Get a big battery

[Sverige]

and are you happy with this ratio?, or do you feel you need more battery or PV to be a better 'balance' if there is such a thing.
Reading over all the replies, it seems to be 5:1 - 6:1 range is where we are converging.

For me it works. I rarely run the batteries down to “zero” (10%), except Nov - mid Feb when the sun here is so low in the sky there is hardly any charging available.

Although my installed PV is 1.9kWh I have some panel shading which limits morning charging, so maybe fairer to reduce that PV figure a bit and then my ratio gets up to 5 or above, so I’m closer to what you might consider a standard ratio. Our consumption is in any case low, so this small system lets me be more or less off grid most of the summer months and at this lattitude I would have to invest very big if I wanted to attempt the same during winter. I’m not even sure it is possible.

But although more battery makes things easier and I could buy some more in the future if the prices halved, for now my storage is quite adequate.

 

[OffGridForGood]

Ah Ha!
she is so busted.
Some of you gents may remember Jackie Stewart - "it is a great great day for motor car racing" in that thick Scottish accent of his.
So imagine Jackie narrating my Solar Assistant and Iotawatt this morning:

It is a great great day for solar power generation,
we see the Solar Assistant SOC reving to 74% this morning, BUT oh, Dryer load has snuck in at that first tight turn at 8:00AM and she's pulled ahead of SOC.
But wait, into that second turn at the 8:30 mark, she has the clothes washer pulling out all the stops and there is hot water on the track folks,
Iotawatt has tipped off the HWT is engaged, and not just a normal track re-heat cycle either! NO! She is using Full Hot Water wash here folks, showing no mercy.
Oh and then some solar has started but it is in overcast, so we are only seeing 700W low speed to start out, but there are a few breaks in the clouds, and we are likely to see some real performance soon out on the solar track today folks.

Now shes pulling into the third turn at 10:00 mark, we are seeing Solar is trying to catch up, gaining but there is a second load in the Dryer, and now Iotawatt is pulling the well pump and washer on, but no hot water this time to slow down her progress,
Oh Wait!, there is some cloud edge folks, that gave Solar a bit of the advantage after that tough third turn, but Dryer is well in the lead, and Solar is falling behind that next cloud...after the tough third turn.
We will have to see if Solar can make up the lost ground as we continue on this great great day for Solar Racing!! back after these messages from our sponsors at SA and Iotawatt...

 

[Nobodybusiness]

Ah Ha!
she is so busted.
Some of you gents may remember Jackie Stewart - "it is a great great day for motor car racing" in that thick Scottish accent of his.
So imagine Jackie narrating my Solar Assistant and Iotawatt this morning:

It is a great great day for solar power generation,
we see the Solar Assistant SOC reving to 74% this morning, BUT oh, Dryer load has snuck in at that first tight turn at 8:00AM and she's pulled ahead of SOC.
But wait, into that second turn at the 8:30 mark, she has the clothes washer pulling out all the stops and there is hot water on the track folks,
Iotawatt has tipped off the HWT is engaged, and not just a normal track re-heat cycle either! NO! She is using Full Hot Water wash here folks, showing no mercy.
Oh and then some solar has started but it is in overcast, so we are only seeing 700W low speed to start out, but there are a few breaks in the clouds, and we are likely to see some real performance soon out on the solar track today folks.

Now shes pulling into the third turn at 10:00 mark, we are seeing Solar is trying to catch up, gaining but there is a second load in the Dryer, and now Iotawatt is pulling the well pump and washer on, but no hot water this time to slow down her progress,
Oh Wait!, there is some cloud edge folks, that gave Solar a bit of the advantage after that tough third turn, but Dryer is well in the lead, and Solar is falling behind that next cloud...after the tough third turn.
We will have to see if Solar can make up the lost ground as we continue on this great great day for Solar Racing!! back after these messages from our sponsors at SA and Iotawatt...

That’s Freaking Hilarious.
I can just hear his voice.
?

 

[G00SE]

I just spit out my coffee ?

