Anyone running solar powered stuff at home?

[MannDude]

I recently bought a 100watt solar panel kit from Amazon and am now waiting for a battery, inverter and a some wiring to come in to get it set up. Obviously, I won't be able to power anything massive from it for a long period of time but the idea is that I'll use it to continually power my Raspberry Pi(s) and perhaps even my laptop. The entire thing is more of a project to learn about solar and electricity in general. If it seems to work well I may expand it and add a second or 3rd panel and grow the battery bank so I can power some other small items such as my surveillance DVR and IP cams, coffee pot and phone chargers. I don't expect this to really offset my energy costs since I live in an ancient house that was built in the 1870's that bleeds heating/cooling efficiency but I still want to play with it and get some hands on learning experience anyhow.

Just curious if anyone here is doing anything cool with solar.

 

[drmike]

I have a bunch of alternative energy stuff here (solar and wind).  Most of it I have piled up in storage though.   Waiting to find a place / raw land to build on where such is more acceptable and less let's steal it environment.

Have one panel on an off grid structure currently.   But I need to relocate it as too much tree shading going on.

I have a bunch of solar lanterns I leave in windows as emergency lights in case of grid offline situation.

Batteries just entirely suck.  Cash sewer and shit lifespan.  Look at Rolls and Nickel old school batteries.

Coffee pot, that's high wattage.  Not something you are going to be running on small setup.

 

[tonyg]

@MannDude Make sure you get a bank of deep cycle batteries.

You'd be surprised how much you can power with deep cycle batteries.

My UPS batteries are a pair of marine 12v deep cycle units that will keep my desktop computer with two monitors, and all the network gear running for about 8 hours without a charge.

 

[MannDude]

@MannDude Make sure you get a bank of deep cycle batteries.

I'm thinking I'll get 2X this to start: http://www.amazon.com/DEEPCYCLE-SOLAR-ENERGY-STORAGE-BATTERY/dp/B008D5YG3G/ref=pd_bxgy_lg_img_y

Seems to be well reviewed and it was recommended as a purchase for the solar panel kit I bought as well.

 

[tonyg]

I guess it depends on what you want out of the system.

But honestly to spend $75 dollars on a 35 AH battery seems excessive.

I would just go down to Walmart or a local big box store and pick up a pair of marine deep cycle batteries and wire them in parallel.

My batteries are 2X 109 AH units and I think I paid somewhere around $95 each. These things are big and heavy!

Of course if you really want performance buy at least 4 RV deep cycle 6V batteries.

 

[drmike]

I guess it depends on what you want out of the system.

But honestly to spend $75 dollars on a 35 AH battery seems excessive.

I would just go down to Walmart or a local big box store and pick up a pair of marine deep cycle batteries and wire them in parallel.

My batteries are 2X 109 AH units and I think I paid somewhere around $95 each. These things are big and heavy!

Of course if you really want performance buy at least 4 RV deep cycle 6V batteries.

I've prior bought the Walmart batteries and they were at least then horrid (forget which manufacturer).

There aren't many cheap and tolerable batteries out there - deep cycle wise.   These are intended for things like small boats where someone might discharge some while fishing then turns on big enough motor and alternator to smack those cells with a lot of charge power.

Rolls brand batteries are the long time go to favorite for a lot of folks.  There are others, but you aren't going to find them at your local retailers.

I shop local farm, boating, and RV shops where they service and sell gear.  Might find something good, available, made domestically, and known by those folks.

Batteries all said are a PITA.  I can't emphasize enough how much of the weakest link they are in a power system.  Going big on AH is recommended, as discharge and discharge depth are a valid issue that reduces capacity and lifespan of the batteries.   You should stick to 20% discharge maximum optimally.  If you had 70AH, that means drawing out 14AH max.

I recommend while on grid, buying a good battery charger for your system and a cheap LCD meter that outputs battery info live time and current flow.  This is in addition to your controller and should give better values than such does.  Don't forget your inline fuses for all of this, just in case something happens with accidental discharge, lightening, etc.

 

[JahAGR]

Inverters are generally inefficient, so you want to do direct DC-DC for whatever you can. Lots of little switching 12v-5v boards available on eBay for peanuts that would be good for running a raspi, phone charging, etc. Same goes for 12v step-up to run laptops. For $5 the efficiency of those probably isn't the best but it should beat the pants off running an inverter and then stepping that down again

Good battery tips from drmike, especially re: charging and discharging. A good battery should have a datasheet available that will list recommended charging rates. Usually on bigger ones they'll list a few different uses, giving different rates for floating (UPS type) usage vs cycle usage. Obviously with solar you're somewhat at the mercy of the sun and won't have the flexibility available by charging from mains.

