In-Laws w/ Solar Panels...but no batteries?

[bizutch]

Thanksgiving yesterday. Went to my mother in law's house & remembered this summer her & her ex-husband were both sold solar panels for their houses. Here's the sad part. We went through Hurricane Helene & they had NO power. From conversations with both of them, they have reverse metering so power bills went from $200-300 monthly to roughly $60. This is senior citizen speak, so not hard fast numbers.

Went downstairs to inspect her panel. It just has a breaker in the panel labeled solar. Went outside (yes I should have taken a picture) and there is a box that has what looks like 3 offset breakers & I can't remember how they were labeled.

So, correct me if I'm wrong. They SHOULD have solar power during a blackout, but it's capped at what the sun can pump into the house in real time.

My questions, so I can help them moving forward:
1. Should they be able to cut off the HVAC & dryer & just run 120v outlets during the daytime if there is an outage?
2. How do they know WHAT kind of power is being generated by the solar array to know what devices to cut on?
3. What is an affordable battery and/or inverter for their systems they could purchase during Black Friday?

It's insane the amount of solar installs around here that are just useless after dark.
I'm totally new to all this stuff. But with what little I've learned, I can't believe installers are selling this stuff on roofs with NO storage.

Both my father in law and mother in law are on fixed incomes, so it sounded great to them. But this sucks. Senior citizens in a once in a thousand year flood power outage with no knowledge of their systems.

I mean, shouldn't they have been able to charge up devices by cutting most breakers off at the least? They know nothing of these things on their homes.

Maybe the most surprising part is just looking at their breaker box, I can tell there is zero "plug and play" for external battery storage. So an electrician is going to have to come wire whatever I show them.

 

[Q-Dog]

So, correct me if I'm wrong. They SHOULD have solar power during a blackout, but it's capped at what the sun can pump into the house in real time.

No, if it is a grid tie system with microinverters, the inverters must shut down when the power is cut.

 

[bizutch]

No, if it is a grid tie system with microinverters, the inverters must shut down when the power is cut.

No clue what you mean by micro-inverters. Why does it shut down?
What solutions do they have to still have any sort of off grid power when there's a blackout?
They both said the companies offered "battery backup"

 

[wpns]

They both said the companies offered "battery backup"

If they didn’t chose that option then they didn’t get ‘power without grid’.

If you want to help them add ‘power without grid’ (which will require batteries) you’ll have to start with the contract they have with their installer.

It could be they don’t even own their system and can’t make changes to it (all too common when unscrupulous solar companies sell to seniors).

Anyway, long story short, you need to find out what they have, first from a contract and ownership point of view, and then (if they own it) from a technical standpoint.

 

[740GLE]

If they were offered battery back up, they probably saw the price of the extra equipment and said no thank you.

Do you know if they bought the system outright or did they lease the system?

A standard run of the mill grid tied system is “shut down” when the grid source is lost for “safety” and ease of equipment design and costs.

 

[SouthernSolar]

What you're describing is the most popular and common roof top solar system in the US. Everyone I know with solar has that system. Except me.

If you call a solar installer, that's the system they are going to offer most likely.

The battery back up almost doubles the cost IIRC.

Each panel has a small inverter attached to it . Usually around 250 to 600 watts. These simply feed power into the circuit breaker box like you discribed. The inverters are designed NOT to make power unless they sense voltage in the breaker box.

It is a good system since if one panel is shaded, you only lose power from that one inverter. It bad if want back up power.

I am not sure how you add battery backup to that system

 

[wpns]

I am not sure how you add battery backup to that system

AC coupled battery backup is a whole nother nightmare, IMHO you wire the panels to a proper AIO. And yes, that means getting up on the roof and removing the micro inverters and adding RSD boxes and changing from AC wiring to DC wiring and essentially rebuilding the system from scratch. it’s going to be a nightmare, either way. Before you muck about it with it, though, make sure they actually own it.

 

[Johneb]

Need to know which inverter. The most popular around here is the sol-ark with micro inverters. They can have battery backup but they require 400v batteries. Huge money.

 

[1201]

Is it wise to spend another $5-10k for battery backup for a 1000 year event?

 

[tschmidty]

Is it wise to spend another $5-10k for battery backup for a 1000 year event?

