Did you install the 4,700uF cap?
If you did, then re-check the solder connections.
The power & charge status LEDs will do that without the cap.
the LEDs will blink when the input current is low.ShirleyD wrote:Tried it again today and somehow the LEDs are just fine, not blinking anymore.
The "DONE" LED will not come on until 4.1~4.2V.ShirleyD wrote:when the voltage hit 3.7V i expected "CHRG" to turn off and "DONE" to turn on
john444 wrote: The "DONE" LED will not come on until 4.1~4.2V.
It sounds as if the cell is still charging.
Can you use your meter to measure the current into the 390?
The battery i have is a polymer lithium ion (3.7V, 850mAh).
the LED didnt light up. Can you tell me why?
Can i put a dc/dc converter between the charger and the solar panel to boost up the voltage to 6V? Do you think that would work?
And how do i measure the current that my solar panel puts out? (I would need to put my meter in series between the solar panel and one terminal of DCIN, to let current flow through the meter to measure. But its a USB port, how do i do that?
That is exactly what is happening. The 390 is taking as much current as the solar-panel will put out while not letting the voltage collapse below the charging voltage. the 390 is a pretty smart charger.ShirleyD wrote:the blinking stopped whenever i held the solar panel closer to the light. But the voltage at DCIN remained unchanged. So i am guess is it just an increase in the current but no change in voltage?
No. You are mistaken here. The battery voltage will reach 4.2V when it is fully charged then drop back to 3.7V when the charger shuts off. As Adafruit said, your battery will spend most of it's life at about 3.7V.ShirleyD wrote:What i dont understand here is that the battery voltage will never be 4.2V
Not sure about this one. Some white LEDs need over 3V to work. If you use a red LED (~1.5Vf) then you should use a resistor of about 200-ohm to prevent blowing it. Otherwise, LEDs only work with one polarity. The longer lead goes to +.ShirleyD wrote:I connected a LED to the load terminals on the board. But it surprised me that the LED didnt light up.
No, if you are not getting enough power to run the 390 with a solid charging light, then you don't have enough power to run a boost-ckt.ShirleyD wrote:Can i put a dc/dc converter between the charger and the solar panel to boost up the voltage to 6V? Do you think that would work?
ShirleyD wrote:how do i measure the current that my solar panel puts out?