(Part 2) Reddit mentions: The best renewable energy controllers

Here's a 'shopping list' for as light-weight a system that I can think of throwing together from 'off the shelf' components:

>Solar Panels:
Two of these will give you a light-weight solution for 400 watts of power!
https://www.amazon.com/Dokio-Monocrystalline-foldable-Inverter-Controller/dp/B075SZMFP2/

>Charge Controller:
The included controller won't be terribly useful I'm afraid, because it's for Lead Acid, and is a crappy PWM controller anyways. So, let's assume you're going to DIY this a bit and build a weatherproof box for your battery and a controller like this one:
https://www.amazon.com/Solar-Controller-Monitor-Temp-Sensor-Package/dp/B06XNP1BGR/

>Batteries:
Here's where you drop the real cash; At least one but preferably TWO of these guys.
https://www.amazon.com/LiFePO4-volt-Deep-Cycle-Battery/dp/B06XX197GJ/

>Inverter:
If you'll be needing AC power, you'll want something like this:
www.amazon.com/AIMS-Power-Watt-Inverter-Cables/dp/B002AMPHHC/

>Container of sorts:
You'll be needing something weatherproof for all this non-weatherproof stuff to sit inside. Find the 'weatherproof storage lockers' at sporting goods stores, and you can machine them to be what you need for stuff like this. It'll need to fit your batteries, inverter, and charge controller, and you'll need to mount them in there somehow so it doesn't bounce around. Then all you need is some slick weatherproof electrical connectors to mount going through the wall of the box, and you've got yourself a great system. You can even put in things like a 12 socket and weatherproof volt meter to keep an eye on your battery voltage.

Overall, this would cost probably around $3000. But, it'd work well. :)

If you can give me more specs on what sort of weight you can carry, you could have the option of switching to Lead Acid as a battery type; but that would add like 150 pounds of weight to this whole setup, but you'd save $1500 or there about on the batteries, and you COULD use the included cheap PWM controllers... but honestly that MPPT I think would be worth the extra cash.

The comparable product (excluding the panels, and assuming you only got one battery) would be the Goal Zero Yeti 1400 Lithium. It's $1700 and is about the same thing, again excluding the panels.

Honestly, for your purposes, the Goal Zero Yeti looks pretty good if you're not really into the DIY stuff; cause you'd be looking at $1700 plus $500 for the 400 watts of panels, so $2200 total. That's not bad! (Assuming you DIY it like I'm suggesting, and only use one battery, you're looking at around $2000. So, really, not much cheaper if the weight matters to you.)

I'd like to first mention that yes there are lots of details with voltage, amps and watts but keep in mind that they requirements for one device don't always affect another. For example the solar panels need to have a Voc that fits the range of the charge controller your inverter and batteries don't care about the Voc of the panels. They care about the output of the charge controller and not what's going into it. I recommend to start with the overall watt and watt hour needs of the system and then drill down to find components that fit those needs.

The first step is to figure out how much power you need both in daily consumption and peak draw. To find this you need to figure out what you'll be running, how much power they draw and how long they run for. Lets take a small AC unit as an example. Lets assume it draws 500 watts and runs for a total of 10 hours a day. 500 watts X 10 hours = 5000 watt hours or 5 kwh. To run just this load you'll need at least 1 KW of solar panels as in Texas in the summer you get about 5 peak sun hours so 1 KW X 5 peak sun hours = 5 kwh. Now there are loses in the system so you'll need a bit more.

Then you'll need a battery to store the power. A good starting point is twice your daily usages. So if you use 5 kwh's in a day you should have 10 kwh's of storage. With this large of storage I wouldn't want to go with anything lower then a 48v battery. Reason is volts x amps = watts. The higher the volts means the amps are lower which gives you more efficiency and means you buy smaller wiring and save money.

Now you'll need an inverter that can run the load. Lots of them can run a continuous load of 500w but the hard part is actually starting the AC unit. Pumps like AC's, refrigerators and air compressors have a lot of force they need to over come to start rotating so they have a very high initial or surge load before lowering to their continuous load. This surge load varies quite a bit but from what I understand is typically around 5-10x the continuous load. So if an AC unit draws 500w while running it could draw 2500-5000w while starting. So its easy to see why you'll need a large inverter even though the continuous load isn't that high. Most inverters can surge to 2x their continuous load so if an inverter is rated at 2500w it should be able to surge to 5000w. Now keep in mind that a lot of the cheaper inverters are over rated quite a bit. So a cheap 2500w inverter might actually only surge 2500w and run 1250w continuously.

