A newbies DIY solar install

[Gale Hawkins]

I am looking at selling my old Chevy that I don't drive anymore, to pay for a solar grid that would net me a few dollars saved. No bass boat, but pretty much the same issue!
David from jax

That sounds like a plan. I don't think some people understand the payback is going to come faster and faster as rates go up up and up.

 

[ning]

I wish I had a off-grid system without grid tie.

You can also have grid-tie with off-grid capability ("microgrid" / whole house backup). Benefits are that while on-grid, you can use power mindlessly, and when off-grid, everything works but you may want to reduce usage.

Eg when we have a "wind event" here in the summer and the utility shuts off power, I probably shouldn't run my A/C as I do when on-grid, but it's summer (ie tons of sun) so everything else is ok.

Of course, with how much battery we have and how little the sun shines during the winter, I'd avoid running everything but the well (and furnace if we didn't have the ability to heat with wood) if it looked like a protracted failure then.

I'm looking into adding an LP generator as a further backup to my system (we have a spare 300 gallon tank); it would only run when the batteries were discharged to a configured low point, and then it would run until they recharged to some higher level - much more efficient use of a generator than running the furnace, refrigerator, and occasionally the well, since generators still suck the gas even under light load - and they run any time you're pulling even just one watt.

 

[Gale Hawkins]

You can also have grid-tie with off-grid capability ("microgrid" / whole house backup). Benefits are that while on-grid, you can use power mindlessly, and when off-grid, everything works but you may want to reduce usage.

Eg when we have a "wind event" here in the summer and the utility shuts off power, I probably shouldn't run my A/C as I do when on-grid, but it's summer (ie tons of sun) so everything else is ok.

Of course, with how much battery we have and how little the sun shines during the winter, I'd avoid running everything but the well (and furnace if we didn't have the ability to heat with wood) if it looked like a protracted failure then.

I'm looking into adding an LP generator as a further backup to my system (we have a spare 300 gallon tank); it would only run when the batteries were discharged to a configured low point, and then it would run until they recharged to some higher level - much more efficient use of a generator than running the furnace, refrigerator, and occasionally the well, since generators still suck the gas even under light load - and they run any time you're pulling even just one watt.

Thanks for those details.

I agree it is normally Rock solid and even when the power goes out they have it back in from 30 minutes to 4 hours but we had the ice storm in 2009 and now the 2021 tornado.

Thankfully after lunch they got us back up that did not have tornado damage to our individual grids.

 

[ponytug]

I know everyone's circumstances are different but with us we just don't have outages and going off grid to plan for a once in a lifetime event just doesn't make sense to me. I know we only get about 3.5 cents on overproduction but with our rate at 11.7 cents that's 30% of retail. Our production vs consumption is also only calculated at the end of each billing cycle and credits are good for 12 months. The way I look at it grid tied allows me to store 30% of my overproduction for up to 12 months with no batteries to purchase or maintain.

That's what we do, though we added batteries as the grid was getting so unstable here. With WFH, the payback on the batteries is very quick.

Still as a general rule, we get to over produce during the summer, and use it during the winter, even though it is not 1:1 anymore. That is a heck of a battery.

All the best,

Peter

 

[sandman2234]

One thing is certain
For some it makes sense. For others it doesn't.

I'd say my limit on what's "worth it" is 8-10 year payback.

Too many variables to nail down an exact....but it's clear I'm pretty well outside 8-10 year.

The other unknown is that the less you use....the more per KWh you pay.

When I use a tiny 200kwh at my shop....bill is still $70. Now imagine adding another $10 because my $47 service charge goes to $57.

Only way to ever see a $50 bill here is to use ZERO electric. And that would just be the $47.75 service charge + tax...lol

LD1,
What would be the payback time if you went with a battery based system to store the surplus solar power you are generating during the day, instead of selling it back to the grid? That would eliminate the "$57" plus give you the ability to use the daylight power later in the evening? That would free up a lot more money per month and do away with the required charges. Not sure how far your shop is from the house, but if you used a battery charger from the shop as a backup to charge the battery, when the battery didn't have enough power to make it thru the nights, or during longer winter days. Just a thought....but it seems like it might get you closer to making that jump, lol!
David from jax

David from jax

 

[ning]

As I stated earlier, I have a wide-open placed ground mount of 10.24kW DC, 7.68kW DC array.

