Whole home UPS

[Solar_newb]

Our electric provider has some pretty random outages. I currently have a 22kW Generac feeding ann auto transfer switch which ties to my 200 amp service. What I would like to do is have a battery backup to that can sustain this for a short period of time for true uninterruptible power. Currently we get some random outages of 10 or so seconds which triggers the generator and sometimes the transfer switch never actually switches because the power is back on. In the end, I would like to go solar, but for now I was thinking a battery bank and an all in one or something similar that would solve the current problem. This would require a generator output from the controller or a way to trigger the ATS.I am looking for suggestions.

 

[Rider]

Just going thru this now. I got an Anker F3800, and will soon get their Smart Home panel. I have an existing 30A generator input on interlock into my 200A service panel. I've been in contact with Anker about a specific scenario where I can use the generator via the interlock while grid power is down, while still using the F3800. They say as long as the generator has a pure sine output, it should be OK.

In this scenario, grid power goes down, and the F3800 kicks in providing power to a separately installed sub-panel with critical circuits. If the F3800 is becoming depleted, or you want to run something on the main panel that is a power hog, you can plug in the generator via the interlock and turn it on. The F3800 will sense "grid" power and go back into standby so the generator can run the loads and charge the F3800 back up. When ready, turn off the generator and the F3800 will again kick in and provide power. Yours will be a bit different because your genny is connected differently.

 

[aliarifat794]

You can consider using Lithium Iron Phosphate batteries for your battery bank. LiFePO4 batteries are recommended for their long life, safety, and performance. Choose a hybrid inverter that can handle the load of your critical appliances and has a seamless transition capability from grid to battery power.

 

[Solar_newb]

I am looking for the best hybrid system for my use case. I have looked at some of the EG4 setups, but not sure what would be best.

 

[OffGridInTheCity]

I'm with you and went down a similar rabbit hole myself several years ago because of my off-grid solar -> grid -> solar every day switchovers and I've had long experience with APC UPSs.

I settled on a targeted approach via dual APC UPS 3000s and wired specific Solar/Grid -> UPS -> home circuits to offices, TV area, and kitchen - for units with sensitive circuits. The rest of the stuff remembers it's settings or does OK or resumes without intervention after short outages - things like my Rheeme hybrid hot water heater and Lennox whole house heat-pump remember their settings resume unattended after short outages.

I know this is not what you're thinking but 'whole house' (100a or 200a @ 240v/120v) is not common equipment! (think insanely expensive or heavy or x)

If you're inclined to go solar, then perhaps look at AIO unit(s) with built-in ATS/UPS large enough for the whole house and feed you're generator into these or with battery, directly to battery charging. At a whole house level this might be cheaper / make more sense than a really big UPS.

 

[Solar_newb]

I have enough Lifepo at my finger tips to power the house for a day. They are not tied into anything currently. This is what lead me to look into using an all in one. I am just a newb at what the best setup is for this type of system.

 

[SolarFlares]

I went through a similar process when I was looking into getting solar. I wanted the most simple option that would power my whole house when the grid went down. It led me to getting a solark 15k which can be used to power my whole house with no critical loads panel.

You can use this or something similar like a EG 18kpv without any solar. Either model will be grid tied and connect to your batteries and generator. There are a lot of things left for you to look into for sizing (your generator is pretty large so you might have more load or multiple panels idk) but this should get you started on your research.

Take a look through this thread - https://diysolarforum.com/threads/s...ak-coverage-on-solark-15k.85227/#post-1114638

https://www.sol-ark.com/residential/15k-whole-home-inverter/

https://eg4electronics.com/categories/inverters/eg4-18kpv-12lv-all-in-one-hybrid-inverter/

 

[wpns]

Definitely do a power survey so you know what your peak load is and then size an EG4 ESS (18Kpv plus PowerPro batteries) to suit. Just put it in a place where the fan noise won't bother you once you add solar.

 

[DIYrich]

Two Growatt sph 10000-tl-us can provide 20kW of power. You will need 400ah (20 kWh) of batteries to power them during peak draw. Scale as needed, up to 6 units (60 kWh or 250 amps).

Add solar as desired.

Batteries will last 1 hour under full continuous draw. About half a day for average load of a good size house.

Many AIO have isolation circuits to disconnect from the grid. They can also control the generator to recharge batteries for an extended outtage.

