Ok, as some of you know, I've been building a LiIon battery charger with an Arduino, and I noticed something today that I thought was ... odd ...
When I put a depleated 18650 in the Arduino, and hit it with 4.1 volts, best current draw it will do is .8 amps. It's got a C rating of 3000. However when I was at my friends place and I charged the same battery on one of his wiz bang $100 battery chargers, it said that the battery was charging at 1.5 amps.
So I thought I'd bring something up that I noticed when I was experimenting with the arduino project. A few weeks ago when I was trying to get one of my 18650's to charge at 1 amp, I cranked up the supply voltage until I hit that current. But what I noticed was when I took a voltage reading off the battery while it was charging, it was only at 3.9 volts HOWEVER when I disconnected it from the charging source, it was showing a voltage of like 4.8 FROM THE CHARGE SOURCE... so connected to the battery, it reads 3.9 but disconnected, it reads 4.8 and the only variable that's changing is the connecting and disconnecting from the battery being charged.
Now people say never apply more than 4.1 volts o a standard LiIon cell, but if the voltage across the battery never exceeds 4.1 even though the charging source may be cranked higher than that, is it possible that this might be the only way to charge a battery at half its C rating?
Thoughts?
When I put a depleated 18650 in the Arduino, and hit it with 4.1 volts, best current draw it will do is .8 amps. It's got a C rating of 3000. However when I was at my friends place and I charged the same battery on one of his wiz bang $100 battery chargers, it said that the battery was charging at 1.5 amps.
So I thought I'd bring something up that I noticed when I was experimenting with the arduino project. A few weeks ago when I was trying to get one of my 18650's to charge at 1 amp, I cranked up the supply voltage until I hit that current. But what I noticed was when I took a voltage reading off the battery while it was charging, it was only at 3.9 volts HOWEVER when I disconnected it from the charging source, it was showing a voltage of like 4.8 FROM THE CHARGE SOURCE... so connected to the battery, it reads 3.9 but disconnected, it reads 4.8 and the only variable that's changing is the connecting and disconnecting from the battery being charged.
Now people say never apply more than 4.1 volts o a standard LiIon cell, but if the voltage across the battery never exceeds 4.1 even though the charging source may be cranked higher than that, is it possible that this might be the only way to charge a battery at half its C rating?
Thoughts?
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