Hello Forum.
It has been too long since I posted. I have missed all my blinky experiments
and its a joy to return to making after a hiatus.
I am trying to make a simple setup with a small solar panel (probably 6V), 3.7V LiPo Battery, and an LED
I am thinking of using the Adafruit sold White LED Backlight module: https://www.adafruit.com/product/1626
or the warm white sequins.
What I need is for it to turn on at night and off to charge during the day.
I have seen a variety of schematics online that I can try but wanted to see if there was any integrated
LiPo charging board that could also do this. I know I could use a full board and run it Arduino style, but
I want to keep this a simple as possible.
I keep taking apart Solar Garden Lights and perhaps that may be cheaper then building myself.
Any input appreciated.
Simple Day/Night Solar Circuit
Moderators: adafruit_support_bill, adafruit
Please be positive and constructive with your questions and comments.
- adafruit_support_bill
- Posts: 88098
- Joined: Sat Feb 07, 2009 10:11 am
Re: Simple Day/Night Solar Circuit
LiPo cells are finicky and require a charge controller to safely control the charge cycle. And since solar cells are not the most stable of power sources, it is best to use a charge controller designed for that purpose such as the bq24074: https://www.adafruit.com/product/4755
For a smaller - lower-cost option, NiMH cells are much less fussy to deal with. Our Evil Mad Scientist friends have a nice post on the subject here:
https://www.evilmadscientist.com/2008/s ... -circuits/
For a smaller - lower-cost option, NiMH cells are much less fussy to deal with. Our Evil Mad Scientist friends have a nice post on the subject here:
https://www.evilmadscientist.com/2008/s ... -circuits/
- sokbok
- Posts: 12
- Joined: Thu May 17, 2012 12:15 am
Re: Simple Day/Night Solar Circuit
@adafurit_support_bill
Thank you for the thoughtful response.
Yes that Evil Mad Scientist post is a great resource.
NiMH cells are 1.2V and from what I can read online, they prefer to charge at 1.45V
I want to use the Voltaic 1W, 6V panel, offered by Adafruit:https://www.adafruit.com/product/3809
Peak Voltage is 6.5V.
VoC = 7.7V
Imp = 180 mA
and 4 of these NiMH batteries: https://www.batteryjunction.com/tenergy ... MREALw_wcB
4 x 1.45 = 5.8V which I think is probably ok for that 6V panel.
The C/10 value of those cells is 200mA and that 1 W panel puts out 180mA so that also seems good.
If I put 2 of the adafruit sold LED backlight strips in series I should be ok I think. Their forward voltage is 3.2 but should work under 4.8V or should I do 2 LEDs in parallel with some resistors? https://www.adafruit.com/product/1626#technical-details ??
Thank you for the thoughtful response.
Yes that Evil Mad Scientist post is a great resource.
NiMH cells are 1.2V and from what I can read online, they prefer to charge at 1.45V
I want to use the Voltaic 1W, 6V panel, offered by Adafruit:https://www.adafruit.com/product/3809
Peak Voltage is 6.5V.
VoC = 7.7V
Imp = 180 mA
and 4 of these NiMH batteries: https://www.batteryjunction.com/tenergy ... MREALw_wcB
4 x 1.45 = 5.8V which I think is probably ok for that 6V panel.
The C/10 value of those cells is 200mA and that 1 W panel puts out 180mA so that also seems good.
If I put 2 of the adafruit sold LED backlight strips in series I should be ok I think. Their forward voltage is 3.2 but should work under 4.8V or should I do 2 LEDs in parallel with some resistors? https://www.adafruit.com/product/1626#technical-details ??
- adafruit_support_bill
- Posts: 88098
- Joined: Sat Feb 07, 2009 10:11 am
Re: Simple Day/Night Solar Circuit
Best to add some current limiting resistors. One in series with each of the two backlight modules. 100 ohm resistors should work.
Please be positive and constructive with your questions and comments.