates to an average fan current of 204.8mA or ~0.2A, a power output of 1041.3 mwatts or ~1watt and energy usage of 28272.6 mwh or ~28.7 watt hours.

Although the 28.7 watt-hours of energy delivered during the power bank test was 57% of that indicated in the advertising (10000 mAh*5 volts =50,000 mwh or ~50 watt-hours), I was very pleased with the test on multiple levels.

The 27 hours of cooking from the 150g power bank would be great for week-long backpacking trips. Unusually, the test that I had dreamed up actually worked according to theory on the first try. Having an inbuilt charge indicator on the power bank is also a comforting feature on the Nitecore. “Much better than the sudden unannounced stop of my previous simple power banks.”

In the early hours of ‘in-house’ testing, there was a tiny but persistent little hum from the laptop fan rig. I was asked, by a somewhat disinterested family member, how long this would go on!!!? I confidently said to that family member; “I reckon that it will go for about 30 hours!” Call it pride or vanity, but it is nice to have an informed guestimate confirmed by objective measurement. It is also a great check against accepting an erroneous bullshit result from complex theoretical calculations.

My delight with 27 hours of fan operation also stems from its potential to be used for my other backpacking endeavours (dreams) of making abundant hot water for alpine hot water bottles and hot bush showers etc.

As an unromantic application, the 27 hours of run time will be helpful with mundane overnight use of the blower to burn out damp stumps on my farm. It has been set to work and has burnt out its first stump on a single charge. It did this task overnight under a sheet of roofing iron that kept the rain off. The stump is now just a hole in the ground so here is a photo of another stump that is partway through its self-destruction with the aid of a USB fire blower.

Lastly, the Nitecore power bank should efficiently provide USB power for up to a week of remote backpacking camping. When coupled with a light, cheap and effective backpacking solar charger it should make an excellent combination for longer trips, particularly if solar charging is optimized.

Tim