My recommendations are:
Battle born lithium batteries - https://battlebornbatteries.com/. They're made to a be a drop in replacement for lead acid and should last a long time
PCM60X charge controller - https://www.amazon.com/MPP-SOLAR-PCM60X-controller-regulator/dp/B00OUKVFBE. I have one and it works pretty well. I've seen a number of other people using them and having good experiences with them. They don't have some fancy features that some of the Midnites have, but they're also a lot cheaper and definitely do work.
Solar panes - As many as you can fit/afford and larger is typically cheaper.
The inverter larger depends on what loads you actually have. I have a cheap Reliable Electric 1500w one. It works pretty well and was pretty cheap, but it is a cheap brand and there are better options out there.

I hope this helps give some understanding. I know I left some stuff out though.

Hey, thanks for responding! Great save on trying to run parallels on 4 batteries, I guess that site was a little misleading.. It made the parallel system seem like a great idea. Looks like I will be going with the single battery (and save some dollars in the process!).

For the power specs of the motor, I found the following link on the product website and about midway down is what I think are the specs needed. I am new to this so I am not sure how to do the maths. Will you please elaborate on how to do this?

Roger that on the charge controller, I didnt know it had to be so involved. Do you think a basic smart controller like this would work? https://www.amazon.com/dp/B01F5WFK5C?psc=1 ? or do I actually need to get one that I manually set the voltage for? If the latter than can you explain why? Not doubting you, I just want to understand the concepts.
I am rigging this all together for an inflatable trolling/fishing boat which will be stored when not in use. I will only have the solar panel setup when out and actually on the water if this makes any difference.

As for the battery: SLA v FLA - honestly, I never heard of an FLA battery before. I tried to search online to check prices (both walmart and batteries + bulbs) and only found small amp hour ones. Is FLA more expensive overall? Would one with enough ah be able to fit in a marine box that size 24-27 fits? Other than longevity what is the difference between the two?

Thank you again for taking the time to help me out. This is my first time ever doing a project with literally all of these objects. Figured it would be a good intro project into batteries and solar + using power at the same time. I am learning so much!

edit: spelling

Like others have said, it's a mistake to run any sort of electrical heating device off of a solar power system. This includes, kettles, electric blankets, hair dryers, etc. They simply require too much power unless you have a huge battery bank and a very large inverter.

For charging phones, you could just wire up your own cigarette lighter port. You can buy a combo cigarette lighter port and 2 USB ports for like $7 at Walmart. You just have to wire it into your car's 12V system and stick it to your dashboard or something. You can use a cigarette lighter inverter in it for small devices. It might be enough to run a laptop charger. You'd have to check the amperage limits. (I use a cigarette lighter inverter for my phone's special AC Adapter which has quick charge. I don't get quick charge just using a USB port.)

Have you considered buying a "solar generator"? They're all-in-one solutions for moderate power needs. It's basically a box that contains battery, inverter, and charge controller. All you need to do is add solar panels. The portable folding ones might be good, or you can get traditional ones and mount them on your roof. Here's an article about them that links to other comparisons between them. He even built his own using relatively inexpensive batteries (with an added battery management system), and a normal charge controller and inverter.

That site is run by William Prowse who has a ton of useful videos and tutorials on solar power, including several plans.

Of course, you can always build a full solar power system by buying all the separate parts and wiring them together. I'm not going to lie, it's not easy. The best thing to do is watch hours of YouTube videos and read tons of forums posts and articles to learn about all the parts, what they do, and which ones work with each other. You gotta watch out for misinformation, though. There are some... "older people" who are set in their ways and will tell you all you need are lead acid batteries and a PWM charge controller instead of an MPPT one. What those mean is a topic for a different day. Or you can follow a plan online and buy the exact parts they do, but then you wouldn't know how to adjust it for your own needs.

Here are some of the questions you need to be able to answer in order to design a solar power system:

• How many watts of power do each of your devices use, and how many hours a day do you plan on using them?
  
  • You can buy a Kill-A-Watt to accurately measure the wattage your AC devices use.
    
• How many rainy days in a row do you need to survive before you have to either stop using power or charge your battery through other means? (Alternator, generator, wall charger.)
  
  • 2-3 days is the most you can really hope for in a van. You simply don't have enough space for panels.
    
• How much sun (insolation) do you get, on average, in the locations you will be at the times you plan to be there?
  
  • Are you going to live year-round in one place, or travel all over?
    
  • Do you plan on spending any time in Winter in Northern locations with less sun?
    
