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Where can I but a JD1803 chip? Answered

I recently went to my favorite store,The Dollar Tree-everything for a dollar, and found some small solar lights.  When I opened it up I found one bright white LED, a solar cell (about 2,5V) , a AAA NI-Cad battery and a Joule Thief on a chip. I have been building these as artsy  gifts for people so reducing the circuit board down to about 1/4"x1/4" seems great. The chip is four in line pins,  However upon looking I can't seem to find them. I did find that they were, of course, made for a Chinese manufacturer. Can anyone help??


Our 99c Only has a bunch of these garden lights. I'm posting a picture of the guts: LED, resistor, switch, JD1803, battery, and solar cell (3cm x 3.5cm) ... for a dollar! (Battery reads: Ni-Cd AAA200mAh 1.2V)

A couple of notes: the JD1803 turns off the LED when there's enough light to charge the battery. (If you pull the battery out and put the unit in the sun, the LED comes on.) The current coming out of the solar cell seems to be about one amp. Is that possible?

I'd like to rework one of these into an iPhone charger. Simple? Do I need another solar cell? Should I keep the battery/batteries in the system for backup?

I don't have the electronics experience to invent the system itself. I'd be happy to reward the guy who describes a practical system here with a couple of these units.


The current would be closer to 10 mA - or a liittle bit more if you're lucky. It's designed to barely charge the 200mAh battery if left in the sun all day long. I measured 10mAh shorted under a bright light.

A rough calculation for a phone battery: 10 times the capacity (2000mAh) and about 3 times the voltage (4.2V) means 30 of these solar lights would need all day to charge your iPhone. (50 to be on the safe side, a couple hundred if you don't have all day).

Plus this chip doesn't help with the charging at all, it just boosts the voltage so the LED can run on a single 1.2V battery. For charging, you might just as well use the solar panel and a diode.
For a proper liIon charger, I'd buy a TP4056 (around $2 -$2.50 as a finished module, at DX  http://dx.com/p/1a-lithium-battery-charging-module-blue-205188 or elsewhere.) Add a thermistor, if you want to be extra careful. That on a matching 5W solar panel would charge a liion battery.

For a phone charger you probably only need a somehow stable 5V on a usb port.  (iPhones might be different.) I'd get a usb car charger (also at the dollar store) and put a large enough solar panel on the end where normally the car goes ;)

Thanks for taking the time on this. I understand I can charge off USB or in a car. I was thinking of something truly portable, for hiking, etc.

Not a car. A solar panel. You get the car usb charger from the dollar store and put the phone on one end and a solar panel on the other. (- goes on the outside, + on the inside pin).

If you take it apart, the spring is plus, the red wire says ground and is minus. (Stupid color choice). These two points take your solar cell. The chip is MC34063A and can handle up to 40V.

A 12V cell would of course work. But anything above 6V should work. The charger has a maximum of 1A, which means any solar panel above 5W won't make it charge any faster. (Well, not quite: A 10 or 15W panel would give you 5W even on a non ideal day.)

Can't tell if you're kidding. Is it that these are really weak solar cells (on the garden light), but stronger cells are available, so you don't need 30 of them? If we're talking just a few, it would probably be worth the trouble to sew some into the top of my backpack. (Do I need a charged iPhone on a camping trip? Not really, although I do use the compass, and there is limited GPS service pretty much everywhere.)

"If we're talking just a few, it would probably be worth the trouble to sew some into the top of my backpack."
--FYI, you can buy solar iPhone chargers on ebay for a few bucks that work at least as well as something assembled from these. I only pack my phone in the bush for emerg calls, but it lives in the top pouch and the panel is velcroed to the map pocket of my pack lid. I wouldn't want to have to use it to charge the battery from dead but it keeps up with the standby draw of the phone: I've come out after two weeks with a full battery.
It's a good idea, since the top of your pack is always outside and is easy to keep facing the sun...but there are better and easier ways to get there IMHO.

They are really weak solar cells. Only useful for stuff, that needs very little power. Like one single small LED (~0.06 Watt) after several hours of charging, or running a digital clock, a small microprocessor, ...

The amount you needed to charge a phone with them makes them pricier than buying a large solar cell.

