Educate me on backup generators

[theoldwizard1]

How close are we to having battery backups as a viable/affordable option? I keep looking at the Tesla Wall and wondering if that is "ready for prime time" as a simple backup. In the last 40 years, we have had many 1 to 3 hour outages, about ten 1 to 3 days, and one 5 day outage.

They' re very viable for short outages, but not for providing backup power on a long one.

We are closer than you think !

2,000-3,000Wh of LiFePO4 batteries will run MOST of your house for those 1 to 3 hour outages. It would take 10Kwh - 20KWh to go for a couple of days. The price of batteries has fallen like a STONE in the past couple of year.

Many POCOs now have lower rates for "off peak" hours. With some solar/wind and off-peak charging, the pay back MAY be reasonable !

The big expense now a days is an inverter large enough to handle a house and the automatic transfer switch ! Still, don't expect to be able to run LARGE loads (water heater, stove, dryer, A/C-heat pump).

 

[Sumboodie]

Anyone today with electronics in the house needs an inverter style generator. The THD on non-inverter units is high enough to damage electronics which everything has electronics in it now - HVAC, refrig, washer, dryer, tv, audio visual etc.. Because of the cost, best to figure out what really has to run, and for how long. We use backup batteries for our CPAPs but we rarely lose power for more than a couple hours, a day at the most. If you get ice storms and are out for a week etc., then you need to figure the bare minimums. As others have said, a generator requires fuel so you have to think ahead where that fuel is coming from.

They make invertor back up gen sets?
I googled and nothing is coming up. I bought an inverter one, but it's a little thing on wheels that uses the gasoline. One of the very few things I have using that stinky stuff. Almost everything is diesel.

 

[dcg9381]

I went through this a few years ago.

We live in a rural area with occasional outages, but my wife uses a CPAP and doesn't sleep well without it.

For CPAP, I'd consider a battery backup option. Even with an auto-start generator, you'll have a lag until it gets spun up.

So, Generac vs Kohler?

I went over and over on this, decided there wasn't much of a difference in the air-cooled space. I ended up getting a 20k generac at a huge discount (used). Zero issues with it.

I have had problems with Generac components. I have 3 "load shed" devices in my home - one disconnects a 100A service panel and the other disconnects an AC unit. These units are "dumb" - all they do is close a relay contactor after a power outage on a timer, you offset the timers so things don't all start at once. They also monitor frequency, so if generator RPM drops they disconnect. I've had two fail. Generac support for "end consumer" *****, they push me through a dealer and want a diagnostic before they will warranty anything.

How many kW? Home is 2300 sq ft, stove and water heater are propane, oven is electric, other normal appliances are electric. We're on a well and use a mini split for heating and cooling.

People are going to say "load calc" and that's fine... The better way to do it, IMHO is to install a montior on the main panel that tells you KW draw, so you can actually look. Your POC "might" have an interface where you can look at power draw as another means to estimate if it gets down into the by minute level.

We almost never go over 16kW for a 3000 ft house. Propane water heater - everything else is electric. 6 tons of AC on the house.

I'm thinking of an auto transfer switch, any reason not to?

Yes, auto-start (auto transfer) is the way to go...

 

[dcg9381]

How close are we to having battery backups as a viable/affordable option? I keep looking at the Tesla Wall and wondering if that is "ready for prime time" as a simple backup. In the last 40 years, we have had many 1 to 3 hour outages, about ten 1 to 3 days, and one 5 day outage. That is for multiple houses (worst was hurricane Helene on St Simons). So, I'd like something that could support 3 days full house.

I do some "side work" in this space.
Affordable? The generator is by far a more affordable option and will provide you power for extended outages. You need a massive battery bank (think well north of $50k all-in) to do that.

Where these systems excel is that they basically switch so fast that you never know you lost power.

But even the Tesla Power wall will only do a "portion" of your home (due to current limits) - you usually need 2-4 to "reasonably cover" a typical 2000-3000 sqft home.

