Charging LED with TP4056 board

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tjohnson

Joined Dec 23, 2014
611
I'm using this battery charger circuit for a project in an enclosure:

The board has a red LED that lights up when the battery is charging, and a blue LED that lights up when it is fully charged. Because the board is in an enclosure, these LEDs are not visible and I want to wire my own that will light up when the battery is charging and turn off when it is fully charged/not charging.

If I wire it to the IN+/- terminals, the LED stays on when the battery is fully charged, not just during charging. If I wire it to the BAT+/- terminals, the LED lights up whenever current is drawn from the battery, but I only want it on when current is going into the battery. I've thought of trying to solder the LED in parallel with the tiny red one on board, but I feel like there should be a better way to do this that I'm not thinking of. Is there one?

EDIT: I just realized that I could have the LED do the opposite behavior as well, to stay off during charging and turn on when the battery is fully charged (I think this might be more common). The wiring issue would still exist, but I wonder which behavior would be preferable?
 
Last edited:

Dodgydave

Joined Jun 22, 2012
11,285
Remove the leds on the pcb and put ordinary leds on your box, wire them to the original led pads, just make sure you get the polarity right.

Option 2)

Put see-through pespex dowels over the leds and protrude them through the box.
 

longpole001

Joined Sep 16, 2014
62
the internal transistors for the charge /standby appear to have a 5ma max draw if you go by the data sheets so should keep the led current draw to 5ma

I have used 100R with 5v , drawing 20ma , and have had no issues with the 4056E chip

4056E is clone chip , which seems to be a good clone , from what i have seen ,
the internal transistors
 
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