Overclocked
Member
No, Not the batteries
The charger itself. Its based on the MCP73831 IC (Link to Datasheet). The Schematic and Board I used are included in the zip file (Eagle PCB files). This is the 2nd Time Ive redid this board, the first time the IC kept overheating as well. The 2nd time I reworked the PCB, and even before soldering, I put in a little Arctic Silver (Thermal Compound for CPUs) in the space underneath but this doesnt seem to alleviate the heat problem.
I am using a Supply of 4.34V and a charge current of 200mA. I am actually charging a LiFePO4 battery, hence the diode, to drop 0.3V. It still works and has actually completed charging on One battery. LiFePO4 batteries need 3.8V Max but are charged the same way LiPolys Are. But In any case, The Voltage measured at the LiPol Terminal Confirms this, so the battery isnt the problem.
On my Supply I have a current meter, And it swings, as does the voltage. it goes from 200mA down to 0 and back up. The Output voltage swings from 3.7 down to 2.7 (or so). Theres no way this is normal. The IC is Hot, Like a hot cup of tea you just stuck your finger in.
I dont know what to do to Resolve this. A small Fan works But My original Plan was to Charge Batteries via Solar. If I need a fan to cool the IC off, it would defeat the purpose. I could technically use a LM317 circuit (theres a few floating around the web) and use a PIC micro to monitor the Voltage and current But, Why over engineer something?
I am using a Supply of 4.34V and a charge current of 200mA. I am actually charging a LiFePO4 battery, hence the diode, to drop 0.3V. It still works and has actually completed charging on One battery. LiFePO4 batteries need 3.8V Max but are charged the same way LiPolys Are. But In any case, The Voltage measured at the LiPol Terminal Confirms this, so the battery isnt the problem.
On my Supply I have a current meter, And it swings, as does the voltage. it goes from 200mA down to 0 and back up. The Output voltage swings from 3.7 down to 2.7 (or so). Theres no way this is normal. The IC is Hot, Like a hot cup of tea you just stuck your finger in.
I dont know what to do to Resolve this. A small Fan works But My original Plan was to Charge Batteries via Solar. If I need a fan to cool the IC off, it would defeat the purpose. I could technically use a LM317 circuit (theres a few floating around the web) and use a PIC micro to monitor the Voltage and current But, Why over engineer something?