Help please with identification of few components for troubleshooting (Solar Water Fountain circuit)

[Techie_hobby1]

Need some help please with a few components on this small board so that I can troubleshoot the circuit.

The PCB is a Single sided board fairly simple circuitry has a +ve and -ve Solar cell power input, a 7.4v 1500mAh (dual 18630 cell) power in which the Solar panel charges the cells, and lastly the Output goes to a DC connector...
J1 is actually 1P1T Switch (in ON position completes Battery cell circuit
J2 - to DC Output
J3 is Battery cell connector

however I am struggling to identify if:
Y1 (SOT-23) are NPN Transistors, MOSFET's or 11v Zener's. I am fairly sure they are NPN Transistors though because I get a 0.6v diode reading on Collector and Emitter with +ve on Base.
Same for Y2 (SOT-23) being PNP with -ve on Base and 0.6v on Collector and Emitter.

The 8 pin IC is a little odd though but with no markings is making it a lot harder.

If I am incorrect with any of the above please can you advise further
Many thanks

[truclacicr]

Y1 = SS8050.

https://www.google.com/search?imgtyp...Cisz%3Am&udm=2

Y2 = SS8550.

https://www.google.com/search?imgtyp...Cisz%3Am&udm=2

To identify the IC, you would need to identify its pinout.

https://ipv4.google.com/search?q=fil...8%20OR%20soic8

[stj]

the switch has fractured soldering

[Techie_hobby1]

truclacicr
Thanks as always. I think sometimes I over think it in regard to the component searching, and try to use the sites that let you search by the Marking code, instead of trying to do a standard google image search first.
In regard to the IC 8pin SOIC connections are as follows ( I think it is just 555 timer chip - but just want some clarification please):
Pins are as follows:
Pin 1 connected to Cathode of D1 diode and bridged with pin 4
Pin 4 goes to collector of PNP (Q3) transistor via current limiting resistor
Pin 2 goes to collector of NPN (Q4)and also to collector of NPN (Q1)
Pin 8 goes to Anode of the same D1 diode, to DC positive

[Techie_hobby1]

stj
Thank you for pointing that out. I actually didn't see that one. I think I managed to locate a few that were broken/cracked.. and still going through them slowly

[Techie_hobby1]

truclacicr
whoops I forgot to include pin 7 of the IC, which connects to the base of NPN Q5 transistor

[Techie_hobby1]

truclacicr
Now I am really baffled.. I have just realised it does not have any connection to pin 3 (Ouput) so can't be a 555 timer can it

[stj]

the chipis probably a 2cell lithium charger or a microcontroller.

[Techie_hobby1]

stl truclacicr
Very quickly hand drawn a schematic - could have switched a few things around but think you get the jist

[Techie_hobby1]

stjtruclacicr
im still having a few difficulties with this circuit.
i have tried reaching to other sites but they too are not coming back with anything useful.

i swapped out the battery pack for 2 x 3500mAh cells and it seemed to work for about a week, but now it seems like they are not charging.
How would be a good way to test that these are actually charging with the sun???

Regarding that 8 pin IC..still unsure what it is and how I can identify it???

[truclacicr]

The circuit diagram is busting my brain. I presume that DC+ and DC- are the terminals of a pump motor, in which case it makes no sense to connect Q5 as in your circuit. Instead, it would make more sense to connect the emitter to ground.

Another problem is the absence of a path for the charging current from Solar+ to Bat+ via the IC. How is the battery being charged?

I can't understand what D1 is doing.

[stj]

when the battery switch is on, the solar panel is connected to the battery through a series of resistors.
so for it to work you need either NiMH batteries or the lithiums need a protection-board.
because it has no charge control - it just pumps power to the cells till the sun goes down!

NiMH also will last longer outside - Lithium wont like getting baked in the day and frozen at night.
thats why solar lights are NiMH based.

[truclacicr]

AFAICS, those resistors are too large for any charging current. Instead, they appear to be bias resistors.

[Techie_hobby1]

The circuit diagram is busting my brain. I presume that DC+ and DC- are the terminals of a pump motor, in which case it makes no sense to connect Q5 as in your circuit. Instead, it would make more sense to connect the emitter to ground.

Another problem is the absence of a path for the charging current from Solar+ to Bat+ via the IC. How is the battery being charged?

I can't understand what D1 is doing.

truclacicr Yes that is correct, the DC + & DC- are what the pump motor connects to.

truclacicr stj - so am I right in thinking that these Batteries don't actually charge up at all??

Ideally this circuit needs altering so that it can charge the batteries during the sunlight, and then once charged when sunlight switches to sunset have the batteries take over and power the circuit for as long as they can.

stj - re NiMh cells, do they require a BMS like Li-Ion cells require.


So we are still unsure what the IC is.. I took a look at some of the links that Truclaclcr identified, and there is 1 possible match being the CN3302 but I am struggling to work out if this matches the circuit that I have?

[Techie_hobby1]

truclacicr stj
I stand corrected it is definitely not a CN3302 because after looking at the typical applications it mentions MOSFET's in the design which we know these are NPN and PNP transistors and GND is Pin 4 on this IC

I have had to put this one aside for a few days as I have been given something else to take a look at..but would really be grateful of any further assistance. I have been searching through those IC's and none of the pin configurations seem to match up
I had a light bulb moment where I thought the IC might just have been a Boost Regulator which can be used in Solar Charging (CE6370 series) but again pin config does not completely match up.
Ground in definitely PIN 1 as it take its Ground signal through D1 diode which originally takes its GND from Solar Panel -ve

Apart from that all the other IC's have GND on PIN 4 that I have come across

[truclacicr]

The batteries must be charged by the panel ... somehow. However, there is something missing from your circuit.

Measure the battery voltage in the dark, then do the same in bright sunlight. Alternatively, disconnect the battery and see whether the IC is getting any supply voltage from the panel.

Disconnect the panel and measure the battery voltage at the IC. This will tell you which ICs pins are connected to the panel and to the battery

[Techie_hobby1]

truclacicr stj Thank you so much, this will give me a better understanding of what is going on with this circuit..

I will also take some time to go back (trace back) all the traces, connections and components to ensure that I have not made a silly error.. this will hopefully rule out any head scratching from both yours STJ's and anyone else who is looking at this.

I think I might have rushed this one a little too quickly in the hope that I could have fixed it quickly for my friend.
She has been without the solar fountain for some time now so I might take some more measurements and photos (many close up) but return it back to her (also give your heads a bit of a break from it) and just have it so it runs without the battery backup for now (then when the weather dips again, disconnect it from her fence and take another look at it)...

Needless to say this is not over and not a finished repair just yet... and TO BE CONTINUED!!!! haha