A long time ago, I purchased a really cheap Lipo charger that can be powered through a USB. It works great with the 3.7V RC heli batteries I have, and I'm now considering building something out of it.
Here's my intentions: power a microcontroller using the lipo, when that lipo is also connected the the chargin circuit. And my question is is this something I can do without frying the circuit? I'm still a bit shaky in electronics, so I thought I'd come here to see if anyone had answers.
Here's the picture and schematics:
The schematic is supposedly the correct one. It looks like the battery goes to where it says Bat+ and Bat-, but if you can determine from this if I can place a microcontroller with the battery without damaging anything, that would be really helpful.
I just stumbled across that, it is a first rate rate primer for those of using these batteries.
Also, that supply is going to vary between ~4.2V and ~3.4 V. Not quite the 5V or 3.3V many microcontrollers need and not quite enough over what it takes to drive a voltage regulator for 3.3V.
Otherwise your basic idea has some merit. It is just that old devil in the details and LiPos have built in devils.
I don’t intend on charging the lipo all the time. The intentions were to put this circuit on a mobile robot, and have it so that in order to charge it whenever needed, I only have to plug it in through the USB. My concern is if anything would be damaged through my setup with the microcontroller being directly wired to the lipo.
On careful examination of the schematic, I see the TEMP pin being the ground of the battery, and the BAT pin, I guess where the TP4056 reads the voltage of the battery to activate one of the LEDs to indicate the charge… I actually think this might work if I wired the microcontroller to the lipo according to the schematic. (I guess there’s only way to find out…)
Meh, I still have lots to learn on electrical shenanigans Thanks for the link, it’s definitely going to help.
The temp sensor (What plugs in to the TEMP pin) is there to monitor quick charges to make sure the battery does not overheat. Just ignore it.
I’m still skeptical of running a MC off of just a 1C (3.7V) LiPo. Note that prices on LiPos have come way down and you can get multicell balance chargers for not much money:
With all that said, have at it. It will probably work fine, you’ll learn something, and the absolute worse that can happen is a small fire you can’t put out. I love robotics in the morning!
Thanks for the link, it’s definitely going to help.