Get some fuse blocks too. A big battery like what you're looking at can pump out a shitload of current, so in the event of a short your wiring will become a (smoky) fuse unless you provide one yourself.

At some point I have a project in mind to run an IP camera from solar power. It'd be in an area that would be a pain to run power to, but could easily be reached by a decent wifi antenna. Would probably just be a one-panel, one-battery job.

 

[gordonrp]

My home solar setup, top tip; ground your inverter. 

 

[drmike]

 Obviously with solar you're somewhat at the mercy of the sun and won't have the flexibility available by charging from mains.

There's a solution to that, a petrol or other fueled DC genset.   Such is recommended in off grid situations in the north where cloudy days can go one for weeks.

DC PWM generator is pretty simple.   A car alternator will suffice or more cheaply, a DC motor from an e-bike.  You connect the petrol motor to the generator  piece with a belt ideally - will need matching fit pulley arms on both.  That's about all there is to it.  You bolt it all down good and tight and crank it up (with connections in place obviously).

I have a similar setup that is human pedal generated for spring fitness - run that each spring to get back into cycling shape

 

[MannDude]

Thanks for the responses everyone!

I'm holding off on pulling the trigger on the rest of the kit, it's sitting in my Amazon shopping cart but am still reading and learning a bit more.

Also waiting for the backyards trees to fill in with Spring time leaves so I can bet a better idea of where to mount the panel (ground mount). City came and cut some trees down and there seems to be a great sunny spot that gets sunlight all day but will wait a tad longer before mounting anything.

My home solar setup, top tip; ground your inverter. 

Care to share your specs? What are you powering off that?

 

[gordonrp]

I need to take a new pic, but in the pic the specs are;

• Tracer 4210 40 Amp MPPT
  http://www.amazon.com/gp/product/B00E7NI9PE/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
  
• MT-5 LCD Display
  http://www.amazon.com/MT-5-Tracer1210RN-Tracer1215RN-Tracer2210RN-Tracer2215RN/dp/B00ECVWDGC/ref=pd_bxgy_lg_text_y
• 3000w inverter
• 6x deep cycle batteries
• 6x 100w panels
• Batteries hooked up as 12V, in a spider web style, rather than chained, this prevents any single battery (e.g. the one at the end of the chain before the inverter) from being most charged/discharged all the time (which would shorten it's life).

It powers my fiber connection, a lot of IP cams, couple of computers, and the A/C unit in my little workshop. We used the setup for power for tools (shop vac, work lights, etc) while our house was being completely rewired. 

Since the pic I've got another two batteries, and have repositioned my panels, I'm going to rewire the battery bank as 24v and swap out the inverter. The charge controller already supports 24v.

Like you I started with 100w on Amazon, and it turned into an addicting hobby. I would suggest making sure you get a 24v charge controller, and 24v inverter from the start, as most everyone who does 12v switches to 24v at some point anyway. 24v will result in less loss over longer runs (e.g. from panels), and a bit more efficiency when converting back to 110v AC.

 

[MannDude]

I need to take a new pic, but in the pic the specs are;

• Tracer 4210 40 Amp MPPT http://www.amazon.com/gp/product/B00E7NI9PE/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
  
• MT-5 LCD Display http://www.amazon.com/MT-5-Tracer1210RN-Tracer1215RN-Tracer2210RN-Tracer2215RN/dp/B00ECVWDGC/ref=pd_bxgy_lg_text_y
• 3000w inverter
• 6x deep cycle batteries
• 6x 100w panels
• Batteries hooked up as 12V, in a spider web style, rather than chained, this prevents any single battery (e.g. the one at the end of the chain before the inverter) from being most charged/discharged all the time (which would shorten it's life).

It powers my fiber connection, a lot of IP cams, couple of computers, and the A/C unit in my little workshop. We used the setup for power for tools (shop vac, work lights, etc) while our house was being completely rewired. 

Since the pic I've got another two batteries, and have repositioned my panels, I'm going to rewire the battery bank as 24v and swap out the inverter. The charge controller already supports 24v.

Like you I started with 100w on Amazon, and it turned into an addicting hobby. I would suggest making sure you get a 24v charge controller, and 24v inverter from the start, as most everyone who does 12v switches to 24v at some point anyway. 24v will result in less loss over longer runs (e.g. from panels), and a bit more efficiency when converting back to 110v AC.