I mean you added a zero but w/e. Here in WNC (where OP is) we were 2 feet above the 100 year flood level.

Love the optimization that you think it will be another 1000 years.

 

[Lawrence_SoCal]

Why does it shut down?

because
1. it is unsafe, and therefore against rules/code (law?) to allow energy export onto grid when grid power is down (ie safety hazard to first responders, linemen, etc)
2. such simple grid-tied systems are WAY cheaper than one that can isolate itself from grid (ie, sunlight backup or battery backup)

What solutions do they have to still have any sort of off grid power when there's a blackout?

battery backup, or generator

They both said the companies offered "battery backup"

At significant expense, and they turned it down, right?

I currently have grid-tied micro-inverter (DC to AC conversion on each panel) solar. Power outages are so rare, and battery tech hopefully on cusp of change to safer (even than LFP) and longer lasting... so I'm holding off for the time being, as there isn't a ROI for me at this point. My system likely to look a lot light you in-laws, with a small solar sub-panel, with a couple of breakers, hooked up to main panel, larger breaker, labelled solar. And only works when grid is up.

Once I decide I want/need to have solar working when grid is down, then I'll need a MID (a micro interconnect device, ie a device that disconnects house from Power Company grid and forms 'micro-grid' for the house.) Once you have a grid-forming MID, you can have sunlight backup (ie solar keep working when grid goes down... BUT there are complications due to variable output of solar and potential damage to electrical gear in the house depending on loads... hence sunlight backup not really being a thing). For safe, reliable power when grid goes down, you need a battery (or Energy Storage System/ESS) and something to convert AC to DC (and back again).
Then you have to decide budget and requirements in terms of electrical load at house, and then Inverter size and battery capacity, whether Whole home backup (simpler) or only partial (critical loads backup... will requiring electrical re-wiring to some extent... how much? depends). For me, a whole house backup would be cheaper, but that is because my electrical load peaks are low enough, that a typical Hybrid Inverters can handle it, so a critical loads sub-panel would be extra cost with no real value for me. ymmv (or your in-laws, in this case)

In my case, with REALLY expensive time of use rates, a smaller battery might make more financial sense and avoid grid import during evening peak rate hours. But in many places, you are getting battery for backup purposes so need to think worst case (winter PV production) and house energy usage. from that you can determine required battery size, with some buffer room, to cover day and be able to recharge from solar during day (assuming sunny).

 

[1201]

I mean you added a zero but w/e. Here in WNC (where OP is) we were 2 feet above the 100 year flood level.

Love the optimization that you think it will be another 1000 years.

I was just going by what the op said "once in a thousand years event"

 

[Lawrence_SoCal]

To add to my earlier reply, in my case (install 2 years ago), simply adding the MID and associated wiring would have been $3-5K, and maybe a lot more due to code implications with gas meter near flush-mounted combo electric meter/main (breaker) load panel (ie code change since house construction 40+ years ago). Then a local code compliant grid-connected ESS and associated wiring to MID? At least another $5K [thinking EG4 PowerWall], or more likely $10K plus [ignoring a recent (2-3 months ago?) local vendor quote of $23+K for a single Tesla PowerWall 3 install ?!?!?!]

So, for a code compliant, grid-connected UL certified battery backup install, in some areas, adding $20K for a 10-15kWh ESS to a solar install isn't out of the ordinary. So, if rare power outages, skipping that expense for now? totally understandable

 

[windsurfer]

Is it wise to spend another $5-10k for battery backup for a 1000 year event?

Going to need some new names, 100, 500, and 1000 year storms are becoming much more frequent.

 

[wpns]

Going to need some new names, 100, 500, and 1000 year storms are becoming much more frequent.

Turns out they are called that for ease of public understanding, what they actually are is storms with yearly probabilities of 1%, 0.5%, and 0.1% so they are unlikely but can happen any (or every) year, and don’t start a countdown timer till the next one.

“Think how much worse it would be if this global warming thing were real.”

 

[bizutch]

because
1. it is unsafe, and therefore against rules/code (law?) to allow energy export onto grid when grid power is down (ie safety hazard to first responders, linemen, etc)
2. such simple grid-tied systems are WAY cheaper than one that can isolate itself from grid (ie, sunlight backup or battery backup)

battery backup, or generator

At significant expense, and they turned it down, right?

