(Part 2) Best products from r/solar

Okay, so four people, all with laptops and tablets and iPhones, plus a CPAP. It sounds like the CPAP has a battery pack already, which is great.

So let's add battery capacity using rough numbers (you can look up the actuals using model numbers if you like). That's 4 laptops @ 7500mAh (milliamp hours) each, four phones @ 2000Ah each, and four tablets @ 4000mAh each. Thats 54,000mAh or 54Ah (amp hours) of batteries to charge.

A 100Ah marine cell (basically a car battery that swaps maximum acid/lead contact area for thicker internal lead plates) from Wal-Mart ($100) has 100Ah, and you do not want to run a wet cell below 50% or so; so a fully-charged marine cell will just about cover one charge for everything except the CPAP and lights.

The Yeti is one-third of the marine cell (33Ah), but with a battery that can be more deeply discharged. Certainly they charge a high premium for packaging and convenience. My gut is that careful use and one marine cell will do you, but considering short cloudy days, you may need more than one panel to keep it juiced. For example, that 100W panel may put out as little as 7 amps (at charging voltage) even in the best conditions, so it would take over seven hours in full summer sun to recharge the half-discharged battery every day.

As I have no real experience in running a fully-12V system, I would make a new post worded something like this:

__

Hi, blah blah,

There are four of us. Between us we have electronics whose total added battery capacity is 55Ah. We project our use as a group will overall require recharging about (xx%) of that per day.^1 There is also a CPAP machine with a (xxAh) battery.** We have a 6 day trip planned to (rough location), which is (weather, specifically cloudiness) this time of year with (hours) of daylight. We'd like to use solar for reliably charging these, and also for running a string of LEDs most of the night.

We have confirmed each of our laptops can be charged using 12V charging accessories.^2 We'd rather build something than spend the money on a pre-packaged solution such as Goal Zero or Yeti, but if they are our best solution, fine.

We're currently considering a 12V 100Ah marine cell and 200W of 12V panels^3 with an MPPT charge controller. Our two main questions;

— Do our needs match up with this system^4 ?

— Can we run all this at 12V without a 120V inverter; perhaps just a line conditioner or a DC-DC converter? Can you recommend one? What about the LEDs; is the best solution to run battery lanterns and recharge those, or run them off the system?

We're new at this, so any other advice is appreciated as well. Thanks!
_____

^1. ^Assuming ^you ^are ^not ^going ^to ^be ^staring ^at ^screens, ^this ^may ^be ^well ^below ^100%. ^Have ^a ^conversation ^with ^your ^friends ^and ^discuss. ^Do ^math.

^2. ^Verify ^DC ^charger ^before ^posting; ^also ^this ^is ^assuming ^your ^laptops ^can ^charge ^off ^12V? ^if ^they ^do ^not ^you ^are ^back ^to ^needing ^a ^120V ^inverter. ^I ^did ^a ^bit ^of ^Googling ^and ^it ^appears ^laptop ^chargers ^work ^on ^a ^modified-sinewave ^inverter ^but ^with ^excess ^signal ^noise ^and ^possibility ^of ^shortened ^charger ^life. ^Considering ^there ^are ^four ^people, ^I ^would ^definitely ^get ^a ^pure ^sine ^wave ^inverter ^to ^remove ^that ^possibility ^and ^keep ^the ^peace.

^3. ^Considering ^winter, ^clouds, ^short ^days.


^4. ^Always ^check ^your ^sources, ^in ^this ^case ^me.


Good luck! Oh, and consider these if you have propane. Ran one for ten weeks as a freezer off a 30-pound tank:
http://www.amazon.com/Dometic-CF-035AC110-Coolmatic-Control-Refrigerator/dp/B0017YFDGO/ref=sr_1_1?ie=UTF8&qid=1417627768&sr=8-1&keywords=dometic+33

Edit: Formatting

all solar modules are rated with STC (Standard Test Conditions). This of course does not exist in nature, but gives you a standard to compare them to. the 60W models are pretty much the minimum for laptop charging.
Noon time is not important, what is, is that the array is pointed at the sun. You can hang it so that it gets clear coverage from the sun with no shadows to get max output which should be close to 90% of STC capacity. The cooler the array stays the better so hung up, it tends to get cool from air flow. laying down works ok but only when sun is high.