Nice!

Well, where I am located at now I'm unsure if I can get away with a larger array. I do believe I'd have to have a minimum of 4 panels before I'd be in the 24v arena and because I live in the historic district of my city (actually, it's the largest historic district in the US) I'm sure those bastards on the historic board will complain if they catch wind... "Houses in the 1870's didn't have large solar panels in the backyard!"

But I definitely want to see about powering my workstation from it and my RPI. I've been working from my laptop+second monitor with a regular keyboard and mouse for the past couple days and find it's more than enough to do my job as well as I was doing it on my power hungry monster box of a PC workstation.

I'm using about 35watts or less at any given time with my laptop + second monitor. Cut that in half if I run the laptop off battery power.

Assuming I wanted to operate like that for say... 9 hours a day, what would you recommend as far as setup goes? I'm still having trouble figuring out needs like that as this is all new to me.

 

[Mid]

unless you have (regular/lengthy) power cuts or you have interest, there is no need to go for solar (let the govt do it). 

on your part, if you could minimize your usage, it would be great 

- a modest 21" lcd monitor instead of theater-like multiples;

- a laptop instead of a desktop;

- an LED/CFL instead of normal bulbs;

- solar water heater instead of electric; (SWH highly priced in US?)

- use of fans instead of ACs or at least only a "few hours AC" (any body in US does this?)

- use of energy efficient appliances 

 

[gordonrp]

@MannDude 12v inverters are cheaper than 24v no doubt, and if you're just doing small scale then you prob wont care about the 12v->24v efficiency differences. 

These are the panels I have, I'd suggest this kit if you're getting 2 panels;

http://www.amazon.com/200W-Mono-Starter-Kit-Controller/dp/B00BCRG22A/ref=sr_1_4?ie=UTF8&qid=1427811601&sr=8-4&keywords=renogy+kit

If you don't need the "z brackets" then there are 100w kits without the brackets for a bit cheaper IIRC.

As for wattage, I use a constant 103w without the computers running, but running all my ip cams, fiber modem, switches, etc. Powering on the two fanless i3 ssd computers (no monitors, they're servers) adds ~100w. I can run it all constantly and not worry about battery life, and have a couple of days full battery usage spare.

For calculations on run time I would suggest assuming you have 9 hours a day of half the panel output capacity, so if its 100w, then you probably have ~18.75w that you can use constantly 24 hours a day. In Texas here that is a safe bet with roof based panels, but in your location you may need to reduce it. The rough "50%" efficiency is intended to account for shade, clouds, inverter losses, etc. 

With that formula with my 600w of panels I have ~112w I can use constantly 24/7. Now, being in Texas I can actually use quite a bit more, my batteries are almost always full (which is desired anyway rather than deep discharging them), but it allows me to have a few days reserve power. We actually get a few overcast days in the winter each year, etc. The battery bank allows me to run my A/C unit in my workshop, use the shop vac, etc on weekends without having to worry about deep discharge etc

 

[drmike]

Well, where I am located at now I'm unsure if I can get away with a larger array. I do believe I'd have to have a minimum of 4 panels before I'd be in the 24v arena and because I live in the historic district of my city (actually, it's the largest historic district in the US) I'm sure those bastards on the historic board will complain if they catch wind... "Houses in the 1870's didn't have large solar panels in the backyard!"

Assuming I wanted to operate like that for say... 9 hours a day, what would you recommend as far as setup goes? I'm still having trouble figuring out needs like that as this is all new to me.

Zoning nazis and code enforcement can't say f-ck about ground mounted panels in your yard.  Don't let them try either.  Property ownership starts at property line, start manning up if need be.  Putting them on building in you area would possibly run into permits and all sort of drama.  Avoid all of it with ground mount and stick to DC wiring. If you want to do do AC inverter then down the line and on the slide.  Some jurisidictions may claim control over such when you start monkeying with AC, even if not grid tied.

9 hours x 35 watts = 315 watts.   You have losses and battery inefficiencies and I always overdo those.  So 400 watts.   To get 400 watts into batteries in 4 hours of sunlight on a kind sunny day, you need 100 watts of solar x 4 hours of capture.

Since the sun doesn't shine every day usable in your area, you certainly need to bank reserve. Another 100 watts should suffice.  That gives you an extra 7-8A of storable power.

Battery wise you need 35AH to cover your draw at 100% pull from the cells.  You want to dip into batteries maybe 20%.  That means running 700AH of battery storage.

