Author Topic: Solar Project question/suggestion needed  (Read 2396 times)

Offline Greekman

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Solar Project question/suggestion needed
« on: May 23, 2017, 11:59:47 AM »
Well, i would like the members' viewpoint on what I intend to do.

For the time being I will be buying 4 3W solar panels to make a small appliances solar system (charging battery banks and a 7+Ah SLA battery)
Initially I was thinking of connecting the panels in such a way as to have either a 19V (4S) or a 5V (4P) output. Purpose was to skip the 19 to 5V converter.
(I have designed the wiring and switching method, and it is easily workable)

But now I wonder if it worths the trouble. What do you think?

Offline Carl

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Re: Solar Project question/suggestion needed
« Reply #1 on: May 23, 2017, 01:02:14 PM »
 :popcorn:  MMMM..popcorn with Lithium has a hearty flavor.
I would suggest a 12 volt system to then power proper Lithium Ion chargers etc as you do not have the panel count for charging a 4S battery pack ,in my opinion.

Offline Greekman

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Re: Solar Project question/suggestion needed
« Reply #2 on: May 23, 2017, 04:04:07 PM »
no i meant regular power banks that are USB charged, not the DIY style

Offline Carl

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Re: Solar Project question/suggestion needed
« Reply #3 on: May 23, 2017, 06:37:26 PM »
Good luck.

Offline kid_couteau

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Re: Solar Project question/suggestion needed
« Reply #4 on: May 25, 2017, 03:43:06 AM »
This is just my thoughts on it.
Aim for at least 50 watts minimum for panels.

Solar is not as powerful as the youtube vids make it out to be.

I am planning on doing something similar as you and for a 7AH SLA battery if you want to charge it in a day go at least 50 watts.

HTH
Kid

Online iam4liberty

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Re: Solar Project question/suggestion needed
« Reply #5 on: May 25, 2017, 06:10:40 AM »
But now I wonder if it worths the trouble. What do you think?

Parallel would allow you to add panels one at a time to the system if you find you need faster charging.  Plus, it is more resiliant.  If a panel gets damaged you can simply remove it and still have a working system without other modifications.

Offline Carl

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Re: Solar Project question/suggestion needed
« Reply #6 on: May 25, 2017, 06:31:49 AM »
I would not suggest power-bank USB devices for power as the batteries are temperature sensitive and usually the solar panel is of little use as few produce the expected power. a single 50 to 120 watt panel with a charge controller will be far more useful when combined with an 18 to 50 amp hour battery.There are 20 to 50 watt 12 volt systems but often at way more cost than they are worth and AVOID folding panels as they do not handle sun and weather and folding for much use and are more a gimmick (toy) than usable power source.

  Solar panels are rated at max voltage times max current and a 60 watt panel is 20 volts times 3 amps ,so when you actually USE it ,you will see the 3 amps ,while in peak sun (5 to 6 hours a day for my location)and the 12 to 14 volts of your battery means you get 36 to 42 watts at max efficiency from  a 60 watt panel . This is the way of the world. Solar is great in places other power is not available,but really not an economical power source also when a mobilized power bank has a problem...the whole system will suffer. Also,a single leaf from a tree on my panel will drop it's output to well under 10% of it's capability.

Just my thoughts.