Hi, as a family hobbie project Im trying to build an rc solar car. In this first step im trying to make it work but a cabled controled, later i would like to try and use a arduino as controler. I was trying to find an easy way of making a car work in lower solar radiation or when the car neebs more energy that the panel can provide. I found this video XL4015 Solar PV USB & Motor Linear Current Booster - YouTube but i have some noob questions:
You have to build the voltage divider so that the output voltage at the panel optimal point lands in the activation voltage of the mosfet right?
What are those black triangules in the circuit?
What mosfet should i use.
Is there any better way of building something like this?
Thanks in advance
That's just a MPPT controller - it will help optimise the output from your panels, but it can't magically create power in the absence of sufficient light!
You'll need a battery to be able to store energy from when there's a surplus, and deliver it when the motor needs.
This is what hybrid cars do (with a small ICE instead PV).
Electrical power (Watts) is calculated as Voltage x Current. When you boost the current you have to reduce the voltage and when you boost the voltage you have to reduce the current.
With a switchmode voltage regulator that reduces voltage anyway, this can be uses as an advantage because you can get more current out of the regulator than you feed-in.
Swithmode regulators can be very efficient but linear voltage regulators don't boost the current. They just waste the extra energy.
Transformers (for AC voltage) are also very efficient. A 120V to 12V transformer can put-out 1A at 12V while "pulling" a little more than 100mA from the120V power outlet.
Hi again,
Thanks for the anskers. I know it won't generate more power, but keeping the panel in the optimal voltage will keep energy flowing to the motors rather then lowering the voltage to 0 with results in 0 energie transfer.
My questions were in the direction of trying to implement that circuit test it out.
Could you guys give me some help?
Thanks in advance
Hi,
So this circuito in the video won't boost the current? I tought that if you had like 12v 1a on the painel, you could get like 6v 2a.
Could you recomend any switchmode regulator?
Thanks in advance
No, there are typically 10-20% losses in the conversion, so you might get 6V 1.8A.
Use your multimeter to measure the power output (voltage x current) of the solar panel under cloudy conditions and report back.
Hi,
I measured and i got around 7w with about VOC od 18.8v.
I have been looking around and I found a circuit that uses two capacitor that are dicharged to the motor. Don't know if thats an option too.
Thanks in advance
See post #2; for "battery" read "capacitor" - or, to be generic, "energy store"
Thanks for all the help.
So even if I use a battery I have to use a charge controlar with mppt would be ideial.
Would that circuit in the video do it? Or can i use a arduino to create such a circuit?
Thanks in advance
Adafruit sells one.
I dont think they can take a 12v panel,
What about something like this:
http://www.voltscommissar.net/minimax/minimax.htm
Thanks in advance
Hi, @bombix
Can you please give us some specs on your car?
Battery size, Ah, V
Motor specs.
Vehicle mass.
Systems range with existing hardware.
Is the RC car of anything specific competitions of some sort or just recreation.
Thanks.. Tom..
Hi @TomGeorge,
The car is not for a competition but is based in one i saw with my son. Its actually inspired by the australian solar car challenge.
In this case i use those yellow arduino gearboxes to make an 4 wheeled veicule.
My original plan was not to use any batteries.
The veicule weights at the moment 1,4 kg.
Thanks in advance
Hi,
What surface area of PV are you aiming to use?
This will govern the amount of solar energy you will be able to collect and indicate if a PV would be viable to supply some reasonable charge to your batteries.
Thanks.. Tom..
6V at 1 to 2 Amperes should do. I suggest a 5xAA NiMH battery pack, as they take a lot of abuse, and any solar panel with voltage > 7V to charge it. No charge controller is needed with small panels, just a voltage regulator.
Nice,
I just wondering, the maximizer circuit discharges two caps to keep the panel at the max point.
Can i simulate such a circuit with an arduino?
Thanks in advance
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