Lipo battery - PCB Wire trace length

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IoTAll
 
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Lipo battery - PCB Wire trace length

Post by IoTAll »

Hi!

I am working on a project using a M0 Feather board with multiple breakout boards, powered a Lipo battery.

I was originally using the feather lipo battery port to power the whole project and everything was always working fine.
Then I needed to have a ON/OFF switch for this battery.

To do this, I made a custom made PCB where the feather and breakouts are plugged in, and the battery and ON/OFF switch are connected on 2 specific JST connectors (thanks to large vias) further away from the feather (around 10-12cm) on this PCB.
I started to notice that some parts of the project were now behaving unexpectidly sometimes without understanding why.

After this I added a separate Lipo battery charger from Adafruit, as the charge from the feather was too slow. This was added again thanks to another JST connector on the PCB at aroudn this 12cm distance.

The strange behaviours were now happening all the time.

I am starting to thing that between the project (feather board + breakouts, etc), and the Lipo battery, I had 3 JST connectors and around 12cm of copper traces which is maybe causing the issue.

If I connect the Lipo batck to the feather battery port, all works good again.

Anyone could confirm that those "long" traces and the JST connectors could cause issues?
Or should I look further for another reason?

Thanks a lot!!

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adafruit_support_bill
 
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Re: Lipo battery - PCB Wire trace length

Post by adafruit_support_bill »

Long leads or traces by themselves should not be an issue if they are sized sufficiently to conduct the necessary current without significant voltage drop. Contact resistance can also contribute to voltage drop. Measure the voltage between the battery terminals and the corresponding pins on the Feather to see if there is any issue there.

Another possibility is interference. Longer traces make better antennae for picking up noise. Try moving your circuit away from any potential EMI sources. If there are EMI sources in your circuit itself you may need to re-locate components and/or re-route wires to minimize the noise coupling.

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IoTAll
 
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Re: Lipo battery - PCB Wire trace length

Post by IoTAll »

ok thanks!
I checked the voltage drop and there is none.

Layeb the EMI, I will test more.

Thanks a lot again!!

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