How do I wire this solar usb doohickey?

[Porkpie]

Hi folks,
I bought one of these "Solar Regulator Voltage Stabilizer Charge Controller with Indicator Lamp Design Dual USB Charge Voltage Controller Regulator" off Amazon (but see the same product here on Aliexpress).

No documentation came with it, so I just soldered the red to one + and the black to the - ... and it didn't work.

Wait for a sunny day... still doesn't work. Maybe I used the wrong terminals, so I put on a couple of alligator clip jumpers to the other terminals—and it works!

So, desolder and resolder to the other terminals... and it doesn't work. Add jumpers—and it works!

Can someone explain what the heck is going on here, and what I should do?

Thank you for any help you can give.

 

[Bud Martin]

What is the spec of the solar panel?
What DC Voltage do you read on the the Red and Black wires when NOT connected to the board and when connected to the board?
What happen if you use 12V power supply instead of the solar panel?
What is the part number as printed on the board? I see Z???????????????

Specifications:
Main color: black
Main material: ABS
Input voltage: 5-30v
Output voltage: USB output 5V type-C output 5V
Output current: 3000 mA (max)
DC output: equal solar output voltage
Product size: 65 * 45 * 15mm / 2.6 * 1.8 * 0.6inches(Length * Width * Height)
Package size: 80 * 50 * 30mm / 3.1 * 2 * 1.1inches(Length * Width * Height)
Package weight: about 35g / 1.2ounces

 

[Porkpie]

Hi Bud, thanks for reading. I have attached a couple of photos of the panel specs and the board serial number.

The voltage is weird. It reads instantaneously on my meter... like it flashes the volts, then changes to 1.
I have tried googling how to meter a solar panel, but have had a hard time finding and understanding it.
So, in that brief flash, it is reading between 18 and 19V.

Similarly, when I plug the board in and meter the solder joints on the board, it reads between 18 and 19.

I am afraid I don't have a 12V power source at hand.

Thanks for any help you can give.

 

[Nobodybusiness]

Hi Bud, thanks for reading. I have attached a couple of photos of the panel specs and the board serial number.

The voltage is weird. It reads instantaneously on my meter... like it flashes the volts, then changes to 1.
I have tried googling how to meter a solar panel, but have had a hard time finding and understanding it.
So, in that brief flash, it is reading between 18 and 19V.

Similarly, when I plug the board in and meter the solder joints on the board, it reads between 18 and 19.

I am afraid I don't have a 12V power source at hand.

Thanks for any help you can give. View attachment 134867View attachment 134868

I see 2x 12vin.

Have you tried The other one for S&G?

Perhaps it has to have power on both at same time or 1 is for regulated input and one is for Solar?

 

[Porkpie]

I see 2x 12vin.

Have you tried The other one for S&G?

Perhaps it has to have power on both at same time or 1 is for regulated input and one is for Solar?

Dang. Yes, both sides say 12Vin.
The listed specs on the board say 5-30V, so I thought the panel producing 18 would be fine.

What is S&G?

 

[Nobodybusiness]

Dang. Yes, both sides say 12Vin.
The listed specs on the board say 5-30V, so I thought the panel producing 18 would be fine.

What is S&G?

Shits and Giggles..?

 

[Porkpie]

Yes, I started with them soldered to the other side and it didn't work, so I tried jumpers to this side, which worked.
But when I moved them to this side it didn't work...until I jumpered it back.

Is it normal or common to have to power both sides? I am happy to do more soldering, I was just assuming that I don't know what I am doing here.

 

[Nobodybusiness]

Yes, I started with them soldered to the other side and it didn't work, so I tried jumpers to this side, which worked.
But when I moved them to this side it didn't work...until I jumpered it back.

Is it normal or common to have to power both sides? I am happy to do more soldering, I was just assuming that I don't know what I am doing here.

I have not seen many with 2 inputs but that doesn’t mean anything.

Without a manual it makes it difficult to ascertain.

Some of the guys on here can look at the PCB traces, components and tell you what’s going on.

 

[RCinFLA]

My guess is the side you have wired is for PV panel and VN2 is for battery since it appears to have a blocking diode.

The buck switcher, CN3903 just down converts to 5vdc for the USB Vbus.

https://www.aliexpress.us/item/3256802896188696.html

PV probably does not charge battery unless there is more circuitry on other side of board for charging battery from PV.

