What do I need for a new setup?

Just picked up 6x Kyocera 36v 250 Watt Panels (KD250GX-LFB). Got a decent deal on them and they were brand new! So after reading and some research, I don't know what components I need to get? I know I need to get a MPPT charge controller, but what should I get? I want to run these 6 panels off grid on my detached garage for just basic lights and small power tools. Of course I need batteries, etc, but I just wanted to get an idea of what components I will need to make this work?
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Bill
Assume in the real world your 1500 watts of panels will actually really produce about 1200 watts of power (look up NOCT rating). Assume that a 12V system charges at 14.4VDC, a 24V system at 29.3VDC, and a 48V system charges at 59.3VDC (Trojan specs). Assume that a battery bank likes to be charged at 1/10th of its amphour rating.
1200watts divided by 14.4VDC = 83amps which is too much amperage for a 12V battery (single string)
1200watts divided by 29.6VDC = 41amps, about right for 370-420AH Trojan L-16 batteries.
1200watts divided by 59.3VDC = 20amps, about right for a 225AH Trojan T-105 battery.
Your panels could adequately charge TWO 12V strings of L-16 batteries, or ONE 24V string of L-16 batteries, or ONE string of smaller T-105 batteries in a 48V string. Each battery configuration would have roughly eqivilent storage capacities.
420AH X 2 X 12V =10080 watthours of power
420AH X 24V = 10080 watthours.
225AH X 48V = 10800 watthours.
Lastly, assuming you never, ever want to drain your batteries more than 50%, and 10-15% daily consumption is about right, then you'll have between 1000 and 5000 watthours of capacity depending on how much you're willing to deplete. For L-16's, Trojan says that at 50% depletion their battery will last about 2000 cycles (that's ~5 years). At less than 20% depletion, those same L-16's might last for +5000 cycles (13 years). You decide for yourself whether you want more power, or longer lasting batteries, you don't get both.
Now that you know what amps you can produce, you can go about selecting a charge controller. For just 20 amps, you could select Midnight's Kid.
https://ressupply.com/charge-controllers/midnite-solar-mnkid-b-the-kid-charge-controller
In the 40 amp range though you'll need a more capable controller. Look at this Morning Star or Outback.
https://ressupply.com/charge-controllers/morningstar-ts-mppt-45-tristar-charge-controller
https://ressupply.com/charge-controllers/outback-flexmax-fm60-charge-controller
If you'll be producing up to 80 something amps, you'll need a high capacity controller like Midnight's 150 Classic. It can handle up to 96amps at 12V.
https://ressupply.com/charge-controllers/midnite-solar-classic-150-charge-controller.
The last thing you'll need to think about is an inverter. Most likely you'll want an pure sine wave inverter if you're using power tools. Your choice will depend on your system voltage. For anything above 1000Watts, you really want a 24V system, and anything past 2000 you'll want 48V. My 48V system can power my 1.5hp well pump.
If the small power tools include a circular saw, for example, you'll want a good pure sine wave inverter ~1500w. You could do that with 12v, but 24v may be a better choice. You will want a unit designed to be hardwired, which you can wire up to a standard AC breaker panel.
Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
With the MPPT controllers that I identified for you, the controller acts as a transformer to bring the voltage of the panel down to exactly what the battery wants. When the controller is connected to a 12V batteries, it will transform the voltage down to ~14V to charge the 12V battery. Connect the same controller to a 24V battery, and it will drop the voltage down to about 28V. As the voltage is transformed down, the amperage gets bumped up, so the wattage stays the same.
What that means in the real-world is that you can put panels in series to raise their output far above what the battery is. High voltage cuts down on the thickness of the copper wire that runs from the panels to the system. You can also put the panels further away from the rest of the system because voltage drop is less important. What you can do is wire three panels in series to get ~91VDC. You can make two 3-panel arrays, each producing about 8.2 amps at 91V (that's called a 3S2P configuration). Alternatively you could make 3 arrays of two panels in series (2S3P configuration), each array putting out 8.2 amps at ~60V.
