Solar and realistic expectations and perhaps a referral

[dm9289]

Short version I am reasonably familiar with residential utility interactive systems. A close friend from the local PA electrical union with roughly 30 years experience wanted to self install a ground mount PV system for his home to go off grid, which sparked tons of discussion.

He has a gas heated house about 1500 SQft with a 200amp 120/240 single phase system and a large detached 3 car garage about 100ft away. He wanted to house inverters and batteries in that garage. (cold location not normally heated)
His main purpose for solar was car charging he has a chevy bolt 240volt 32.5 amp charger plus a Ford cmax 240volt 16 amp charger.
He wanted to but this internet system

Complete Off-Grid Solar Kit - 13,000W 120/240V Output / 48VDC [20.5kWh EG4-LifePower4 Lithium Powerwall] 48VDC + 11,040 Watts of Solar PV | [KIT-E0000]​

Complete Off-Grid Solar Kit EG4 6000XP | 12000W Output | 48V 120/240V Split Phase + 12800 Watts of Solar PV [KIT-E0009]

Explore energy independence with Off-Grid Solar Kits, EG4® 6000XP inverters. Choose components, batteries, and panels. Revolutionize your energy with EG4.

signaturesolar.com

He wanted to at minimum supply the garage completely off solar and batteries but have an ability to switch the main house to solar via manual transfer switch also. He will likely have to recharge car daily due to nature of his job. WE live in an area of PA with very little sunlight and to me it seemed on gray days these units do run but at about 15%.

To experience folks does this scenario seem likely to work

 

[ggunn]

Short version I am reasonably familiar with residential utility interactive systems. A close friend from the local PA electrical union with roughly 30 years experience wanted to self install a ground mount PV system for his home to go off grid, which sparked tons of discussion.

He has a gas heated house about 1500 SQft with a 200amp 120/240 single phase system and a large detached 3 car garage about 100ft away. He wanted to house inverters and batteries in that garage. (cold location not normally heated)
His main purpose for solar was car charging he has a chevy bolt 240volt 32.5 amp charger plus a Ford cmax 240volt 16 amp charger.
He wanted to but this internet system

Complete Off-Grid Solar Kit - 13,000W 120/240V Output / 48VDC [20.5kWh EG4-LifePower4 Lithium Powerwall] 48VDC + 11,040 Watts of Solar PV | [KIT-E0000]​

Complete Off-Grid Solar Kit EG4 6000XP | 12000W Output | 48V 120/240V Split Phase + 12800 Watts of Solar PV [KIT-E0009]

Explore energy independence with Off-Grid Solar Kits, EG4® 6000XP inverters. Choose components, batteries, and panels. Revolutionize your energy with EG4.

signaturesolar.com

He wanted to at minimum supply the garage completely off solar and batteries but have an ability to switch the main house to solar via manual transfer switch also. He will likely have to recharge car daily due to nature of his job. WE live in an area of PA with very little sunlight and to me it seemed on gray days these units do run but at about 15%.

To experience folks does this scenario seem likely to work

If he has available and reliable grid power, his money would be much better spent on a grid tied PV system than on any off grid equipment.

 

[dm9289]

If he has available and reliable grid power, his money would be much better spent on a grid tied PV system than on any off grid equipment.

That was my opinion also

 

[jaggedben]

First, I have never heard of that manufacturer, and the price seems to good to be true (what's the warranty and support?)

Second it seems like he's proposing to store solar energy in a 20kWh battery and then use it to charge a 60+kwh EV battery. You can easily see the problem with that, (even before adding in depth of discharge and round trip efficiency).

Third, if he wants to use solar to offset his EV energy use, a grid tied system is likely to be much more cost effective.

 

[electrofelon]

Sounds like a horrible idea. He should just do a standard grid tied system. There are sun hour charts he could look at to get an idea of the available energy during the winter months.

 

[pv_n00b]

This is not an area for DIY. Maybe he can get a competent off-grid designer to design a system that will work and then he can install it. But buying a kit like that and just hoping for the best is going to lead to sadness.

