USB / DC / Solar Lithium Ion/Polymer charger

[arturolaz]

Hi,

I have bought this charger and a 2700mA battery, how can i calculate the charging times through usb and through a 6v 2W solar panel??

I want to extend the cable of the solar panel, would that afect the performance??

Thanks!

[ransomhall]

The USB "standard" charge rate is 500mA, but that can vary quite a bit either way. 2700 mAh/500mA = 5.4 hours. This is an approximation. Your actual results will vary. 1 Watt = 1Volt Amp, so 2W/6V = .333 A, or 333mA. 2700mAh/333mA = 8.1 hours to charge. Again, this is theoretical max. Lots of things affect actual charge times (like a few clouds ).

Extending the cable (within reason) on the solar panel will not impact performance. Extending it a foot or two is fine. Extending it 100 feet is not a good idea.

[arturolaz]

thanks a lot for your answer, now all is clear about that, but i have another question. If I change the current limit resistor to 1kohm it will accept 1A max, correct?? Now everytime i conect it to usb or solar panel it will try to get 1A or just will accept 1A as max charging current??

What im trying to do is to conect it to a wall power supply that can supply 1A but i also want to continue using it with the solar panel and with the usb of my computer.

Thanks!

[adafruit]

it should automatically adjust to the maximum that can be drawn from USB/DC or Solar. 1 Amp is max but in reality it may be less based on the panel or computer