SparkFun Forums

[GDSever]

Is there anything unique I need to do to get the "External LED footprint" working for the LiPo Charger?

https://www.sparkfun.com/products/10161

I have tried a variety of LEDs and none of them seem to want to illuminate while charging, even though the small onboard one is lit up. I must be missing something minor or be having a serious case of stupid. Based on the schematic and board layout, it should work...

[Mee_n_Mac]

Assuming you don't have it in backwards, it could be that the onboard LED has a lower Vf that the one you're adding. That effectively "shorts out" your LED. Desolder the existing LED.

[GDSever]

No, don't have it in backwards - The onboard one is a tiny SMD one, and the external one I was trying to use is a standard 5mm one. I suppose I could fire up the hot air rework station and remove the SMD one. I wish SF had put in a solder pad or something to render the onboard one inactive instead...

[GDSever]

I did some more testing - basically I pulled out every LED I had in the drawer and tried them. Here's what I found.

I have several dead LEDs that need to go in the trash (ugh... not sure how that happened)
Red LEDs (that aren't dead) seem to be OK.
Yellow LEDs work, but they barely illuminate.
Green LEDs do not work at all.

So based on this - I am thinking your Vf theory is correct.

[blistick]

Hi @GDSever,

I'm having the same problem you had in attaching an external LED to this Sparkfun LiPoly charger. Did you ever confirm that deactivating the built-in LED will allow the external LED to light?

I'm wondering if cutting the trace to the built-in LED would be an option?

Thanks for any info.

Best,

Bart Listick