Tesla has competition. There are systems that are essentially "hybrid" inverters that can do solar, a moderate generator backup, and buffer it all through battery power. This is the best of all worlds. As long as you have a large enough hybrid inverter (or more than one) you can get by with a smaller generator. Generator charges the batteries when full power is not being used.

Are battery backup "generators" viable and who has a good support and installation system for those of us without solar panels?

"Solar generator" is a dumb name IMHO. It's just a box with an inverter, batteries, and usually a means to charge via solar.

Whole house backup systems that combine a generator, solar, inverter, and batteries are absolutely viable. Not cheap, but viable. You'll want a good local installer that's going to be around for a while.

 

[theoldwizard1]

I have had problems with Generac components. I have 3 "load shed" devices in my home - one disconnects a 100A service panel and the other disconnects an AC unit. These units are "dumb" - all they do is close a relay contactor after a power outage on a timer, you offset the timers so things don't all start at once.

My buddy went "simple" on load shedding. The house was wired for a second meter for the A/C (different rate because the POCO can interrupt the service). The rest of the house is connected to the generator.

Between the A/C unit and its dedicated meter, they added a load center with generator interlock. The generator input for this interlock is wired to the "rest of the house" load center. If he wants A/C when the power is out (generator is ON), he must manually switch the interlock !

Why ? Because now they could installed a smaller generator and it did not require an automatic load shedding transfer switch. BIG SAVINGS !

 

[dcg9381]

My buddy went "simple" on load shedding. The house was wired for a second meter for the A/C (different rate because the POCO can interrupt the service). The rest of the house is connected to the generator.

I thought there was an NEC rule against residential and "dual feed"? I do note that there is an exception for "backup power", but I've never seen it used outside of commercial space.

Why ? Because now they could installed a smaller generator and it did not require an automatic load shedding transfer switch. BIG SAVINGS !

If you're going to do that (small manual generator is cheaper and you can use an inverter gen) why not just do a generator input feed, interlock, and manually switch the breakers for load management? I'm staring to see inverter gens over 7kW.

We're on a "well pump" (water collection) - it's 350 feet away from the house. To power that up, I have to use a separate generator (manual).. But the pressure tank provides a reasonable amount of water before all pressure dies.

I really like the design of Generac's load shed devices. No complicated wiring. I did not like that two of them failed (board clearly overheated) but the newer ones seem to have a different board and no failures since. But I don't see why they'd be specific to use with a Generac generator. They'd work with any genset.

 

[theoldwizard1]

I thought there was an NEC rule against residential and "dual feed"? I do note that there is an exception for "backup power", but I've never seen it used outside of commercial space.

I know what you are saying, but dedicated meter for A/C is common around here !

If you're going to do that (small manual generator is cheaper and you can use an inverter gen) why not just do a generator input feed, interlock, and manually switch the breakers for load management?

Because he and his wife wanted automatic for most loads in the house. You can live without A/C for many hours.

If you are willing to do things manually (and save a HUGE AMOUNT OF $,$$$), a 3kW - 4kW manual start inverter generator, connected to your load center via a generator inlet and interlock is the way to go ! If you can live without 240VAC load, buy a 120VAC inverter generator and connect L1 to L2 on the generator cord.

 

[mm08822]

sounds like someone screwed up on the transfer switch programming.

Na. I dont like generac's default settings. They let the voltage get too low before triggering a start/transfer and not high enough before transfer back to POCO.

 

[LopezBart]

For CPAP, I'd consider a battery backup option. Even with an auto-start generator, you'll have a lag until it gets spun up.

I have a CPAP that will run on 12VDC; a gel cell lead-acid battery will easily last the night. If power outage continues, I can recharge it from a vehicle. If the power outage lasts weeks, we have bigger problems.

 

[theoldwizard1]

I have lived in this house for over 48 years. We have had less than 10 outages that lasted over an hour in that time. Two that lasted longer than 4 hours. One lasted about a day and a half. Another lasted about 3 days.

