In countries like the UK where we have a lower than average amount of sunlight (mainly due to cloud coverage), the performance of solar garden lights tends to be optimised for the lower light exposure.
Some lights tend to run at higher current though, and while being brighter they don't last long at all when it gets dark.
Most of these lights use a dedicated chip for complete control including charging, light sensing and driving the LED from a lower voltage cell by stepping the voltage up with a pulsed inductor.
By changing the value of the inductor you can change the current and intensity of the LED. Strangely, increasing the inductor vlaue reduces the current. So a 47uH inductor will make the LED bright, while a 470uH inductor will make it run at much lower current.
The dollar-store lights tend to use a 470uH inductor so they can skimp on the size of the solar cell and battery.
In this video I change the inductor in a light to reduce the LED current and get a longer run-time at night.
Datasheet for the XD 5252F chip in the rather unusual form of a JPG image.
http://www.xingdong-et.com/wp-content/uploads/2013/05/TO-94-XD-5252F-1.jpg
Some lights tend to run at higher current though, and while being brighter they don't last long at all when it gets dark.
Most of these lights use a dedicated chip for complete control including charging, light sensing and driving the LED from a lower voltage cell by stepping the voltage up with a pulsed inductor.
By changing the value of the inductor you can change the current and intensity of the LED. Strangely, increasing the inductor vlaue reduces the current. So a 47uH inductor will make the LED bright, while a 470uH inductor will make it run at much lower current.
The dollar-store lights tend to use a 470uH inductor so they can skimp on the size of the solar cell and battery.
In this video I change the inductor in a light to reduce the LED current and get a longer run-time at night.
Datasheet for the XD 5252F chip in the rather unusual form of a JPG image.
http://www.xingdong-et.com/wp-content/uploads/2013/05/TO-94-XD-5252F-1.jpg
Top tips 👍
Ohhh now I get it🤦🏻.
I just used a .2 Watt solar panel and a 1500mah battery and put in a 20 ma led at 20,000 mcd. The inductor is about 150 to 160 uh.
Bye bye rosey off you go to Birmingham via Great Western. Learnt 1963 UK Army
Very old, I know but I was thinking you could have added the other/original small inductor in series to give a few more uH and lessen the current just a tad more, yes? And/or, any inkling at this late time how the light made out longevity-wise?
Rite Big Dude! Nowt wrong wid a bit of profanity, as RUSH would say "sickness to insanity, prayers to Profanity"!
As mentioned if I'm not cutting the back off the components I use a similar small pair of pliers but with bent ends (or bent nose if you will) and use them as a lever against the circuit board works a treat, not that yours doesn't! TFS, GB 🙂
Could you show how to add a 3.7 battery to one of those $1 solar lights?
Couldn't you just put two 470uH inductors in parallel (achieving 235)?
Billy brown, whaaaa?
You said it too fast for me to break the words apart. As to say your words ran together on my end, brother.
Clive, When I learned the resistor code in High School electronics in California, I was taught Bad Boys R*** Our Young Girls But Violet G** Wil******". 🙀🙀🙀
Hello. Can i replace the battery eith an energizer rechargeable battery ??
But doesn't increasing the inductance also increase the back EMF that provides the pulsed voltage supplied to the LEDs? And if that's too high, isn't that a problem? Where is that extra voltage dropped? By decreasing the current, voltage increases, so power dissipation stays the same, right? Can you tell me what I'm misunderstanding please?
Just use the ferrite inductor in an old am radio.
Hello i am trying to experiment but the datasheet is no longer available, can you host a photo of the datasheet please ?
I have an issue with a solar frog light ( from wagner )it is a beautiful thing and It has always worked well , but now it runs for about 5 seconds. Could this be a capacitor fault ?
I always put in a decent capacity AA removing the rubbish one fitted but is there a way of installing 2 AA batteries so it lasts longer between decent bright days ?
I realise the output from the solar panel is small but in the summer nights are short but it seems with the low capacity batteries these things come with one dull day and they don't light up the next night!
PS the best solar lamp i have found so far is the poundland £5 one with the remote solar panel thats has a movement sensor the 3 batteries mean its never failed to come on even in the middle of winter !
One other super easy way to increase the run time is to glue a piece of ferrite material parallel onto the inductor modestly increasing its value. 🙂
run inductors in parallel to halve the inductance. In series to increase it.