Voltage Regulating Circuit Recommendations

[Sunim]

Hello,

What do you think about a simple Zener Diode voltage regulator such as this
http://www.electronics-tutorials.ws/diode/diode_7.html

vs a pre-made voltage regulator such as this:
http://www.mouser.com/new/Texas-Instruments/ti-tlv333-regulator/

I'm hooking up two solar panels (20W each) and I want to keep a constant 12 volt current. I would prefer to have a very low dropout voltage.

I understand the Zener Diode regulator so I want to go with that one. But it I feel like I'd be better off with a pre-made setup.

 

[Bluejets]

12 volt is voltage not voltage current.
Low dropout refers to a low difference input to output, not a thing I would imagine you would have a problem with considering you are using solar panels.
If you give some indication of where this is headed it might be more helpful.

 

[Scotophor]

Both of those voltage regulation solutions are linear, which means inefficient. However, if your solar panels are sufficiently oversized for the expected load, then inefficiency doesn't really matter in this situation. Please tell us more about this project, such as what you will be powering.

 

[Sunim]

woops, yeah meant 12 volts and efficiency.

The solar panels are advertised to be 20W each.
I haven't had a chance to do a good measurement on them because it's been cloudy the past two days. But with partial cloud cover one of them had an open circuit voltage of about 8.5V.

I'm trying to charge this device...

http://www.amazon.com/gp/product/B00HFMUBYG/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

 

[Sunim]

hmm, it seems solar panels are not as easy as I thought. This is the one I have.
http://www.amazon.com/X-DRAGON-Effi...417914374&sr=8-1&keywords=xdragon+solar+panel

It's looking like it will be much easier just to use this one to charge my phone/tablet and get a different one if I want the battery charged as well.

It looks like a non-linear regulator would be something like an MPPT? such as - http://www.freechargecontroller.org/ ?

 

[(*steve*)]

The "best" method to use these would be to connect two or more in series and then use a MPPT regulator to charge a battery, and then use that battery to power your 12V charger for the phone or tablet.

This way it will work even at night.

If you place both in series, AND if your charger can cope with the full open circuit voltage AND the total power required is less than 20W THEN it may be acceptable to just power the charger from the panels connected in series. However it will drop out (and may be slow to recover) as clouds pass, and certainly it won't work at night

 

[Sunim]

Thanks Steve! I'll have to think about it. Not sure if I want to use it without a MPPT, but those seem to be hard to find for this application.