 

[Kenny_]

The problem with panels to battery is somewhat complex: Can your panels fill your batteries, and cover a load for a day? Will it be able to do the same for enough batteries for 3 days? 4 days? What is the longest stretch you will have without sun?
....

Yeah, this. There should be some kind of guide...kinda like the #of panels for your area based on sun....to get the proper average ratio of Battery to Solar for your location.... Maybe there is...I'm kinda new to all this..

 

[pvdude]

15560pv to 55104 kWh = 3.5:1
No sell back, FLA batteries.
Genset charges the batteries if no PV.
Hope to expand PV Winter 23-24, too many cloudy days here.

 

[ksmithaz1]

Limited sun came out around 11 AM. Mostly cloudy but did get to 40% by 1 pm. I turned on the dishwasher since I reached 40% and let it run after lunch. Went out and cut down 3 trees. It actually turned to mostly clear skies but by 4 PM the clouds rolled back in heavy and no production. Ended up at 52% charge. Wife came home when I was cutting down trees. Later the wind died down and I went to burn brush and sharpen saws. Came in at 10 PM, she had decided to run the dryer and must have had about every electrical appliance on in the house. In less than 3 hours the battery dropped to 31%. Over 10 Kwh in 3 hours.

I am amazed by her ability to load the system down and really use up power.......

"Honey please don't start a load in the Dryer after around 3:30..."
4:15 "I'm putting in the last load now"
-- "Umm OK", (Pretty sure that is the first load, not the last load), "You know it would be better...."
5:15 "Oh I forgot I need to run these linen's they only need to dry for 30 minutes, ...
-- "Sigh"

Flipped over to the grid at ~0100.

Meanwhile the PV batteries were at 100% at 12, and I didn't charge her car all the way because we were going to be doing laundry during the day, which we didn't do because we waited until 3. So I squandered 20 or so KWH of PV because I had no place to put the juice from noon until 4 instead of eating it up doing laundry. I have my electric hwh shared on a priority switch with the dryer. Pretty much runs about 80% of the time between heating water and drying clothes on laundry day.

I feel your pain, and I give up.

I'll need 90-120KWH of batteries to keep up with mine. During the week I toss at least 40KWH/day. With another 30KWH I might be able to just charge her car on Sat, and have enough excess from Friday to see me thru the night. Then Sunday can just be a push. This only works if the day is reasonably sunny. We do get cloudy days once a month or so. 60 more KWH (90 total) is probably a more practicable amount. Then just find a place to stuff more panels to take care of the day-charge on the EV. Kind of makes sense to walk it up on both sides. Adding battery makes sense if you have enough overproduction, but there is a diminishing return. I think here about 22KW of panels and 90 KWH would put me 100% off-grid. That's 4:1 bat/kwhv/kw.

 

[OffGridForGood]

Honey please don't start a load in the Dryer after around 3:30..."
4:15 "I'm putting in the last load now"
-- "Umm OK", (Pretty sure that is the first load, not the last load), "You know it would be better...."
5:15 "Oh I forgot I need to run these linen's they only need to dry for 30 minutes, ...
-- "Sigh"

My Offical Solar Tester at just after 5:00pm locally is on her FORTH Dryer load...pretty sure this morning she said Two loads today dear, pretty sure I said 'can you wait til the sun pokes through the clouds'...SOC is losing ground sitting about 34% after a mostly cloudy day with very brief periods where the sun found a break between them...need more battery.

 

[ksmithaz1]

Yeah, this. There should be some kind of guide...kinda like the #of panels for your area based on sun....to get the proper average ratio of Battery to Solar for your location.... Maybe there is...I'm kinda new to all this..