    You buy large enough batteries so that you can get those 2 days of usage, and you buy enough solar panels so that you can get back those two days of usage with one day of sun. For the most part, the number of solar panels you can fit on your van is the limiting factor. You can buy a ton of batteries which will last you a week, but there's no point if you can't charge them back to full in one day.
    
    Regarding batteries, you also have to account for the fact that traditional lead acid batteries take a long time to charge because of their high internal resistance. With too large of batteries, if you discharge them too deeply, no amount of solar panels will help. The batteries can only take so much current at once, and there simply aren't enough hours of sun in a day to provide it, no matter how many panels you have. If you don't charge the batteries to full regularly, you will literally destroy them. (None of this applies to lithium ion batteries, which are so much better for solar, but they cost a lot more up front, but last much longer.)
    
    It's a balancing act between battery size, solar panel wattage, and amount of sun.
    
    Then you have to answer these other questions:
    
    
• What's the peak amperage my panels will provide based on location, time of year, angle of tilt (or not), and coldest ambient temperature?
  
• How large of a solar charge controller do I need to support the above?
  
• How many continuous amps can my battery bank provide?
  
• How many continuous amps do I need to support an AC inverter of a given size?
  
• Do I need a pure sine wave inverter, or can I get away with a cheaper modified sine wave one?
  
• How large do the wires need to be that go from my battery to inverter, or charge controller to battery, or the battery to fuse box and then to my 12V devices? (fans, fridge, lights, etc.)
  
• What size fuses do I need for all these connections?
  
• And much more...
  
  You can forget about all that and just follow someone's plan online. Well, except the fuses and wires for each 12V device. You'll still need to figure that out. Will Prowse has this "Classic 400W solar package" that you can follow to the T and get by just fine, but you won't know if that's even good enough for you until you figure out your power usage. But if it is, then the article and video are great.
  
  There's even a link to everything on Amazon, although the last time I checked, the specific charge controller he links is no longer available except from random sellers. There's a newer model instead. Oh, wait, he links to eBay now, but it's $51 more expensive than the new model on Amazon ($209 vs $158). I would just buy the new model. It's what I did. But the rest of the advice, plans, etc, is pretty good. Except all inverters suck if you read the negative reviews, even the one he links. They often can't really handle the wattage they claim. (I personally went with a Samlex brand inverter, which was nearly the same price, but less than half the wattage rating, which is much more realistic.)
  
  I used his videos a bit in helping design my system, but I have 600W of panels to suit my higher needs, so I had to scale some things up. I run two strings of 3 panels in series (2x3). This gives me a good balance of voltage and current.
  
  I don't have a battery that can support a 2000W inverter, so I bought a 600W one. I bought a 170 Ah Renogy lithium ion battery. Renogy suggests no more than 100A of continuous draw (more than 150A, and it will turn itself off). 100A is less then gentle to the battery, though. You can multiply the DC amperage by 10 to get an estimate of the wattage of an inverter it can run. So 100A could run a 1000W inverter. If I bought a second battery and wired it in parallel with my current one, I could get 200A continuous, but this battery was $1300. I'm going to live with what I got for a while. (In retrospect, I should have bought 2 100Ah batteries instead, but supply was very limited, and they cost more per amp-hour, $950 each.)
  
  After my (literal) months of researching and teaching myself about batteries, solar power, and all that, I have come to the conclusion that buying lead acid batteries is a mistake. This includes traditional flooded lead acid, sealed AGM, deep cycle marine, etc. Unless you treat them super gently, charge them to nearly full every day, never discharge them lower then 50%, equalize the cells on a schedule, etc., then they will only last a couple of years before you end up buying new ones. In the long run, lithium ion is cheaper.
  
  Good lithium ion batteries can be discharged "100%", be left for long term as low as 20-30%, don't need special equalization, weigh half as much, and have almost zero internal resistance so they charge faster. And they will last 10 years, easy. Even longer if you treat them extra gentle. The only problem is the upfront cost. I could have purchased 4 Trojan T-105 6V deep cycle golf cart batteries for 1/3 the cost of my one battery, and I would have had even more capacity, but the size, weight, fragility, and the whole spewing acidic vapor was a turn off. In 10 years, I'd probably replace them 3 times, at least, making them cost the same or more. I've read many experienced solar power users say you should expect to replace them in 1 year because you're going to do something wrong in your first year and ruin them.
  
  (There is one downside to lithium ion batteries I should mention. You can't charge them directly from a van's alternator. They draw too much current and will fry it! You instead would need to use a battery-to-battery charger. A found a good one for about $200, though I didn't buy it and I don't have a link handy. Just something to consider.)
  