 

[Madcodger]

A big problem many people have in your situation is that they don't want ANY interruption to their power, even for a portion of a second, and that gets difficult for an entire house. Basically, you would need all loads to be powered by though the battery, at all times, with the grid serving as only a recharging source for the battery. That's certainly possible, but what you end up creating is an off grid system that uses the grid instead of solar as the power source, and most people don't want to go to that expense. Even higher end equipment (e.g., Victron) that switches back and forth between grid or battery as the power source produces an interruption of a portion of a second, that's noticeable. I see it every time the inverter tells the generator to start and the inverter sees that AC come in. Lights dim or go off-on, HVAC equipment stutters a bit, etc.

What I suggest is putting all sensitive electronics (computers, modems, routers, security systems, VOIP equipment, gaming devices, etc) on a good quality UPS so that they have truly uninterrupted power. TVs or screens go on one as well if a short interruption or reset bothers you. If the outage is long enough the generator will turn on (10 seconds is common) but your sensitive devices will have been protected. To me. that's much simpler and easier than trying to produce a truly uninterruptible supply for an entire house.

 

[dfw_dude]

my 6000xp + 2x EG4 indoor batteries do the job nicely. 28kwh worth of on site storage. Primarily fed by my ground mount array in the back yard

Basically whole house except central HVAC and electric tankless are backed up and on a transfer switch. I can generate about 25kwh a day from solar, and should we have meh weather, it fails over to the grid if available. In super emergency situation I can feed in power from a propane generator.

Between texas ice storms, and possible brown outs this summer from the heat, I'll always be able to get along fine no matter what the grid is doing.

whole system paid dividends weeks ago when 600k people local to me were without power for 24-48 hours, everything critical just kept running like usual for the 30 hours I had no grid power.

 

[Luk88]

I have gone through similar planning phase (until I decided to add more solar and expand the system) but I'm doing it on the cheap and my generator is pull start not automatic (that's fine as I'm not expecting to use it unless a long outage happens December/January.

I second the power survey idea. It is quite essential.

The way I initially have done it is I have separated all essential systems (security cameras, internet access, wifi, lighting) onto one AC output of a two output AIO inverter. This is only a 1200W output, but it's more that enough as it runs at 250W most of the time. Then the secondary output(~3kW) powers my heat pump (for cooling in the summer) to utilise excess energy. Second output switches off if battery drops under a certain voltage.

A second 6.2kW AIO inverter has other loads I want on during the outage without any interruption. For example my TV, computers in my WFH office, electric kettle, oven.

This works pretty well. Computers never notice switching between grid/battery even in appliance mode (ups mode can be set to switch faster). Although I have manual transfer switches I only use them for maintenance. Inverters switch from/to grid bypass internally as required.

What are disadvantages? You need to have enough wiring going to your main electrical panel to supply both grid power and backup power.

So why am I upgrading? Two reasons. First my inverters use two different voltage batteries and I'd like to use one. Second I'd prefer other house loads such as induction hob (5.2kW) washing machine (2.5kW), dishwasher(2.2kW), microwave(1.5kW) and so on for a total of 25kW to also stay on. So I'm upping it to 2x10kW + 6.2kW.

Unless it isn't clear each inverter uses its own AC out line but all will use the same battery , my house is wired for 3 phase power so it is pretty easy to change. Using battery by multiple inverters unware of each other is a challenge, but not a massive one.

One of the reasons I didn't go down the whole house ups route from the start is that I have a 24kW 3 phase tankless water heater and feeding that would be too expensive off grid so it has to stay on grid.

If I didn't have this and my house was wired for 2 phase (like yours) I'd probably choose the whole house UPS.

All you need for this is a big battery and two hybrid inverters that support split phase(here in the EU usually you look for models that support parallel connections and they support multiphase too - not sure how about with split phase).

These inverters need to be 10kW each at least. Many companies make them.

The battery needs to be capable of 400A at 16S voltages. Most ESS focused lifepo cells are made for 0.5C discharge so you're looking for 800AH at 16S if you plan on maxing it out frequently. One option would be 16s3p using EVE MB31 cells if you choose a DIY battery.

 

[SolarFlares]

A big problem many people have in your situation is that they don't want ANY interruption to their power, even for a portion of a second, and that gets difficult for an entire house. Basically, you would need all loads to be powered by though the battery, at all times, with the grid serving as only a recharging source for the battery. That's certainly possible, but what you end up creating is an off grid system that uses the grid instead of solar as the power source, and most people don't want to go to that expense. Even higher end equipment (e.g., Victron) that switches back and forth between grid or battery as the power source produces an interruption of a portion of a second, that's noticeable. I see it every time the inverter tells the generator to start and the inverter sees that AC come in. Lights dim or go off-on, HVAC equipment stutters a bit, etc.