I think you really have to work up to it from your daily baseline:

1) I started with enough solar inverter output to feed my highest demand. To this end I stuck a sensor on my panel feed, and started recording.
-- I wanted 240V@100A to meet maximum demand
2) Next you will need to figure out the solar output to meet your average daily demand. A perfect day is ~6hours of 100% sunshine.
-- daily kwh = 6hr * panel watts so daily/6 = total panel. Eg 96KWH/day 96/6 = 16 KW of panels for 6 hours.
-- Buffer the number by ~25% for battery charge/discharge loss, and again by where you live.
3) PV is actually on a curve production time here is as much as 10 hours in the summer, much less at the moment. If you expect to be off grid you will need to be storing the difference between usage and production during that window. Using 8 hours as a median you'll need batteries to handle around 2/3 of your daily production, so with our example 96/3 * 2 = 64. Call it about 64KWH of battery minimum. Generally you will not be using as much energy out of sunshine time in sunny hot places. OTOH if you are in colder environments and you are using electric to heat, it's going to kill you if nights are REALLY cold.

This should give you a starting point. Then add panels and then batteries to create your needed buffers based on your environment and desires. I'd go panels first, as they are the least expensive to buy, and most obnoxious to mount, wire, and connect. Further without the excess power to feed your batteries, more battery is useless.

Note: I picked 96KWH/day. That is for my 1500sqft here in phoenix. However for a more northern climate, with gas heat or a pellet stove or something, probably much lower. If you are in an extreme like Juneau,AK where you are lucky to get an hour of sunlight/day and it rains 9 days out of 10, you would have to seriously over-panel hence the complexity. I don't mind hitting the grid off peak here and there and have the luxury of incredibly stable grid, and an abundance of sunlite, so I'm reaping a huge TOU benefit, in summer, even with only 30KWH of batteries. I'll be adding another stack of 30, then I'll reconfigure and bump up the panels. Keep in mind that every KW you over-panel is now storable, so you get a diminishing return as you get past your total daily needs. ie you just need enough excess pv and battery to keep you thru your worst no-sun intervals, and/or above average days.

 

[Zwy]

My Offical Solar Tester at just after 5:00pm locally is on her FORTH Dryer load...pretty sure this morning she said Two loads today dear, pretty sure I said 'can you wait til the sun pokes through the clouds'...SOC is losing ground sitting about 34% after a mostly cloudy day with very brief periods where the sun found a break between them...need more battery.

Made it thru the night well, was down to about 20% in the morning. I never turned grid power on to the inverters. Sun came out later in the morning and we ended up at 71% for the day. Sitting at 55% this morning.

One more battery of about 280Ah would probably be enough.

It's never enough.

 

[NC_hydro]

I had 26 ash trees to cut down, some over 4 feet in diameter. I'm trying to decide what to do will all the wood. Nobody wants it because the Emerald Ash Borer is killing every ash tree in the area. Tree cutters are just hauling the ash away to a compost site. I might use it for heat in the dead of winter for quite a few years. Loads Tester rolls her eyes when I mention heating with wood.

She'll change her mind when she can pull up next to nice warm fire on a cold day. A large portion of my wood pile is Ash for that same reason. Makes excellent firewood.

 

[prometheanfire]

Current start is 14-15kw of panels and ~30kwh of battery, so 1:2 ratio, but want to expand to 90kwh of battery with 30kwh held in reserve (~1 day of usage in winter).

Have an electric dryer as well, if it becomes a problem I'm going to replace it with a heat pump unit (GE makes a large one if you don't want miele). I'd suggest that to all the other load testers here too. As a bonus it doesn't vent your nice conditioned air out doors.

 

[NC_hydro]

Current: 350watts of hydro, 12kwh of FLA battery (that's figuring 50% useable and charge inefficiencies)
Future: 1,500 watts of hydro, 4kw of panels, and 45kwh of battery (Trophy). Panels will be extra on top. Once or twice a year, we have to shut off hydro to prevent the pipes from freezing. Although last winter, when we had to shut it off, it was also cloudy, but usually, when it's that cold, it is sunny.

 

[Zwy]

Current start is 14-15kw of panels and ~30kwh of battery, so 1:2 ratio, but want to expand to 90kwh of battery with 30kwh held in reserve (~1 day of usage in winter).

