# BLE Characteristic UUID issue for BatteryLevel

**URL:** <https://community.thunkable.com/t/ble-characteristic-uuid-issue-for-batterylevel/3157751>\
**Category:** BLE / BlueTooth\
**Tags:** solved\
**Created:** [August 25, 2024, 9:26am UTC](https://community.thunkable.com/t/ble-characteristic-uuid-issue-for-batterylevel/3157751 "2024-08-25T09:26:13Z")\
**Posts on this page:** 1\
**Showing post:** 3

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**Author:** ![matt\_conroy](https://sea1.discourse-cdn.com/flex015/user_avatar/community.thunkable.com/matt_conroy/32/150843_2.png) [@matt\_conroy](https://community.thunkable.com/u/matt_conroy)\
**Post date:** [August 26, 2024, 1:12pm UTC](https://community.thunkable.com/t/ble-characteristic-uuid-issue-for-batterylevel/3157751/3 "2024-08-26T13:12:25Z")

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@didier.coymanohatdl If the documentation only gives four characters for the value, they are assuming you’ll use the default characterstic UUID.

It is discussed more in this previous topic.

> [@Trying to connect Bluetooth BP cuff, but struggling with the "characteristic UUID" stuff](https://community.thunkable.com/t/trying-to-connect-bluetooth-bp-cuff-but-struggling-with-the-characteristic-uuid-stuff/1849525/4):
>
> This is the default or base UUID for all characteristic IDs if not set by the factory. The default is 00000000-0000-1000-8000-00805F9B34FB If the manufacturer is giving you only 4 digit then it is assumed that you need to use the default UUID. It starts with 8 hexadecimal digits and you need to add your 4 digit hexadecimal number as the second part of it. So instead of all zeros it would be 0000 plus your code FFF4

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_[View the full topic](https://community.thunkable.com/t/ble-characteristic-uuid-issue-for-batterylevel/3157751)._