Larger capacity FP2 battery

Right. I run a fairly battery-optimized environment already (FP Open OS, no apps with any trackers whatsoever, wifi and mobile network access restricted with AFWall+, all that helps a lot, and my battery lasts me fairly long, but lasting longer is almost always better. That’s why I’m wondering. Is there no way to make a battery with larger capacity that fits in the same size? I’m not an expert, but I’d suspect that progress in battery technology might open new possibilities there… Anyhow. I might just replace the rather dated battery with a new one, and probably also invest in a powerbank for situations when I can’t charge for longer periods.

Trying to take battery capacity to the max while keeping the dimensions of the battery low was the reason those Samsung phones kept going up in flames.
I would rather Fairphone does not re-enact that experiment. :wink:

Take a look here for example:

Batteries like this, leave no room for design flaws or manufacturing errors, no matter how tiny.


what is about a middleway between max capacity and the original capacity?

I am no tech-expert.
This iFixIt teardown compares (step 4) the battery of the “Galaxy Note 7” to the later “Fan Edition”.

I guess the value that really matters is the 13.48 Wh of the Note 7, that was reduced to 12.32.
For the FP2 this value is 9.2

That obviously leaves room for improvement, but as the iPhone 6 has a value of 6.91, it’s not as bad as it seems.

Here’s another article from CNET explaining the measures Samsung has take to keep such a desaster from happening again. Clearly something a company the size of Fairphone can not do and survive economically.


Development of better batteries or better capacity is an interesting topic, and there’s development in that direction, though I don’t currently have any interesting related articles at hand.

Also, smartphones have become larger since the release of FP2, with a better screen to size ratio (“smaller bezels”). In general, they have larger battery size.

Every time when I had a larger battery (ThinkPad T61, Nokia N810) it did help a lot I admit, but also because the old battery was simply flakey, and they both had a severe disadvantage apart from being non-official battery: the physical size changed. Not only that, it also modifies the weight of the device (just like replacing a DVD drive in a laptop changes the weight). A powerbank can only help so much with a battery on its way out, and quickcharge isn’t good for your batteries.

1 Like

Unfortunately this is an article in German and behind a paywall, but it nicely describes the physics behind lithium batteries and why you can’t improve capacity as much as one would wish.

1 Like

I use spare batteries (3 x), it is easy to change the batt. It is more handy than a powerbank and is uses less space. I have a sleave that contains the phone and a spare batt. (Freitag phone wallet, made of recycled products.



1 Like

Spare batteries are not recommended as they mess with the battery percentage display. The phone stores statistics about the battery and uses those to calculate the battery percentage. If you use a different battery than the one the phone is used to or constantly change them then it might display 20% and two seconds later the phone turns off because the battery is at 0%.

1 Like

I use spare batteries for 2,5 years now, with no problems other than that the batterie was worn, became a bit thikker.
I charge the battery with a separate charger.

I’d rather there’d be a LiFePO_4 battery with less (about half) capacity but longer lifetime - and less environmental footprint. With Android 8 even half the original capacity can make the phone’s energy last for one day.

Or maybe a fuel cell (with methanol)? That would be truly awesome.

1 Like

depends on usage
habits, of course.
Under what I would call semi-heavy usage (small games like wordfeud, Insta, WhatsApp, Twidere) checking/using/posting about every 5 mins, my battery lasts about 6-8 hours.

And it depends on the age of the battery. Lithium polymer types age much faster than lithium iron phosphate, which makes their nominal charge a mere number.

But yes, usage and habits add to the equation.


is the 2420 mAh Battery which lasts me about 1, maybe 2 days (depending on usage)

Woah. My barely lasts 6 hours if I’m lucky. I’ve never had it go a day without needing a charge! (and that’s two phones after my first was replaced because it kept crashing!) :open_mouth:

@delanthear, I’m also inclined to think it’s caused by one of your apps, as my phone with a 2,5 year old 2420 mAh battery usually lasts just until the end of the day with wifi on & the default Android 6 OS. I typically use WhatsApp & e-mail occasionally during the day. If I use GPS navigation or SnapChat (for some reason, taking & sending a picture there takes a lot of battery power) it will drain faster.


I absolutely agree!!!

Hi Folks,

I’ve been owning a FP2 for nearly a year now. One of the first things I remarked was the lack of battery power. So a friend and me decides to find a way to put more juice into it.
The design is intended to:

  • meet safety regulations by taking the hardware of an existing battery case for another phone
  • Add heat sink capacity by including a 1€ coin above the CPU
  • maintain one unique external USB port for charging (both battery and phone) and data access
  • cost less than 50€ in total

We found a way with a KiwiBird battery case originally designed for Samsung Galaxy S7 (similar dimensions as FP2).
I just posted hte design on Thingiverse:

Some photos here:

Feel free to share your ideas and comments! If there is interest, I might open a new thread to post more details about how we designed this…


Nicely done, is it possible you could show how it looks on the inside?

1 Like

Good job @ThinkTwice, you should definitely create a new topic about your project and post the link here!

1 Like

This topic was automatically closed 182 days after the last reply. New replies are no longer allowed.