This one comes with USB chargers as well which are quite convenient, and I added a lithium battery pack that I could charge so that phones and things can be charged at night (from the battery).

I use this battery bank but (solar on it is way too small to do anything but it is a cheap battery):
https://www.amazon.com/gp/product/B019B81BIQ/ref=oh_aui_detailpage_o08_s02?ie=UTF8&psc=1

This is another addition (it was wired up backwards for the attachment to the solar array but when switched around it works great). I can use this with a car adapter to charge more USB devices as well as run a colman mine fridge during sunny hours:
https://www.amazon.com/gp/product/B00B2HDUNY/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

The array puts out 18V so any device needs to be 12V-24V compatible but many car chargers are if you check the specs.
something like this lets you charge 3 USB devices at once with the above lighter adapter: https://www.amazon.com/Vano-USB-Cigarette-Lighter-Charger/dp/B00QPAT7A8/ref=pd_sim_107_3?_encoding=UTF8&psc=1&refRID=0YN3Q516XTZNKB2NA0F2

Actually just found this one which looks like it could use the built in jumper cables that come with the array instead of the lighter port: https://www.amazon.com/6-Port-USB-Car-Charger-50W-Fast-Car-Charger-Adapter-Built-in-Fuse-Smart-Technology-2Ft-Universal-12V-24V-DC-Power-Cord-for-iphone-Android-and-Other-USB-Powered-Devices/dp/B016JUJ6V8/ref=cm_cr_dp_d_rvw_txt?ie=UTF8

Thank you so much for your detailed reply!! I really appreciate it.

So I went ahead and got an electricity usage meter so that I can see how much power the devices I plan on taking with me will use. Like you said, this will allow me to better plan my setup. I should have done this first actually.

Another setup I'm considering is a power generator similar to something like this. What I'd like though is that it has 2 inputs for charging: one from the car and one from the solar panel. I don't want to be having to change inputs when I drive, and then change it again when I'm stopped. Most of the power generators/stations I've seen only have one DC input though. I tried looking for a male to female DC splitter but the ones I've found I don't think are strong enough to run the current from the two charging sources simultaneously.. the only one on Amazon I found is 22 AWG, which according to wikipedia can handle at most 6-7 amps. Did I understand that correctly? Does a DC splitter with a lower AWG even exist?

Another feature I'd like is the ability to use the generator while it's charging, but unfortunately even here most of the units I've seen cannot do this.

I'm going to wait till I have a better idea of the max amount of power I'll need before I research this again.

Thanks for the advice on how to run the fridge efficiently btw. I didn't even consider this. Those are excellent points. Also your idea on the passive water supply for the evap cooler, that's brilliant! I'm going to try fitting that into my design. And I say this bc it can't be that big, but I can perhaps have a half a gallon bottle..

This is basically what I have. I bought a different battery and inverter because I have an account at batteries Plus but this is a widely accepted quality battery and a decent inverter. I would recommend buying at least the battery local as shipping them is expensive.

NOTE I did not include fuses/breakers in this list but you definitely should build these into your design.

https://www.amazon.com/Renogy-Watts-Volts-Polycrystalline-Starter/dp/B00DCEKKQ0/ref=sr_1_2?ie=UTF8&qid=1487256044&sr=8-2&keywords=renogy+100w+starter+kit

https://www.amazon.com/Trojan-T27-AGM-Group-Purpose-Battery/dp/B00NY0RAW4/ref=sr_1_1?ie=UTF8&qid=1487256242&sr=8-1&keywords=trojan+12volt

https://www.amazon.com/34-97-2-15-17-ENERGIZER-Inverter-charging/dp/B01N5LUMDF/ref=sr_1_16?ie=UTF8&qid=1487256346&sr=8-16&keywords=500w+inverter