 

[Bud Martin]

Looking at the top side of the board, the 12Vin 2 has blocking diode for reverse polarity protection. In 1 does not have the protection, that is what I see on the board, not sure why you need to feed both Vin to make it works.

 

[RCinFLA]

Diode D3 on positive VN2 input has anode of diode connection on VN2 positive to block backwash from PV side into battery. Cathode of D3 likely connects directly to PV + input so with battery on VN2, it takes over supplying power if PV drops out.

The buck switcher may operate erratically if battery is not present on VN2. It could use some electrolytic filter caps on DC-DC converter input or PV inputs to help its stability. There will also be a lot of ripple current on PV panel from DC-DC converter that will reduce PV output efficiency.

 

[Porkpie]

My guess is the side you have wired is for PV panel and VN2 is for battery since it appears to have a blocking diode.

The buck switcher, CN3903 just down converts to 5vdc for the USB Vbus.

https://www.aliexpress.us/item/3256802896188696.html

PV probably does not charge battery unless there is more circuitry on other side of board for charging battery from PV.

Thanks RC.
Can I ask how you were able to identify this buck switcher? Do you just know what ones are used, or are there identifying features?
And no, nothing on the other side. I hoped to just plug this into a panel to charge phones or whatnot in case of power outage.

 

[Porkpie]

Looking at the top side of the board, the 12Vin 2 has blocking diode for reverse polarity protection. In 1 does not have the protection, that is what I see on the board, not sure why you need to feed both Vin to make it works.

Thanks Bud. That helps me understand more about how the board is laid out.

 

[Porkpie]

Diode D3 on positive VN2 input has anode of diode connection on VN2 positive to block backwash from PV side into battery. Cathode of D3 likely connects directly to PV + input so with battery on VN2, it takes over supplying power if PV drops out.

The buck switcher may operate erratically if battery is not present on VN2. It could use some electrolytic filter caps on DC-DC converter input or PV inputs to help its stability. There will also be a lot of ripple current on PV panel from DC-DC converter that will reduce PV output efficiency.

Thanks RC.

So, I could add an eight-pack of AA cells to the VN2, but that seems extreme.

Are the filter caps a cheap little thing I would solder inline from the PV on VN1?

So it seems like the board wants 12V input on both sides to be happy.

Do you have any thoughts on what the consequences would be of making permanent jumpers, assuming I continue to power with this panel?
Would I burn out the board, or burn out my phones?

I don't have a 12V plug I could use to test the output, so I was just going off an app on my phone...which seemed happy when I had it plugged in with the jumpers.

 

[RCinFLA]

Thanks RC.
Can I ask how you were able to identify this buck switcher? Do you just know what ones are used, or are there identifying features?

Just read the part number from second pict and searched for data sheet. Sorry could not find full data sheet.

'EPad' is back of package 'belly' pedestal pad for heat sinking. It is soldered to ground of PCB for heat sinking on IC.

Recommend you add two 500-1000 uF 25v-35v rated electrolytic capacitors on empty pads either side of C1. Positive side down in pict.

Battery would provide a fall back. If 5v is loaded more than just PV can deliver the 5v supply output will collapse and it may not collapse gracefully. It may have some chopping oscillations as it collapses. Battery would prevent this.

 

[Porkpie]

Just read the part number from second pict and searched for data sheet. Sorry could not find full data sheet.

'EPad' is back of package 'belly' pedestal pad for heat sinking. It is soldered to ground of PCB for heat sinking on IC.

Recommend you add two 500-1000 uF 25v-35v rated electrolytic capacitors on empty pads either side of C1. Positive side down in pict.

Battery would provide a fall back. If 5v is loaded more than just PV can deliver the 5v supply output will collapse and it may not collapse gracefully. It may have some chopping oscillations as it collapses. Battery would prevent this.

Thanks for your patience with me RC. If this was a carpentry project I would not be so clueless!
So, just to make sure I understand... I should add specified capacitors to the spots C2 and C6.
The longer lead on the capacitor will be positive, and I should put that on the "bottom" pad as shown in the first picture.
These will have to be surface mounted, as there are no holes through the board on those pads.

My soldering skills come from jewelry and plumbing...so I can see solder flow, but these things are very small. I have a pencil soldering iron that gets surprisingly hot.
Is there a great risk I will cook whatever that is in spot C1?

Thanks again