Instructions to wire up smartphone


I would like to measure the power consumption of a smartphone. I have opened up a Samsung Galaxy as in this Qoitech video: How to measure smartphone energy consumption (Samsung S7 example) - YouTube
And this summary:
How to measure smartphone energy consumption (Samsung S7 Example) - Qoitech

However, the bullet points 2. and 3. in the blog post are a too high level for me.

Could someone provide me with step-by-step instructions by any chance?

Does anyone have pointers to very detailed guidance?

Many thanks

Hi and welcome to the forum,

What we did, was simply to replace the + and - wire, to the battery, with cables to Otii Arc/Ace.

By doing this, we kept the last cable as is, connected to the protection circuit of the battery.
You most likely need to add capacitors (as shown in the picture) as close as possible to the phone connector. Choose MLCC (multilayer ceramic capacitor) that has low ESR value. You might need a couple of hundred uF. This depends on the current bursts that the phone consumes and how long cables you have to your Otii Arc/Ace.

What you also can do, but make sure you so this right, is to open up the LiPo battery, revealing the protection circuit and the two connectors to the LiPo cell. Then cut the connectors to the LiPo cell + and -.
This is the dangerous part, make sure that you do not short circuit the LiPo cell + and - when you cut it since you now are on the side that is not protected by the protection circuits. You have the risk of fire and explosions if you short circuit the connectors.

Then, as a final step, solder wires, where the LiPo cell * and - was connected to the protection circuit, and connect them to Otii Arc/Ace main channel.
Also here, you most likely need to add capacitors as above.

An unprotected LiPo cell looks something like this

I hope this helped!

Best regards,

Hi Bjorn

thank you very much for sharing your approach here.

I had gone for a simpler approach: only disconnected the PCB board (yellow circle) from the battery by cutting through the connectors to the batteries (red circle)

I then connected a battery (supplying 4V) to the PCB.

What I observe is that the unit draws about 2W of power. And the PCB is getting warm - but the phone remains off. :frowning:

Any explanation for why this might be the case?

Many thanks


Yes, so you went for my second approach above, removing the unprotected LiPo cell and using the cells battery circuit.
Have you connected the right polarity?

Best regards,