Learning DIY Solar Resources?

[AntiGroundhogDay]

Contemplating building out a RAM Promaster with enough solar and Li-ion batteries to run a portable A/C like Hurried Year: http://hurriedyear.com/2017/05/29/solar-powered-air-conditioner-in-a-sprinter-van/

A lot of Youtubers describe their setups, but there's only so much detail that can be crammed into a 10min video.

Where would you point someone to learn any and everything required to design and implement a solar/battery setup in their van?  I'm looking for as much detail as possible as I really want to understand how everything works for future troubleshooting, safety, and design a system that provides great value.  Are there solar specific forums?  Some guru's website where he/she painstakingly walks you through every little step?  Thx.

 

[John61CT]

My way. Develop google-fu superpowers including using quotes, OR, dashes and site-specific site: and link: keywords

Use a good outlining note taking app with tagging and full text search.

Start with book yes dead trees recommendations, and DC mobile solar electric 101 pages.

As you come across jargon keywords, note them down for later googling, don't just gloss over stuff that's over your head.

As you're googling, note down the top discussion forums, good threads to come back and parse later, and knowledgeable users to focus on.

But in early stages look more for good reference sites, like Maine Sail's, and take good notes, saving specific links per topic etc.

As you climb the learning curve, you will soon begin to be able to start answering noob questions and correcting misinformation.

Sometimes you will overstep and "correct" someone who actually knows a lot more than you. Ask me how I know

Try to avoid this by lurking for a while in any forum and getting to know who's who and of course reading a lot of past threads searching with "site:"

But you can learn a lot by "semi-trolling" an extreme position you're not 100% sure about, getting corrected and/or watching the gurus debate the finer points and criteria for an over- generalization. Just don't leave misinformation out there uncorrected, acknowledge when you are wrong so others aren't misled.

Eventually, your accumulated knowledge base will make you much more of an expert than most, and after you gain good hands-on experience, there may be an income source there, or you can create a website or write a book yourself.

 

[KathyC]

Where would you point someone to learn any and everything required to design and implement a solar/battery setup in their van?

Personally, I don't think there is one single source of information that will have "everything", but I found that, after reading all of Bob's great content here (and reading the forums), the next step in my learning was from a blog called "Road Less Traveled" by Mark & Emily Fagan and "RV Solar Made Simple" specifically:

http://roadslesstraveled.us/rv-solar/

I really got a lot out of their well documented experiences.

I also think the Northern Arizona Wind & Sun Education center is extremely useful:

https://www.solar-electric.com/learning-center/

 

[WalkaboutTed]

Me? I just waded into (at that point) the 74 pages of threads on this CRVL electrical board. Let's just say that it took a while. Pick and choose subjects that seem relevant to your needs. There are several posters who know A LOT (Sternwake, JohnCT64, Highdesertranger and a few more who are quite knowledgeable). Pay attention to their posts. It was a bit overwhelming at first, but became easier to understand. And, it's all in one place.

The other main source, which was great because it had simple black and white pictures and diagrams was a book called "Sailboat Electrics Simplified" by Don Casey. It's on Amazon both hardcover and kindle. Because its for boats and highly conductive and corrosive salt water, he is very safety conscious.

Good learning!
Ted

 

[John61CT]

DC electrics 101 http://c34.org/bbs/index.php/topic,5977.0.html

 

[jonyjoe303]

solarpaneltalk.com is all solar forum. Plus I learn alot from watching youtube. Just don't confuse your positives and negatives, and make sure you use alot of fuses on everything.

I started out using 17ah jump pack for a house battery, 4 years later I moved up to lithium. I've been using the liion 18650 laptop cells and have built a large 94 ah 3s battery pack (168 18650 cells), and have been using lithium for the past year. But now I'm getting ready to move into the lifepo4 cells. I bought 80 lifepo4 cells (110 ah worth) about 2 weeks ago but cannot put them together until I figure out how to connect them. The only thing holding me back is that I can't solder them with my 60 watt solder iron.  I'm researching how to tab weld them. 

I looked at the hurried year article, and was surprise at the batteries he is using, 260ah agm batteries (162 pound each), he has 3 batteries  (486 lbs). 310 dollars a battery.

I recommend you research lifepo4 cells before you invest too much money on the li-ion 18650 (I still have over 300x 18650 cells). The lifepo4 I bought are brand new 36650 5.5 ah cells, 80 of them cost me 154 dollars, that is cheaper than the recycle 18650 which average about 2 ah. The lifepo4 are huge compared to the 18650, they are about the size of a D size battery but taller. 80 x 36650 cells weigh 28 lbs. Until I actually build my lifepo4 battery pack and test it, I can't really recommend them but I do see them as a possible replacement for the 18650. But 18650 cells are lighter, the 94 ah battery pack weighs about 20 lbs. 4x 18650 fit in the space of 1x 36650.

