When Grid input to AIO's just sits unused.

[Mattb4]

It struck me this afternoon as I sit with full batteries (before noon!) and hardly any loads (cool weather has cut back any A/C needs and my hot water tank is up to heat) that it has been months since my AIO's have had to transfer to AC Bypass to power anything. AC in does not do anything anymore. Having good battery capacity to carry me through most days and more than sufficient PV panel watts to charge said batteries leaves the grid as emergency backup to the loads wired to my AIO's.

So it makes me think about how necessary is having grid as backup? While true I still use the grid for high outdoor temperature A/C loads during overnight and also for those few items that are 240vAC (I only run 120vAC AIO's) a lot of the time now I am not using any grid at all.

Something to contemplate in the future about maintaining a grid connection is the monthly minimum cost (about $25 all said and done with taxes and surcharges) or ramping up some more solar and batteries (perhaps installing one of the nifty 240/120VAC 10kW AIO's that some folks are reviewing in other Threads) or simply keeping a gas generator for emergency purposes.

Is keeping the grid as emergency backup worthwhile? Interesting beautiful Sunny day musings.

 

[Rednecktek]

Ask us again in February, that's the only way to know for sure.

 

[Danke]

Propane and a generator (mostly to charge the batteries if ever needed) is all I plan for back up.

 

[Adam De Lay]

Depending on where you're located, if you can get through a nasty winter with no problems, then why keep the grid as the backup? Like Danke said, just use a generator for those few times you might have to supplement your solar. Doesn't even have to be any substantial generator if you have a chargeverter.

 

[Madcodger]

I can only think of two reasons to grid connect, but I'm debating them with myself right now.

1) If I can do net metering it allows me to avoid fossil fuel (or wood) heat because I can bank credits in summer and then use them Nov-March, when the sun is a bit scarce here in the north. It's darn expensive to put in enough battery and panels to do that without net metering.

2) If the inverter goes kaput and I install a bypass switch before the inverter, It allows the house to remain powered without the need for days and days of generator use if it takes awhile to get the right parts. The pandemic taught us a lot about that.

Decisions, decisions...

 

[Mattb4]

Ask us again in February, that's the only way to know for sure.

But it is Sunny and nice out right now. Everything is great.

 

[LydMekk]

Let's talk in November, December, January and partly February hereabouts...
Rain for 3 days and/or dark clouds and I'm in trouble and need to suckle on "Miss Grid"
This is pointing back to the "Fest or famine" thread, amiright?
Generators are too noisy...

 

[Steve_S]

I can only think of two reasons to grid connect, but I'm debating them with myself right now.

1) If I can do net metering it allows me to avoid fossil fuel (or wood) heat because I can bank credits in summer and then use them Nov-March, when the sun is a bit scarce here in the north. It's darn expensive to put in enough battery and panels to do that without net metering.

2) If the inverter goes kaput and I install a bypass switch before the inverter, It allows the house to remain powered without the need for days and days of generator use if it takes awhile to get the right parts. The pandemic taught us a lot about that.

Decisions, decisions...

It's all relative, where I am in winter I "may" get 3 hours of useable sunshine when lucky at temps of -30C/-22F.
My heating runs for 4 hours within 24 hours to maintain 25C/77F inside (Radiant Heating with insulated thermal slab foundation).
Home design (passive solar) also keeps the house cool in summer and the AC was disposed of. Even when it is a 40C/104F, the house never goes above 27C/80F albeit the humidity remains but its not bad.

I run on 24V Battery System, 40kWh of LFP which provides me with 10 days of power as I only use between 3.5-4.0kWh per day (year round).
Rarely, when I run my bank down to 10%, the Genset fires up and within 8 hours of Gen Time the bank is at 100% (even with the passthrough to house) and I am good for 10 more days. Generator charging provides 80A to the bank + any solar incoming on top. This does not happen very much and after the final upgrade (being done now) the additional 2370W of Panel + Midnite Classic-150 coupled to the existing 2080W of Panel + Midnite Classic-200 in Parallel will resolve that need. The two array's will provide up to 172A Charge for the bank, which should solve the low sun production times.

