Living off the grid minimilist style - Solar battery charger

Mr. Peabody said:

Wow that's cheap

Solar stuff is getting really cheap, hell of a lot cheaper than it was a decade ago.

If he's only going to be there another year, I wouldn't even bother with the cost for Lithium-iron phosphates.

Keith Tanner said:

We're basically talking about a very simple RV setup like the one in my Westy. I've got a 100W panel and about 100 Ah of battery (I forget exactly what) with a controller. Voila. As long as the fan isn't some sort of monster, that would be enough to run some LED lights and a phone charger for a few days. Set up the panel in the sun, aim it properly and run wires to the tent. Voila. Most charge controllers can be set to cut the battery power once the battery is discharged to a certain point in order to protect it.

Dunno just how penny pinching we're being, but take this and add a marine battery and you're basically done: https://www.amazon.com/WEIZE-Starter-Efficiency-Monocrystalline-Applications/dp/B08LH7PL4N/

I'd actually be tempted to splurge a little and spend another $21 to get Renogy. That's who made my panels and they've been around for a while.

https://www.amazon.com/Renogy-Monocrystalline-Negative-Controller-Connectors/dp/B00BFCNFRM

I have not used solar since the 70's when we built a water system on the roof, tied into the water heater with a fancy (for the times) controller. As PV are coming down in price, I am interested, but have not kept up with tech. Is there really any difference in the two you posted othe than brand?

Also:

What is the difference in the MPPT and PWM? I notice the less amp rating cost more? To late for me to look up; hope you don't mind me picking your brain! Are either controller expandable for a larger battery bank, or more panels, or do ya have to upgrade that as you expand for more Ah?

I was surprised, with all the super high efficiency numbers being bandied about, that they list these panels at 21 %. I know that is great efficiency, but does not match the "they said" super duper numbers I've heard.

Our house roof is in a good place, and I can run some low wattage lines for DC and LED stuff, but I'd have to build up a VERY little bit at a time.

The thing that pulls me to the Renogy kit is the brand - I know them, they've been around for a while. Stuff like solar and LED lights are always a little sketchy at the bottom end of the market so I tend to go with known entities.

Solar pricing has fallen pretty dramatically.

As for MPPT vs PWM - PWM is a simpler, cheaper tech. It doesn't deal as well with multiple panels (they have to be matched) or multiple batteries (ditto). It's also not as efficient. MPPT will harvest more of the solar energy and can deal with voltage mismatches from what I recall - for example, I have a 100W panel on the roof of my van and a plug for a secondary panel should I decide to use it. An MPPT controller allows that panel to be something different than my 100W roof panel.

Here's how Renogy explains it

In this simple system - one panel, one battery - that is pretty oversized compared to the 18Ah setup that's being used now, the PWM will do just fine.

03Panther said:

I was surprised, with all the super high efficiency numbers being bandied about, that they list these panels at 21 %. I know that is great efficiency, but does not match the "they said" super duper numbers I've heard.

That 21% metric is how much of the sunlight ray they use, and what is so impressive about today's tech. I think the OG panels from the 70s were single-digits.

We are to the point where to gain more efficiency from panels we either have to find new materials that harvest from more of the physical wavelength, or sandwich two different materials together to harvest multiple kinds of light.

In reply to Keith Tanner :

Thanks for the info., and link. 
small hijack, since I'll be looking into much larger systems, but all info is good!

Last week we ordered the kit Keith recommended and today we went to visit my nephew in Jackson SC. 

This morning we scouted the layout. This afternoon we drove over to Aiken to pick up a 80 aH deep cycle battery and weather proof box off Craigslist. That guy ended up being 5 minutes from an electrical shop that had been recommended. We got 200 feet of low voltage landscaping wire. 

After a lengthy bathroom break we headed back to the farm and laid the wire in place after carrying the battery 200 yards from the parking area. 

Casa de nephew

The wire is on top of this log to cross the sometimes creek.

Then we ran it through these woods.

That view is from the clearing back to the tent. This is the view to the south in the same location. 

Then we went for pizza and beer at a local brewery in Augusta. 

Tomorrow morning we hit Lowes and then actually do work. 

We spent a couple of hours gathering supplies this morning. Found a fan that'll run off USB in Lowes. That was my biggest concern of buying local. 

I always try to do the hard part of a project first so we started wiring up the tent. Soon discovered that I need another 5 meter of strip LEDs for inside. 

Our goal was get the kitchen/outside lights ran before lunch. My nephew showed up and five minutes later he flipped the light switch to get this.

Lunch is all stuff fresh off the farm. This is the high life. 

Ran to Lowes after lunch and grabbed another 12 feet of lights. These are RGB with a remote so as Lil Stampie pointed out Nephew Stampie can set the mood.

Took apart the USB car lighter we bought this morning and soldered wires to it. 

Lil Stampie said it looked janky.  I made it jankier with duct tape cause that fixes everything. 

We wired the inside and tested. First the mood lighting. 

Fan

And it charges a phone.

Lil Stampie showed his extreme confidence in me by then exclaiming "How the hell did that work!?"

Next wire up the solar controller and fuse the house wiring. 

