# Is AUX\_CHARGING the same as AUX5?

**URL:** <https://discuss.blues.com/t/is-aux-charging-the-same-as-aux5/2891>\
**Category:** Notecarrier F\
**Created:** [March 2, 2025, 5:55am UTC](https://discuss.blues.com/t/is-aux-charging-the-same-as-aux5/2891 "2025-03-02T05:55:00Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![jfaer](https://avatars.discourse-cdn.com/v4/letter/j/5f8ce5/32.png) [@jfaer](https://discuss.blues.com/u/jfaer)\
**Post date:** [March 2, 2025, 5:55am UTC](https://discuss.blues.com/t/is-aux-charging-the-same-as-aux5/2891/1 "2025-03-02T05:55:00Z")

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The [`card.carrier` API](https://dev.blues.io/api-reference/notecard-api/card-requests/7-x/#card-carrier) says

> Uses the `AUX5` pin on the Notecard edge connector to notify the Notecard that the pin is connected to a Notecarrier that supports charging, using open-drain.

There are a couple other threads about this pin/API:

- [Access to charging status pin of BQ2421 on Notecarrier AF](https://discuss.blues.com/t/access-to-charging-status-pin-of-bq2421-on-notecarrier-af/555)
- [LiPo Charging via USB Using Notecarrier F -- LED indicator?](https://discuss.blues.com/t/lipo-charging-via-usb-using-notecarrier-f-led-indicator/1946)

Both of those threads seem to mention AUX5 explicitly, but the current version of the Notecarrier F datasheet shows the CHG pin from the BQ24210 connecting to AUX\_CHARGING on the Notecard.

 ![image](https://us1.discourse-cdn.com/flex020/uploads/blues/original/2X/c/cd32c540ebb5846266282b04b1e495ae3a832fa2.png)

Is AUX\_CHARGING the same as AUX5?

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<div class="post-metadata">

**Author:** ![jfaer](https://avatars.discourse-cdn.com/v4/letter/j/5f8ce5/32.png) [@jfaer](https://discuss.blues.com/u/jfaer)\
**Post date:** [March 2, 2025, 6:03am UTC](https://discuss.blues.com/t/is-aux-charging-the-same-as-aux5/2891/2 "2025-03-02T06:03:58Z")

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Anecdotally, `card.carrier` doesn’t seem to ever return `"charging": true` with my Notecarrier F 😕

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**Author:** ![jfaer](https://avatars.discourse-cdn.com/v4/letter/j/5f8ce5/32.png) [@jfaer](https://discuss.blues.com/u/jfaer)\
**Post date:** [March 2, 2025, 4:19pm UTC](https://discuss.blues.com/t/is-aux-charging-the-same-as-aux5/2891/3 "2025-03-02T16:19:05Z")

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Nevermind 😅

You have to actually plug a power source into the Notecarrier F (and not the Swan) if you want it to start charging. It does appear that AUX\_CHARGING might be the same as AUX5.

TBD if it indicates when it’s done charging

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**Author:** ![RobLauer](https://sea2.discourse-cdn.com/flex020/user_avatar/discuss.blues.com/roblauer/32/1567_2.png) [@RobLauer](https://discuss.blues.com/u/RobLauer)\
**Post date:** [March 2, 2025, 4:26pm UTC](https://discuss.blues.com/t/is-aux-charging-the-same-as-aux5/2891/4 "2025-03-02T16:26:08Z")

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Hi @jfaer,

Good to hear (I was just about to try and replicate this myself 🙂). And yes you are correct that `AUX_CHARGING` == `AUX_5` and we’ll get that updated in the docs.

Thanks!  
Rob