Rasmus Godske
Member
- Joined
- Jun 7, 2018
- Messages
- 39
I'm working on my testing circuit, for testing my cells but it have some weird behavior that I can't figure out...
When connecting my 5V(actually 5.8V) powersupply to the VCC and ground and no battery connected,the voltage at Shunt+ and Shunt- appears to be at1.7V with lots of noise(Picture 2). This is supposed to be 0V, when ChargeEn is a 0V and the mosfet is "closed", so I can detect when no batteries are connected. Also the red light indicating when the it's charging, are lighting up veery slightly, so it's clearly getting some current to run. I got the idea of enable/disable the TP4056 charger from BrettWatty, so I imagined it would work when I break the connection between IN- and ground with the mosfet.
Also when connecting a battery the TP4056 board heats up quite a lot, too hot to touch. It does seem to charge though, but it shouldn't get that hot. When using a USB to as power supply, it doesn't heat up anywhere close to that.
I have spent many frustratinghours trying to figure this out, but can't seem to find the cause of these problems... So I'm asking for help to find the cause of the strange behavior of my circuit.
Picture 1:
Circuit
Picture 2:
Oscilloscope with showing the voltages at shunt+(Yellow) and shunt-(Blue), while no batteries connected, and DrainEn, and ChargeEn is at 0V.
Frequency = ~100Hz
Amplitude =~300mA
When connecting my 5V(actually 5.8V) powersupply to the VCC and ground and no battery connected,the voltage at Shunt+ and Shunt- appears to be at1.7V with lots of noise(Picture 2). This is supposed to be 0V, when ChargeEn is a 0V and the mosfet is "closed", so I can detect when no batteries are connected. Also the red light indicating when the it's charging, are lighting up veery slightly, so it's clearly getting some current to run. I got the idea of enable/disable the TP4056 charger from BrettWatty, so I imagined it would work when I break the connection between IN- and ground with the mosfet.
Also when connecting a battery the TP4056 board heats up quite a lot, too hot to touch. It does seem to charge though, but it shouldn't get that hot. When using a USB to as power supply, it doesn't heat up anywhere close to that.
I have spent many frustratinghours trying to figure this out, but can't seem to find the cause of these problems... So I'm asking for help to find the cause of the strange behavior of my circuit.
Picture 1:
Circuit
Picture 2:
Oscilloscope with showing the voltages at shunt+(Yellow) and shunt-(Blue), while no batteries connected, and DrainEn, and ChargeEn is at 0V.
Frequency = ~100Hz
Amplitude =~300mA