solar boat having solar panel power problem

ashish7811

i have made solar boat having 4V 400mA rating solar panel. when i put under sunlight there is no problem
but i have to run it under helogen light so when i put it undet bulb then it gives me only 200mA current at 25 cm distance i can't decrease distance i m using 1381 solar engine using 5.5V/1F gold capacitor
so problem is my motor cannot get enough initial torque to get start and i cannot observe charging and discharging of capacitor
now what should i do?

Danger

Welcome to PF, Ashish.
I suspect that it's because the halogen light's restricted frequency range covers only half of what your cells are designed to work with. Wait for someone else to answer before acting, but my initial suggestions would be to either replace the halogen source with full-spectrum fluorescents or switch to cells that are attuned to the specific output of halogens.
Those would probably be either too expensive or physically/practically not achievable. Other than that, all that I can think of is to double the number of cells that you use, or find some way to collect and concentrate the available light to double your watts/metre^2.

Yeti08

That depends on what you can modify - the light bulb? the solar array? the distance? the motor?

Solar cells are tricky since they are rarely exposed to the conditions at which they are rated.

OmCheeto

I would recommend measuring the voltage across the capacitor.
I would then find the suffix on your 1381.
If the voltage across the capacitor does not reach the rated trigger voltage of the 1381 device, your boat will never run.


ps. everything I know about the 1381 solar engine I've learned in the last 10 minutes.

ashish7811

no i am using 1381I(2.7V trigger voltage)
and bullet high torque motor(150-160 mA at no load condition ,2000-3000 rpm )
but boat is working not like under solar light
i cannot change my distance and halogen flourescent tube?
should i change motor or
what if i connect 4V 200mA and 0.5V 750mA two solar panel in siries or parallel?
ad one another thing i have to run boat in tunnel having 300 cm lengh so what should i do ? i cannot observe chrging and discharging of capacitor!

OmCheeto

I don't understand. You can read the 200ma from the solar panel, but you cannot read the voltage across the capacitor? Does this mean you only have an ammeter? That would be nonsense! How can you do experiments without proper test equipment?

ashish7811

no u could not understand properly i have multimeter.what indicate voltage across capacitor. and what should voltage across capacitor?

OmCheeto

The voltage should go up to 2.7 volts and then the motor should start.

ashish7811

no i told u my boat is running

DaveC426913

What you told us is:

ashish7811

ya can change simple 3V 2000-3000 RPM instead of bullet high torque motor
or should i change i circuit to get more power at a time?

sophiecentaur

A capacitor is not a good storage medium for the energy from a solar cell. The stored charge is only CV and the volts are very low. I suggest that the starting current for the motor is enough to discharge the capacitor so much that it never gets going.
The only way around that would be to charge several capacitors in parallel then connect them in series to get more volts. That's why they use rechargeable batteries - they have a nearly constant voltage / charge characteristic!
Also, have you observed the voltage on the capacitor with the solar cell charging it and without the motor connected? Perhaps it is never actually charging to the required voltage. You could wait for the C to charge up then connect it.

I have also been very disappointed by solar cell performance under tungsten light. They go far better when there's a lot of blue and UV!

ashish7811

hi can anyone tell me where i can get solar panel(having higher current rating)?

OmCheeto

Yes.

5 watts for $40
10 watts for $108
10,000 watts for $36,000, but I think you'll need a bigger boat.