Photovoltaic Cell Enquirys

[jansonfinn]

Hi,

Would like to experiment with Photovoltaic cell. Anyone here familiar with it?

Lets say, I wanna use it to charge my Nimh batt. How should I buy go about buying the PV cells? By the Solar Cell Panel size or by the specs given by the manufacturer?

[foxkilo]

Spec voltage, current

You need to know how much voltage you need, and the current. From these two figures, you can purchase the solar cells - assuming you are not limited by other restrictions like space and weight.

The problem with solar cells is that the usual, commonly available stuff has low power output, so at higher voltages, the current output is really pathetic... 50mA or 100mA per piece of about quarter A4 page size approx. Ok, I guess for trickle charging NiMH or NiCd TX batts.

[foxkilo]

Forgot to add... you can then series connect or parallel connect these cells, to get higher voltage or current, just like ordinary batteries.

[Super-Hornet]

All the silicon based photovoltaic (or solar cell) are 0.5Volt (typical) per cell.

Just like Li-Poly or NiMH, each cell has the fixed voltage regardless about the size. The bigger the size, the higher the current it produced.

Because of the low voltage output per cell, normally it is connected in parallel in order to increase the current.

Other than to connect in parallel (to increase current) and in series (to increase voltage), you can also connect in series in order to increase the voltage to much higher. Higher voltage, u do not required thicker wires. Then at the end of it, u step it down to the voltage u want using DC-DC Converter.

SH

[jansonfinn]

I have a piece of Solar Cell Panel, but it seems faulty, as it doesn't charge the nimh. How do I check for the Solar Cell Panel?

1. Connect the volt meter at the polarity ends of the Solar Cell Panel
2. Put it under the sun
3. Get the readings from the volt meter

If readings on the volt meter = Solar Cell Panel is fine.
No readings on the volt meter = Solar Cell Panel is damage.

Is my assumption right?

[Super-Hornet]

Solar Cell behave just like a diode... this is because it has P and N junction.

Thus, if u use multimeter and set to Diode measurement or conductivity mode, you should be able to measure it like normal diode. That is, one side is conducting and the reverse will not.

But the easiest is definitely shine a light source to it, and then measure the solar cell using multimeter with negative probe on the top (facing light) and the positive probe at the back of the plate.

SH

[jansonfinn]

Solar Cell behave just like a diode... this is because it has P and N junction.

Thus, if u use multimeter and set to Diode measurement or conductivity mode, you should be able to measure it like normal diode. That is, one side is conducting and the reverse will not.

But the easiest is definitely shine a light source to it, and then measure the solar cell using multimeter with negative probe on the top (facing light) and the positive probe at the back of the plate.

SH

Thanks SH & Foxkilo for the info. Will test it later when I reach home.

[ManOnTheMoon]

hi,

just curious to know? the solar cells you are referring to?

do u know which type they are or how they look like?

I presume its a thin film type and not wafer- if so, what type of thin film? organic?silicon?

[jansonfinn]

@ManOnTheMoon, I'm not sure which type r they as they look all the same to me.

But I presume it is the silicon type, look like those used in the calculator.

@SH, the problem came from the detached wire. The cable is very thin & fragile, thinner then a strand of hair. Very difficult to solder compare to those lipos, motors, escs. Even the helping hand was not able to help me to hold the tiny cables & the solar cell

[Super-Hornet]

If your solar cell is like those silicon wafer type, then it is Silicon based.
If yours is those flexible type, a bit of translucent, then it is highly a organic type.
If yours is a sandwich of 2 glass, then it is amorphous type.

The armorphous has a sort of like copper color type and like those u normally seen in calculator. Those type... normally the contact is like those contact to LCD display type...which is considered very difficult to resoldered.

If yours is silicon based, then it can solder. It is normally etch with conductive material. U just have to solder onto the conductive material.

SH

[mh3400]

enjoying reading your replied

SH , u are living Encyclomedia

[ManOnTheMoon]

@ManOnTheMoon, I'm not sure which type r they as they look all the same to me.

But I presume it is the silicon type, look like those used in the calculator.

@SH, the problem came from the detached wire. The cable is very thin & fragile, thinner then a strand of hair. Very difficult to solder compare to those lipos, motors, escs. Even the helping hand was not able to help me to hold the tiny cables & the solar cell

i presume it should be amorphous then..Anyway, organic ones are cheap and have very poor lifetime.

i am not sure if these wires come impregnated with soldering flux. But soldering flux for solar cells is different (not sure whether slightly different or vastly different) but i once soldered electrical wire to a solar cell with usual soldering flux and it didnt hold.

but with actual flux that solar companies use to attach tabbing wires to silicon cells, it worked flawlessly..

So, am not sure for your case. you can probably get away with soldering it if you ensure the surface is very clean before soldering. Anyway, i presume if the LHS sell these kinds of cells, it should possibly be soldered at home.