 

[ggunn]

This is not an area for DIY. Maybe he can get a competent off-grid designer to design a system that will work and then he can install it. But buying a kit like that and just hoping for the best is going to lead to sadness.

Agreed. Offgrid systems are complex to install and maintain, and they require a deep level of understanding of the technology on the part of both the installer and the system owner. They are by no stretch of the imagination a "set it and forget it" energy management strategy. Grid tied PV, on the other hand, pretty much is. Grid tied PV has a good chance of paying for itself in the long run, but offgrid PV will never come close. In general, offgrid PV is only economically viable when the grid is either not available or so expensive to get connected to that the expense and trouble are justified.

OTOH, if the guy has money to burn and wants to buy a system as a toy to play with, and he doesn't depend on it to work reliably if at all, then it might be something he'd want to do, but it is more than likely he will be disappointed in the results.

 

[winnie]

1) To get a better understanding of the available solar resource, see NREL PV Watts.

PVWatts

Estimates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installations

pvwatts.nrel.gov

2) As others have noted, a true off grid system requires significant design work and expense to create a 'set and forget' system which mimics the grid.

3) IMHO a grid tie PV system is a good fit for a competent diy self install. The OP describes someone they know from their electrical union, so my guess is an electrician who hasn't done PV. Sounds to me like a perfect diy candidate.

4) Most EVs are driven at only a fraction of their range each day. If these vehicles are usually at home during the day, solar charging might be a good fit.

Jon

 

[dm9289]

First, I have never heard of that manufacturer, and the price seems to good to be true (what's the warranty and support?)

Second it seems like he's proposing to store solar energy in a 20kWh battery and then use it to charge a 60+kwh EV battery. You can easily see the problem with that, (even before adding in depth of discharge and round trip efficiency).

Third, if he wants to use solar to offset his EV energy use, a grid tied system is likely to be much more cost effective.

Thank you, sir, for your experience I'm starting to take a few free solar NABCEP online classes. I am descent with the NEC info but not so good with proper application.

Sounds like a horrible idea. He should just do a standard grid tied system. There are sun hour charts he could look at to get an idea of the available energy during the winter months.

Thank you

 

[dm9289]

This is not an area for DIY. Maybe he can get a competent off-grid designer to design a system that will work and then he can install it. But buying a kit like that and just hoping for the best is going to lead to sadness.

Thanks Im trying to find an engineer to look this over Trinity solar may supply me with some input

 

[dm9289]

Agreed. Offgrid systems are complex to install and maintain, and they require a deep level of understanding of the technology on the part of both the installer and the system owner. They are by no stretch of the imagination a "set it and forget it" energy management strategy. Grid tied PV, on the other hand, pretty much is. Grid tied PV has a good chance of paying for itself in the long run, but offgrid PV will never come close. In general, offgrid PV is only economically viable when the grid is either not available or so expensive to get connected to that the expense and trouble are justified.

OTOH, if the guy has money to burn and wants to buy a system as a toy to play with, and he doesn't depend on it to work reliably if at all, then it might be something he'd want to do, but it is more than likely he will be disappointed in the results.

Thanks Im in the middle of a free 6hr Nabcep course to help me with inspections, but I will likely have to go deeper

 

[dm9289]

1) To get a better understanding of the available solar resource, see NREL PV Watts.

PVWatts

Estimates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installations

pvwatts.nrel.gov

2) As others have noted, a true off grid system requires significant design work and expense to create a 'set and forget' system which mimics the grid.

3) IMHO a grid tie PV system is a good fit for a competent diy self install. The OP describes someone they know from their electrical union, so my guess is an electrician who hasn't done PV. Sounds to me like a perfect diy candidate.

4) Most EVs are driven at only a fraction of their range each day. If these vehicles are usually at home during the day, solar charging might be a good fit.

Jon

Yes Winnie he never has done it but 30 years in Electrical Industry and is a very independent person. Thanks for the resource

 

[ggunn]

Thanks Im in the middle of a free 6hr Nabcep course to help me with inspections, but I will likely have to go deeper

A 6 hr NABCEP course is not going to train you anywhere nearly enough to design and install offgrid PV systems.