Today was stormy and gray; here's the production:

As you can see, it only beat our consumption during a brief time and overall produced only 6kWh today. I've seen darker days, too though there certainly wasn't any sun or thinning of clouds either.

This production wasn't enough by itself to keep furnace, fridge, freezer, and occasional well going in an extended power failure (we have 30kWh of battery) if needed in the winter.

I think I'll start figuring out how big of a back-up generator I need... I don't need a transfer switch (I've got that as part of the battery system), and I could actually wire in any 240V generator but one with electric start would be nice

Sent from my Pixel 3 XL using TractorByNet mobile app

 

[LD1]

LD1,
What would be the payback time if you went with a battery based system to store the surplus solar power you are generating during the day, instead of selling it back to the grid? That would eliminate the "$57" plus give you the ability to use the daylight power later in the evening? That would free up a lot more money per month and do away with the required charges. Not sure how far your shop is from the house, but if you used a battery charger from the shop as a backup to charge the battery, when the battery didn't have enough power to make it thru the nights, or during longer winter days. Just a thought....but it seems like it might get you closer to making that jump, lol!
David from jax

David from jax

No desire at all to buy and maintain a bunch of batteries. I have reliable grid, and power is cheap enough.

Can't answer the cost of payback because I have not priced a battery system. But I as posted a few other times....my yearly cost is only $2400.

So for an off grid to beat a 15 year payback....simple math says it needs installed for less than $36k

 

[sandman2234]

So in theory if you had gotten a 15 yr payback 20 years ago you would have been paid back for 5 years.

On another slant -
Has anyone seen a good DIY solar carport implementation? If so any good links?
I've got to replace a carport that was about 20x40. Basically I need to roof over the area to keep stuff underneath protected from the Mississippi sun and rain.
The previous carport was only paneled down on one side so I'm not looking for a complete enclosure.
I could orient it in a solar friendly angle.
But I'm thinking those big panels on frames could easily be adapted to a carport roof.

And I am thinking the carport isn't wind rated enough to add solar panels to it and withstand a Cat 1 hurricane or even close. I hate the idea of adding solar panels just to have them blown away at the first hint of a storm.
You may have a substantial carport, but I am envisioning one of those kinds like a lot of people are installing these days that just bolt to a slab in a few hours of time.
David from jax

 

[ponytug]

As I stated earlier, I have a wide-open placed ground mount of 10.24kW DC, 7.68kW DC array.

Today was stormy and gray; here's the production:View attachment 724808

As you can see, it only beat our consumption during a brief time and overall produced only 6kWh today. I've seen darker days, too though there certainly wasn't any sun or thinning of clouds either.

This production wasn't enough by itself to keep furnace, fridge, freezer, and occasional well going in an extended power failure (we have 30kWh of battery) if needed in the winter.

I think I'll start figuring out how big of a back-up generator I need... I don't need a transfer switch (I've got that as part of the battery system), and I could actually wire in any 240V generator but one with electric start would be nice

Sent from my Pixel 3 XL using TractorByNet mobile app

Since you have batteries, you can size the generator to run for six or eight hours flat, at 60-80% load taking the batteries to 80+% charge and then run off the batteries until the next day, for maximum efficiency.

And I am thinking the carport isn't wind rated enough to add solar panels to it and withstand a Cat 1 hurricane or even close. I hate the idea of adding solar panels just to have them blown away at the first hint of a storm.
You may have a substantial carport, but I am envisioning one of those kinds like a lot of people are installing these days that just bolt to a slab in a few hours of time.
David from jax

Many of the ones that I looked at are already hurricane rated, with differing foundation and materials depending on what wind speed rating you want/need. Just FYI. Ditto ground mounts.

All the best,

Peter

 

[ning]

No desire at all to buy and maintain a bunch of batteries. I have reliable grid, and power is cheap enough.

Can't answer the cost of payback because I have not priced a battery system. But I as posted a few other times....my yearly cost is only $2400.

So for an off grid to beat a 15 year payback....simple math says it needs installed for less than $36k

With Lithium batteries, there's no battery maintenance. Obviously if your system uses golf cart batteries, it's an entirely different story.

The math doesn't support battery-backup just for avoiding utility bills at all, though some areas have a hefty rebate to change that math (with the caveat that the battery system has to be used to support the grid sometimes).