Have an electric dryer as well, if it becomes a problem I'm going to replace it with a heat pump unit (GE makes a large one if you don't want miele). I'd suggest that to all the other load testers here too. As a bonus it doesn't vent your nice conditioned air out doors.

Do you have the model of the GE unit? I've looked several times, still the smaller units I've found.

 

[G00SE]

Do you have the model of the GE unit? I've looked several times, still the smaller units I've found.

GE makes the 4.8cu Ft combo unit as their largest.
Whirlpool, Samsung and LG have a heat pump dryer in the 7.3-7.8 range that are not combos.

I’m really interested in the GE profile myself. Unless Maytag comes out with one, my wife had a pair of Maytag neptunes in 2009 and every washer/dryer set we have used or own since then gets compared to those

 

[JRH]

The batteries were not $60k.
Total cost about 60K.
Even with the current rates I pay it was 10 years payback.
I did all the work myself.

I got 4 X 20kwh of some big old global power 400ah batteries in barter.
115kwh were DIY.
I bought 75kwh of SOK from Current Connected in case my DIY crapped out which hasn’t happened yet.
So technically I have 270Kwh.


More panels is definitely more cost effective.
Have to modify my Sinclair rack every time I add panels. Add another post and 3 Z Purlins and move my Cantilevers to the end.
Have plenty of land but if I put the array in the very best spot it would be 800-1000 Feet from the inverter building and be in the middle of the grassed area.
Wife wasn’t having that.

Our house sits at the very back of the property.

Barns, houses, neighbors 80 Ft Pine trees, my own trees, outbuildings.
I mapped it out for the best spot closest to the inverters and still 200 feet.

Did it more for the shit days then anything.
I can go 3 days on all electric house with Zero charging.

At least I can always add more panels now and not worry about batteries.

I wanted off the Grid.
Raising rates, unstable, subject to stupid rules.
Independence is worth it to me.

I’m just astounded by all these numbers being thrown around about pv watts —-batt bank power, system costs , daily draw… everyone here but me must be rich as hell……compared to 5 years ago these are just amazing numbers and production…
im envious..
J.

 

[Kenny_]

No me, I'm whinging over 4 panels I bought last week and tried to cancel but there are coming anyway....I won't die from it but I have no system to hook them to. May have to return them...if I can....

 

[Solarcabin Channel]

I’m just astounded by all these numbers being thrown around about pv watts —-batt bank power, system costs , daily draw… everyone here but me must be rich as hell……compared to 5 years ago these are just amazing numbers and production…
im envious..
J.

everyone here but me must be rich as hell

Nope, not rich and my system is just 1.4Kw and off grid 20+ years with a small system.

However, I paid cash to build my cabin and have no house payments, no utility bills and freedom.

I also have most of the same necessary appliances as any modern home and I retired at 49 but still work when I want online.

I wouldn't want a big expensive system or big expensive house but to each their own!

 

[Kenny_]

Nope, not rich and my system is just 1.4Kw and off grid 20+ years with a small system.

However, I paid cash to build my cabin and have no house payments, no utility bills and freedom.

I also have most of the same necessary appliances as any modern home and I retired at 49 but still work when I want online.

I wouldn't want a big expensive system or big expensive house but to each their own!

I've been considering a tiny home on some land somewhere off grid....

 

[Solarcabin Channel]

I've been considering a tiny home on some land somewhere off grid....

People looking for land to go off grid:

Look on the land auction websites, check tax sales, talk to locals.

I don't recommend going too far away from civilization and you will need to resupply, get health care and have other services.

I am 10 miles from a one store town and 30 miles from a bigger city. Far enough to have my peace and security but close enough to get stuff and have some socializing and be safe.

Look around small towns that have the services you need and ask around, read the paper and look for the tax sales. Old timers may want to split off some land. I avoid realtors but they may list undeveloped land.

Consider land with an old fixer upper house that has good bones. Cheaper to remodel than build new and lots of materials to salvage. There are lots of those just sitting empty that could be made in to a fine off grid cabin.

Good luck!