I now own a 6,000W (peak) 240VAC generator, a 4,000W (peak) 120VAC inverter generator and a 1,200W (continuous) 12VDC input/120VAC output inverter. The 4,000W inverter generator is easy to haul to someone else's home. Inverter is for camping.

 

[fitter30]

I'm very rural. Use a cheap electic start Champion gen converted to lp 6500 watt 7500 peak. Have lp log stove for heat. Can run the refrigerator, lp cook stove, electric water heater, lights, well pump, tv internet, streaming ,computors and 5k window ac for bedroom. Not all at one time. Longest time 8 days normally 1-3 days and if its out for hour I'll turn it on. 500 gallon lp tank just had it topped off. Have a outdoor generator reciprocal,flex hose for lp and generator 6' cord.

 

[mike93lx]

I thought there was an NEC rule against residential and "dual feed"? I do note that there is an exception for "backup power", but I've never seen it used outside of commercial space.

If you're going to do that (small manual generator is cheaper and you can use an inverter gen) why not just do a generator input feed, interlock, and manually switch the breakers for load management? I'm staring to see inverter gens over 7kW.

We're on a "well pump" (water collection) - it's 350 feet away from the house. To power that up, I have to use a separate generator (manual).. But the pressure tank provides a reasonable amount of water before all pressure dies.

I really like the design of Generac's load shed devices. No complicated wiring. I did not like that two of them failed (board clearly overheated) but the newer ones seem to have a different board and no failures since. But I don't see why they'd be specific to use with a Generac generator. They'd work with any genset.

I think a battery big enough to handle peak loads with an auto start generator that runs solely to recharge the batteries would be cool. Let logic manage the generator to keep the batteries within a state of charge range.

"unfortunately" my power is reliable enough to not need this.

 

[imagineer]

FWIW, I installed a 24kW Generac running on natural gas, so it's de-rated to 21kW. I bought it from Menards (including the ATS) and did the install myself. Including a larger gas meter and cabling, it cost me about $8500. IMO, worth every penny. It kicks on within 10 seconds of a power outage and provides peace of mind.

My only regret, albeit a small one, was not researching the ramifications of buying it myself and not through a Generac installer. I wasn't intending to install it myself, but I wasn't able to find anyone to do the installation on a generator they didn't provide, so I was stuck doing it myself. Also, because I didn't buy from a Generac servicing dealer, tech support direct from Generac was poor (had a lot of problems getting it connected to the house WIFI).

 

[mm08822]

I really like the design of Generac's load shed devices. No complicated wiring. I did not like that two of them failed (board clearly overheated) but the newer ones seem to have a different board and no failures since. But I don't see why they'd be specific to use with a Generac generator. They'd work with any genset.

I'm surprised Generac hasn't marketed use beyond their HSB gens. It's only a frequency monitor with a time delay built in. Could work with any decent sized HSB gen.

I put 4 of these in a customer's house on the ac units and several years later they all failed simultaneously - same day! Each had the same failure marks on the boards. I think he took a spike from the grid and they all were smoked simultaneously. I replaced them for cost b/c I felt bad for him. I also put lollipop suppressors on the line side of each.

Generac also changed the contactor from NO to NC and reversed the logic driving the coil. So I'm thinking the original board design was on the cheap instead of being able to handle constant coil load and run the board level components 24-7.

 

[Mtpisgah]

We were quoted $40k and $35k for a whole house generator for our 6,000-sf home. Four heat pumps, a mini split in the garage, wine cellar cooling unit, and all the usual stuff. It is just my wife and me, so we could do without a reduced load during an outage. We told the installers that and they still act like we need to run every HVAC unit at the same time. We are still thinking about it.

 

[mm08822]

We were quoted $40k and $35k for a whole house generator for our 6,000-sf home. Four heat pumps, a mini split in the garage, wine cellar cooling unit, and all the usual stuff. It is just my wife and me, so we could do without a reduced load during an outage. We told the installers that and they still act like we need to run every HVAC unit at the same time. We are still thinking about it.

