✏ Long term power for the Fairphone 2 (solar?)


I would like to start a discussion about external power supplies for our FP2 and other tricks to reduce the power consumption of our FP2.

I think there is 2 scenarios :

  • Few days of autonomy
  • Long term autonomy

Let start with the few day autonomy

Any big power tank should work. Is there some fair devices ?
[Edit by @Stefan:] For example WakaWaka Base 10 (10,000mAh battery)

Long term autonomy

For the the long term autonomy question, lets say 2 weeks and more, without the possibility to have access to cells or electricity. Use of phone to take pictures, listen to music a while, use GPS sometimes.
Solutions I are :

  • Solar pannels with/without battery
  • Hand crank generator
  • Adaptator for electricity from bicycle
  • Heat transformator
  • … others ?

Solar pannels

The important device specifications are (not imporance ordered):

  • Weight
  • Dimentions
  • Ability to install it
  • Power production in different scenarios
  • Environemental impact
  • Environement proof (water, dirt, shocks)

We’ll look at HeLi-on. Is it rainproof ? Is it durable and environementally ok ?

Hand crank generator

Like this one

Bicycle dynamo adaptator

Like this one

Heat transformers

(Have to find again the links)


Reduce power consumption : https://forum.fairphone.com/t/fp2-battery-saving-challenge/
Keep your battery in good health : https://forum.fairphone.com/t/fp2-battery-health-and-duration/ and https://forum.fairphone.com/t/a-little-guide-to-fairphones-battery-fp1-fp1u/


Concerning the solar panels:

Continuing the discussion from Potential for a solar panel under the transparent back cover?:

I think my recently started thread about a “FP2 battery saving challenge” would fit into your aim wherefore I linked to it:

I added your 2 links.

I find this topic very interesting! I like the idea of having my phone offgrid (and coud see myself using an alternative charger even with electricity available nearby…)

  • Does anybody have experiences with different solar charger? --> waka waka but also poweradd or instapark mercury (or any solar charger in general!)
  • reviews I have read about handcrank generator were far from enthusiastic… (in terms of durability but also effectiveness…). any durable product?

EDIT: very interesting (and recent) reviews of solarpanel/powerbanks https://www.youtube.com/watch?v=dIvhcY3_alY and solar panels https://www.youtube.com/watch?v=MgRloFSeWoE

When we recharge phone, the phone is kind of switched on. Is it possible to desactivate that ? Is is power consuming ?

You could remove the battery from the phone and charge it in a separate charger, but I’m not sure it would really be significant.
There’s an important loss of power in the charge itself, and in the conversion from AC to 5V DC. You can feel this loss of energy as the charger, phone and battery dissipate heat and become hot.
And on a larger scale, around 10% of electricity production is spent on transportation, ie lost in electrical lines.

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There’s also Kraftwerk
It’s a project by a German Start-up and was a huge success a while ago on kickstarter.
They’re developing some new kind of a portable fuel cell that runs on lighter gas.

Unfortunately, they fell a bit behind schedule, but I really hope they’re gonna make it :slight_smile:

A good alternative is WakaWaka.
It’s uses solar. On their website it says:

"We’re a social impact company on a mission to provide universal access to the abundant energy of the sun.

We help people plug into the sun. For power and for light. In an emergency or for play. In the middle of the city or way off the beaten path."

Disclaimer: I just love the idea nothing more.

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Why not a replacement propane fuel cell battery instead of the current Li-Ion battery?

Over 10 years ago there was a company preparing to offer that - a fuel cell battery for mobile phones. All you would do is remove the battery and refill it with lighter fuel. More or less an instantaneous recharge time and a long standby time.

The fairphone would need a few vent holes in the case for the fuel cell by- product of carbon dioxide and water.

Do you have any news about these fuel cells ?

It was a suggestion which in my opinion would be a better solution to the bigger battery problem.

Fuel cell involves a lot of more problem, starting with “I need to convert heat into electricity on a very compact volume” ,very good explanation here https://what-if.xkcd.com/128/

Hi folks,

it is possible and has been for some time ...




And I hear iPhone is looking at a hydrogen based replacement fuel

So has anyone heard that a fuel cell battery for mobile (and not a charger fuel cell) is very near to launch, now the specs for aircraft safety has been worked out. So the solar panel could make the hydrogen for the mobile battery fuel cell.