Question about Solar Phone Charger

[Guest]

Im just wondering if this MPPT can handle 20Volt at 2 Amps

Can someone help me clarify this?

http://www.ebay.com/itm/5V2A-USB-Reduce-Stabilize-Voltage-Board-DIY-Kit-Cover-for-Solar-Fold-Bag-Charger-/262179215102?hash=item3d0b1956fe:g:egMAAOSwMmBVr5n3

Features and uses:

This product is mainly used in solar folding bag and solar charger, which can be any of Apple and other mobile phone, MP3, MP5 and other digital products charge.

1. Wide input voltage range, the input DC voltage 6 ~ 20V, 5V DC output voltage can be stable.(INPUT : Photovoltaic panels 6-20V, best for 9V; DC power supply 5-20V, best for 7.2V)

2. Can the maximum output current of 2A.

3. High conversion efficiency, up to 95%.

4. Industrial Temperature Range: -40 ℃ ~ + 85 ℃

5.USB female output, may be any 5V digital products charge.

6. matching plastic shell, more beautiful shape.

[Sunking]

I can tell you right now it is not MPPT by looking at the picture of the Circuit Board. It is PWM. The second dead give away is its price. The only way it can possible deliver 2-amps is if the panel Imp = 2 amps. For that controller you want to use a panel with a Vmp of 6 to 7 volts with an Imp of 2 amps. That would be 6-volt 12 to 15 watt panel.

Catch is if you were to use say a standard 12 volt battery panel with a Vmp of 18 volts and Imp of 2 amps is a 40 watt panel.

The controller is a POS Chi-Com made equipment.

[Guest]

So a Panel that is
20 Volt @ 2 Amp wouldn't work?

Kewl its a PWM Now I know.

Each string produces about 3.40 volt @ 0.34 Amp
36 Cells total. I plan to put in series

[Sunking]

So a Panel that is
20 Volt @ 2 Amp wouldn't work?

It might but you need to know the specs. A 12 volt 40 watt battery panel has Vmp of 18 volts and Imp of 2 amps. Stating 20 volts at 2 amps is inconclusive jibberish.

Any 12 volt battery panel has a Vmp of 16 to 18 volts and a Voc of 22 to 24 volts. The gotcha is Voc. I have no idea what the Voc of this mystery 20 volt 2 amp panel is. If the Voc is 20 volts or higher, don't use it.

What you want is a panel with a Imp of 2 amps, and a Voc or no higher than 20 volts. Ideally you want a panel with a Vmp of 6 to 8 volts and Imp of 2 Amps. A panel with a Vmp of 6 to 8 volts will have a Voc of 10 to 12 volts well below the limits of the controller maximum Voc of 20 volts GOTCHA. Go to 20 volts or higher Voc, and you will let the magic smoke out of the controller.

Ideally you want a 6-volt 20 watt battery panel. Such a panel will have a:

Voc = 11-12 volts
Vmp = 8 to 9 volts
Imp = 2 Amps
Isc = 2.2 to 2.5 amps

Do not under any circumstances exceed 2 amps Imp or 20 volts Voc.

Thanks I will have to research this more tonight.

[Guest]

You Got Me.

I dont know what Voc Vmp or Imp is.. Im sorry Im just not that technical into electronics

I just hope this one works. Ive tested the chip on few solar panels already but nothing as big as this one.

I just learned what a Pulse width modulation is...

[Guest]

What I mean to say is that. My solar panel has a maximum of 20.4 Volts and a maximum of 2.28 amps.
I tested 1 string of cells With my 500watt Lamp

So I tested how much the solar panel will handle

I know in direct sunlight I wont go over 2.00 amps

[Sunking]

give it a try and see what happens. If it smokes you are out $6 for the controller. No big deal, the panel or battery will not be hurt.

[Guest]

I like that attitude! haha

[Sunking]

I like that attitude! haha

I can fix it. Get yourself a few diodes wired in series to drop the voltage of the panel.

[Guest]

I can fix it. Get yourself a few diodes wired in series to drop the voltage of the panel.

Should I connect a Diode in this system anyways? or does the PWM handle all that? Im losing power during non-sunny day

Are you suggesting I could get a Diode that is 1amp 20V. Why not just 1 diode instead of many. I know its probably cheaper but Idk about cheaper

[Guest]

Ive been testing the panel today And the panel gets alittle over 20V, Testing it with my 500watt lamp No smoking or nothing, Its charging fine. Cant wait to test in sunlight to see how much amps it will truly make.

[Sunking]

[QUOTE=GoldCobra;n317516]

Should I connect a Diode in this system anyways? or does the PWM handle all that? /QUOTE]If you are seeing voltages 20 or more yes. A Diode will just drop the voltage 0.6 volts, and will not affect current. So 4 Diodes would drop the voltage 2.4 volts. Will not cause any problem with the controller. It will just help keep the Magic Smoke in the controller where it belongs.

Like I said, its a $6 controller. If you Smoke it, gget another one with some diodes. Make sure the Diodes are rated for at least 2-amps. Diodes are dirt cheap. If you got any old TV's, Radios.ect you can find and salvage them. If you have any old time TV fix it shop they have a lot of them just lying around. Any Ham radio operator or radio shop will have them. If you live in a city Ham Radio Fest are about to start in the Summer. There weill be thousands of Diodes there. You can buy a bag full of them for a buck at a Ham Radio Swap. Hell if you are a kid one of the ole fossils will likely give them to you.

[Guest]

Im not worried about these controllers. Ive got over 20 of them I can smoke a bunch.
Today is a sunny Day I will test with only 1 diode in it.
I dont forsee any problems