Umm....... what were you quoted - details?
Ac units can be put on load shed interlocks or contactors to reduce the calculated load size of the gen.

I would hold off for now until more details are known.

 

[mike93lx]

We were quoted $40k and $35k for a whole house generator for our 6,000-sf home. Four heat pumps, a mini split in the garage, wine cellar cooling unit, and all the usual stuff. It is just my wife and me, so we could do without a reduced load during an outage. We told the installers that and they still act like we need to run every HVAC unit at the same time. We are still thinking about it.

Do the whole house system.

You live in a very nice house and live well. If you load shed and have stuff down, I pretty much guarantee it will piss you off during the first long outage and you'll be wondering why you were "cheap".

 

[dcg9381]

I put 4 of these in a customer's house on the ac units and several years later they all failed simultaneously - same day! Each had the same failure marks on the boards. I think he took a spike from the grid and they all were smoked simultaneously. I replaced them for cost b/c I felt bad for him. I also put lollipop suppressors on the line side of each.

That's really odd. I have 3 of them. 2/3 have failed, but at different times. Same deal - clear heat marks and distortion on the board. Was kinda a pain in the *** as one of these covers the sub-panel in my garage and the fridge was leaking before I noticed. I had to hold the relay closed with vice grips or something like that while I got a replacement.

What I'm not happy about as a consumer was Generac required me to take these into a dealer who charges a "diagnostic fee" in order to warranty them. I ended up replacing them out of pocket within warranty period. The board was clearly fried but the local dealer had a "minimum diagnostic fee".

Generac also changed the contactor from NO to NC and reversed the logic driving the coil. So I'm thinking the original board design was on the cheap instead of being able to handle constant coil load and run the board level components 24-7.

So they fail closed now? Sounds like they've changed the board AND the coil. I simply swapped the boards (which was way easier than wrestling the wiring) - probably before they changed the coil type.

What's a lollipop suppressor?

 

[dcg9381]

I think a battery big enough to handle peak loads with an auto start generator that runs solely to recharge the batteries would be cool. Let logic manage the generator to keep the batteries within a state of charge range.
"unfortunately" my power is reliable enough to not need this.

For sure.. And even better than that, they can make use of PV power when the grid is down. Unlike my 4-year old "grid tie" inverter which disconnects from the grid when the power is out. These systems are so fast you won't even notice a power outage again.

Most of our outages here are "brown out" related, so they're pretty short. And I'm on a "protected" portion of the grid (fire station). I'd prefer not to have to run a 20kW generator, but I didn't design for these more advanced hybrid inverter systems. And the price of enough batteries to give me 90A@240V is way over what I paid for a "used" 20kW generator.

I've been playing with Victron inverters in my mobile "cargo trailer". They have a really cool feature on a 3000 watt inverter that they call "power plus". Basically it will grid sync, so with a 3000 watt inverter + grid power, you can push it up to 5000 watts. It's super cool to be able to set the inverter to pull 9 amps @ 120V from the grid and let the inverter + solar cover the rest. AC goes off, the batteries charge. Great UI interface to control it too. Victron is aimed at the "mobile" space, but no reason you couldn't feed it to a generator inlet and an interlock.

 

[mm08822]

That's really odd. I have 3 of them. 2/3 have failed, but at different times. Same deal - clear heat marks and distortion on the board. Was kinda a pain in the *** as one of these covers the sub-panel in my garage and the fridge was leaking before I noticed. I had to hold the relay closed with vice grips or something like that while I got a replacement.

What I'm not happy about as a consumer was Generac required me to take these into a dealer who charges a "diagnostic fee" in order to warranty them. I ended up replacing them out of pocket within warranty period. The board was clearly fried but the local dealer had a "minimum diagnostic fee".

So they fail closed now? Sounds like they've changed the board AND the coil. I simply swapped the boards (which was way easier than wrestling the wiring) - probably before they changed the coil type.