  (Continued in reply)

Don't necessarily agree with lithium batteries being the only option here.
When you don't plan to use this more than 10 years I would not make the investment in lithium batteries unless you really have no space to sacrifice.
some decent AGM batteries in parallel in a 24V or 48V setup should net you enough capacity to last the day, It will take quite some space and extra weight though but save so much money.

I'm a big fan of this charge controller: https://www.amazon.com/Victron-SmartSolar-Charge-Controller-Bluetooth/dp/B073ZJ43L1/ref=sr_1_1?s=lawn-garden&ie=UTF8&qid=1523449725&sr=1-1&keywords=victron%2Bsmart%2Bsolar&th=1
but might be slightly expensive. Be 100% sure to get the "Smart Solar" one and not the older "Blue Solar" as that does not come with built in bluetooth.

for panels, definitely go for flexible monocrystaline (smaller) panels. Do note that you can only bend them like 30 degrees along the long edge, so get some measurements and figure out how many you can realistically fit on the camper. If you don't get near 1000W you probably will not manage 600W for 6 hours.

Has a much bigger battery, has an AC inverter. Only issue is the inverter is rated up to 120w. This mean you can run a laptop and other small devices but don't expect to get to run things throughout the weekend. Much better than what op linked. However w/ the panel it's almost 4x the price.

It sucks that the solar panels cost extra but if you were to buy now, the 25w panels are on sale. I would get two and hopefully get up to 50w (under optimal conditions).

It would be nice for car camping or a camper. If it's a permanent or even semi permanent installation, It would be better to purchase a larger panel, solar controller/charger, deep cycle large capacity battery and an inverter.

100w panel ($120) - https://www.amazon.com/Renogy-Watts-Volts-Monocrystalline-Solar/dp/B009Z6CW7O/

Simple Charger/Controller ($15) - https://www.amazon.com/dp/B074WZB5XY/

AC inverter ($35) - https://www.amazon.com/POTEK-Inverter-Converter-Charging-Smartphones/dp/B01B3ZQG4O/

100Ah SLA Battery (Apprx $100) - Autoparts/Big Box Stores

Ends up being a $270-$300 investment. That's not bad. If you were to buy the monoprice system w/ larger solar panel, it would be close to $300 and it wouldn't anywhere as efficient as if you were to make your own system. Only thing are sacrificing is portability and weight. A 8Ah battery will be much smaller and lighter than a 100Ah+ SLAB but won't last anywhere as long. If you have a rainy/cloudy week, good luck.

Here's a list and example found on amazon for all the major parts. I'll also include a wiring diagram at the end.

Solar Panel $169.99 - 100W Flexible & Thin

Solar Cable $18.99 - 20ft with male and female heads (cut in half for + & -)

[Charge Controller]
(https://smile.amazon.com/gp/product/B019QSX0CG/ref=oh_aui_detailpage_o09_s00?ie=UTF8&psc=1) $34.99 - 30A gives you room to add more panels

Battery $160 - 100Ah AGM will provide enough power depending on fridge but requires no maintenance

Fuse Panel $35 - 6 circuits with negative and cover

12V Sockets $6 - Get some of these for plugging in appliances and phones. You can buy 12V adapters for almost any electronic besides most kitchen appliances.

Pick up some 10 gauge stranded wire from your local hardware store (home depot) to wire the battery and fuse panel to the charge controller. You shouldn't need much since you want the battery as close as possible to the controller. You can buy smaller wire (16 or 18 guage) for wiring outlets/appliances to the fuse panel. 50ft of that should be fine unless you want multiple outlets on the other side of the van.

You'll also need some ATC blade fuses for your fuse panel. You can buy these at a local auto parts store pretty cheap. 15 amps should be enough than anything you'll be pulling.

To connect the wire ends to the battery and fuse panel you will need these wire terminals for the corresponding wire guages you are using. Along with these female terminals to connect to the 12V sockets. All of these can be found at your local auto parts store for cheap sometimes all together in a kit.

You'll also want a pair of wire strippers/crimper for wiring.

This is the best wiring diagram I can find. Most are so overcomplicated. This diagram does not show the fuse panel but you can see the empty slots on the far right of the charge controller where you insert the wiring for that, it's called the "load." This diagram also shows an inverter which is something I didn't go into because you will only need that if you HAVE to run a 110V appliance. I know you mentioned a kettle but maybe you could just install a gas stove in your van and use that to heat water? That's what we use :) Installing the inverter should be pretty straight forward though if you need it but remember you will waste energy going from 12v to 110v so 12v is more efficient.

