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Zsolt Pinter
Li-ion battery, DC & AC PCB Qualification Test Engineer at Bosch Power Tools
Li-ion battery, DC & AC PCB Qualification Test Engineer at Bosch Power Tools
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Project: Resurrecting the Nexus 4 part 2

I am a qualified professional. Do not try this at home if you don't know exactly what you are doing. You have been warned.
I still use the broken display Nexus 4 as a smart TV, and love it, I still can do much more things as a TV (details in the end of this post).
But the battery died twice a year due to constant charging and hot temperature. (I still believe that it outputs 1080p 60FPS through HDMI, even it has 720p display which generates lot more heat than a normal usage).
I decided I won't buy batteries anymore, so I show you how to run your phone without a battery:

1) Just remove the battery:
The phone did not start with USB charger without the battery. The RGB notification LED was showing red light while the charger was connected.

2) Hardware needed:
I bought a 12V 5A power supply from the local store (this overkill was the cheapest) and I bought this cheap DC-DC converter from Ebay:
http://www.ebay.com/itm/400691048584

3) Get the electronics out from the battery:
The battery has a protection circuit inside, I needed to take it out. This is a dangerous operation, you easily can short the battery which can cause fire and serious damage (check Note 7), take care like a surgeon.
First, I checked the voltage on the cell terminals, and I used a DC electronic load to drain it. Keep it mind, 0% not equals with 0V. When the phone shows 0%, the battery still has a huge amount of energy for over-discharge protection. For safety reasons, the battery needs to be over-discharged. In this condition, the battery can be opened from the top with removing the insulation tape first. The electronic module can be safely cut off with an insulated tool. Be very careful not to short anything.

4) Cell simulation:
I connected the power supply output to the input of the DC-DC converter and I set the output voltage to 4.25V CV mode, in this way the phone won't try to charge the electronics (the microUSB to HDMI Slimport adapter will try to charge!). Try to use short wires to avoid voltage drops.
This value is for my device only, and may differ from other models.
I measured around 0.7A while using the phone, but it changed often. The current limit is currently set to 1A, but if I will notice signal drops, or random power off, I will increase it to a higher value.
I connected the DC-DC converter output to the battery electronics main terminals. Again, the polarity is extremely important!

5) Cleaning up:
After I checked that the phone can boot successfully, and the battery is shown as 100% fully charged (which never will drain), I drilled 2 small holes for the wires. Next time I will make a nice little box to hide the PCBA.
For improvement, maybe I will attach a small heatshink in the future because the device quickly gets rather hot.

I think I am the only person who runs a broken display Nexus 4 without battery for the best smart TV experience :D

Part one is accessible here:
https://plus.google.com/+ZsoltPinters/posts/Q8G5GZXfnGF
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21/01/2017
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+Android Police​​​​​​ FYI:
Audio latency is still in issue with Android O:
I just tested my Nexus 6P (Android O) with the Superpowered Latency Test App: 47 ms (worse than my Nexus 5 with Android M).

Pixel results with Nougat:
https://plus.google.com/+ZsoltPinters/posts/KVvevjDe7w6

Nexus 5 results with Marshmallow:
https://plus.google.com/+ZsoltPinters/posts/XgsUNZCCafZ

http://superpowered.com/latency
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#AndroidO HelloOoOOO 
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Android O. I don't always lose internet connection, but when I do, there is a new major Android preview version release.
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And that's why I will never ever use popular password managers like LastPass. They are useful, they work great, they are cool, just won't pass a year without a LastPass vulnerability.
I already downloaded LastPass 2 times, I almost started using as daily password manager, but luckily I always stepped back and remembered these vulnerability news in time.

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Since the NSA leak we all know that the spyware is on your computer right now, it's on the hard disk firmware.
Because the chances are low that you can build your own hard drive, one possibility is to install Linux on the HDD itself.
(Hint: this rabbit hole is deeper than it looks).

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So how can I access screen search, text grabbing, screen translation and full screen screenshot that I used a lot from now? #assistant.
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