What's a lollipop suppressor?

I was in dis-belief when he told they all failed and at once. Customer had HVAC company out and none of the ac units had power. All of their respective cb's were on. He by-passed the contactors and all ac units ran.

I could understand a diagnostic fee IF the unit was not defective. It should have been refundable it the product was faulty within its warranty period.

Obviously, Generac (like any other mfr) has the product life-cycle history and knows early on when a design and/or component selection isn't cutting it. Hence, a "quiet" product upgrade and keep the same part #. Admit no fault or short-coming. Let the customers take it on the chin, sales numbers increase!
What you replaced must have been within the same part version. If it weren't, you would have found the contactor state was reversed and spent lots of time discovering the sneaky b*stards fixed a f*k up.

 

[dcg9381]

What you replaced must have been within the same part version. If it weren't, you would have found the contactor state was reversed and spent lots of time discovering the sneaky b*stards fixed a f*k up.

Probably. Generac wouldn't sell me the board, so I bought new units and swapped the boards. They were definitely "default open" at the time... But I appreciate your comment because I'll have to deal with it if another fails.

 

[theoldwizard1]

Can run the refrigerator, lp cook stove, electric water heater, lights, well pump, tv internet, streaming, computers and 5k window ac for bedroom. Not all at one time.

Curious. what is you "load" strategy ?

The big loads are water heater, pump and A/C. Without the water heater (why not switch to LP?) and with a MicroAir EasyStart™ on the pump and the A/C, you could probably run all of that.

 

[theoldwizard1]

I think a battery big enough to handle peak loads with an auto start generator that runs solely to recharge the batteries would be cool. Let logic manage the generator to keep the batteries within a state of charge range.

This is what most high end RVs are doing. They have 2 inputs to the inverter/charger/transfer switch. On for "shore power" and one for a generator that typically has an autostart function.

 

[Jetfixr320]

I run my house on a 6000 watt Generac but I don’t run my electric stove off of it or the dryer. I will not say how it’s connected to the house as it seems to upset all the sparky’s on here. Depending on how big of a unit you get the transfer switch may do the whole house or may only do certain circuits. You’ll basically need to figure out what circuits you want to run and size the unit and transfer switch to those needs.


Oh it’s not Kohler anymore as they sold off the power generation part of the company. The new name is Rehlko.

They wouldn't like mine either.

 

[Stuart in MN]

What's a lollipop suppressor?

I assume they were referring to a metal oxide varistor, or MOV. They're used to suppress surges and are kind of shaped like a lollipop.

 

[fitter30]

Curious. what is you "load" strategy ?

The big loads are water heater, pump and A/C. Without the water heater (why not switch to LP?) and with a MicroAir EasyStart™ on the pump and the A/C, you could probably run all of that.

There is just two of us. Water heater is on only for heating the 40 gallons in times where loads are light except when bathing. Water heater 14.6 amps, well pump 7 amps and 5.4 amps for lights, internet and tv. Refrigerator is off till bathing is done and well pump is off. Normally heat and ac is from two mini splits both 3 head 2 ton. Haven't lost power in the summer for any length of time but have a 5 k window unit for a bedroom if needed.

 

[fozzy]

Thanks for all the info and great suggestions! I’ll find a local pro installer and go from there.

I am in the hurricane threat zone so a whole home generator was a must for me. I didn't want to load-shed, and the price difference in Generac generators between whole home and incremental load-shed was laughable so that decision was easy.

I have NG and I am not at all confident in my ability to install the system and ATS myself. I did exactly what has been recommended previously- found a local dealer/installer that provides post-install service with a deep parts stock and am pleased with the results. Consult was one hour- tech came out, reviewed and calculated the load required to run everything in my house uninterrupted, I signed the contract, paid the deposit, and scheduled the install.