The reason I'm moving into the lifepo4 is because I couldnt figure out a good way to fully charge my 3s li-ion battery with my solar charge controller, I could only charge them to 12 volts and then the bms stop charging. Lifepo4 is a 4s batterypack and you can technically charge them to 14.4 volts without tripping the bms. 

When you build a batterypack build a small one first to get familiar with how to connect all the balance wires, how to connect the bms, test them, then you can build much larger ones. And capacity test all your 18650 cells, I highly recommend the opus btc3100 charger, it can charge/discharge/test 4 cells at a time, it charges/discharges at 1 amp. It is time consuming to test each cell (takes about 5 hours per cell). After charging them to 4.20 volts, let them sit for 3 hours and then check the voltage, if the voltage goes below 4.18 volts, I wouldnt use it on a battery pack. Batteries that don't hold charge well, will give you a batterypack that will have balance problems.   

Also consider using a swampcooler to augment the AC. Today was a hot day in california right now its midnight and I'm still running my swampcooler since the sun went down from a modest 33 ah lithium batterypack. There might be days when a swampcooler is all you need, less than 3 amps of power.

 

[AntiGroundhogDay]

Thank you all for the information. I had considered a swamp cooler but bring from the humid East coast, I read they don't work well here and they require a lot of water to work.

 

[John61CT]

For people looking to get a LiFePO4 bank together, I recommend buying the large rectangular 3.2V prismatic cells, in around half or a third the AH rating you want in total.

The cells alone will cost 3-7x a lead bank.

It takes 4 in series to make 12V, so 60AH cells times 2 strings (4S2P) or 8 cells will make 12V @ 120AH.

3 strings is 180AH. If you need a larger total then go to 80AH, 100AH etc.

To me it's just not worth the time and effort to solder the smaller cells together, get the big prismatic ones with standard bolt terminals.

Most people claim you HAVE to have a "canned" BMS system to protect the bank, most of which are expensive. Some claim you can do without some of their features and DIY a BMS with less expensive protective hardware.

You do need all your charge sources to have adjustable voltage setpoints, don't exceed 13.8V for bank longevity.

LFP doesn't work in freezing temps.

 

[Trebor English]

Where would you point someone to learn any and everything required to design and implement a solar/battery setup in their van?  I'm looking for as much detail as possible 

Air conditioning is at the leading edge of solar technology.  Few people make it work.  It takes a lot of skill, determination, knowledge, and money to tackle the biggest solar proect possible. 

 www.technomadia.com have a lot of information and experience with big solar.  Search posts by BradKW and jimindenver for big solar here.

 

[jonyjoe303]

Until you actually try a swampcooler you won't really know if it will work for you. Texas where I grew up can get very humid in the summer, but growing up all we used to stay cool  was a giant swampcooler, and this cool the entire house. I visited florida before and it reminded of texas weather. On a hot day my small swampcooler might go through 4 liters of water, so water use is not that bad.

The AC used in the van that "hurried year" is using gets the temperature down to 75 if the outside temperature is 90. The problem I see is trying to cool the entire van. The swampcooler creates a small comfort zone, the van might be 98 degrees, but were the swampcooler is blowing it will be 80 degrees. I can stay in the comfort zone all day long no matter how hot its outside. For 3 amps of power it's very efficient, at night I can throttle it down to less than one 1 amp. "Hurried year" states that if his batterybank starts to get low he opens the door to cool down with a fan, with my swampcooler the battery never gets low, the solar panel puts out 15 amps, I can run several swampcoolers on solar alone. In 4 years I never encounter a situation where I had to open a door/window. The only problem with swampcoolers you have to build your own, I havent seen one advertised that has the features needed for everyday use. 
picture of swampcooler internals




I looked at the lifepo4 prismatic cells but they are expensive, about 800 dollars for something in the 100 ah range. Soldering the li-ion laptop batteries is no problem, but the lifepo4 cylindrical, the solder won't stick to them. If I could only get the solder to stick, building the battery pack would be a 3 day job working on and off on it. Soldering itself might be a 3 hour job, putting all 80 fuses on the cells. The BMS for the lifepo4 I bought was 6 dollars for a 30 amp one, you can get a BMS to crank over engines in the 40 dollar range and I see some in the 100 dollar range. 
I been using a different range of BMS on the li-ion battery packs I build, and some of the cheaper ones work better than some of the expensive BMS. I always test each BMS on a small "out of balance" batterypack to make sure they will work before I put it on a large battery pack. I found some BMS won't shut off the charging if the battery goes out of balance, thats why I always test them.

size comparison between li-ion 18650 2 ah and lifepo4 36650 5.5 ah
top view while the 18650 is smaller 4 x 18650 = 8 ah in the same space as a single 5.5 ah 36650

side view notice how much taller the 36650 is in comparison

 

[John61CT]

Until you actually try a swampcooler you won't really know if it will work for you.

I bet the "polar tubes" idea

https://vanlivingforum.com/showthread.php?pid=309258#pid309258

would work real well in an adapted version. If there isn't enough surplus energy to freeze more, then revert back to using water.