Hope this can help you (and maybe others) in some way. I plan on making a more in depth version of this guide in the near future along with a video but finding the time has been difficult! Let me know any more questions you have :D

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.

you probably want to use leds for the lighting as you can very cheaply aquire and run some 12v leds straight off the battery without needing an inverter.

Same goes for a cell phone charger. Use a 12v car charger.

If those are the only 2 things you need to power you'll have plenty of juice in that battery.

Why that battery in particular?

If you're getting a solar panel you'll need a charge controller, and neither of those will be super portable anyway.

Consider a 12v 7ah sealed lead acid battery.

They are super cheap for their capacity.


As far as the solar panel, something like this would work.


it includes a charge controller.



here's a couple images of one of the solar power kits ive put together.

http://i.imgur.com/nfA1GnO.jpg

http://i.imgur.com/rQKQ1uD.jpg

4 x 12v 7ah SLA batteries
1 10 watt solar panel

1 charge controller (much better than the ones that are often included with inexpensive panels

1 200w inverter


I can run just about anything with this setup.

12v devices and wires can be connected straight to the "Load" terminals on the charge controller.
Anything 110v can be plugged into the inverter.

The thing I REALLY like about that inverter is is has 4 usb charging ports that are on even when the inverter is off.

2 x 2 amp usb.

2 x 1 amp usb.

Yes it would be stationary if it end up being small hiding under ground or in between the shrubs.

It would be a string of lights. To light the two big palm and shrub on the front yard. mostly using the linked 1w eagle eye LEDs.
I might use a LED string but the big 16 ft unit pull from 1 to 2 amps.

Yes I was looking for a small controller like the one in the Alpha LED I linked above that one work with the solar panel. Once the solar panel drop below a set point then the Light come on as it know is dark.

I searched for 'energy harvesting chips' but no much luck. I would prefer something more like plug and play. screw on terminal to hold the wire or similar.

I did found this less expensive controller HQRP Solar 10A
But it don't have built in timer like the Sunlight controller.

I would much prefer a chip style controller they are way smaller, but not sure if they can handle a 40w panel.

I want the cheapest, lightest, smallest, best way to get 3 amps at 12 volts 24 hours a day for 7 days straight at 47 degrees latitude in the summer in the US. How would I do it?

My thinking is 100watt panel at $150 I kind of like the flexible for my application, and lighter is better here:

https://www.amazon.com/DOKIO-Monocrystalline-Flexible-Lightweight-Irregular/dp/B074G1CN6N/ref=sr_1_10?s=lawn-garden&ie=UTF8&qid=1525191310&sr=1-10&keywords=100+watt+solar+panel


This could work, but the metal and glass and weight will be harder to mount: https://www.amazon.com/Newpowa-Polycrystalline-Efficiency-Module-Marine/dp/B00L6LZRXM/ref=sr_1_7?s=lawn-garden&ie=UTF8&qid=1525191310&sr=1-7&keywords=100+watt+solar+panel

A second panel, esp. flexible is not out of the question.

A mppt controller at $100 I'd like the controller to have the possiblity of a second panel.

Can I get away with one of these: https://www.amazon.com/dp/B071ZVD7R5/ref=sspa_dk_detail_1?psc=1&pd_rd_i=B071ZVD7R5&pd_rd_wg=TpZ8s&pd_rd_r=3NBQTEN5HQV42CS632RT&pd_rd_w=nuxLH

Or is something like this better: www.amazon.com/HQST-MPPT-Solar-Charge-Controller/dp/B01B28DBX6/ref=sr_1_11?s

How close can you run the controller to the limit, is a 20amp controller good for 200watts of panels, or is it better to not be so close and go to 30amp?


A 4x10 amp hour 12v in parallel, LiFeP04 bank at $500 (battery might be a bit small, but 3 amp constant might be a bit exaggerated and a dark period might be ok)

https://bmsbattery.com/ebike-battery/652-12v-10ah-38120s-lifepo4-battery-4-cells-ebike-battery-pack-battery.html 17lbs


SLA could work probably x2 www.amazon.com/HQST-MPPT-Solar-Charge-Controller/dp/B01B28DBX6/ref=sr_1_11?s Can you run the SLA as far down as a LiFEPO4? 3x the weight, but 1/3 the cost. How does the life compare?


Am I thinking wrong, or missing something significant other than wires and connectors?

Are their controller considerations if looking at LiFEPO4 vs. SLA?

Let me see if I can organize it into something reasonably understandable.

