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Small Cabin Forum / Off-Grid Living / Rejoice or did I size solar wrong?
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Nobadays
Member
# Posted: 28 Jun 2019 18:42 - Edited by: Nobadays
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So the system is up and running. 5 days now without needing the generator except for a couple of building projects outside... no outside outlet or I could have used solar.

Hoping to learn from you all!

The system:
1470 watts of panels
8kw Chevy Volt storage (160amp hrs - more like 300 inFLA)
Schneider SW 4048 inverter/charger, 60/150 Charge Controller

Before the panels went online, after charging with the generator we were able to get 2.5 days on just batteries before hit 45.0vdc where the warning went off. LBCO is set to 43.0vdc. The kids/grandkids were here so late nights playing dominoes and little regard for power conservation.

Bulk and Absorption are now both set at 48.3vdc and float at 48.2vdc (had float at 48.0vdc but seemed to stay at 47.8vdc so raised it a couple of points.)

Bedtime around 9PM finds us around 46.8 -47.6vdc SOC depending on if we watch TV or read.

Mornings around 5:30-6:00AM will see SOC usually around 46.2vdc then dropping to around 46.0 - 46.1vdc just before Bulk charging begins for the day.

By no later than 11:00AM the modules are charged and we float the rest of the day.

We do plan to add an electric fridge... no more waking up at 4AM to the sound of the CO2 alarm... previous owner had not serviced the propane fridge and I hadn't thought about it... close call!!

Does this scenario sound good? I know my array is oversized but got a smoking deal on the panels. Do I need more storage? Seems like a lot of power not being captured... but we seem to have enough and then some for daily use.

Your thoughts!

toyota_mdt_tech
Member
# Posted: 28 Jun 2019 20:55
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Man, sure sounds good, but I think Creeky is the final say on this.

Cowracer
Member
# Posted: 28 Jun 2019 20:55
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Nobody ever laid in bed at night and went "man, I wish I had put in smaller panels"

Tim

ICC
Member
# Posted: 28 Jun 2019 20:57 - Edited by: ICC
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2.5 days before low battery sounds great. Getting recharged before noon is also great. That helps especially when days are cloudy. That also gives you the ability to do heavy consumption tasks in the afternoon without depleting the battery a lot. Gives room for A/C _mini-split in particular) if wanted someday. Mini-split is also great for cold weather heating. I would much rather have more battery capacity than what is needed for todays uses as that gives you space to grow. Same for more panels than bare bones.

Wilbour
Member
# Posted: 28 Jun 2019 21:39 - Edited by: Wilbour
Reply 


I hear the same thing from Ontario Lakeside, his overnight use is replenished before noon. I as well have the same scenario. Being 2.5 days into it before needing a recharge seems reasonable. I cannot see myself needing to be prepared for longer. My consumption is less so I only have 2kw. Gets me 2 days with zero sun.

If you have reason to be nervous, you can always cut back and be a little more conservative. Heck, even on grid we've encountered times when a catastrophe hits and the power company asks us to cut back for a few days.

I even had one of those thermostats that the power utility controlled and when everyone was running their AC full tilt they bumped mine up. Needless to say I no longer have that thermostat.

Welcome to the clean and quiet way of power!

Wilbour
Member
# Posted: 28 Jun 2019 21:44
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LBCO is Low Battery Cut Off

LCBO is something totally different to Ontarians.


DaveBell
Member
# Posted: 29 Jun 2019 03:32
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Where are the pictures?

Nobadays
Member
# Posted: 29 Jun 2019 07:44
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Thanks for the votes of confidence! I’m new to this full house solar so am still stumbling through. My thinking with the oversized array was I could always add storage if needed but getting up on the roof is not for an older one armed man. Son in law and grandson put the panels up.

Here’s some pictures though since I’m posting from my phone pretty sure they will be sideways.
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Steve_S
Member
# Posted: 29 Jun 2019 09:38
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I think your alright and if your in Float by that time, really no worries, I'm in float usually by 10 am on a sunny day, sometimes earlier. Watch & observe your system, too early to tell how it will pan out overall, especially if your changing things around.

NOT all electric fridges are created equal, so when out shopping, pay attention to the Kwh used per month / per year and do serious shopping around and look for deals... Costco can actually have some good deals if you hit at the right time.

I would suggest the use of a Kill-A-Watt type meter on anything your not certain on as to power usage. A power bar can be a really good saver to kill devices which use phantom power.

Side Note: In my 120VAC installation, I included several switched plugs in the Radiant Heating closet, communications closet (only powered when I need them). this simplified much of those types of issues.

creeky
Member
# Posted: 29 Jun 2019 10:21
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I would put my LBCO at 40v. That's roughly 3.4v / cell. Some folks are more aggressive. But I like to balance "dang I need that last drop" vs "dang I'd like these batteries to last until I pass them on to my yet unborn grandkids."

I just got feedback on solar output. Last year I got this deal on 305s. So the guy has 3 305s putting out 1169 peak. Cool eh.

And he, in a shady location, did almost 16kwh over three days.

Solar rules!

Happy fridge shopping. My electric fridge upgrade has now saved me 1.25x365x6.5=$2,965.63 in propane costs. Not including driving into town and ...

