1 volt Usb charger

Tzashi

Im wondering if I can charge a phone battery which I think runs of 3.5 or so volts of a 1Volt solar panel, how quickly the charge is doesn't matter just that it is charging

ShRT

Tzashi wrote: »

Im wondering if I can charge a phone battery which I think runs of 3.5 or so volts of a 1Volt solar panel, how quickly the charge is doesn't matter just that it is charging

The phone battery will be at 3.7v and requires a special charging chip to manage the charging. These typically take in 5v so you would need to boost your voltage from the panel to the 5v. Again you can get boost chips but these take in more than 1v typically.

1 volt that's two cells. Pretty useless unless you can put more of them in series.

The charger is built into the phone. What most people refer to as phone chargers are constant voltage supplies.

If you can get >9V solar, a car USB power socket and the phone that came with the battery then Bob's yer Uncle.

Solar cells are current sources, you won't see max. rated volts unless they're at peak output or open circuit.

You can charge a li-ion/ni-cd cell with 4VDC from any source but it'll probably explode if you overcharge it..the lithium ones especially.

Those E-cigarettes have the 5V charge regulator you need; pretty low current though...150mA iirc.

Usually it's solar to battery (storage) to regulator to appliance (phone battery + charger). The battery will help regulate the fluctuating PV output and buffer the supply. The regulator is to keep the power within the confines of your appliance's acceptable thresholds.

Tzashi

I have 8 solar cells, if I put 5 im series to bring ot up to 5 volts and then the rest in parallel would that work?

ShRT

What is the rated current output of the cells? Or do you have a link to where you bought them?

Tzashi

Tzashi wrote: »

I have 8 solar cells, if I put 5 im series to bring ot up to 5 volts and then the rest in parallel would that work?

Not unless it's incredibly sunny.
They're a current source not a voltage source.
I'd aim for at least 8V. So a single string then.

Tzashi

rapidonline(.)com(/)Electrical-Power(/)Small-Solar-Panel-1V-150mA-37-0438?sourceRefKey=w5xHP9-ZC&filterSearchScope=1

sorry cant post full links

Honestly its really just a proof of concept like it's part of my technology leaving cert project, the panels track the sun using a stepper motor for 360 x-axis movement and a servo for 90 y-axis movement, i was going to connect the panels to a USB and then have it charge a phone or something, like as a last resort i can have it power some leds or something but i think the USB idea is really cool

150mA!

Sounds like over-engineering to me. No offense and not to be discouraging I'd love to see it working if you follow it through. The Y axis is hardly significant, the X access only needs ~180° travel. By the time you power a battery charge controller, photocell, servo controller, stepper motor, phone charger, I'd be surprised if you have a net gain.
Also you have to be very clever about the servo control otherwise it will waste a lot of energy tracking the sun behind cloud and shading when it ought to be steadfast.

The scale is too small imho. If you were to go for a >100W module, a hydraulic ram, a few photodiodes or clever box that reads the panel output with manual tilt and 12V lead acid @ >80Ah then you'd be expecting 20% gain over a fixed panel and a whole lot of moving parts that require maintenance.

For simply charging a phone I'd stick one of these in there, and to be honest I wouldn't bother with the solar on a cost versus return basis.

Having said that I do charge my phone (amongst other loads) on a 150W module, manually tracked when I can be bothered, 225Ah@ 12V and a 45A solar controller.

Tzashi

Well all that will be working off a 9V battery its meant to be a proof of concept, its a trailer with all this attached to it, full scale there would be a much larger surface area able to power alot more. I mainly just wanna know if it will show the charging icon when its plugged in

ShRT

/switches on educational mode

Seeing as its for a LC project i'll try and guide you in the right direction rather than hand hold.

1) Have a look at your own phone charger to see what it says on the charger in terms of mA and V output - you now know your power requirements.
2) As your phone charges via usb, check out the usb power spec
3) Check out voltage regulators and how they work. (LM7805 is a good search term)
4) if you have access to a power supply (like this one) set the voltage to one specified for your phone and the current to 150mA and see does it charge.
5) Don't forget to see what the output of the panels is when the sunlight is low
6) Replicate that on the power supply to see will it charge your phone.

Out of interest, how are you going to control the stepper and servo?

Trailer like a car trailer?
Stick a decent battery in the middle let the pv charge the big battery in it's own time and run your loads off that.

Better off with 6V batteries with 9V PV (if you can get a low drop out regulator) or 12V batteries with 18V PV(if you get more PV cells) because you can get decent battery sizes cheap. Have a look at house alarm batteries + buck converter/5V regulator.
Charge light guaranteed, now as to whether 150mApeak PV can keep up to that demand longterm and run all it's ancillaries...well I'm sure you'll find out.

Tzashi

The stepper motor im using requires 12V so ill probably run the circuit off that, im using the genie E18 board, ive got 3 LDRs used as a comparator so i can program the stepper and servos, i was planning on leaving the solar cells in a separate circuit but i guess i could charge the battery with it, the problem with that is there is no obvious way of showing that the solar cells are working

Tzashi

Tzashi wrote: »

i guess i could charge the battery with it,

You need ~15V to charge a 12V battery, and your lekytronics won't like the variable charging voltages. Best rate the solar panel 150% battery voltage.

Tzashi wrote: »

the problem with that is there is no obvious way of showing that the solar cells are working

Ammeter?

Tzashi

well yeah i could use an Ammeter of course but i guess i just wanted it to be cooler because thats how you get the marks

Pity you don't get marks for keeping it simple. Big panel -> charge controller -> big battery -> car charger -> charge phone -> call a man about a rear axle hub with thrust roller bearings and get started on the wind turbine...much better if ya ask me.
Integrate a zero centre ammeter in the circuit anyways and carry on with your design, then you can see charge and draw. Presto extra marks!

Tzashi

Sir Liamalot wrote: »

Pity you don't get marks for keeping it simple

I know but hey for my own side projects i'll keep things simple, btw anyone have any Irish electronic suppliers or electronic retail shops in dublin area, id rather support out economy rather than england haha

Radionics
Farnell

Biggest problem I see you having is because you are working at such a small level your control electronics are going to consume much of your power harvest. When you up-scale the electronics will run for the same power but a much lesser proportion of the whole and a well balanced ram doesn't take a lot to run on intelligent software.

Best of luck with it anyways. Photons can get mad addictive.