ESP8266 Community Forum

My ESP has been reporting 23952 free heap; is this plenty or not enough? At what point should I start to get worried about that lack of free heap?

My reason for asking is that I'm trying to debug a crash that occurs after posting a web request and posting to MQTT. Interestingly the crash happens after the https request and MQTT publish execute successfully.



Here is my code: https://github.com/openenergymonitor/Em ... rc/src.ino

You should install the EspExceptionDecoder from https://github.com/me-no-dev/EspExceptionDecoder to get more meaningful stacktrace.

Yes, I have installed the debugger. It's bee useful in helping me track the cause of the crash. I actually managed to fix the crashing last night It was due to an incorrect string conversion method.

However, muy initial question still stands: how much free heap is not enough? As I keep expanding my application and free heap keeps reducing when should I get worried? Is there a recommended amount of free heap the ESP requires to run happily or can the free heap by taken down to almost zero by a large application?

glyn wrote:However, muy initial question still stands: how much free heap is not enough? As I keep expanding my application and free heap keeps reducing when should I get worried? Is there a recommended amount of free heap the ESP requires to run happily or can the free heap by taken down to almost zero by a large application?

My program is also reasonably large and when the web server is started the heap gets down to around 12.000. Below 9000 some of my larger pages (7 KB on disk, not internal memory) are not handled anymore and that for example happens when there's no WiFi STA available and I need to start my own AP. So I limited the number of pages the client can connect to (they are not necessary in AP mode anyway) and I am shaving the html to get it as small as possible without losing functionality. That worked so far.
It looks like you still have some room to grow (shrink the heap).