I just stumbled across this thread searching for this same chip from a Dollar Tree halloween solar light. My contribution isn't to the Joule thief chip, but rather something else REALLY AWESOME you can get at Dollar Tree. Today I spotted a 12V accessory plug to USB charger, yes, USB Car Charger, for $1. INTERESTING note that the packaging actually warns you not to start your vehicle with the adapter plugged in as it might damage your USB device. Thanks, and true. I figured I had to bite on this just to inform the world of my findings, and what a find! About the warning: starter motors after being tuned off can dump >100V into the 12V supply of the vehicle. The chip inside is rated for up to +40V input, not bad, but not 100V either.

Turns out, in the guts of this $1 gem is an ON Semi MC34063A buck/boost/inverter swiching controller and a nice, fairly efficient, SMPS rated at 1.0V on the packaging. The datasheet actually says 1.5A, not sure what the limit is. So for $1, you get the housing, a fuse & holder, regulator chip that is ADJUSTABLE and tolerates up to 40V, 3 caps, inductor, red LED, USB jack, 4 resistors (change them to change voltage output!), and rectifier diode.

I've been getting tired of Arduino community running on all these old-tech "high dropout" regulators and just bought some 2 Amp adjustable switchers off eBay, reasonably cheap but 4x the $1 gem here, and Buck only. A little hacking and you could make almost anything out of these parts on the cheap!

So, not just a Buck for a buck, but possibly a Boost and Invert too!

Love that place, I have to make an instructable out of my cookie cooling rack to taco shell frying jig trick.... also found a clip-on light with 1220-size Lithium batteries that seem to fit nicely in my Seeedstudio real-time clock which did not come with batteries. 2 for $1 plus free LEDs & retro reflector beats $6 for a single battery at the Shack!

Oh yeah. The Dollar Tree is one of my favorite places to shop, along with Good Will, Catholic Charities, and other thrift shops where you can find old toys with electronics in them for anywhere from a quarter to a dollar.

Did not realize that leaving devices plugged into the car while starting was a problem. Thanks for that heads up. Also the info on the adjustable regulator. Gooood stuff.

Thanx again

Sorry, a correction, SMPS rated at 1.0V should read 1.0A @ 5V.


6 years ago

I found this JD1803 in a garden light from Walmart in Canada. They are $3 each and have a super bright white LED and a fading diffused RGB LED, one AAA ni cad. It is a very simple circuit. I'm a pretty big noob when it comes to circuits, I have a question:
I was wondering if there were some way to modify the circuit so the LED runs even in daylight and still have the solar panel charging the battery? I guess my real question is, has anyone worked around a JD1803 in this manner before? It seems like a very convenient joule thief.

Sorry, this is a bad question if I haven't given you the circuit layout for reference. I will need to investigate it a bit more with the multimeter. If you remove the solar power from the JD1803 it will always light up the LED (voltage dropout darkness detection).

Remove the plus cable coming from the solar panel from the SBAT-pin of the chip, the LED should now light up even in daylight. Take an extra diode and connect the plus cable through this diode to the plus side of the battery or the BAT-pin.

The diode should point towards the battery (anode+ at solar, cathode- at battery). The solar panel is now parallel to the battery and will charge whenever the voltage is higher than battery_voltage + diode_voltage (Use a Schottky to loose only 0.3V instead of 0.7V)

You probably can also use two solar panels from different lights in series. I say probably, since I don't know how much charge your battery wants. (Make that a " works most likely": the voltage of the panels goes down when under load, and the LED will drain more power than a tiny solar panel delivers under normal conditions.)

Thanks a bunch for your reply!

I plan on trying it out and testing the voltages soon. The circuit already has a diode soldered in, probably for the solar -> battery charging. Perhaps I could pull that out and use it in the separate parallel battery charging circuit.

I want to use this for an LED that will only be on periodically controlled by an external switch, so it won't matter if the panel isn't very strong.

Thanks for the ideas and help, I am very new to this.

Is this it? SKU 16608?

These guys have a store near where I live. So I'm definitely going to be looking for this artifact.  If I can find one, and glean any data from taking it apart, I'll try to remember to write back and share what I have discovered.

I'm pretty sure this would be a new low-price record for solar powered yard lights, or at least the lowest I have seen.

