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Link44
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# Posted: 27 Jul 2021 11:22pm
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Hello,
long time listener, first time caller.
I have been pouring over all the wonderful information here and my head hurts trying to figure out what kind of solar setup I need.
A little back ground. I bought some fairly heavy wooded land in Southern Oregon and want to build a 12x16 shabin with half of that space having a loft. I'd like to keep it simple but not full caveman. The list what I'd like to run.
9w led bulbs 6hrs a day= 54 wh
12w cell phone charger 2hrs a day = 24wh
7w ceiling fan 6hrs a day = 42wh
84w shurflo water pump 2hrs a day = 168wh
41w led tv 2hrs a day = 82wh
15w dvd player 2 hrs a day = 30wh
60w fridge 24hrs a day = 1440wh ?
So 460AH of battery right?
I've been looking at Renology's 400watt set up with a MPPT controller. I was thinking about (2) 6 volts in parallel, but I have also read series is king and to avoid parallel connections.
I would appreciate some advice on whether this set up will run the fridge and what inverter I should run.
I will have at least 50 to 60 feet from where the panels will have to sit in comparision to the shabin. Also the 24 versus 12 volt, which way is better in this situation.
Sorry for the long first post.
Thank you
Link
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gcrank1
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# Posted: 28 Jul 2021 12:58am - Edited by: gcrank1
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Hi Link
Welcome to The Great Adventure 
Couple of things right off; more to come:
Renology is often not recommended. I dont have any of it but, iirc, it is regarded as bottom tier stuff?
Mppt is generally considered smart.
Real deal solar hours is HUGE; ie, a compromised location/positioning will hurt badly.
The array (all panels hooked up together is an array) needs to be able to run all your stuff on a good 'solar day' as well as charge the bat-bank full asap. That is, you dont want to be depleting the bat-bank will day use, save it for late aft/evenings.
With Flooded Lead Acid batteries, one or more, sealed or not, you can only draw down a Max of 1/2 the rated amp hours or you are killing them. You are much better off only using 30ish% on a regular basis with 50% as occasional. Many recommend a 3 day bat-bank buffer for bad weather, minimal charging times.
2 hours run time per day on your water pump seems huge.
The LED lights often will be just one running, but they use so little power, no worries.
Same with the usb charger and even the little fan.
These use so little that Ive come to basically not even regard them any more.
The tv and radio use a moderate amount, and if you end up like us, not used as much or as often as initially thought.
But that 'fridge.....theres the hog. There is quite a bit of different ways to approach keeping food cool-cold, a study in itself. Fwiw, to run my 4.5cf Heier 120vac was going to cost me big in battery bank, so we went with a good sized Yeti-clone ice chest that stays at the cabin. For multi-day stays we bring one conventional cooler full of home-made ice bottles and one chest of cooled food for right away and frozen food for days later. All this gets set up in the big chest once there. It works out great for us.
Many people go with a new or used rv type propane powered fridge rather than electric.
I have a 90'+ run from array/bats to the cabin so I invert to 120ac at the bats. For me, definitely, and for you likely, that 50-60' run would require pretty large wire to run off 12v. The 'line losses' can be huge! Going to straight 120vac asap for me was great (I had started with 12vdc, then combo 12vdc and some 120vac).
You can also have a line loss problem array to the charge controller. This is where mppt lets you use 24v in from the array, which can be farther away if needed.
The charge controller will switch that 24v in to 12v for the bat-bank (or 24v IF you wanted to do that as a bat-bank).
The bat-bank and inverter need to be matched for voltage and close together and your best sun exposure for the array may not be close to them.
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Steve_S
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# Posted: 28 Jul 2021 05:49am - Edited by: Steve_S
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The general unwritten rule is to not draw more than 250A from a battery bank (excepting surge handling).
12V@250A=3000W (25A AC),
24V@250A=6000W (50A AC),
48V@250A=12,000W (100A AC).
Using 24V example: 50A AC can be either 50A @ 120V or 25A @ 240V Split Phase (so two 25A legs).
Running long DC Wires is inefficient due to line losses (this is why AC dominates the world).
As mentioned by gcrank1 Lead/AGM/FLA you can only use 50% of capacity or you are damaging them. Real Deep Cycle Solar Batteries are not cheap and motive batteries do not survive this kind of use yet some folks do so.
Also RENOGY is a Marketing genius that sucks folks into buying their KRAP ! RUN AWAY FROM IT !
I'm FT Offgrid, 100% Solar, rural & remote, I run 24VDC System with 4000W/12000W Inverter-Charger, have 22kWh of Heavy Lead (Rolls Surette S-550 Deep Cycle) Battery Bank (now backup) and 30.4kWh of LFP (LiFePO4) which is my main bank.
My 428AH Lead bank is 8x S550, which at todays cost is around $3500 and that only provides 214 useable Amp Hours / 5.136 kWh.