Depending on what you really want to power this may be way more than you need. You really should start by figuring out the load you want to power and then design your system around that number. This is a great little tool for figuring out how much power the devices you want to power will use and it's certainly cheaper than buying too much system and finding out you could have done what you wanted with half as much as you bought.

https://www.amazon.com/P3-P4400-Electricity-Usage-Monitor/dp/B00009MDBU/ref=sr_1_1?ie=UTF8&qid=1487256555&sr=8-1&keywords=killawatt

I'm certainly not an expert at solar but am learning so feel free to PM any other questions.

I was actually looking at a 12v 5aH alarm battery that fits the dimensions of the remaining space of the box. it's an SLA but I wish I could find a gel cell with the same dimensions. As for the panel, I've settle on not being able to run the amp on it, but I am pretty certain I can fit a big enough panel for a trickle charge that will at least extend the life of the battery when the lid is open. To fully recharge in a reasonable amount of time I guess I'll just hook it up to my motorcycle tender.

Key here is space for the battery and being able to fit it in the lid for the panel, kind of limits my options but I've been enjoying the learning experience of learning about solar and refreshing on some basics.

You need to stay within the amperage limitations of your wiring and charge controller.

For instance, this is a good charge controller that can do 75v and 15 amps, so in theory you would think it could do 1125 watts. But that's not the way it works. You need to keep peak voltage and amperage under 100/15, and load voltage and amperage will be a good bit less.

You could run three 300w panels like this in parallel with a charge controller that can handle 40v 30 amps, or you could run the same panels in series with a charge controller that can handle 120v 10 amps. The wiring needs to handle the amperage, so much smaller wiring would be needed for the latter.

If you did more, smaller panels, like six 150w panels, you could do a series/parallel combination for something like 80v at 15-20 amps. That would go very nicely with this charge controller.

And then there's the decision of how likely you are to want to expand the system and if you should buy equipment that can handle more panels.

Create a short list of your preferred charge controllers and their capacities, then start shopping for panels and do the quick math. If the panels were the same dollar-per-watt I would probably do six 150w in series/parallel with the controller I mentioned above. If you think it's likely you may expand capacity, I would go with three 300w panels in parallel with this controller, then you could add 6 more of the same (2700w total) in series/parallel without changing your charge controller or wiring.

No, that won't work. It's only got a 10W solar panel. That means sitting at the top of the highest mountain in the world at noon, clear skies, with a tracking mount that follows the sun, you might see 10W if you're lucky. In the real world, you might average 5 during the day if the Sun's out.

That's nothing. If you had LED lights that drew 5W (not much light), you can see that the Sun won't even power the lights much less a pump even when the sun's shining. You'd have nothing available to charge a battery to keep things running at night.

You have to figure out how much power your pump and lights use. "Not much" isn’t good enough.

You correctly noticed that the device in your link didn't have an outlet for the pump. If your pump has a standard plug, you need an inverter to convert the battery voltage to plug power. Better is to get a 12 Volt pump that directly runs off the battery. Same for the LED lights - there are lots of 12 volt LED lights for recreational vehicles and campers.

Search Amazon for 'aquarium pump 12v'. Here's a $12 unit that draws 5W. That's pretty good. The LED lights will be more, surprisingly. Actually, depending upon what you need, I'd buy the inexpensive solar LED lights; you'll never be able to build something cheaper.

So, you need 5W for the pump. Let's guess 4 days without sun. 4 days times 24 hours times 5W is 480 Whr. Call it 500 Whr. That's how much battery you need. Double that since 12v battery lifetime goes down if discharged less than 50%.

1000whr at 12 V is 83 AmpHr which is how 12 V batteries are rated.