First up, the controller: https://i.redd.it/zmxxkfwqy9g31.jpg

Stuffed in that box are:

• 1 HiLetGo ESP8266 NodeMCU
  
• 1 Analog voltage sensor
  
• 2 Double Relay control boards (https://www.amazon.com/gp/product/B078478SZ9)
  
• 1 Voltage Regulator (https://www.amazon.com/gp/product/B01GJ0SC2C)
  
• 1 MPPT Solar Charge Controller (https://www.amazon.com/gp/product/B07PT7HBRF)
  
• 1 Waterproof Ultrasonic sensor module (https://www.amazon.com/gp/product/B07FQCNXPP)
  
  For the valves, I'm using a 1" Motorized Ball valve for the outlet (https://www.amazon.com/gp/product/B06X9B4P45) and a 1/2" Motorized Ball valve for the inlet (https://www.amazon.com/gp/product/B06X99PHJJ)
  
  Each of the relay modules control one of the ball valves. The valves are 2 wire, reverse polarity and operate on anywhere from 9 to 24v, so I just use battery voltage. In their normal closed position, both relays on the board are set to ground. When I want to open/close the valve, I switch the appropriate relay on the module to on (+12v).
  
  The ultrasonic sensor is set at the top of the tank and measures the distance to the surface. It's not the cleanest of signals, but it will give a rough idea on where the water level is in relation to the top of the tank. You can then transform that into a rough percentage.
  
  I use ESPHome on the NodeMCU, just for simplicity. The code is pretty long, but not very complicated. Just a bunch of different switches to abstract the base functionality into something cleaner for Home Assistant. I'll clean it up and put it in a github account or something like that and link it here later, likewise with the Home Assistant code that I use to run it.

I enjoy your videos, and would love to do something similar myself sometime.

One question: you are using this charger (the MPT 7210-A), right?

I am wondering if a better alternative for an MPPT voltage boosting charge controller might be this one (seems to be usually called the 'CTK300-II' ). I found this video about the CTK300-II that reviewed it favorably.

But I don't know enough about MPPT to really gauge. Would you ever consider doing a direct comparison?

> a decent but good enough controller at 12v?

It's hard to go wrong with any well-known MPPT controller, even the inexpensive ones.

> I'll upgrade to that 75v [panel controller] when I get some more panels.

At this power level the equivalent Chinese A-series controller doesn't have much cost advantage over the (made in India) Victron 75/15: $80 w/out bluetooth or $110 with. So pick whatever you like. By the time you get to the 40A-50A range the pretty blue Victron costs 2x what the ugly Chinese stuff does.

I do like the idea of Victron's adaptive Absorption duration feature, although apparently it can get confused. I assume a future update will address that buglet.

When I made the decision in the 40-50A range I went with the Chinese EpEver because of lower-priced accessories and ridonculously massive heatsinking. I overpanel the and last time I checked Victron wasn't amused by such shenanigans. Getting the Chinese one at half the price didn't hurt my feelings either.

BTW, most of Renogy's MPPT line is rebadged EpEver. There's a small premium associated with it but apparently one gets decent support. I don't need support and don't want to underwrite anyone else's need for support.

$3680 for 480Wp seems expensive, even if it would include the batteries, which is doesn't.

I would suggest a 24V battery system.
You'll need one (or more) solar battery charger, this example says 40A, 1000Wp and Vsolar is 100Vmax. $235.00

Solar panels, 1000Wp, Voc = 37.8V, for $1339.99
To connect these to this controller, you need 2 parallel strings of 2 panels in series.
These panels are 160x100cm, if you want to mount them on the roof, make sure they do not get any shadow, from A/C, ventilation pipes, sky-light, whatever.
If this size is too big, you can buy 9 of these, connect them with 3 parallel strings of 3 panels in series each, $1071.00
pvwatts v1 gives a rough indication of available solar energy in your area.

120Vac inverter, you need a "pure sine wave" inverter, some appliances don't work with 'modified sine wave', the 'Watt'-rating depends on how much energy you are using at the same time, a 3000W costs $1298.00.
$235 + $1340 + $1298 = $2873, add some for cables/connectors, and you have double the energy available (excl. batteries).

The battery capacity (Ah) needs to be 10x the charge current (40A) = 400Ah, like 4x 6V-428Ah, $1523.00

Is it worth it.
Make a note of every electrical appliance, how many Watts they are, and how many hours/day they are running, incl. day/night time use, and are they running at the same time.
From that you can make a list every 15min(1hr) of Watts needed (120Vac inverter), and kWh/day/night (batteries).
The A/C and water heater are probably big energy users, and then think of how many days the batteries have to last if there are clouds and the PV panels are working at 10%.

Once you have all the data and have further questions we can look into that.

