Solar garden light kit
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Posted by
julia sinclair
on
May 23rd, 2011
HiI made your solar circuit but the light comes on when the sun is shinning on the solar panel not when it goes dark. What component recognises the dark or no light?
Your help would be appreciated as I hope to do this project after 1/2 term
Thanks Julia
Response by
geoffhampson
on
May 23rd, 2011
It is the voltage on the solar cell that determines if it is light or dark. In the teaching notes that were supplied with this kit is a fault finding flow chart. Assuming that the LED is always on and there is only one fault with the board then the problem will be fixed by checking:R1 for dry joints.
R1 & R2 are in the right place.
C1 for a short.
The solar cell is in the right way around and for dry joints.
Q1 for dry joints or shorts.
If you are still struggling to get the board to work feel free to Email support at Kitronik.
Posted by
phil
on
Nov 21st, 2011
Hello. I am hoping to incorporate the solar garden light kit into concrete garden ornaments that I make, but would like to have two led's ie for the eyes etc.1. Is this possible
2. What would be the revised cost of the kit with the extra led
3. Could it be adapted to accept two of the colour changing led's and what would be the cost of that kit.
Thank you in advance
Phil
Response by
geoffhampson
on
Nov 21st, 2011
The issue would be that the light has been designed so that the solar panel is matched to the LED, so that on all but a winter day the battery is charged by the same amount the LED uses. By adding a 2nd LED the battery would be discharged twice as fast. You could put the two LEDs in parallel off the same current limit resistor in which case it would take the same amount of current, however the LEDs would be dimmer.Additional LEDs are available separately - enter 3546 in the search box (top right).
This kit runs off a single AA battery at 1.5V, but the LED has a forward voltage of 3V so wouldn't work directly off the battery, instead the kit works by driving the LED only for 50% of the time but at twice the voltage. This is done so fast that you can’t see that the LED isn't constantly on, but it would mean that if you connected a colour changing LED to the board it would keep resetting and never move off red.
Posted by
Alan Rowse
on
Feb 23rd, 2012
Hi Kitronik,I am using this kit with some u/grad trainee teachers in conjunction with a sutainability project brief, do you know if it is possible to simulate the operation of the cct using Circuit Wizard? I have tried this but failed to get the correct operation. It may be a software limitation as the cct is fine and operates as described in the booklet.
Best wishes, Alan
Response by
geoffhampson
on
Feb 23rd, 2012
It wouldn’t surprise me that you are struggling to get the circuit to simulate. Both circuit wizard and crocodile clips have in my experience been poor at modelling circuits where the voltages are rapidly changing, which is the case in this circuit. I should however point out that when voltages change slowly the software simulates it very well.Since this circuit runs off a 1.5V battery and the LED needs 3.5V the circuit switches the LED on and off many times a second. When the LED is off power is pumped in to the inductor, this is then used to increase the voltage feed in to the LED but for a shorter time. Because all this is happening very quickly and the software models it sampling the voltages at a slower rate it doesn’t simulate. Unfortunately I don’t have the software to try this, however I suspect if you change some of the component values it might well simulate. I would try changing C2 from a 1nF to a 1uF capacitor. If that doesn’t work try changing L1, L2 or R3.
Posted by
Ian Boulton
on
May 8th, 2012
I want to fit the solar panel into a recess which has a dia of 71mm. Can I simply trim the corners of the panel?Otherwise can I use 4 mini cells wired together which fit ok and give the same voltage and wattage?
Response by
geoffhampson
on
May 8th, 2012
The active section of the cell is the part in the middle, with the silver lines, there is a section around the edge which is not electrically part of the solar cell. So yes, as long as you are careful it would be possible to remove the corners on the solar cell.
Posted by
ben
on
Jun 28th, 2012
Hi. I have this kit and I would like to collect the power from 5 solar cells and I want to know if I can store the power to use it when I need it with for example switch. Thank you very much.
Response by
geoffhampson
on
Jun 28th, 2012
You could parallel up 5 solar cells and use them with something else. However most of the circuit is involved in switching the LEDs on and off. All you need to charge the battery is a diode to stop the current flowing back in to the solar cell at night. I suspect you might be better buy solar cells on their own. You have miss typed you Email address if you Email support I can give you more info. 