I went by the local DT today, but found no instances of that solar yard light. I talked to a clerk, and she said seen them, but they sold out in just a few days.

Regarding this question of where to find the chip, and/or the rest of the parts,  it may be the case that the cheapest place for you to find them is at the local dollar store.  Unless you want to buy a few thousand of those chips, the chip-mongers are not going to give you a super low price.  Moreover, besides the chip, you also need an inductor, a rechargeable cell, a solar panel, an LED, and maybe a few other components.  Finding all those parts for less than 1 USD, is going to be difficult for an individual.

Unless of course you also own a factory in Guangdong province.

Anyway this is part of the twisted economics of today's world.  There are many electronic parts that are cheaper to buy, already built into something from the dollar store, than it is to buy the same part separately from a part-monger.  The dollar store can be best place in town to find parts, depending on the part.  This is a phenomenon I have remarked on before, here:

Walgreen's just had a sale last week: Their 2.99 solar light (138292, 049022532847) was 74 cents.

Here some details:

Chip inside is labeled 5252F - probably equivalent to a QX5252: pinout is like Qx5252 (not JD1803), and the circuit looks pretty much like the diagram above, The inductance is 190µH.

The solar panel is bigger than in the cheap $1 lights and came right off with a little pressure (thumb) from the inside, I'll use that on a clock. The box survived the disassembly and makes a nice steel covered project box.

I guess, most China made solar lights will have a similar chip inside. Using the diagram above, the circuit is easy enough, so one can come up with the pinout. If the solar light has a photocell (little round sensor) on the top, the chip will have another pin to enable the boost converter.

With Walgreen's and Dollar Store solar lights the solar cell works also as day/night sensor: If there isn't a high enough voltage on SBAT, the boost converter starts and turns the LED on. Solar lights that have an extra sensor, will have a chip with an extra sensor input: The light can be turned on and off with that sensor input, independent on what the voltage on SBAT is.

Hope that helps.

Wow! Thanks for the intel, and for the screwdriver work, and for sharing it with the rest of the class!

With the help of google I translated the QX5252 data sheet. No guarantee that I got it right.

The closest I found so far would be a ZXLD383 for $1.56 at mouser. Looks like Dollarstore is cheaper ... Plus you also get a 150uH inductor, a 4-cell solar panel, and a 200mAh AAA. Not bad for a dollar.

The circuit in the dollar store yardlight is identical to an application note for the QX5252 (sorry, also not available anywhere). But the pinout seems to be different.
The QX5252 has (side of writing left to right): SBAT, BAT, VSS(GND), LX
The JD1803 looks like: GND, LX, SBAT, BAT
The coil controls also the Amperage to the LED: 150uH, 25mA. 33uH, 110mA.

Another similar chip would be ANA608. -Also not available in small quantities.


I think I might try the chip from Mouser. Even a $1.56 it will save me time in coil winding and free-forming the joule thief circuit. I use this this to make night lights for kids , robot nuts, etc. So far I have made almost 100 of these and although I enjoy the challenge of creating the electronics from scratch, This chip lets me concentrate more on the aesthetics of the finished package. Thanks for the help!

I think, the Joule-Thief-circuit drains the battery down to 0.3V.

The ZXLD383 and the Dollar-store chip are more designed for normal battery voltage. They boost the normal voltage up high enough to run a LED (and keep the current somewhat stable). At 1.2V or more you get 80% to 90% efficiency, at 0.8V only about 10%. Any lower and the chip will stop working.

If you want to drain a battery as low as possible, the Joule Thief might be better. But if you're planning on using a rechargeable battery, both the Dollar store chip or the ZXLD383 would work. - If you go with the ZXLD383,you still need an inductor for a few cents (10 uH for 20-30mA). If you go with the dollar store chip, either take the whole circuit out and use it without the solar panel, or desolder the chip and the inductor only.


I found a data sheet if you care to hack Chinese but it should be understandable. How do I up load it?

I don't know how to upload a pdf, but you could add a link to it.

Here's the one for the QX5252 (also chinese):


7 years ago

JD1803 is functionally equivalent to QX5252. Go to www.qxmd.com/index.aspx, enter QX5252 into query box on top-right of screen under English and a new page will list all data PDFs. Only in Chinese so far as I can tell but still readable.