 

[ggunn]

As others have noted, a true off grid system requires significant design work and expense to create a 'set and forget' system which mimics the grid

It still won't be "set it and forget it" no matter how well designed it is and no matter how much one spends on it unless it is ridiculously oversized for normal usage.

 

[dm9289]

1) To get a better understanding of the available solar resource, see NREL PV Watts.

PVWatts

Estimates the energy production and cost of energy of grid-connected photovoltaic (PV) energy systems throughout the world. It allows homeowners, small building owners, installers and manufacturers to easily develop estimates of the performance of potential PV installations

pvwatts.nrel.gov

2) As others have noted, a true off grid system requires significant design work and expense to create a 'set and forget' system which mimics the grid.

3) IMHO a grid tie PV system is a good fit for a competent diy self install. The OP describes someone they know from their electrical union, so my guess is an electrician who hasn't done PV. Sounds to me like a perfect diy candidate.

4) Most EVs are driven at only a fraction of their range each day. If these vehicles are usually at home during the day, solar charging might be a good fit.

A 6 hr NABCEP course is not going to train you anywhere nearly enough to design and install offgrid PV systems.

I agree I do inspect residential grid interactive systems but im trying to understand better cost vs payback.

 

[dm9289]

It still won't be "set it and forget it" no matter how well designed it is and no matter how much one spends on it unless it is ridiculously oversized for normal usage.

Yeah I think many like the idea of being off grid but the actual cost and inconvenience is very high, if you have high draw electric items such as electric cars it becomes even less practical

 

[Mag]

Hello,i am the "electrician", I talked to Signature Solar and I will need to double the kit package. 48 panels,8 lyth. iron phos. batteries.(36kwh). with a pos. 4 extra in the future.(54kwnh) The panels are bifacial,so they charge from both sides. I have 2 acres of flat ground to mount the system. The bolt needs 20 to 30 kw a day on average. This is why I will install a transfer switch to "either or" the inputs to figure what i need. A grid tie system adds extra cost that could use the money for other stuff. Right now with the 40,000 I spend on this system,and the my cost on my electric bill,it should take 16 to 17 years to pay off. That's if the cost from my Electtic co. doesn't increase.

 

[electrofelon]

A grid tie system adds extra cost that could use the money for other stuff.

I am skeptical of that claim

 

[winnie]

At the present time, batteries are very expensive vs the grid being cheap.

In many locations you can essentially use the grid as a free battery, but this is very tariff dependent. IMHO this 'free battery ' isn't fair and the tariffs are changing to make things more fair.

I could imagine local tariffs being really anti solar, making grid interconnection really expensive.

Something you (@Mag ) will need to read up on is the levelized cost of energy storage. But in a nutshell batteries have a limited number of charge discharge cycles and cost some amount. Every kWh stored and discharged from the battery uses a bit of battery life and gets assigned a bit of battery cost. This cost of 'used up battery life' is often greater than the cost of grid electricity.

Put another way, if you get a free kWh of electricity, store it in a battery and then use that kWh at your convenience, the dollar cost of the used up battery life is usually greater than simply buying a kWh from the grid.

Where 'off grid' might work for EV charging is if it is direct solar to EV with no battery other than the one in the EV.

Basically PV is the cheapest source of electricity, without any incentives or special treatment, but with one huge caveat: it is cheap if you use the electricity when the sun is shining.

If you want electricity at your convenience then you either need expensive energy storage, or you need to make use of the grid.

Charging EV batteries is possibly a very good match, if your car is parked at home when the sun is shining.

I don't know if anyone sells an off grid 'inverter' (not a good name for a PV to EV interface) that eliminates the local battery.

Jon

 

[Mag]

The batteries i am using will be Lithium Iron phosphate, witch are able to have a deep dischage and recharge to 80% at least 7000 times witch is about 15 years. They are warranty of 10 years,and can couple 64 together.