NEW PRODUCT – USB/DC Lithium Polymer battery charger 5-12V – 4.2v. Charge your single-cell lithium ion/polymer battery any which way you like with this board. Have a USB connection? No problem, just plug into the miniUSB connector. Only have a wall adapter? Any standard 2.1mm DC adapter which puts out 5 to 12VDC will work fine. If both are plugged in, the charger will automatically choose whichever has the highest voltage.
Other nice things about this charger include multiple LEDs for power & charging status, including a charging LED which will blink when the battery is full. If the charger gets too hot from high-speed charging, it will slow down the charge rate automatically. You can easily adjust the charge rate up to 1.2A or down to 100mA.
Charges one single-cell Lithium ion/polymer battery at 4.2V with constant current/constant voltage
Three indicator LEDs – green for Power, orange for charging and red for error
Charging LED will blink when the battery is full
You don’t have to worry about heat dissipation in the charger, even when plugging in a 12V DC power jack – thermal protection inside will slow down the charge rate to prevent damage
2 JST connections so you can keep the battery plugged in and powering your project
Terminal block connections galore (if you don’t like JST connectors) just solder in 3.5mm terminal blocks
Default charge rate is about 280mA, but you can easily change this by soldering in a through-hole resistor on. The chip can do 100-1200 mA charging
Safety timer will stop charging after about 14 hours
The chip supports a standard 10K thermistor, which we have stuffed as a standard resistor. You can solder in a thermistor easily
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tz, according to the datasheet the max max is 13.5V. There’s a protection diode that will drop about .3V so say the absolute max is 13.8V. If you think you’ll be plugging this into a Car, solder a 1n4001 inline on the positive wire to the charger and you’ll be safe up to 14.5V
lithium ion batteries have a nominal of 3.7v but when fully charged are 4.2v that is why you’ll see both/either numbers
Just a thought for later versions…rather than “Battery In” and “Battery Out” labels, something like “Battery” and “Load” might make for easier comprehension. Maybe it’s just lack of sleep, but I spent a good two minutes staring at the photo trying to sort out why a *charging* battery was attached to “in” rather than “out.” I get it now…but still, with my little walnut-size brain that can’t remember squat…when I order one of these, first thing I’ll be doing when it arrives is tape my own labels over it so I don’t forget.
Two concerns.
1. "12v" in the automobile is typically 13.5v or occasionally as much as 14.5. Will this blow it up? I don’t know but don’t want to try.
2. It says 4.2v. I thought most LiPos used 3.7v. Perhaps this is just current or a typo, but I do worry without an explanation of the extra .5v.
tz, according to the datasheet the max max is 13.5V. There’s a protection diode that will drop about .3V so say the absolute max is 13.8V. If you think you’ll be plugging this into a Car, solder a 1n4001 inline on the positive wire to the charger and you’ll be safe up to 14.5V
lithium ion batteries have a nominal of 3.7v but when fully charged are 4.2v that is why you’ll see both/either numbers
Just a thought for later versions…rather than “Battery In” and “Battery Out” labels, something like “Battery” and “Load” might make for easier comprehension. Maybe it’s just lack of sleep, but I spent a good two minutes staring at the photo trying to sort out why a *charging* battery was attached to “in” rather than “out.” I get it now…but still, with my little walnut-size brain that can’t remember squat…when I order one of these, first thing I’ll be doing when it arrives is tape my own labels over it so I don’t forget.
Thx for the suggestion, we have a lot of PCBs made…but will consider it for the next round!