Lesson Learned Dept.
A respectable "Inverter" generator that can provide power to charge batteries & supply passthrough to home such as those from Honda, Champion are the best backup power to have... Strongly suggested to use a Generator that runs on LPG, as it will not sour or gumm over time...
It is far cheaper to Conserve Energy than it is to generate & store it, so eliminating old / inefficient appliances & devices pays back far quicker. Design Improvements to a home, employing Passive Technologies that use no energy is also a huge saver and it does NOT have to cost much to do... Many are shocked at how they can do thins cheaply... everyone assumes that it's all costly when it is not.

Consider my use case: My Champion 4650W Inverter Genny uses 2.3 US gallons for an 8 hour run that provides 10 days of battery power. Last year (2022) was the darkest winter here in 80 Years and I only ran genset 4 times from December to March. BTW: The "Grid" is $75,000 away and staying put ! My Solar Excursion cost far less and never goes out like the grid (17 times this yr so far).

 

[Steve_S]

Let's talk in November, December, January and partly February hereabouts...
Rain for 3 days and/or dark clouds and I'm in trouble and need to suckle on "Miss Grid"
This is pointing back to the "Fest or famine" thread, amiright?
Generators are too noisy...

Being in Spain and you have these issues ? I have to brush 30cm+ snow off my 45 degree ground mount racks during that time periods and you certainly don't have too (lucky for you). Thing is, you should have a good sense of your generating capacity & usage now, so reconsidering your battery bank may be worthwhile, you have a respectable setup that can handle a big bank...

 

[ed6269]

I have been thinking the same thing and would like to just be done with the grid and that pesky monthly minimum charge but then December thru February happens and I always back off .
I had an idea to just run a cord from my neighbors house with a killawatt meter to reimburse them for power used to recharge the batteries when needed but I haven't had the nerve to ask them YET.

 

[Mattb4]

I have been thinking the same thing and would like to just be done with the grid and that pesky monthly minimum charge ...

I have taken advantage of new technology to eliminate many of my monthly charges. After decades of paying for POTS phone service I went to a pay as I go cell phone that cost me about $6/mo for my needs and gives me a device that I can carry with me and access the net when needed. The land line was around $40/mo basic and charged extra for any long distance calls (and with my rural location it was almost all long distance). I have saved paying that difference now for about 10 years.Darn near $4,000 and I have not missed it.

I used to have satellite TV but after the advent of digital broadcasting and streaming to my TV I cut the cord and went OTA which is pretty much free versus $55/mo with the sat co. Have not missed paying that for the last 7 years.

Hard to not have any monthly charges but getting rid of those that have minimums even when you use next to nothing is nice to do. Pay as I go.

 

[Ampster]

Is keeping the grid as emergency backup worthwhile?

Murphy's Law is unpredictable. My winter loads are greater than winter production so the grid is more than emergency backup for me. At True Up I have a small credit. I need the grid as a seasonal battery.

 

[Quattrohead]

I have actually been going through the worst part of the season now, mega hot and humid here in Florida but rather a lot of thunderstorms and overcast. It was terrible in July but a little better in August where I only had to connect to grid twice to supplement the battery.

 

[houseofancients]

I can only think of two reasons to grid connect, but I'm debating them with myself right now.

1) If I can do net metering it allows me to avoid fossil fuel (or wood) heat because I can bank credits in summer and then use them Nov-March, when the sun is a bit scarce here in the north. It's darn expensive to put in enough battery and panels to do that without net metering.

2) If the inverter goes kaput and I install a bypass switch before the inverter, It allows the house to remain powered without the need for days and days of generator use if it takes awhile to get the right parts. The pandemic taught us a lot about that.

Decisions, decisions...

And you just listed my reasons to leave the grid intact.
Next to that, stupid rules here dictate that a house is obligated to be connected to the grid..


Plus .. I hate the noise, smell and exhaust of a genny

 

[LydMekk]

Being in Spain and you have these issues ? I have to brush 30cm+ snow off my 45 degree ground mount racks during that time periods and you certainly don't have too (lucky for you). Thing is, you should have a good sense of your generating capacity & usage now, so reconsidering your battery bank may be worthwhile, you have a respectable setup that can handle a big bank...

