5 watt "12 volt" solar panel

weirdjim

weirdjim

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weirdjim
I've used google, gone to the usual sources for offshore (alibaba, aliexpress, and all the rest) and have come up dry.

A "12 volt" solar panel has to be above 15 volts with a light load to let the MPP charger work its magic. THe problem is that none of the suppliers seem willing to share what their max voltage output is only that it will "charge a 12 volt battery" which is an ambiguous spec at best.

Yeah, I know there are tons of them on Amazon, but most of them are way above my design price point.

Anybody got a reliable source (domestic or offshore) for this rascal? It can actually be anywhere between 3 and 6 watts and meet the requirements of my design.

Thanks,

Jim
 
If you have the MPP controller, it can be any voltage above 15v as you mentioned. We built an off-grid solar system for a 12v system (for the Scouts and youth camping) with panels each providing over 100 volts. The MPP lowers the voltage and inversely increases the amperage. The MMP controllers have an advanced algorithm that are much more efficient than the others.
 
I design my own MPP controllers. I just need the right solar panel to go with it. As I said, I only need an inexpensive 3 to 6 watt panel. I'll optimize the controller as a function of max power output.

Finding an inexpensive one seems to be a problem.

THanks,

Jim
 
weirdjim said:
Anybody got a reliable source (domestic or offshore) for this rascal?
Click to expand...
Try Eco-Worthy panels on Ebay. Have bought a couple dozen from them. Most nominal 12 volt panels have an open circuit voltage of 22v and a max voltage (loaded) of 18v. They usually show the specs in the info chart.
 
Bell206 said:
Try Eco-Worthy panels on Ebay. Have bought a couple dozen from them. Most nominal 12 volt panels have an open circuit voltage of 22v and a max voltage (loaded) of 18v. They usually show the specs in the info chart.
Click to expand...

Thanks, Bell, I'll give them a try.

Jim
 
I have seen 18-23 VDC Max on a portable radio setup with a "12V" 5W solar panel.
 
IK04 said:
I have seen 18-23 VDC Max on a portable radio setup with a "12V" 5W solar panel.
Click to expand...
Yeah, me too. But my front end is good up to 45 volts so I think I can handle it. Besides the MPP on the device I'm looking at maxes at 18 volts.

Jim
 
A couple of ideas.
1) connect two solar arrays in series to get the voltage you need.
2) Buy or design your own DC - DC converter to generate a higher voltage. Wikipedia can get you started. Also, you might be able to modify a design for really high voltage supplies from a ARRL Handbook.(American Radio Relay League)
 
Crashnburn said:
A couple of ideas.
1) connect two solar arrays in series to get the voltage you need.
2) Buy or design your own DC - DC converter to generate a higher voltage. Wikipedia can get you started. Also, you might be able to modify a design for really high voltage supplies from a ARRL Handbook.(American Radio Relay League)
Click to expand...
(Chuckle)

I guess you really don't know too much about me, do you?

But thanks anyway.

Jim
 
I don’t think I have ever seen a 12V panel that wasn’t 18-22V open circuit. Not saying they aren’t out there, but the efficiency/current capability falls off if they don’t have a fair bit of headroom between rated and open circuit.
 
I looked at a couple panels and the data sheets tended to show Vmax power in the 17-18 volt range and V open circuit to be around 21-22 volts. Sounds like a little too stout for your project. Will keep looking and cogitating on it.



Siliconsolar.com might have what you need...
 
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If you're building the charger, is building the panel off the table?

You can buy individual cells from a supplier like Sunpower, they have real datasheets.
 
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