The installer handled EVERYTHING- pulled all of the permits, scheduled the gas company for install day, showed up on install day and in less than 8 hours had everything installed and tested. By my estimate, I paid close to twice if I had bought and installed everything myself but I don't have a single regret. The company I used does one thing: install and service Generac generators and they do it well. The peace of mind I had on the install and have with a generator was well worth the extra money.

 

[mm08822]

I am in the hurricane threat zone so a whole home generator was a must for me. I didn't want to load-shed, and the price difference in Generac generators between whole home and incremental load-shed was laughable so that decision was easy.

I have NG and I am not at all confident in my ability to install the system and ATS myself. I did exactly what has been recommended previously- found a local dealer/installer that provides post-install service with a deep parts stock and am pleased with the results. Consult was one hour- tech came out, reviewed and calculated the load required to run everything in my house uninterrupted, I signed the contract, paid the deposit, and scheduled the install.

The installer handled EVERYTHING- pulled all of the permits, scheduled the gas company for install day, showed up on install day and in less than 8 hours had everything installed and tested. By my estimate, I paid close to twice if I had bought and installed everything myself but I don't have a single regret. The company I used does one thing: install and service Generac generators and they do it well. The peace of mind I had on the install and have with a generator was well worth the extra money.

The manuals are self-explanatory. Unless you are starting way out of your knowledge-base, it's hard to screw up. RTFM before you buy, before you do anything.........it really is easy. The short-cuts "b/c I know better than everyone else" is where it goes down hill.

Be honest with yourself and act accordingly! If nothing more, know what your installer should be doing! As Sy Simms said 10,000x, "An educated consumer is our best customer!"

 

[Snapped-off]

I am in the hurricane threat zone so a whole home generator was a must for me. I didn't want to load-shed, and the price difference in Generac generators between whole home and incremental load-shed was laughable so that decision was easy.

I have NG and I am not at all confident in my ability to install the system and ATS myself. I did exactly what has been recommended previously- found a local dealer/installer that provides post-install service with a deep parts stock and am pleased with the results. Consult was one hour- tech came out, reviewed and calculated the load required to run everything in my house uninterrupted, I signed the contract, paid the deposit, and scheduled the install.

The installer handled EVERYTHING- pulled all of the permits, scheduled the gas company for install day, showed up on install day and in less than 8 hours had everything installed and tested. By my estimate, I paid close to twice if I had bought and installed everything myself but I don't have a single regret. The company I used does one thing: install and service Generac generators and they do it well. The peace of mind I had on the install and have with a generator was well worth the extra money.

Sounds like you had a good and competent installer.

I'd advise the OP to look through Foodie's recent install thread, for shady stuff to look out for.

 

[fozzy]

The manuals are self-explanatory. Unless you are starting way out of your knowledge-base, it's hard to screw up. RTFM before you buy, before you do anything.........it really is easy. The short-cuts "b/c I know better than everyone else" is where it goes down hill.

Be honest with yourself and act accordingly! If nothing more, know what your installer should be doing! As Sy Simms said 10,000x, "An educated consumer is our best customer!"

I did RTFM before I bought because I am one of those guys and agree with you that everyone should. I had to take several electrical engineering courses in college, but I know my limitations and don't touch electricity or gas for that matter. It may be really easy, but I'm happy to pay a professional for their knowledge and skills in these areas to ensure I don't hurt myself or others. I also appreciated that the installer lined up the power company and county inspector to ensure everything was complete in less than a day.

 

[chuck356]

In 2014 we bought a Generac 14KW with ATS from a friend who was buying in to be a dealer at the time. Sold it to me for dealer cost, had a neighbor install and pipe the propane to the generator, then paid my buddy who is an electrician to install the ATS and make it all work. After he finished it, he fired it up and had me go inside and turn on everything I could that was electric and he would measure the draw, I did and it pulled around 10 or 11 KW, we figured that would be good. Fast forward to 2025, it has worked out well, never an issue when on generator power, the longest it has had to run was 2 1/2 or 3 days a couple summers ago after a big storm. I have been able to take care of 90% of the maintenance/repair issues, it has been a great unit so far.