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Solar panel example for LT-Spice?

Started by Peabody May 25, 2021
I'm working on a TP4056-based 1S LIPO solar charger which includes a load 
sharing (aka power path) function. But I don't have a panel to test with.  
So I'd like to simulate the circuit in LT-Spice.

But I've never used spice, LT or otherwise, so I was hoping to find an 
example of a solar panel equivalent circuit that I could import, then add 
the rest of the circuit, which is pretty simple.

Can someone suggest where I would find such a file?  It would be something 
like a 5V panel, 200mA.


On Tue, 25 May 2021 19:14:37 -0500, Peabody
<waybackNO584SPAM44@yahoo.com> wrote:

>I'm working on a TP4056-based 1S LIPO solar charger which includes a load >sharing (aka power path) function. But I don't have a panel to test with. >So I'd like to simulate the circuit in LT-Spice. > >But I've never used spice, LT or otherwise, so I was hoping to find an >example of a solar panel equivalent circuit that I could import, then add >the rest of the circuit, which is pretty simple. > >Can someone suggest where I would find such a file? It would be something >like a 5V panel, 200mA. >
Wild guess to open discussion: a string of silicon power diodes with a parallel current source that represents illumination. LT Spice is great. It shouldn't take long to enter and run a circuit; ask here if it doesn't work. There are no doubt a lot of tutorials on youtube.
On Tue, 25 May 2021 19:14:37 -0500, Peabody
<waybackNO584SPAM44@yahoo.com> wrote:

>I'm working on a TP4056-based 1S LIPO solar charger which includes a load >sharing (aka power path) function. But I don't have a panel to test with. >So I'd like to simulate the circuit in LT-Spice. > >But I've never used spice, LT or otherwise, so I was hoping to find an >example of a solar panel equivalent circuit that I could import, then add >the rest of the circuit, which is pretty simple. > >Can someone suggest where I would find such a file? It would be something >like a 5V panel, 200mA. >
Get a panel. You may have to settle for 12V, based on availability from current consumer cast-offs. RL
On 05/26/2021 02:14 AM, Peabody wrote:
> I'm working on a TP4056-based 1S LIPO solar charger which includes a load > sharing (aka power path) function. But I don't have a panel to test with. > So I'd like to simulate the circuit in LT-Spice. > > But I've never used spice, LT or otherwise, so I was hoping to find an > example of a solar panel equivalent circuit that I could import, then add > the rest of the circuit, which is pretty simple. > > Can someone suggest where I would find such a file? It would be something > like a 5V panel, 200mA. > >
Put this in your standard.dio: *I_DD=Isc-Voc/Ri=8.563-0.622/1.156=8.024 *I_s=300n(guess) *U_T=26mV *U_D=0.622 *n*U_T*ln(I_DD/IS)=U_D *n=U_D/(U_T*ln(I_DD/IS))=1.398 *duh.. have2guess for a better fit *I_s=3n .model PVCELL D(Is=3n N=1.1)^M This in an .asc: Version 4 SHEET 1 988 812 WIRE -288 192 -288 176 WIRE -288 704 -352 704 WIRE -288 768 -352 768 WIRE -192 176 -288 176 WIRE -192 176 -192 64 WIRE 64 64 -192 64 FLAG -192 256 0 FLAG -288 768 0 FLAG 64 144 0 SYMBOL current -192 256 R180 WINDOW 0 24 88 Left 0 WINDOW 3 24 0 Left 0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName I1 SYMATTR Value 8.563 SYMBOL diode -304 192 R0 SYMATTR InstName D1 SYMATTR Value PVCELL SYMBOL diode -304 256 R0 SYMATTR InstName D2 SYMATTR Value PVCELL SYMBOL diode -304 320 R0 SYMATTR InstName D3 SYMATTR Value PVCELL SYMBOL diode -304 384 R0 SYMATTR InstName D4 SYMATTR Value PVCELL SYMBOL diode -304 448 R0 SYMATTR InstName D5 SYMATTR Value PVCELL SYMBOL diode -304 512 R0 SYMATTR InstName D6 SYMATTR Value PVCELL SYMBOL diode -304 576 R0 SYMATTR InstName D7 SYMATTR Value PVCELL SYMBOL diode -304 640 R0 SYMATTR InstName D8 SYMATTR Value PVCELL SYMBOL diode -368 704 R0 SYMATTR InstName D9 SYMATTR Value PVCELL SYMBOL current 64 64 R0 WINDOW 123 0 0 Left 0 WINDOW 39 0 0 Left 0 SYMATTR InstName I2 SYMATTR Value PWL(0 0 1 8.563) TEXT -370 796 Left 0 !.tran 0 1 0 0.001
Apologies,

A phony carriage return slipped in...
More correct:

*I_DD=Isc-Voc/Ri=8.563-0.622/1.156=8.024
*I_s=300n(guess)
*U_T=26mV
*U_D=0.622
*n*U_T*ln(I_DD/IS)=U_D
*n=U_D/(U_T*ln(I_DD/IS))=1.398
*duh.. have2guess for a better fit
*I_s=3n
.model PVCELL      D(Is=3n N=1.1)


On 26/05/2021 02.36, John Larkin wrote:
> On Tue, 25 May 2021 19:14:37 -0500, Peabody > <waybackNO584SPAM44@yahoo.com> wrote: > >> I'm working on a TP4056-based 1S LIPO solar charger which includes a load >> sharing (aka power path) function. But I don't have a panel to test with. >> So I'd like to simulate the circuit in LT-Spice. >> >> But I've never used spice, LT or otherwise, so I was hoping to find an >> example of a solar panel equivalent circuit that I could import, then add >> the rest of the circuit, which is pretty simple. >> >> Can someone suggest where I would find such a file? It would be something >> like a 5V panel, 200mA. >> > > Wild guess to open discussion: a string of silicon power diodes with a > parallel current source that represents illumination. > > LT Spice is great. It shouldn't take long to enter and run a circuit; > ask here if it doesn't work. There are no doubt a lot of tutorials on > youtube. >
Yes, back when I was doing a MPPT function in a Space design, we just used the diode string for simulation and test Just remember to add a lot of capacitance, since that can be huge on solar arrays Cheers Klaus
Johann Klammer says...

 > Put this in your standard.dio:

Thanks very much.

Can you tell me what all of that produces - in terms of the
open circuit voltage and the short circuit current of a
panel?  Sorry to be so dense, but I have no experience with
simulation at all.  So does all of this create a new
"device" that I can place on the schematic?

On 05/27/2021 04:25 AM, Peabody wrote:
> Johann Klammer says... > > > Put this in your standard.dio: > > Thanks very much. > > Can you tell me what all of that produces - in terms of the > open circuit voltage and the short circuit current of a > panel? Sorry to be so dense, but I have no experience with > simulation at all. So does all of this create a new > "device" that I can place on the schematic? >
It's all guesses. bad ones. I tried to calculate an N. but it turned ot wrong. so it's trial and error basically. (the lines starting with * are all comments)