You cannot get a powerful enough wind turbine capable of giving you 5kW's for the same price as a phone, nor is 5kW's the same as 5kWh's in fact it's DRASTICALLY DIFFERENT. If your system produces 5kW's that is 5kWh's per hour for a total of 60kWh's per day(5x12 because i'm just guessing it will only run half the time but it all depends on the wind). The average house uses roughly 2kWh a hour so this turbine would be more then enough to power two houses.

From the picture you can see that this turbine is extremely tiny. For reference here is a $550 wind turbine from Amazon which only produces 600 watts at maximum so unless the indian company made some amazing breakthrough's what they are claim is completely and utterly a gigantic scam/lie.

Also if you look at the picture they provided it seems as if they have basically taken a car alternator popped on some blades on the front and called it a day. While using a car alternator can work with wind turbines you do need to do a lot of alterations to designs since you will need to provide startup power(12v) and also build a circuit which can sense speed of blades turning which engages the power for the alternator. You'd also need to gear the alternator because it's designed to spin quite rapidly which you won't be able to get with just straight blades.

true looks like almost a $120 difference.. damn

PWM

vs.

MPPT

edit: any thoughts on this one? sounds pretty great for a 200W setup.

My solar panel is like the Grape Solar that Home Depot currently sells for $89. It's 100 watt polycrystaline. The 100 watt monocrystaline are a bit smaller but the poly are alleged to produce a bit more on overcast days. I paid $108 a couple of years ago.

The charge controller I got was the cheapest I could find.

https://www.amazon.com/gp/aw/d/B074TB6FS8/

It is PWM. MPPT would perform better but getting a second solar panel and a 20 amp controller would improve performance more.

This controller has a voltage setting that the instructions call "float" but it means what you want. I keep it set to 14.4 in the summer and 14.8 in the winter. When the battery is lower than the set voltage the panel is on. When the voltage gets up to the set voltage the controller goes off and on to keep the battery at the set voltage. When the sun goes down the charging stops.

The "right" way is to have a 3 stage charger. Bulk gets the battery up to the absorb level, 14.6 volts with temperature compensation. Then when the battery is full the voltage is reduced to 13.8 volts, the float level. The problem is that the charger doesn't know when the battery is full and stopping the charging by going to float often happens too soon leaving the battery undercharged.

My scheme will tend to over charge. I have a flooded battery so adding water is possible. AGM and gel betteries are sealed, can't be watered. I use a hydrometer to verify the state of charge. I measure the amount of distilled water my battery uses. It takes 20 to 30 ml per cell per month. I take that to mean that the battery does get some charging after it is full causing electrolysis.

The battery is a deep cycle group size 24.

https://m.samsclub.com/ip/duracell-marine-battery-group-size-24dcc/prod3590221

I needed a new battery as the old one got to the end of the 3 year warranty and started self discharging. After 3 days it wouldn't start the engine. A new one was $100. The battery I got was the biggest that I thought would fit in the original location. I got the one with the most amp hours, the least cold cranking amps, and the most weight. It was only $80.

AGM batteries are 150% to 200% the price of flooded batteries. AGM batteries can't be tested with a $10 hydrometer. The electronic monitoring stuff is in the $150 neighborhood. AGM batteries like high charge rates, some have a minimum charge rate specification. That's expensive to provide with solar.

If ypu really want a deep cycle battery, get a pair of flooded 6 volt golf cart batteries. That will give a seriously low cost solution. The actual cost must be calculated based on the number of discharge / charge cycles. They have thick lead plates.

I have an 85 amp maxi fuse at the battery. It feeds a #6 wire 9 feet that goes to a $10 fuse box behind the driver's seat. There is a 3 foot #8 wire from the fuse box to the solar controller. There is a 30 amp fuse in the fuse box to protect the wire to the solar controller and the panel wiring.

I got a 120 volt clamp on desk lamp. I gutted it and used an automotive led light to rebuild it.

I have an ancient netbook computer that runs off 12 volts. After dark the battery voltage is low enough for it to work. 14 volts is too high, it shuts off. Mostly I use my cell phone for everything. I have 2 usb ports on the solar controller and another one on the inverter.

I have a Maxxair fan. It is a 14 inch RV fan.

I use the $25 Harbor Freight 400/800 inverter to run my electric shaver 3 minutes per day.

I have never had the battery fail to start the engine. I pay attention and don't take too much from the battery.

After using the system for a year I decided to go crazy and have a fridge. I recommend the $240 Alpicool C20. I don't have one.

