Smartphone without a battery (2022)

Related (and on the frontpage): https://news.ycombinator.com/item?id=46239177

I'm happy that my smartphone, Librem 5, can already run without a battery.

I came here to be dismissive ("power is power, what's the big deal?"), but this is a legitimately useful guide on how to fake a battery. Thanks for this.

I have a box full of old unique phones that while I technically can get replacement batteries, the replacements have generally been awful and bloated very quickly.

I will have to give a go at this guide to extend some life to these phones

> Basic phone charger <1A USB power supply was not enough to even finish booting, but a ~2A was enough to boot and launch octo4a

So it's drawing >1A over a single diode? Let's say 1.4A and 700mV voltage drop over the diode, then it's roughly 1W over the diode. Won't it get pretty hot?

I see the author implemented a true circuit board.

Huh? What do you mean? Their own product page states that it comes with a 4,500mAh User-Replaceable battery.

I assume GP means that it’ll work with no battery connected if plugged in.

It is criminal that supercomputers in our pockets have expiration dates.

Even cheapest phone these days is hundreds times more powerful than PS2, has better camera on par or better with most feature phones back in the days and cellular/wifi. They can be used for detection, automation or just plain fun/gaming.

But no, you can't install Linux to overcome bloated, insecure abandonware (old Androids, iOS). Built-in, hot pillow of a battery that is pain in the ass to remove and even then it can't work without it.

I understand. I got a Linux phone & its remarkably decent - its called Jolla

https://jolla.com/

Correct.

I need to know if this is running e-banking a.k.a. "we are secure, yet is that you that made this payment" apps?

People are nuts, that's all there is to it. They're worried about thinness, but meanwhile buy phones that are so tall and wide they cannot actually fit in a pocket. There's no benefit whatsoever to the thinness, except that someone else's phone is thicker. And no, water damage is not a concern. You can absolutely build phones with a battery compartment that can safely be fully submerged in water.

The diagram calls it a 1N4001 which is rated to sustain 1A (but 40% over is probably fine). A safe 1N5400 would still be pennies.

Author should've just used a $1 adjustable buck converter with USB-C in. There would be no issues with heat, or the need for a big capacitor even.

Tangentially related, I have recently been using my S10+ as a makeshift media server running Jellyfin in Termux. The main problem I had was that it is unsafe to keep a device perpetually charging and my first thought was to create a Routine to turn on the charger when the battery is above a certain threshold and off when it is below. This post gives me an alternative idea to try.

I have an old Samsung that runs Android 4.4 and runs directly from USB without a battery. It's a shame phones don't do this anymore.

We have a 64-bit Toshiba tablet mounted on the wall in our kitchen that works wonderfully as a control surface for HomeAssistant. The battery was easy to remove and it runs off of its own barrel plug connector.

We were thinking to reproduce this in our hallway, but all the spare touchscreen devices (tablets and phones that were our own and from family/friends) have these integrated batteries, and research seems to suggest that none of them will work without a battery anyways, so we are going to attempt to do something like this with an old iPhone or Android phone.

We have some PinePhones lying around that have removable batteries and run just fine without them, but alas they are so underpowered that they can't really run the bloated HomeAssistant web portal, and we don't want to write a custom frontend.

I have a 6.9 inch screen, which is the biggest if not extremely close, and it fits in my pocket just fine. It fits well because it's so thin.

In a broader context, it’s actually a bit of an oddity that computers had this brief moment of hackability. You can probably turn an old washing machine into a lathe, but it would be crazy for its manufacturer to even acknowledge this idea.

Can it reliably send and receive calls and texts yet though? https://old.reddit.com/r/Purism/comments/11ho5xo/the_good_th...

I love stuff like this. There must be millions of similar old Android devices that can still perform tasks like this, or even tiny web servers. Similar to what raspberry PIs are used for, but more powerful.