Yeah, no snow here ^^ but when it first rains it floods. Last year we had rain most of november and first half of december. Not very usual, first time in 9 years with that much. Clouds is often more an issue at wintertime than rain.
More problematic is the shorter days for PV charging and more drain (more dark hours) on the batteries during evening and nighttime in the winter.

Coupled with atleast 2-3 x consumption to heat the house in winter (down to 0c) compared even with heavy AC running in summer whole days...famine it is ^^

 

[Rednecktek]

Isn't that what people have children for? Silly gas users!

 

[OffGridForGood]

1. how many days without sun do you see, what is the variation of this.
2. how much load can you cut when solar is low, ie what do you need vs what is nice to have loads.
3. how much battery do you have.
4. solar- battery- utility- generator {"nearly free/kWh" - 3 cents/kWh - 10 cents/kWh - $1.25/kWh}
5. do you have an EV that can power your solar in an emergency.

 

[Mattb4]

About the only EV I anticipate in my future is one of them power chairs once walking becomes too difficult. My present gas powered wheelchair (a Yamaha Quad ATV) suffices for now. Considering I only go to town once a month for supplies, and that is 70 miles RT, even if gas prices go to $20/gal my old 2000 Chevy 1-ton at 10-11mpg would be uneconomical to replace with an EV.

 

[Steve_S]

Yeah, no snow here ^^ but when it first rains it floods. Last year we had rain most of november and first half of december. Not very usual, first time in 9 years with that much. Clouds is often more an issue at wintertime than rain.
More problematic is the shorter days for PV charging and more drain (more dark hours) on the batteries during evening and nighttime in the winter.

Coupled with atleast 2-3 x consumption to heat the house in winter (down to 0c) compared even with heavy AC running in summer whole days...famine it is ^^

Solar Panel Angle also makes a huge difference and people don't realize that simply a couple of degrees difference can make a huge difference.

Consider that if "totally perfect alignment" gives you the absolute peak production time at Mid-Day on the longest Sun-Hour day for your specific region. So solar production ramps from the morning to the optimal point and then ramps downwards till the sun drops. All good and life is great... BUT it isn't. You found the lurking gotcha that gets many folks, even the hard core.

Using my system as an example. Ground mounts are fixed at 45 Degrees which provides optimal generation angle for September & March. This is the "Optimal Annual Average" and it works but in reality is is NOT OPTIMAL. Lessons Learned Department
Summer Sun Hours are PLENTY, well over 12 hours of bright sun and lot's of time to charge a battery bank... some cloudy, rainy, dark days but nothing to worry about, they never last.
Winter is a different deal, the best angle to capture more sun for longer would be 20 Degrees but that is not practical for my region (snow, winds & ice storms).
So a compromise is needed that improves the Winter Generation without hampering the Summer Generation. Effectively in the summer, you have more time to charge your batteries so instead of having in FLOAT by 12:00 let them hit that by 15:00, which is actually even less stressful on your batteries too...
The Compromise is to favour more towards the Winter Angle which in my case would be 36 Degrees which shifts the "optimal generation angle" to February & October.
! - Alternately, it's also possible to go hybrid and have 1 array optimized for average summer generation and another for optimized average winter generation. Both arrays would still add power and would be pretty level year round as they "trade-off" between each other. This is similar to have East & West facing solar arrays in a sense.
Ideally if we all had Scads of Cash, we'd all have tracking arrays with 12 panels on each... but that's not the real world is it.


Hope it Helps and helps some percolate ideas & solutions for their own systems.

Ohh and in case you aren't aware, I am near the Algonquin Park in Ontario Canada so you have a quick ref.
Also when I talk Angles,

 

[DIYrich]

About the only EV I anticipate in my future is one of them power chairs once walking becomes too difficult. My present gas powered wheelchair (a Yamaha Quad ATV) suffices for now. Considering I only go to town once a month for supplies, and that is 70 miles RT, even if gas prices go to $20/gal my old 2000 Chevy 1-ton at 10-11mpg would be uneconomical to replace with an EV.

If you get a hybrid or phev, I have been exploring ways to tap the high voltage battery as an emergency power source to recharge the solar batteries. The engine can keep the high voltage battery topped up. 15 gallon tank can run for a long time.