My mother in law needed her cube fridge replaced. I bought one at Walmart for $80. Before delivering it I tried plugging it in to my inverter. When I turned on the inverter it wouldn't start the compressor. I tried turning on the inverter then connecting the fridge. It started. I bought myself a fridge. I got a $20 4x8 sheet of polyiso insulation and lined the inside of the fridge. I put 8 pounds of water in ziplock bags in the freezer compartment. I got a $5 electronic thermostat and wired it into the inverter to turn it off. 8 pounds of ice keeps it cold 3 days with no electricity. It takes 6 to 12 amp hours per day. Not bad for $125. The experimentation and effort was interesting. Now that you can get the Alpicool C20 for only $240 my effort is pointless. The ice does make it so that the compressor only runs during the day.

You can have a small amount of electricity at a very affordable price. If you want a microwave oven, a gaming computer, or a projector for movies it will cost more.

A real deep cycle batteries like golf cart batteries should only be discharged 50% of the rated capacity. It is my opinion that not so good small 12 volt deep cycle batteries should be limited to 25% of their capacity. Starter batteries generally don't have amp hour ratings. The reserve capacity is minutes at 23 amps until dead. My old starter battery was 100 minutes. In amp hours that's 23×100÷60=38 amp hours. 50% discharge will kill it in 20 to 30 cycles. If you limit the discharge to 5% with an occasional 10% the battery life won't be horribly shortened. 5% of 38 amp hours is 1.9 amp hours, one cell phone charge. The battery I have now was 75 amp hours when new. Just guessing, if it is 60 amp hours now, 2 years later, that means I can use 15 amp hours over night. That's good for the fan and the phone.

Lead acid batteries need to be recharged right away. Daily is good. Partial charging then discharging more is really bad. Capacity just goes away.

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$575
http://www.sunelec.com/sun-electronics-1224v-74-cf-upright-fridge-and-freezer-bcd210-p-820.html
$562 for 2 solar panels http://www.sunelec.com/sun-solar-panel-210-watts-1850-vmp-p-1648.html
LiFePo4 40ah24v pack $350 from a variety of retailers.

$40 10a charge controller http://www.amazon.com/HQRP-Controller-Regulator-Indicator-Coaster/dp/B002GJ456S

Wire and doodads $100

Time spent installing to code? 8 hours.

Time spent learning what said code is? 54.5 hours

$1627 on your mastercard now to have ice soap and the last cold beer in society? Priceless.

NC Tax credit 0.35($40+$100+$350+$562)=$368 discount Federal Tax credit = $5000.42kw=$210


Net cost after rebates $1627-368-210=$1049
Savings per month not running a normal refrigerator $10.
Payback period 9 years.
Not having a fridge large enough to put a pizza box in= Too bad.

I went with a 1000w array and an inverter and a high effiency refrigerator. I get ~5kwh a day and they hyper refrigerator (18cu ft) uses 2.2 kwh a day in the summer. I can run my house light CFLs and LEDs TV PS3 and computer as well as my refrigerator. But I did it when the federal tax credit was 30% of cost not 30% of cost limited to $500/kwh. Still my net cost after tax credits was similar per watt at $2000. Payback period 8 years.

Get the Frigidaire LGUI1849L and Kenmore 9704388, 18.34 cubic feet, 334 kWh/yr . if you want to use an inverter... About 2.5x as large as the DC version and uses about twice the electricity. I couldn't find this model, got a Frididaire model same size but 375 kwh/year Close enough for me. For my household it uses 2 kwh in the summer and 1 kwh in the winter a day.

any pwm controller or am I looking for something specific?

https://www.amazon.com/Smart-Solar-Charge-Controller-Display/dp/B01F5WFK5C/ref=sr_1_1?ie=UTF8&qid=1485892383&sr=8-1-spons&keywords=pwm+charge+controller&psc=1

You commented that you want to charge at 500A. It took a while for that to sink in. The heat that will generate can't be cost effective.

 

Check out this page http://www.sunshineworks.com/solar-charge-controllers-high-capacity.htm. (Yeah random search result)

If you can charge at 48V instead of 12V your current (and required number of controllers) will drop proportionally.

Check requlations about any wiring IaNaL. But you could go beyond 48V.

So, I had the panels working for over a year with no problems, so I doubt it was the controller.

But there were 6 Renogy flexible solar panels 100W each, nominal voltage of 18.5 I believe, with this charge controller. Two parallel sets of 3 panels in series wired to the controller, wired to the battery.

I think the main thing though was I drained the batteries and had them connect to a 24V/12V step down with no low voltage shutoff. Maybe we just haven't been getting enough sun to power it, and it killed it.