solar phone charger with buck converter - Page 1
Forum section: electronics / projects

author: Arcamax
author_rank: Regular Contributor
timestamp: February 04, 2015, 05:54:37 am
content: Quote from: Seekonk on February 02, 2015, 01:56:00 pmif i use this buck convertor should i still mod it with either zener or lm431http://www.ebay.ca/itm/DC-DC-Buck-Step-Down-Converter-Module-LM2596-Voltage-Regulator-Led-Voltmeter-/160995621268?pt=LH_DefaultDomain_0&hash=item257c163994Also does it matter what the input current of the solar panel to this converters output

author: Seekonk
author_rank: Super Contributor
timestamp: February 04, 2015, 02:46:02 pm
content: I suggest you re-read everything again. Without a circuit to control the input voltage at the panels power point voltage, a buck converter will overload the panels in low light levels. This may be beyond your capabilities. Your constant PMing is inappropriate.

author: Arcamax
author_rank: Regular Contributor
timestamp: February 04, 2015, 08:38:19 pm
content: so its a charge controller i need right.

author: suicidaleggroll
author_rank: Super Contributor
timestamp: February 04, 2015, 08:43:40 pm
content: YesPlease read this thread, it might give you some information about efficiently pulling power from a solar panel:https://www.eevblog.com/forum/beginners/dcdc-converter-that's-efficient/That's talking about a big multi-kW array for a boat, but the same principles apply to a small phone charger.

author: Seekonk
author_rank: Super Contributor
timestamp: February 04, 2015, 09:02:18 pm
content: The basic 2596 is sufficient, adding a display will just suck up power that should go to the phone. If you don't control the power point it will be less efficient. Solar panels are constant current sources. Draw too much current and the voltage drops like a rock.

author: Arcamax
author_rank: Regular Contributor
timestamp: February 05, 2015, 12:12:04 am
content: ok now i know i need a charge controller and that buck converterhttp://www.ebay.ca/itm/1-Pcs-DC-DC-Buck-Converter-Step-Down-Module-LM2596-Power-Output-1-23V-30V-EK-/201126191001?pt=LH_DefaultDomain_0&hash=item2ed40e1f99and you guys say more voltage of solar is better, so should this 18v be good enoughhttp://www.ebay.ca/itm/1PC-3-4W-18V-188mA-Mini-Solar-Panel-Module-System-Epoxy-Cell-Charger-DIY-B045-/311007312320?pt=LH_DefaultDomain_0&hash=item48697af9c0or do i go less current

author: Seekonk
author_rank: Super Contributor
timestamp: February 05, 2015, 03:00:34 pm
content: I wrote a long reply, but site timed out and I lost it. I think I'll just wait till you stop spinning.

author: Arcamax
author_rank: Regular Contributor
timestamp: February 05, 2015, 04:44:18 pm
content: hmmm what

author: Arcamax
author_rank: Regular Contributor
timestamp: February 06, 2015, 07:03:19 pm
content: ok then i think ill get these items then1-step-down dc regulator, looks OK/genuine.http://www.ebay.ca/itm/DC-DC-LM2596-Step-Down-Adjustable-Buck-Converter-Power-Supply-Module1-5V-35V-/360672163864?pt=LH_DefaultDomain_2&hash=item53f9bc78182-probably my own diy charge controller3-this solar panel,http://www.ebay.ca/itm/18V-2-5W-Solar-Panel-Module-Solar-System-Solar-Cells-Charger-DIY-120x194mm-Mini-/361099099137?pt=LH_DefaultDomain_0&hash=item54132efc01(try the ones i have again first). it doesn't matter what buck converters input current from solar and controller does it, the panels i have now are low? mine supposed to be 80mA(max i think)4-zener in case of failure.