If all 12V, 500W solar x 4 hours = 2Kw captured a day.

2000 / 12 = 166AH a day @ 12v.

700AH / 166AH = 4.21 days to fill cells from 0 to full without any draw.

unless you have (regular/lengthy) power cuts or you have interest, there is no need to go for solar (let the govt do it). 

on your part, if you could minimize your usage, it would be great 

- a modest 21" lcd monitor instead of theater-like multiples;

- a laptop instead of a desktop;

- an LED/CFL instead of normal bulbs;

- solar water heater instead of electric; (SWH highly priced in US?)

- use of fans instead of ACs or at least only a "few hours AC" (any body in US does this?)

- use of energy efficient appliances 

He's intending on going off grid and more folks should.  AC power isn't anything to fool with and generally not so wonderful to life on this planet.  DC in contrast is rather harmless, doesn't involve billed utility, doesn't involve a smart meter, doesn't involve a meter reader, doesn't have their wire running all over your property, etc.

With that formula with my 600w of panels I have ~112w I can use constantly 24/7. Now, being in Texas I can actually use quite a bit more, my batteries are almost always full (which is desired anyway rather than deep discharging them), but it allows me to have a few days reserve power. We actually get a few overcast days in the winter each year, etc. The battery bank allows me to run my A/C unit in my workshop, use the shop vac, etc on weekends without having to worry about deep discharge etc

Planet Texas just rocks for solar.  Ideal environment, one of the best in the US for catching sun.

 

[MannDude]

Got around to getting this setup today:

(1x) 100 watt panel (Soon to add 2 more 20watt panels)

(4x) 6v / 75amp batteries (soon to be 6x)





Batteries still had a charge from their use in a golfcart last year. Will charge for a couple days then add the inverter.



Batteries aren't new. Father had six of these from a golfcart he had that he converted to gas powered. They'll do though. Only using four now, may wire in the other two when I add some cheap harbor freight panels he has as well. (2x 20w).

So far my only plans are to power my Raspberry Pi(s) and IR illuminator floodlight. May use it temporarily for other things as well, but have no high load plans for it. ory planning on offsetting any real electrical costs or anything. This is more a learning project/for-fun than anything else.

 

[drmike]

@MannDude,  did you follow the manual for controller to put in correct usage mode?  That controller is targeted towards solar lighting - think walkway lights overhead.  It has a bunch of different modes.  Make sure it's best choice on config for your use.

I have the same controller - I do believe.  Attached to my fubared solar system.  Thinking the sealed lead acid batteries I have are shot.  Probably 7-8 year old cells and I have them in off grid unheated space - so winter freeze wouldn't have been kind to them either and it was a record nasty winter.

I just ordered a 100+ watt panel to address my offgrid building with the issues.  Ideally this next week it gets here and I get it up.  Need lights out there working and intending on putting wifi repeater out there so I can work on stuff and still check online matters.
 

PS: congrats on taking the leap and getting this set up.

 

[HalfEatenPie]

Wowza.  

I gotta start reading up on these systems now.  Totally interesting.  

Anyone have any good quick-start guide to just start reading and get acquainted with this?  Not planning on purchasing anything really but just want to know the equations and logic behind it all.

Or is it just basic electrical engineering?

 

[Neo]

I have a small 100Watt solar island, running well.

For that you just need basic electricla knowledge, how big should be battery when you have 100 Watts, the cables, the charge controler, fuse....

Enought for USB Devices, charge them serveral times, for my Netbook for over 15 hours. When i am using a 12v to 19v Netbook adapter, otherwise with 110Volt power supply i have a higher loss.

Atm: http://solar.x8e.net/about.html

But got a new charge controler, Steca PR1010, pretty neat one.

 

[MannDude]

@MannDude,  did you follow the manual for controller to put in correct usage mode?  That controller is targeted towards solar lighting - think walkway lights overhead.  It has a bunch of different modes.  Make sure it's best choice on config for your use.

Charge controller being used is the same as what came with the kit. It'll work for now however I'll eventually want to replace it with something better as I want one that will visually display more information about what is going on. I feel like some also have phone apps or a local web interface (think router configuration) that will let you view what is happening on your PC and export the info as well.

Sort of an overcast today so far. Was hoping it'd be a nice bright sunny morning as it has been as the panel would have been submerged in sunlight. Once the sun comes out I'll go readjust the panel a bit and go do some readings. Probably will let the batteries charge for a couple days before adding the inverter.