And it would still fit in your pocket even if it was few more millimetre thick. And, it is better to make the pockets bigger by a few millimetres rather than making the phones thicker.

Are real people worried about thinness? I don't think I have ever met anyone outside of a marketing department that has asked for a thinner phone vs one with more battery life.

The iPhone Air is the most recent proof that consumers don't actually care about thinness.

The 1N4001 diode is only rated at 1 A but the article says that the phone draws 2 A at times. Might be worth using a higher rated diode or two in parallel for greater reliability.

Last month I opened a drawer and found my Google Nexus One smartphone. It hadn't been turned on for 10 years and I figured the (easily removable) battery was done. I tried charging it anyway and to my surprise, it actually recovered and charged.

It worked fine when I turned it on, but it's essentially a paperweight now because the US mobile carriers have all upgraded to 5G, and this is a 3G phone.

The thing that struck me while doing this is just how tiny the Nexus One is. It's a full-featured (for the day) smartphone, but it's less than half the size of pretty much all the mainstream smart phones today. Battery life was decent, and the apps were pretty functional.

My current phone is about twice the length, 50% wider, and twice as heavy. Battery life has been getting progressively worse with background apps draining your battery so they can scoop up and market whatever information about you they can. Battery life has also been impacted by the BLE tracking features, which run all the time.

I wish I could upgrade the Nexus One with a 5G radio -- it would be a great phone today.

It will probably be fine, since the 1N4001 is also rated for temporary spikes to 30A.

"For 1N4001 Diode, the maximum current carrying capacity is 1A it withstand peaks up to 30A."

https://components101.com/diodes/1n4001-diode-pinout-datashe...

They're also cheap as chips, so worst case if it blows they can swap out for 2 of them like you suggest.

I think mine is stated as 6.7" and pretty thin. I wouldn't say it fits comfortably in all conditions. In some trousers/shorts it either sticks out a bit or digs in my side when I'm sat and bend (to tie a show, etc).

Same here with Samsung J6. Super thin and light, removable battery, SIM card, microSD, and of course headphone jack. Would be great for everyday use, currently relegated to playing a single white noise .mp3 for kids to sleep.

The 30 A rating is for a non-repetitive half cycle of 60 Hz, aka 8.3 ms. If the phone is drawing 2 A while booting that's much more than 8.3 ms. Obviously it does survive in the application described in the post but it seems like pointless penny pinching to not choose a suitably rated device especially when the article itself talks about inrush current overloading other parts when the 1000 uF capacitor was discussed.

Looks like someone else posted this one though :)

> it’s actually a bit of an oddity that computers had this brief moment of hackability. You can probably turn an old washing machine into a lathe

Yours is a wildly misleading analogy. The design of Washing Machines (WMs) contains no elements solely dedicated to preventing the off-label use of them, the analogy with phones would be a WM that comes surrounded by barbed wire, a moat and self-destruct explosives attached to the WM to brick it in case the owner tried to unscrew some screw or another. Then a technician with an unauthorized key for your home visits you whenever he wants and messes with the WM and its "defenses" at his pleasure.

There was no "brief moment of hackability" for WMs because they were always hackable to the max - as much as the basic usage design allowed. The WM manufacturers neither acknowledged nor prevented the conversion of WMs into lathes or any other artifact for that matter, that's up to the owner to decide. So yeah, make phones like WMs and stop crippling and messing with people's property.

Incidentally, the off-label use of drugs saves a lot of lives every year. Should we add poison to them to prevent that? Because that's what phone manufacturers are doing to the their phones under the merciless prodding of the OS suppliers.

> T-Mobile would have to white list the phone for it to work. This is a real pain, especially since I have been needing to field some really important calls lately.

I guess, there is nothing you can do if your provider bans your hardware.

> it seems like it drops to 2g for the call

This means, the poster is using an outdated modem firmware, which should be upgraded by contacting Purism (AFAIK Purism isn't allowed to freely distribute it).

Calls seem to work fine for me.