One 24V/280AH LFP Pack, DIY'd runs around $2200 and will last 10+ years, maintenance free and with 90% Total Capacity available.
Bang per Buck and ease of installation, the All In One systems are the way to go. Internally they are modular and repairable ad they are far simpler to install. MPP-Solar & Growatt are both good products, Growatt being a step up from MPP.
MPPSolar-USA: https://usamppsolar.com/
Growatt America: https://www.growatt-america.com/list-42.html#product42
Have a Look here for more about AIO's.
https://www.mobile-solarpower.com/all-in-one-122448v-packages.html
You may likely find This Page helpful as well which is my system setup plus (I have to update that to my final config now but am busy with other things) other info.
https://diysolarforum.com/threads/my-diy-off-grid-cabin-setup-in-ontario-canada-24vdc -120vac.1484/
NB, I do not use an AIO, they were not available when I got going. My Solar Controller (Midnite Classic-200 is $1000US and Inverter/Charger is double that. See why I am aiming you towards Known Good Affordable AIO's.
Series & Parallel. (Battery)
Batteries in Series only increase Voltage !
Batteries in Parallel increase Capacity (AH Storage).
IF using Lithium Based Batteries, Series Connections are Heavily Discouraged, Packs should be built for the Voltage Use expected.
Series & Parallel (Solar Panels) this is very normal & common, no issues BUT requires good math and planning.
NOTE: Lead Battery Talk & Lithium Based talk. Many terms are used but in context are applied differently relative to the Chemistries. Many "Lead-isms" do not apply to Lithium based. LFP (LiFePO4) IS the safest of Lithium Chemistries, no explosions or fires very flat & even power curve, 99% Efficient (charge much faster).
IMPORTANT INFO MISSING:
You do not mention if PT or FT usage. That is a factor.
No mention how many days of stored reserve energy you want, most go with 3 days reserve.
Mention closest "CITY" to your property location, this will help to search for Sun Hour Tables & Solar Panel angle info. Good basic resources here to help you if you want. http://www.solarelectricityhandbook.com/solar-calculator.html
Hope it helps, good luck.
Steve_S
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Brettny
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# Posted: 28 Jul 2021 06:09am
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If your 480ah calculations are correct I would for sure go with a bigger battery than 400ah. I assume your talking about getting a FLA (flooded lead acid) battery, even gell/AMG you should double what you need. You would be closer to needing 1,000ah and that's for only 1 day of run time, no cloudy days, no rainy days, no hazy days. you also need to figure out how many hours a solar pannel would actualy see at the location you want to put it. Pannels being 50-60ft away means you will most likely want a 150v input MPPT charge controller. I highly suggest you look for full sized pannels for sale locally. Used pannels that are in good condition are generaly just as good as new
Il tell you a bit about my system. We have a 120v top freezer mini fridge, 2 LED bulbs and phone chargers. I have 615ah @12v coming from 6 GC2 golf cart batteries, a Epever 40a CC, 420w of pannels, a 1200w xantrex inverter and a 30a RV onboard battery charger. I can go about 2 days with minimal sun. Then I just run my 900w inverter generator and charge the battery bank via the 30a charger. We get roughly 3hrs of sun on the pannels.
I have found the key to running a 120v mini fridge is to run it on a $11 programmable timer. 1hr on/off when the sun isnt out.
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Steve_S
Member
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# Posted: 28 Jul 2021 08:11am
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BTW, Just posted a couple of hours ago. 12V/100AH LFP for $399 USD on Amazon Tested GOOD and Teardown Video HERE: https://youtu.be/74iBMHE3StM
These can be set in Series to 48V (not common).
No Low Temp disconnect.
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FishHog
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# Posted: 28 Jul 2021 08:25am
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Quoting: Steve_S Also EPEVER is a Marketing genius that suckets folks into buying their KRAP ! RUN AWAY FROM IT !
This quote surprises me Steve. If you said “Renogyâ€, I wouldn’t be surprised but I thought people generally liked EPEVER for the cost
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Steve_S
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# Posted: 28 Jul 2021 08:46am
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Quoting: FishHog This quote surprises me Steve. If you said “Renogyâ€, I wouldn’t be surprised but I thought people generally liked EPEVER for the cost
Thanks Fish.
Ohh My, fixed, 2nd coffee and while in voice with someone talking about EPEver and OOPS!
EPEver is a Good Quality value brand with a fairly good reputation.
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Nobadays
Member
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# Posted: 28 Jul 2021 09:08am
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Quoting: Link44 60w fridge 24hrs a day = 1440wh ?
Refrigerator usage is generally calculated at 8/day as it will not run 24/7.
