Solar Assembly for ESP32 Load

Thread Starter

tech500

Joined Apr 12, 2021
7
How to keep ESP32 from turning on before battery charge is complete? Also how to protect MCP1700-3302 LDO from over voltage on LDO Vin?
I see the Power LED on the ESP32 try to turn on at 3.29 V. 18650 is connected to B+ and B- of the TP4056.

Final Solar Assembly OFF.jpg
 

Thread Starter

tech500

Joined Apr 12, 2021
7
IRLZ33N switchs off the ESP32 at 3.5 volts. What is the correct voltage supervisor, voltage; for use with the 18650?

Once voltage reaches 3.5 volts; Voltage supervisor turns on IRLZ44N; before battery is fully charged. Is there a way to fully charge 18650; before switching the ESP32 "on."

Not a circuit designer; only a hobbyist wanting to safely, solar charge a single, 18650 for a ESP32 data logger.
 

Thread Starter

tech500

Joined Apr 12, 2021
7
Thank you ericgibbs; apprecate the links. Have read the 18650- battery article and the MakerHawk -charger Amazon link.

Question about the circuit in post #1: Will the TP4056 continue to fully charge the 18650; even if the voltage supervisor has 3.3 V at Vin and turns "ON" the ESP32?
 

ericgibbs

Joined Jan 29, 2010
13,819
How to keep ESP32 from turning on before battery charge is complete?

hi tech,
One method is to use a Comparator IC.
The comparator can be set to switch On/Off at preset input voltage levels, it would also have some level of hysteresis, which would ensure a 'firm' On , Off action.

The LM393 is low cost comparator

E

Added:
Is the battery part of the Charger assembly.?
Also where is Vcc.?

Question about the circuit in post #1: Will the TP4056 continue to fully charge the 18650; even if the voltage supervisor has 3.3 V at Vin and turns "ON" the ESP32?

I would say providing the TP4056 receives the required input voltage, it would continue to charge the 18650, its rated at 1.2Amps
 

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Thread Starter

tech500

Joined Apr 12, 2021
7
Schematic of Solar Power Assembly:Solar Power Assembly.JPG
Would the LM393 be comparing present 18650 voltage to final 18650 charge voltage?
 

ericgibbs

Joined Jan 29, 2010
13,819
hi tech,
You would set the Vthreshold limit on LM393, it would maintain the charge until this limit is reached.
The hysteresis could be set so that the charge did not restart until the battery voltage had fallen to a lower preset level.
E
 

Thread Starter

tech500

Joined Apr 12, 2021
7
Requesting help with designing the circuit for the LM393; as I have no experience with this type of device.

William
 
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