Author Topic: Can someone please explain this to me in Simple terms (Solar setup)  (Read 349 times)

ChristianJ

So I am officially off-grid.

I want to hook up ONE of the 255 watt / 24 v solar panels (from the group buy) to a 12v deep cycle battery I have.

I know I need a charge controller and an inverter (I want to charge my laptop / cell phone only).

Can someone please let me know *what* I need to buy with Amazon / Home Depot links?

I have read all the solar threads on here and it just seems so cryptic. I just want to charge my laptop!

Cheaper is better for now.


RWS

Re: Can someone please explain this to me in Simple terms (Solar setup)
« Reply #1 on: February 14, 2018, 01:49:04 PM »
Look at the data plate on the back of the solar panel.  It will tell you the max fuse size to use.  Probably 15 Amp or there about. 
http://www.acehardware.com/product/index.jsp?productId=1291776

wire the positive solar panel wire to the Plus solar panel terminal on the charge controller.  Wire the minus solar panel wire to the minus solar panel terminal on the charge controller.

https://www.morningstarcorp.com/products/productssunsaver-gen-3/

Wire the battery plus terminal to the plus on the battery.  Use a fuse.  Anything wired to a battery should be fused.  Wire the minus battery terminal of the charge controller to the battery minus post (terminal).  Now you can charge you battery with or without an inverter.

Use large wire #6 or larger for small inverters.  Connect battery plus post to the inverter Plus terminal using a fuse and red wire.  Wire battery minus post to the inverter minus terminal.  Battery wires to the inverter MUST be kept short.  Locate inverter next to your battery.

Turn on the inverter on/off switch.  You have 120 AC.  Plug in something small and check.

Lilburner

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Re: Can someone please explain this to me in Simple terms (Solar setup)
« Reply #2 on: February 14, 2018, 02:06:06 PM »
This is my favorite thing in the whole world. In the absence of people or pets, I'd snuggle with it at night.

http://www.westmountainradio.com/product_info.php?products_id=epic-pwrgate



It's a magic box

You hook it up to any combination of DC input, solar, battery, and output.

If you have solar on there, and it's sunny, the output comes directly from the panel, when the solar fades, you start to draw from the battery, when the solar is going and you're not using it, it charges the battery. Or any other combination of those four things your heart desires.

Normally the DC in would come from a DC power supply, but for total off grid, you could use an automobile for deep backup.
A strong conviction that something must be done is the parent of many bad measures.
~ Daniel Webster

John Galt 1

Re: Can someone please explain this to me in Simple terms (Solar setup)
« Reply #3 on: February 14, 2018, 03:39:46 PM »
This is my favorite thing in the whole world. In the absence of people or pets, I'd snuggle with it at night.

http://www.westmountainradio.com/product_info.php?products_id=epic-pwrgate



It's a magic box

You hook it up to any combination of DC input, solar, battery, and output.

If you have solar on there, and it's sunny, the output comes directly from the panel, when the solar fades, you start to draw from the battery, when the solar is going and you're not using it, it charges the battery. Or any other combination of those four things your heart desires.

Normally the DC in would come from a DC power supply, but for total off grid, you could use an automobile for deep backup.

Interesting little MPPT controller although I think it's 13.8v LA charging voltage is a bit low for a golf cart or RE battery.
With that controllers 10amp max charge output you would be limited to charging no more than 100 amp/hr battery which is probably plenty for what ChristianJ is looking for.        At the same time @ 12v his panel can put out almost 20 amps after the MPPT conversion so he'd only be getting about half the charging his single panel could provide assuming he was willing to pay for that MPPT controller. 

ChristainJ,      For a smaller setup like you're looking at and to keep things inexpensive I'd go with a PMW controller like this one.    https://www.amazon.com/YueYueZou-20amp-Controller-Regulator-Display/dp/B01EJ1A21C/ref=sr_1_4?ie=UTF8&qid=1518639740&sr=8-4&keywords=PMW+controller&refinements=p_72%3A2661619011     $18
You can get much better and more expensive but this controller will handle up to 2 of your panels.       For one panel using a PMW controller I'd suggest a 12v battery between 80 - 150amp/hr (20 hr rate).     Just get a large golf cart battery.

As far as charging your cell phone you don't need an inverter.      Just use a plug into a car ciggarete lighter type USB charger and hook it to your 12v battery.     Some laptops can also be charged from a USB plug. 

Many electronics (like laptop charging transformers) don't play well with an inexpensive modified sine wave (MSW) inverter so I'd suggest a pure sine wave (PSW) inverter.       Prices start around $150.       I've run this $285 inverter for about 6 years with good results.
https://invertersrus.com/product/xantrex-prowatt8061210/
It' won't start up a large refridgerator but it will run my small fridge and 10 cu/ft chest freezer.      I've also run a small (5000 btu) window air conditioner for 2 summers with it.