So 60w fridge 8hr a day = 480wh
Total expected = 880wh/day
Not sure how you are calculating the wh to ah needed. Calculators I use give a whole different number from what you arrived at. But this should help with battery bank sizing, a lot less than you originally figured. I too am a proponent of lithium.
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bc thunder
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# Posted: 28 Jul 2021 09:23am
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Steve_s Great info!!!!
Is there anywhere in Canada to buy that mmp all in one pagages??? I saw a vidio of a guy hooking one up at his cabin and thought, ya eeven I could do that. lol
Thanks......
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Steve_S
Member
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# Posted: 28 Jul 2021 09:49am
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You can get them off Amazon.CA for pretty good deals, the Growatts are a slight notch up. Most are also stackable so they can multiplied for capacity.
BE AWARE of What you are looking at.
HF High Frequency vs LF Low Frequency, Hybrids (variations) for different needs / use cases.
Will Prowse has a several video's showing these in particular because they are so DIY friendly.
https://youtube.com/playlist?list=PL7bvIB2TPsCjn6aAPGc2CHzTl8_sIvyPi
ALSO NOTE: Some are ETL certified, Some UL-US, some UL-C some have CSA-C and CSA-US. If in Canada & you want insurance Co to be happier (not like they are ever happy) look for ULC & CSAc certification. Amazon/EBay vendors sometimes do not mention such.
MPP_USA or Growatt USA can sell & ship us North American certified goodies. Batteries coming from US is another matter. (stupid goes into overdrive on that)
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bc thunder
Member
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# Posted: 28 Jul 2021 09:53am
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Thank you sir, always very informative......
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Link44
Member
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# Posted: 28 Jul 2021 09:59am
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Just read all the replies, I will definately have to slow down and read them at least 2 more times ðŸ˜.
We will be part time usage. Probably 2 straight weeks a year and 5 or 6 weekends.
The closest city is Klamath Falls, I'll look into how much sun we will get. The property could see 4 feet of snow in the winter so I may need to remove the array for winter.
The fridge isnt a nessecity but the timer idea sounds like a winner.
Thanks, Link
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Brettny
Member
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# Posted: 28 Jul 2021 10:27am
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Really the best first step in solar is to really lock down what your loads are and you cant do that with the manufacturers tag very accurately. If you own the fridge(the biggest variable in your system) get a KillAwatt meter and use that fridge with it plugged in. It will track KW over a time period, you could leave it hooked up for months if you wanted.
In the end the crutch is getting more batteries or a generator to charge the batteries. You would be suprised how quiet a $200 900w inverter generator is at the end of a 100ft extension cord.
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gcrank1
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# Posted: 28 Jul 2021 10:45am
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With our 1st cabin, built '83-'84, we rotated 'Marine/RV' batteries on our typical 2-3 day stays. Take the flat one home to recharge, or both if badly depleted, bring back and a quick connect up. We also had old school RV Edison type incandescent DC bulbs, which was most of our draw. Can they ever suck the juice out! LEDs have been a game changer. And Good Lighting is important to me after years of kero-lamps.
If I was starting out again I would build with solar in mind for sun exposure, roof angle, etc. but as a future project.
Id buy an AIO unit or a 100ah LFP battery that I could pull 80+ amps out of in a stay (a 100ah FLA you get out 30ah @ 30%/50ah @ 50%, go deeper and you murder the bat) with no penalty, take it home and recharge. And the LFP bats are Light, waayyy lighter than lugging FLA bats around (which I did for years).
They recharge at home fast if you get the right charger.
I wouldnt even try to use a fridge, def NOT an air conditioner. We use several sizes of fans as needed.
The other game changer for us was the little inverter/generator; ours is a Champion version of the fine Honda EU2000i (now an EU2200i). That quiet gen runs the 'big stuff', tools, 700w microwave, toaster, water heater, etc, as well as a smart charger to the bat-bank when ever it is running.
We could have gone for years like that without solar at all.
Btw, you can run usb chargers on your vehicle as is. The draw is light.
You can even buy 'Edison' looking bulbs cheap on Amazon with their own little solar panel to recharge them (usb plugs/ports). Unplug from the panel and hang them where-ever you want. They are Dandy
My point is that you can start out with battery power without the expense of solar If you keep your usage under control.
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Link44
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# Posted: 28 Jul 2021 12:20pm
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So to figure the amp usage am I dividing my 9w light bulb by 12 or 120?
I do have a Honda EU2000i that we use now with our travel trailer.
We don't have to have a fridge. I do have a mini fridge at home now. I will get a killawatt meter and check it. I am just trying to think ahead and maybe not have to revamp my system everytime we add more load.
Thanks,
Link
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Brettny
Member
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# Posted: 28 Jul 2021 12:24pm - Edited by: Brettny
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You use the light bulbs voltage if that's 12 or 120v.
You also need to calculate the inverters static(no load) and efficiency when loaded.
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