One last thing. Some people get lured into the idea that they can make 12V work well for them because there are so many 12V RV appliances. You are really better off designing at least a 24V system from the start and forgetting about 12V completely. You've already got enough panels to support a 24V system with L-16 batteries, which are the standard for off-grid cabin people like me. The quality inverters out on the market are designed to be hard-wired into a standard electrical panel, and that's what I have done at my own cabin.
Probably the most common mistake may be screwing up with batteries. There are at least a dozen ways to do that.
I can fully appreciate the desire to have back up power but battery's go bad just sitting there and the years fly by. Too bad we can't easily get dry batteries like we used to.
https://www.solar-electric.com/learning-center/batteries-and-charging/deep-cycle-battery-faq.html
Battery Lifespan
The lifespan of a deep cycle battery will vary considerably with how it is used, how it is maintained and charged, temperature, and other factors. It can vary to extremes - we have seen L-16's killed in less than a year by severe overcharging and water loss, and we have a large set of surplus telephone batteries that see only occasional (10-15 times per year) heavy service that was just replaced after 35+ years. We have seen gelled cells destroyed in one day when overcharged with a large automotive charger. We have seen golf cart batteries destroyed without ever being used in less than a year because they were left sitting in a hot garage or warehouse without being charged. Even the so-called "dry charged" (where you add acid when you need them) have a shelf life of 18 months at most. (They are not totally dry - they are actually filled with acid, the plates formed and charged, then the acid is dumped out).
These are some typical (minimum-maximum) expectations for batteries if used in deep cycle service. There are so many variables, such as depth of discharge, maintenance, temperature, how often and how deep cycled, etc. that it is almost impossible to give a fixed number.
I suspect that one could store iron batteries for a very long time. But they are expensive and not made domestically for some reason. With the affordability of large solar arrays, iron batteries become a quite logical choice if they were priced where they should be.
A problem with lithium is the expense and need for cobalt that apparently is only mined in the Congo. Problems with supply could arise. I am also unsold on using hundreds of oversize AA laptop batteries like Tesla uses. Then again.....Tesla batteries are getting the job done.
For Nickle Iron batteries, there is having to change the electrolyte every few years because the electrolyte slowly absorbs the CO2 out of the air and "goes bad". Having to store bags Potassium Hydroxide (sealed against CO2 and Moisture) mixed with distilled or de-ionized water. Supposed to be non-toxic for disposal.
-Bill
pH Value
"Potassium hydroxide has very high alkalinity as measured on the pH scale. This scale goes from 0 to 14 and defines the acidity or alkalinity of a substance, with 7 being neutral, and alkaline being higher than 7. Pure distilled water has a pH of 7. Potassium hydroxide has a pH of 12 to 14. Compare this to ammonia at 10 to 11, and borax at 9."Even higher than sodium hydroxide aka: Drano.
One could really screw up very badly if accidentally mixing normal battery acid with a nickel iron battery base...potassium hydroxide. Going to have to get some of this stuff. For science. Incidentally.....this risk may be part of the reason that nickel iron batteries are generally not readily available. Putting battery acid in a functional nickel iron battery would likely be a somewhat spectacular event.
Yeah, but you'd have to work at it. There is no battery acid laying around to "put" into the cells. Just 15 gal of distilled water.
Like lead acid batteries, who keeps acid around? Just distilled water. Batteries come with their own acid generally. If they do come with a pouch of acid, all that goes into the battery, you don't leave it around to use later.
But they are not efficient, I'm always adding water. But voltage is a great SoC indicator, I never worry about recharging to prevent sulfation, or if I have to EQ this month. The downside is replacing all the electrolyte every half dozen years, it's going to be real messy and a lot of work.
|| Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
|| VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A
solar: http://tinyurl.com/LMR-Solar
gen: http://tinyurl.com/LMR-Lister ,
It seems as though regular batteries may work, more or less, if voltage stays above ~12.2. They can cycle alright but distinctly dislike deep cycles below ~12 volts.
Generally, people do not replace lead acid electrolyte.
Assuming you are talking about lead acid batteries Softdown
Bill