If you do want a higher preforming more efficient controller  (MPPT type controller) I'd suggest this controller which will give you a lot more flexibility to expand your system.      I'd recomend the battery tempature sensor if you go with this unit.      https://www.ecodirect.com/Midnite-Solar-The-Kid-30-Amp-12-48-VDC-p/midnite-solar-kid.htm   

If I can be of any help PM me.     I don't follow threads and may miss any further questions.
« Last Edit: February 14, 2018, 03:53:12 PM by John Galt 1 »

Lilburner

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Re: Can someone please explain this to me in Simple terms (Solar setup)
« Reply #4 on: February 14, 2018, 04:08:43 PM »
The charge voltages and battery chemistries on the Epic PwrGate are fully adjustable. If the onboard settings aren't sufficient, you can hook it to the PC with the included USB cable to make adjustments.

A strong conviction that something must be done is the parent of many bad measures.
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wiseguy

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Re: Can someone please explain this to me in Simple terms (Solar setup)
« Reply #5 on: February 18, 2018, 07:56:55 PM »
Well I have been researching this myself as I have a couple of the 24 volt panels to use. 

There are so many things to consider, so I am going to hit a couple of them. 

How long will you want the battery to last without solar.  You will need to calculate your amps needed and use this to size your batteries.  When using batteries, you should never discharge them more than 50 percent. 
Now you need to figure out how long it will take your panel to recharge the battery.  You can figure no more than 6 hours of peak sun per day, and if your not pointing the solar panels through the day, you can cut that down an hour to 5 hours or less. 

Now the charge controller.  There are PWM and MPPT charge controllers.  You will get only about 60 to 80 percent effiency from the PWM controller.  These are the cheaper controllers.  You will get 90 percent plus out of an MPPT and you can mix voltages. 
The challenge is that with a 24 volt panel and a 12 volt battery bank, you will have an issue.  If you use a PWM charge controller to convert from 24 volt to output 12 volts, you will take a huge power loss of about half. 
The MPPT can easily adapt from the 24 volt panel to 12 volts.  These controllers are more expensive. 
With what you have outlined you can get buy with a lower amperage MPPT charge controller.  Probably a 20 amp. I am looking at this one.  https://www.amazon.com/dp/B00ZV3I3UU/ref=psdc_2236627011_t2_B07429RK43?th=1
But I will be getting a higher amperage model. 
Now about inverters.  If your battery is close to your gear, you can run 12 volts without issue.  This assumes you can get a charger for your laptop. 
If you are only charging the laptop, and maybe a couple of house lights, or even LED Christmas lights, I would get a small 80 watt power inverter from Harborfreight for $20.00. 
I had an electrical guy go over the difference between the modified sine wave and the pure sine wave inverters.  He believed that you should try the cheaper modified sine wave inverter.  If it doesn't cause you a problem, stick with the cheaper ones.  His point is that its only critical for very specific electric motors and even your refigerator can run on modified sine wave.
Little more on batteries.  Your cheapest will be Lead Acid batteries.  A marine battery will give you about 112 amp hours.  Two 6 watt golf cart batteries will give you over 200 amp hours. 
Lithium batteries will last longer, but they are much more expensive. 
I suggest listening to the pod casts done by Steven Harris.  Solar1234.com, (Look for the chicken coop audio pod cast), battery1234.com has several pod casts on choosing batteries and building battery banks. 
Good luck.

John Galt 1

Re: Can someone please explain this to me in Simple terms (Solar setup)
« Reply #6 on: February 28, 2018, 02:49:05 PM »
[I had an electrical guy go over the difference between the modified sine wave and the pure sine wave inverters.  He believed that you should try the cheaper modified sine wave inverter.  If it doesn't cause you a problem, stick with the cheaper ones.  His point is that its only critical for very specific electric motors and even your refigerator can run on modified sine wave.
[/quote]

Addition to quote above.       MSW (modified sine wave) inverters are inexpensive and work fine for short term use with most motors.       It really won't hurt your fridge to run off a MSW inverter for a few weeks but.... MSW power is harder on motors and will cut their life by about 40%, especially PM motors (induction motors are somewhat protected by their capasitors).     Items like voltage transformers run hotter and also have a lower life expectancy with MSW power.

ChristianJ

Re: Can someone please explain this to me in Simple terms (Solar setup)
« Reply #7 on: March 06, 2018, 04:18:08 PM »
I took some of the advice on this thread (Thank you!) and this is what I landed on for now.