Wilbour
Member
# Posted: 29 Jun 2019 10:43
Reply 


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Nobadays
Member
# Posted: 29 Jun 2019 12:10
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Wilbour.... thanks for the “rotations!” Don’t know why iPhones always post pics sideways.

Steven-s. We do have plug-in strips on our tv,Firestick, and all the satellite internet. I know we have a couple other “wall warts” in in-switched receptacles but not pressed for power right now so not worried. We used a kilowatt meter on several appliances before we brought them to the cabin. Actually helped in sizing the system. We have our eye on a fridge that is rated at 296kw/year so less than 1kw per day. The wife wants as big of fridge that will fit the opening under the stairs. Ends up being about a 10cuft fridge. Width is our obstacle as we only have 26” to play with.

Creepy.... I guess I was under the impression that 3.5 volts per cell was the knee and to not go lower than that. I have gen 1 modules not sure if that makes a difference.

Steve_S
Member
# Posted: 29 Jun 2019 12:43
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I used a couple of these and they really work a treat for the use cases. Tad pricey but the convenience is there.

https://store.leviton.com/collections/decora-switches/products/tamper-resistant-rocke r-nema-combination-decora-switch-and-receptacle-white-t5625-w?variant=18216064579

I used all Decora switches & plugs as I prefer them but they also have these in the usual regular format too and they are a little cheaper.

Steve_S
Member
# Posted: 29 Jun 2019 12:44 - Edited by: Steve_S
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duplicate post... weird

Wilbour
Member
# Posted: 29 Jun 2019 12:53
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Quoting: Nobadays
Creepy.... I guess I was under the impression that 3.5 volts per cell was the knee and to not go lower than that. I have gen 1 modules not sure if that makes a difference.


Nobadays, your not scoring points with the master by calling him Creepy. I did that once and he threatened to sick his Roomba after me!

Nobadays
Member
# Posted: 29 Jun 2019 13:04
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Yikes!! Auto correct got me! Sorry CREEKY!

creeky
Member
# Posted: 2 Jul 2019 09:05
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No worries Nobadays. Sorry, but the recall button on the roombadaboom isn't working. It's solar charged so will take awhile to get to you.

Ya. The knee is 3.5 but a bit extra shouldn't hurt. And you will very rarely get there. So when you do. Its just grabbing that last few watts to keep ya going.

redwolfguild
Member
# Posted: 2 Jul 2019 18:51
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Quoting: Cowracer
Nobody ever laid in bed at night and went "man, I wish I had put in smaller panels"



No truer words.

Nobadays
Member
# Posted: 3 Jul 2019 08:10
Reply 


We have had two partly cloudy, thunderstorms hail and rain with just enough sun breaks to put some charge back in the bank. It did hit float both days but early in the day. Last night it was at 47.1 and woke to 46.6.... I think it will hit the 45's before the sun hits the panels again. Feeling pretty confident about adding an ele tric refrigerator. The one we have picked out is a 10.1cuft Magic Chef that is rated at 297kw/year, about .81kw/day. The big box store near our home in AZ has it in stock for $328.00. Not too bad of price. I'm sure there are more efficient ones out there but with our size limitations (26" W maximum) and of course budget, this one will do.... unless anyone has seen a better one!

creeky
Member
# Posted: 3 Jul 2019 11:25
Reply 


I have the Magic Chef too. On the watt meter thing (EM100) it draws 500w per day.

Measured in early summer. When the temps get up I imagine it draws more. Plus I'm one guy. So the fridge isn't opening and closing all the time.

Solar rules!

Nobadays
Member
# Posted: 3 Jul 2019 15:59
Reply 


Thanks Creeky.... good to know! We just ordered a Panda mini washing machine as well.... no more laundromat! When we start using it I'll provide some feedback on energy consumption and the device itself.

Ontario lakeside
Member
# Posted: 3 Jul 2019 18:52
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I just put up a new video about our system working so well that on sunny days we make ice with the excess electricity. Nothing is better than ice made with the power of the sun!

https://www.youtube.com/watch?v=B0mGgOi6I8o&t=24s

Nobadays
Member
# Posted: 3 Jul 2019 19:52
Reply 


Good job "lakeside!" We keep drinks in a cooler presently so an ice maker would be great! We make small blocks in our propane fridge jow but it takes hours to freeze a small block. We seem to go to town about once a week so grab a 20# bag while at the store. It won't last the full week between trips, almost but a day or two short.

Maybe next purchase! Of course my wife is angling for a new cook stove too.... this one turned her pots all black from inefficient burn of propane. I looked at it and realized it was for use with natural gas jot propane. Couldn't find information online to convert it. Low and behold when we moved a large wardrobe we found the book and it had the instructions. Burns great how. The first thing she said was, "there goes my new stove."

Cheers!

Ontario lakeside
Member
# Posted: 3 Jul 2019 20:33
Reply 


Thats a fun story. we converted our stove, it even had the jets included

Wilbour
Member
# Posted: 3 Jul 2019 22:58 - Edited by: Wilbour
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Ontario lakeside

I watched the video. Great idea making ice. Since it's just me and the misses, I fill a water bottle with a little water and slid it into my freezer. In a few hours I have ice for my water. The miracle of an iced drink on a hot day!

Ontario lakeside
Member
# Posted: 3 Jul 2019 23:38
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Wilbour, It is a simple pleasure!

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