What I suggest is putting all sensitive electronics (computers, modems, routers, security systems, VOIP equipment, gaming devices, etc) on a good quality UPS so that they have truly uninterrupted power. TVs or screens go on one as well if a short interruption or reset bothers you. If the outage is long enough the generator will turn on (10 seconds is common) but your sensitive devices will have been protected. To me. that's much simpler and easier than trying to produce a truly uninterruptible supply for an entire house.

This is not true of AIO devices like the solark 15k or the EG4 18kpv or their competitors. They can be powered from the grid and switch to PV/battery fast enough to not cause an outage. Below are the AC output backup transfer times from their spec sheets (5ms and 10ms). I only own the solark (5ms switching time) and can attest that I do not lose AC power when the grid goes down even on sensitive electronics (modem, router, switch, PC). I've been through dozens of grid outages without an issue when it switches from grid to PV/battery.


solark 15k



EG4 18pv

 

[OffGridInTheCity]

This is not true of AIO devices like the solark 15k or the EG4 18kpv or their competitors. They can be powered from the grid and switch to PV/battery fast enough to not cause an outage. Below are the AC output backup transfer times from their spec sheets (5ms and 10ms). I only own the solark (5ms switching time) and can attest that I do not lose AC power when the grid goes down even on sensitive electronics (modem, router, switch, PC). I've been through dozens of grid outages without an issue when it switches from grid to PV/battery.


solark 15k
View attachment 226944


EG4 18pv
View attachment 226945

Interesting - I have used APC UPS 3000(s) and 1500(s) for many years and use them (successfully) to smooth off-grid solar -> grid -> off-grid solar ATS switching for sensitive circuits including computers, tivo - things like that. Found this spec for APC - https://www.apc.com/us/en/faqs/FA158892/

However, I must confess - I thought the idea of UPSs is that these were constantly on AC input -> Battery -> AC output and there was no switching! If AC input goes down, then Battery -> AC output continues till the battery runs down.

I assumed that off-grid or hybrid (with battery) AIOs worked the same way.

"Backup Transfer Time 5ms" for SolArk is fast from what I've read. "Switching Time 10ms" for the EG4 18pv is in range if APC does 10-12ms listed above.

Would be interested (will follow this thread) in confirmation on EG4 switching.

 

[Bkord]

This is not true of AIO devices like the solark 15k or the EG4 18kpv or their competitors. They can be powered from the grid and switch to PV/battery fast enough to not cause an outage. Below are the AC output backup transfer times from their spec sheets (5ms and 10ms). I only own the solark (5ms switching time) and can attest that I do not lose AC power when the grid goes down even on sensitive electronics (modem, router, switch, PC). I've been through dozens of grid outages without an issue when it switches from grid to PV/battery.


solark 15k
View attachment 226944


EG4 18pv
View attachment 226945

Yes solarks are fast, my computer dose not notice.

 

[wpns]

Interesting - I have used APC UPS 3000(s) and 1500(s) for many years and use them (successfully) to smooth off-grid solar -> grid -> off-grid solar ATS switching for sensitive circuits including computers, tivo - things like that. Found this spec for APC - https://www.apc.com/us/en/faqs/FA158892/
View attachment 226946
However, I must confess- I thought these were constantly on Battery -> AC output and there was no switching!, just weather it is AC -> Battery -> AC or Battery -> AC.

"Backup Transfer Time 5ms" for SolArk is fast from what I've read. "Switching Time 10ms" for the EG4 18pv is in range if APC does 10-12ms listed above.

Would be interested (will follow this thread) in confirmation on EG4 switching.

But a single cycle is 16 or 20 ms, and most equipment can hold up for that long, so while you might notice a flicker on low-quality lights, nothing's going to reboot or crash or hang up in that time.

 

[SunDave]

15k owner here. Can confirm switching is fast, but lights will quickly dim just a bit. Computer/TV, or really anything running stays powered on fine.

I should say, I worked with battery backup quite a bit in telcos (phone companies). Most battery backup, even rack-mount, switches quickly. Only the very expensive models run through battery and do the AC/DC/Back to AC conversion necessary to always run this way. I would imagine that is very wasteful as well.