For solar panel, you need a bit over 5W average output. Sun only shines enough for solar 8 hours/day. That's 15W needed during those 8 hours. Assume 4 days no sun. Now you need 60W output during that 8 hours of sun. That basically means a 100W solar panel. Amazon shows a $112 unit.
http://www.amazon.com/ACOPOWER®-Polycrystalline-Photovoltaic-Connectors-Charging/dp/B01586LFJ0/

You need a solar charge controller. Amazon, $22
http://www.amazon.com/Controller-Regulator-Intelligent-Display-12V-24V/dp/B018ICLC3K/

You'll need some wiring, fuses to be safe. Get a 'marine battery' instead of a standard car battery. Marine deep discharge batteries are designed to be discharged over a period of time rather than a normal car battery which just needs to supply a lot of current briefly to start the car. Buy a 75Ahr battery.

If you don't need to handle running through several days of rain, you can drop the solar panel size and battery.

Well, most laptops are about 18-21v input. The best bet is to snag a high power panel, maybe 30-50w, 110v inverter, and large battery with enough capacity to charge. Now, many factors depend on variations. How long will you be using the solar/battery? Hooked up and running 24/7? Just for a few hours (or like, one battery cycle, etc) These will determine the amount of solar power you need, and size of the battery.
You can get small car inverters to attach to the battery. A smaller motorcycle/garden tractor battery might work as well.
Oh, and a charge controller, since 30-50w panel is too larger to directly charge the battery.

From what the sounds of it are, you have a portable folding panel? I don't know many others that have a 12v/USB output. Chances are 1-10w in size?

I'm currently designing an off-grid home. You're welcome to create an account on community.solar and I'll get you free access to my battery management system course video in exchange for a review. I'll periodically update the class with lessons learned as a result of the design process. I also recommend this book as an introductory to solar design. It's great for handy beginners, but it doesn't go too much into off-grid design. Free for kindle unlimited readers.

I designed this kit about 15yrs ago when I worked at Unisolar. (I am a little surprised there are still some available.) It was designed for RV's, but could be used for a tractor trailor.

They could be stick them on top of the trailor. From it you could probably power a small living space and maybe a small refrigerator which would save the cost of idling overnight. The advantage of this product is that it won't break if a rock hits it and don't have to worry about wind uplifting a glass panel.

128W is probably too small, but there are a few kits available !?!

http://www.amazon.com/Unisolar-Flexible-Solar-Panel-Laminate/dp/B006EP6MCU

If you can return that solar panel kit and the battery, that would be ideal.

Again, when I say that marine battery will be useless for running your loads, I mean you'll be able to run it for ~20 minutes or so before the battery is dead and takes DAYS to fully charge again (assuming each day is sunny) before it's useful again.

Also, without an Inverter/Charger (and just a stand alone inverter like you have linked to), you can't use your generator to easily charge the battery/batteries back up.

If you can return the stuff you bought so far and order different equipment, that would be best.

​

EDIT:

Here's the 'super budget build' which you can use to run some random appliances like maybe a small fridge and such, and use your generator fed through the automatic transfer switch while you're there to run the AC:

​

Solar panels:

400 Watts (Either get 4 x 100 Watt panels, or look into getting 2 x 250 Watt panels, like the utility scale 60-cell ones.)

Charge Controller:

EPever Tracer 4210AN MPPT Charge Controller

https://www.amazon.com/EPEVER-Controller-Regulator-Backlight-Lead-Acid/dp/B077HHYYHT/

Batteries:

2 x Universal UB121000-45978 12v 100AH Deep Cycle AGM Battery

https://www.amazon.com/Universal-UB121000-45978-100AH-Cycle-Battery/dp/B00S1RT58C/

Inverter/Charger:

AIMS Power 2000 Watt 24 VDC Pure Sine Inverter / Charger

https://www.amazon.com/Power-Inverter-Charger-6000W-Surge/dp/B00BXTOQD4/

​

This system will cost you about $1600 give or take. But it will be able to at least be moderately useful, and the inverter has a built in transfer switch and charger, so you can use your generator to power the AC while you're there, and then have everything just fail back over to battery when you shut off your generator and AC.

It's also somewhat expandable, which is the reason for the 24 volt nominal battery bank (and inverter) instead of 12 volt nominal.

