How to use a solar panel

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  #1  
Old 09-30-19, 11:16 PM
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How to use a solar panel

I would like to use a solar panel this winter for keeping small electronic devices charged.

I am thinking of purchasing a Renogy 100 watt panel.
https://www.amazon.com/Renogy-100W-S..._1569857480051

I have never used a solar panel. I like this one because it says "Bypass diodes minimize power drop caused by shade and ensure excellent performance in low-light environments."

Since there is not a lot of sun in winter I thought this might help. Also, it says the junction box is waterproof. Another 'must have' feature as I do not want the bother of bringing it inside every day.

I have watched a few YouTube videos, and have come to a conclusion that I will need something, like maybe an inverter? to go with the solar panel.

Don't have any deep cycle batteries or anything like that, just want to keep my phone, laptop, tablet, and headphones charged up.

Could anyone explain what would work for this idea. Maybe this panel isn't the right choice, but it would need to work in cloud cover, and also be left outdoors.
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Old 10-01-19, 04:13 AM
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Without any battery you will be limited to only charging devices when it's sunny. Keep in mind that most solar panels are 12 volts and the devices you wish to charge likely need a different voltage so you will need some way to convert.
 
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Old 10-01-19, 06:01 AM
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In addition to what Pilot has said, 100 watts is reasonably large capacity and you need a charge controller to prevent over/under charging.

If you look closely at the item listing there is a diagram of what you need in addition to the panel for a working system
 
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Old 10-01-19, 08:52 AM
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I have a YouTube video that mentions a pure sine wave inverter for charging delicate electronics. If you 'fast forward' to 4:20 you'll be where I'm talking about. This is the link.

https://m.youtube.com/watch?v=lB8q20QX6bA&t=365s

I'm just wondering if there is a budget friendly inverter I could use to fast track everything without spending more than I can afford. Then later I could get the c​​​​​​​ontroller and
whatever else might be needed​​​​​​.
 
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Old 10-01-19, 09:51 AM
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No.
You first need to make clean and stable 12 volts DC power before you can make use of it.
It is only very small solar panels that can get by without a charge controller........like on a solar butterfly garden light.
 
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Old 10-02-19, 03:24 AM
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Decided on this one:

https://www.amazon.com/gp/aw/d/B074G...0Y2D5AGH&psc=1

Already has a controller which is supposed to have a usb port.

It's waterproof so I can just leave it out. It also says "Excellent performance in low light conditions". These were my two 'must haves'.

I might get a battery later, I don't know.

Thanks for helping.
 
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Old 10-02-19, 04:48 AM
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That is still a very large panel for charging a phone or tablet.

Keep in mind that a charge controller is there to protect a battery from over charging when connected to the panel. Without a battery it won't be of much use but it will come in handy if you get a battery.

One thing to watch out for is many solar panels quit producing power if part of the panel is shaded. So, make sure you have the panel exposed to full sun.

Some of the devices you said you wanted to charge may require different voltages. Make sure your chargers will work with the potentially high (18 VDC) output of the panel or that you are using converters that can handle that voltage. What power does your laptop charger require?
 
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Old 10-02-19, 07:22 AM
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I'm leery of buying a battery because they are so heavy I can't lift them, and also, the whole idea of can't deplete beyond a certain level or the battery is ruined, which then brings up the cost. They're pretty pricey from what I know.

If you know of a battery that would work with my small electronics work load, and is not too heavy or pricey, I'd like to know.

My laptops are both 45 watts.
 
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Old 10-02-19, 11:18 PM
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Is it true the controller keeps the battery from over charging? If so, does that mean the battery can just stay plugged in around the clock and everything will be fine, no over charging and no going below the recommended voltage of the battery?
 
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Old 10-03-19, 04:36 AM
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Yes, that is the job of a charge controller. When the battery is charged is stops the charging process to protect the battery.

The charge controller is just that. It controls charging of the battery. It has nothing to do with how you discharge the battery so it is still possible for you to over discharge the battery.
 
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Old 10-04-19, 12:58 PM
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What is the best way to keep it from depleting beyond its limit. and what are the limitation points and the acceptable 'full' points? How long does it take to deplete to charge status and how long would it take to charge using a 100 watt solar panel (too long, I'm thinking)?
 
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Old 10-08-19, 07:41 AM
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Well, I purchased the solar panel, but it doesn't seem to have independent usb port capability.

There are two usb ports on the included charge controller, but nothing happens when I connect my phone to charge. So, unless I'm mistaken, I need a battery to even use these usb ports.

I have the simplest and least expensive battery in mind to buy. Since, for the time being, I really just need to charge small electronic devices, I don't need a battery. I just need the usb ports to be functional.

This is the battery I have in mind:

https://www.amazon.com/PowerStar-Bat...544480&sr=8-17

Just wondering if this would work.
 
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Old 10-08-19, 01:30 PM
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That battery should work though it might not have a long life. Your solar panel and charge controller will be over sized for a battery that small. Your solar panel and controller can put out about 5 amps in full sun. A battery that small would last longer with a peak charge current of around 2 amps.

If you just want to get your USB charging ports working see if you can get a bad/used battery for free. A old battery won't hold a charge as long as a new battery but it will be able to soak up the charging current from the solar panel and allow the USB's to work.
 
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Old 10-09-19, 06:39 AM
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What about a 9ah or 12ah? Would these make a difference? I have a $30 budget.
The solar panel has alligator clamp style connectors. Is it possible to use these with the tab connections on the battery?

This one is $23.31 including tax.

https://www.amazon.com/Mighty-Max-Ba...626206&sr=8-10
 
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Old 10-09-19, 10:10 AM
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Bigger would be better but 9 or 12 ah is still small for that size a charging system. Keep in mind that most people use a solar panel like that to charge car sized batteries which are much larger.