I currently have grid-tied micro-inverter (DC to AC conversion on each panel) solar. Power outages are so rare, and battery tech hopefully on cusp of change to safer (even than LFP) and longer lasting... so I'm holding off for the time being, as there isn't a ROI for me at this point. My system likely to look a lot light you in-laws, with a small solar sub-panel, with a couple of breakers, hooked up to main panel, larger breaker, labelled solar. And only works when grid is up.

Once I decide I want/need to have solar working when grid is down, then I'll need a MID (a micro interconnect device, ie a device that disconnects house from Power Company grid and forms 'micro-grid' for the house.) Once you have a grid-forming MID, you can have sunlight backup (ie solar keep working when grid goes down... BUT there are complications due to variable output of solar and potential damage to electrical gear in the house depending on loads... hence sunlight backup not really being a thing). For safe, reliable power when grid goes down, you need a battery (or Energy Storage System/ESS) and something to convert AC to DC (and back again).
Then you have to decide budget and requirements in terms of electrical load at house, and then Inverter size and battery capacity, whether Whole home backup (simpler) or only partial (critical loads backup... will requiring electrical re-wiring to some extent... how much? depends). For me, a whole house backup would be cheaper, but that is because my electrical load peaks are low enough, that a typical Hybrid Inverters can handle it, so a critical loads sub-panel would be extra cost with no real value for me. ymmv (or your in-laws, in this case)

In my case, with REALLY expensive time of use rates, a smaller battery might make more financial sense and avoid grid import during evening peak rate hours. But in many places, you are getting battery for backup purposes so need to think worst case (winter PV production) and house energy usage. from that you can determine required battery size, with some buffer room, to cover day and be able to recharge from solar during day (assuming sunny).

Thanks folks. All of that makes sense now.

In regards to 1000 yr flood (probability), I was in Lake Lure for the "Flood of the Century" in 1995 & witnessed that destruction. Blew the mind then. This event is of a magnitude so far beyond that. But as another user stated, it's made me very aware we were unprepared.


Thanks for helping me understand that grid tied systems are simply useless in outages. They're a savings tool, not a "survival" tool.
So I guess the answer to help them both have power in blackouts is what I'm using...dual fuel inverter generator plugged into an EcoFlow or server battery for a few hours.

 

[wpns]

Thanks for helping me understand that grid tied systems are simply useless in outages. They're a savings tool, not a "survival" tool.

Yup, common misconception, which unscrupulous solar sales folks take advantage of.

So I guess the answer to help them both have power in blackouts is what I'm using...dual fuel inverter generator plugged into an EcoFlow or server battery for a few hours.

Indeed, there's no solution other than batteries and/or generator, and rebuilding a grid-tied system (especially with micro inverters) into a battery-backed up one isn't usually worthwhile. I've got three grid-tie inverters sitting in the discard pile because of how poorly I understood this...

 

[Offgrid Jungle]

Plug the AC from the existing system into the GEN port of the 6000XP and cancel the grid-sell-back contract. Add the EG4 battery and you're done. $5k plus install. This turns it into a safety-off grid system. Cheaper than a generator and better for old folks...

 

[bizutch]

Plug the AC from the existing system into the GEN port of the 6000XP and cancel the grid-sell-back contract. Add the EG4 battery and you're done. $5k plus install. This turns it into a safety-off grid system. Cheaper than a generator and better for old folks...

That would make sense to me, but no way is that logic getting conveyed to the in-laws. I'll try to show them the hand truck option via my brother in law, whose a little handy.

 

[Mattb4]

Plug the AC from the existing system into the GEN port of the 6000XP and cancel the grid-sell-back contract. Add the EG4 battery and you're done. $5k plus install. This turns it into a safety-off grid system. Cheaper than a generator and better for old folks...

Don't think that will work. The 6000XP is not designed to create a microgrid to keep the grid tie inverters operational. A hybrid style of AIO could keep the gridtie alive until things broke (no method to stop gridtie output) if it was not AC coupled.

 

[Offgrid Jungle]

Ok, then dump the microgrid inverters and connect the PV panels to the MPPT inputs of the 6000XP.