If it's not too late, I'd add a 12v cig lighter port expander. Those usually come with wire attached, which would make install cleaner. Then he also has the ability to charge multiple things off of the 12v. You'd also pick up a little efficiency with things, like the fan, if it can run 12v natively and not have to go through the lossy 5v buck converter.

In reply to Derick Freese :

Yeah we looked for a hard wired female cigarette lighter socket but nothing I liked in the short time I had available.  I can always put a junction box in that corner if he needs 12v for something in the future.

Wired up battery and controller. 

Battery is set for correct type. Taking a break then solar panel time. 

So my nephew came down earlier than expected and mowed the clearing we were going to use for the panel. That was the end of his day so we decided to go up to the barn and build the stand for the panel. 

First let me say that I was supervising. Lil Stampie and Nephew Stampie were building. We were also using borrowed tools and couldn't find everything I wanted. Lil Stampie has the excuse that he's 13. Nephew Stampie has the excuse that his dad isn't the handy type so he never learned. I have the excuse that I wanted to see what they could do together. Here's the stand.  It's stable ish.

We got it in place and wired at 6:40 pm. The sun was behind clouds and a tree so even though I aimed it towards the sun I wasn't expecting anything

Holy E36 M3 that slow PV blinking means it's charging the battery. Berk me running. I expected to have to wait until the morning to see anything.

So what do you do?  You take your stinky collective asses to the local burger joint and then hit the microbrewery for some more good beer.

My nephew just sent me this picture with only one word "Sick"

Who else is eagerly waiting to see if the battery is charging? :) Or will we get more pictures of food instead? ;)

Keith Tanner said:

Who else is eagerly waiting to see if the battery is charging? :) Or will we get more pictures of food instead? ;)

why not both?

Stampie said:

My nephew just sent me this picture with only one word "Sick"

 

 

 

 

Isn't that stripper pole sort of large diameter?

In reply to bentwrench :

(insert rude joke about SC here)

Keith Tanner said:

Who else is eagerly waiting to see if the battery is charging? :) Or will we get more pictures of food instead? ;)

No picture but this morning before leaving the area Lil Stampie and I went by and moved the panel for a better all around location.  I text my nephew about an hour ago asking him to look after work for a flashing battery light.  That would indicate that it was fully charged and just float charging.  I expected a couple of days as the battery was 1) unknown charge when bought 2) used for testing 3) I told him to use everything last night as he wanted.  He responded that it was flashing as fully charged after work today.  Hot damn that's better than I expected.  So next we need to add a vent fan for his tent.  I noticed working yesterday that his tent got way hotter than outside mid day.  Just keeping it's temp lower will improve his evenings during the summer.  After that we're thinking a 12v cooler/fridge.  My mental math last night said that would require another battery and panel but since it charged so well I'm thinking maybe just another battery.

Just got home from a 5 day off-grid camping session, running the following items:

• ARB Elements refrigerator
• 4x Goal Zero crushlights
• 2x cell phones
• 1x Milwaukee M18 fan and charger for M18 battery

Few notes, since this stuff is sort of my jam.

Back in the day I used to run all this jazz off my starting battery, which was risky to say the least.  Now I have moved it all to be powered off an Anker 800 watt/hour powerbank, and thats a pretty big godsend.  The Anker power bank includes MPPT charging, a bunch of high amp USB outlets, regulated 12V power supply with three outlets (runs a constant 13.2 volts) and 2x 120VAC, 500 watt outlets.  Its very nice having an integrated inverter for my M18 charger.  Previously I had to use a stand-alone inverter.  

A few suggestions if I may - 

• As time and money permits, add another panel and an MPPT controller, a Victron MPPT would be the bees knees.   Make sure both panels are in the sun all the time, wire them in series and pump them into your MPPT.  If I wanted to be 100% off grid in the setup shown, I would want at least 200 watts of solar to give me more cusion.
• Again, as time and money permit, add another battery or 2.  You gotta remember you may get a week of rain, and your solar won't do a whole heck of a lot at that point.  Gotta make hay while the sun shines (literally in this case)
• I have had great success using the Milwaukee M18 lights and fans and charging their batteries as needed.  Probably a little high on the budget, but a great option and the fan really snorts.  The LEDs are awesome too when you need real light.
• Clean the panels, I would do it every day as part of the routine.  A little dirt or leaves will really knock back efficiency.  
• Add proper hard wired disconnects to everything.  Don't rely on the off switch.  Things like phone chargers and those LEDs bleed out watts just sitting there, and in this case every watt counts.  
• Schedule to use the solar surplus.  When your batteries are full, even on a sunny day, they don't get "more full".  Monitor battery voltage and charge state, and when you have good solar and your batteries are already full, start charging up other devices - phones, smaller power banks, M18 batteries, what have you.  Then at night, flip the switches and coast on your charge.  I always try to keep my main batteries full, for example I won't load my fridge when I am on battery, only when I am getting more solar than I am using, or when I am driving.  I'll even drop the temp of my fridge when I am on good solar, let the solar panels cool it down to 28 or 30F at 5PM, then turn turn it up to 38 for the overnight so it doesnt run as much. 
• Solar is the long con - maximize the charge time.  A B C - always be charging.   

C: all the above which includes ample pictures of both food, beer and stuff lit up!