​

EDIT 2:

Is there a bit more to your use case here? No grid power available? Is this a mobile installation? As with a lot of things, 'the devil is in the details'.

I'm starting small and I wanted to see if any of you have ever dealt with this device. I feel like the power for the price is great but if anyone has objections I'd like to hear why.

https://www.amazon.com/Kyng-Power-Generator-Continuous-Rechargeable/dp/B07DVSWLSR/ref=cm_cr_arp_d_product_top?ie=UTF8

Of the two charge controllers you've picked, the cheap one is actually a far better choice for what you want to do.

You want to get a charge controller that lets you run the load through it, and is programmable with either a timer or an adjustable low voltage disconnect. That way you can set it up to run the pump when the sun is shining or when the battery has plenty of charge. The Renogy will only control the charging, so you could find yourself with a very flat battery if you don't add in something else to control discharging.

If you want a branded version of the cheap charge controller, check out this one (but it's basically the same thing).

If you want something with similar features but better quality and functionality you could try this EPsolar controller plus this PC cable and temp sensor.

Okay, heating and cooling are usually things that solar is terrible at doing, but with your needs you can certainly pull this off.

Assuming your heating coil is a 120v unit it's pulling a little over .2 Amps. It would draw a little over 2 Amps if being run off 12 volt, which is what I'm going to build off of. An off-the-shelf good 12v marine battery (better than plain auto batteries because they are built to cycle deeper) that has a 100Ah rating , which since you do not want to run lower than 50%, has 50Ah on call in a fully charged state, will run this for about 25 hours. This is good news and will give you a little slack in that your solar PV cell has two days to charge the battery, plus your draw is low enough, and of the type, that you have no need to invest in more expensive pure sine wave inverters or an MPPT charge controller.

So:

1 x 100Ah 12v marine cell, make sure it is outside or vented; $100 Wal-Mart has good ones sorry to say.

1 x 100W solar cell; part 1 of $165

1 x Inexpensive (non-MPPT) charge controller; part 2 of

1 x El Cheapo low watt modified sine wave 12v – 120v inverter*, $25

http://www.amazon.com/Solar-Panel-Bundle-100W-Monocrystalline/dp/B00B8L6EFA/ref=sr_1_2?ie=UTF8&qid=1406339899&sr=8-2&keywords=renogy+100w

**http://www.amazon.com/outlets-inverter-adapter-notebook-MRI3011BU/dp/B004MDXS0U/ref=sr_1_1?ie=UTF8&qid=1406340128&sr=8-1&keywords=12v+120v+inverter

hmm was preferring something more portable like a powerbank used to charge phones but with 12v output and solar panel to top it up. Like something like this but with a battery: https://www.amazon.com/GIARIDE-Foldable-Charger-Sunpower-Portable/dp/B072KD4XCD

Not sure how that would cope with charging the radios alone. The aim is to have something portable to carry around. It is for game rangers that could be for a few days walking in the wild with no power but need to communicate any poaching.

Thanks, I guess I need to think about this a bit. You think it's worth spending the $200 to switch my AC pump out for the DC pump before I get started with the solar transition? I'm not sure about a $35 pump! I need it to run 24/7 for years. I am running 700 gph right now. The pump I linked above is the one I would go with if I switch to DC.

http://www.amazon.com/Deepwater-Aquatics-Distribution-BLDC5-Brushless/dp/B00STP1OBW

not an expert, but you may want to look for something like this.. https://www.amazon.com/XINPUGUANG-Flexible-Monocrystalline-Battery-Charger/dp/B07HJYMY4M

You can go less than a $3 a watt using [this kit.] (http://www.amazon.com/Unisolar-Flexible-Solar-Panel-Laminate/dp/B006EP6MCU/ref=sr_1_4?s=lawn-garden&ie=UTF8&qid=1342927366&sr=1-4)
You're going to have a bit of challenge on a budget like that though. Batteries will be an additional expense but this is a good learning experience.