You can control how much power your solar panel puts out. Use it in the morning or afternoon when the sun is NOT at it's highest. You can also angle the panel away from the sun at a 30 or 45 degree angle to cut it's power output.

Don't cover part of your panel to cut it's output without doing some experimenting first. Some panels will continue to produce power if part of the panel is shaded but others will almost completely quit if even part of the panel is shaded. Don't worry, you can't hurt the panel by covering it. It just may stop it from producing any power.
 
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Old 10-09-19, 10:24 AM
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What about the clamp style connectors on the solar panel and these smaller size batteries all seem to have tab connections.Will this reduce energy flow?
​​​Not really a proper connection, is it?

You said the 7.5ah battery would not last long, would the 9ah or 12ah last longer?
 
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Old 10-10-19, 12:01 AM
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Will the battery need to be depleted or can it just stay plugged in all the time? If I need to buy an inverter, what type inverter would be right for these smallish batteries?
 

Last edited by fenpeppertree; 10-10-19 at 12:21 AM.
  #18  
Old 10-10-19, 06:41 AM
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Would this work as an inverter for a mighty max 9ah agm battery (which I have purchased on Amazon and am waiting to receive; the battery, not the inverter).

https://www.amazon.com/gp/aw/d/B07F1...EEYDBZNC&psc=1
 
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Old 10-10-19, 08:02 AM
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battery is not that large but would probably look at the car laptop chargers so you would not need an inverter if your just charging batteries they do make universal chargers with adjustable voltages and different charge connectors thats designed to work with a lot of different brands of laptops really no reason to need an inverter unless you are powering something that requires a/c current.
 
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Old 10-11-19, 03:31 AM
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I would like the option for charging a laptop. Can you show me what type device/cable I would need to work with the Mighty Max 9ah agm battery I ordered to do this?

Car laptop chargers have a cigarette port connector, I don't have that. If I don't buy an inverter, all I have are the two usb ports on the solar panel's charge controller.
 
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Old 10-11-19, 05:00 AM
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should be easy to add a female cigarette lighter plug to it by attaching it to the load section of the charge controller, or you could even just cut the cigarette plugin off and attach the wires to the load section of the charge controller by using the charge controller you are protecting the battery also from over discharge, you should read the directions on your charge controller.
 
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Old 10-13-19, 12:09 PM
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OK, thanks for the help.

Should get the battery this week, hope it at least lets me charge my phone and tablet.
 
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Old 10-17-19, 03:11 PM
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Got the battery. It works, but I don't like it. Not enough power.

My question now is:
Is it possible to keep my laptop and tablet going all day with a bigger battery?

I don't think this will be much of a solution for me if it cannot.

The solar panel cannot keep the battery charged more than it's expenditure? In other words, if I am using my laptop and tablet during the day, the battery will deplete and the solar panel will not have the capacity to keep it charged above that which is being used?
 
  #24  
Old 10-17-19, 04:19 PM
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A battery only stores energy. It doesn't make it.

First I would estimate how much it takes to charge or operate your computer for a day and anything else you want to power. Then work back from there and size your system accordingly.

I thought your solar panel was over sized for your needs so that will probably work out good as you can use that extra power for charging a larger battery. Still, calculate your daily load so you know if your solar panel is up to the task. If your using 30 amps per day but your solar panel can only put out 20 amps (for example) per day into a battery won't help your situation.
 
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Old 10-18-19, 12:16 PM
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I'm thinking of buying two 50 or 55 Ah batteries at 30 or 36 pounds each. This will give me 100 or 110Ah total.

These are my current choices:
https://www.amazon.com/gp/aw/d/B00NINSOSG/ref=ox_sc_act_image_8?smid=A33N703ELCFX8U&psc=1

​​
Can't get the other URL to post, but it's a Mighty Max also, at 55Ah.

I would like to use my 45Watt laptop and my Android 8 tablet pretty much throughout the day. How would I go about figuring how much energy that is.

I would not want any more battery size, at this time, so how much time could I get with either set of these batteries at optimal levels.
​​​​
I should mention my solar panel is in a shaded area, but it does seem to charge the 9mA battery I have. Not really sure how long it takes, because I'm not really using it.
 

Last edited by fenpeppertree; 10-18-19 at 12:41 PM.
  #26  
Old 10-18-19, 01:32 PM
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would look at deep cycle batteries they come in a lot of different sizes.
you would need to know how many hours you are using those every day and multiply it by the wattage.
and you probably would also need more solar panels your single 100 watt panel only puts out about 5 amps under good conditions your probably going to be using most of that running the devices witch doesn't leave much left over to charge a discharged battery back up.
 
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Old 10-19-19, 04:56 AM
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Below is a chart showing the output of a solar panel throughout the day. The specifics are not important. What is important is to see how there is a only a short period in the middle of the day when a panel produces near it's full output. All other times the panel produces less power because the sun is lower.



Like Alan73 mentioned. You need to calculate your daily usage. Do the math and figure out how many watt hours your devices consume. This will tell you how much solar panel you need.

As a very rough idea of how much power your "could get" from your solar panel divide the wattage by 3-5 depending on the quality of the panel. Your location, weather and time of year will have an affect but that number 20-33 amp/hr is sort of the maximum you can hope to get on the best day of the year. In winter or on cloudy days you will get less.

Then you also need to factor in the losses from charge controller, inverter and device chargers and power supplies. If using an AC inverter to power your computer's charger the inverter can be a huge power waster. Most pure sine wave inverters are more efficient but you can loose 10-25% of your power in the inverter as waste heat.
 

Last edited by Pilot Dane; 10-19-19 at 04:56 AM. Reason: forgot to include image
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