Run Whole House on Wimpy Generator?
 

I've been seeing "deals" on "power stations" lately; battery plus inverter combos in one. My natural reaction to "all in one" things is that it limits usefulness by locking you into several parameters, and doesn't allow selectively choosing each component for quality, performance, etc.

This got me to thinking I could build my own "power station" using a 12v pure sine wave inverter and battery of my choosing. Once down that rabbit hole, that got me to thinking I could select an inverter sufficiently powerful to run all 120v circuits in my house. The only 240v things I run are the AC, and the oven (range is gas). So, I could switch off my 240v breakers and the mains in a power outage, and wire an inverter directly into the panel (not recommending anyone do this).

I had impulse bought an 800 watt Sportsman GEN1000i generator for $159. This got me to thinking that since my average household load is 600 watts, I should be able to run off my generator if there was a buffer to handle peak loads.

So, my idea is to run generator > 12v battery charger > 12v battery > inverter > breaker panel.

Does this seem feasible? If so, I could potentially run my whole house on 2 gallons of gas per day on a quiet and efficient generator during outages.

Generator
https://i.ebayimg.com/thumbs/images/...SPw/s-l300.jpg

Battery charger TBD. Dad has a 40 amp charger to test the theory with.

Battery... whatever is laying around

Inverter- torn between the $50 cheaper 2500 watt unit that has an LCD screen

https://www.amazon.com/dp/B0BQ3WYBZL...g_paid-20&th=1

https://m.media-amazon.com/images/I/...AC_SL1500_.jpg

and the 2500 watt more expensive unit that has AC out terminals instead of just outlets.



https://m.media-amazon.com/images/I/...AC_SL1500_.jpg

Anyhow, that's the silly project I've been pondering. The advantage of such a system is it can be portable for camping if I wanted to.

Your 120v circuits are going to be wired to one or the other of the 2 phases of the 240v service entrance voltage.

You will have to take that into consideration and jumper the two 120v together. Not a good thing if you forget to un jumper and go back to grid power.

I think you are going to pop something when trying to hook the inverter and generator power together.

Power line workers have been killed by back fed home generated power that reaches the transformer and then gets 'stepped up' to 12k or so volts on the grid that they know is turned off.

Welcome to the forum.

One of the inverters I'm considering doesn't have AC power blocks, so if I were to power both legs of my panel with the full output capability, I think I'd need to use 2 outlets and make sure the hot and the neutrals are sorted out properly.

Sounds like you want at least a 24v system.

Thought about it, then thought 12v is more versatile. Worst case, I run the inverter and a car to charge the battery.

So you see no fundamental flaws with the concept?

12v is for when you are experiencing to use about 2kwh per day or less. For backup power for a refrigerator and a few small items or camping because of the 12v.
Cars only have about 10 amps available for charging with everything off, idling. Burning a L of gas per hour or more for 10 amps sucks.
A 24v alternator strapped to a 3hp predator engine can do better than that, a lot better.

I'm following all that logic, but I'm suggesting a compromise that is versatile in the extremes of powering a house, and a more minimal camping application that supplies lighting and cell phone charging.

12v has the versatility advantage, not efficiency.

I might build this just as a proof or denial of concept because I don't see any info. It would set me back $260 or less, and I'd have an awesome inverter at the end of the day.

A good 24v inverter will cost more than that.

Do you have a well? I sized our original backup generator to handle the surge current needed to start our 240V well pump. I'd turn off the rest of the 240V stuff when we were on generator. It was adequate, but the lights would dim when the well pump kicked on and the microwave was distinctly weird sounding when it was consuming generator juice.

We've since installed a whole house unit because we added an outbuilding and the old generator just couldn't cope anymore.

City water, no well.

Only 240v appliance I run is the oven. Range is gas. AC is only run 2 months of the year, so it's normally off.

Well, I raided my dad's battery pile as well as the unused farm equipment and filled the rear hatch area with about 18 or so. Unfortunately all 3 of the large tractor batteries were sitting at ~2v or less. 2 of them had sufficient electrolyte levels though (no exposed plates). Curious if either will take a decent charge.

Half the car batteries were at 11v or more, so some likely have some life to them.

Anyone have a methodology to test capacity that doesn't involve deeply discharging the battery? Perhaps target a 75% voltage as the discharge cutt-off and extrapolate capacity from that?

Know where to get top dollar for the scrap value? I don't see batteries mentioned on the webpage of the local metal scrapyard, but it's also not on the prohibited list.

I'm have a lead/acid battery manufacturing plant just over the hill from me. That's how I recycle them. They re-use darn near every bit. However I never tried taking a pile of them over to see if they'd give me $.

When my grandmother was still alive, and my parents had just divorced, once in a while I lurked about making a wind power generator using a regular 12V alternator and one of those wind powered roof vents that I used to see while passing in front of a shop in the outskirts of my hometown which had such vents always working, on the way to grandma's house.

My dream is to own property along a river that has a small stream sufficient for micro-hydro power generation. 100% electric house, with no dependency or connection to the utility. Saving $200 in gas/electric per month sounds good to me, not to mention the savings of having EV cars and free electricity.

You need one of these:

https://a.co/d/e43GuED

It measures the AC internal impedance of the battery and computes the capacity from that.
Many AutoZone stores have something similar and will test your battery free, I expect you'll need to be extra friendly to test 18, and not buy anything.
-m

My friends that live upriver have exactly that. A Century Farm with a broken down dam and barn with a 60ft ridgeline 30ft in the air athwart the prevailing winds (up and down the valley). It's a huge vortex generator prolly good for 10s of kilowatts itself.

They spend their days in Leftist struggle.

From the description, I don't see any mention of capacity measure. I'm not sure how one would extrapolate capacity from an internal impedance measurement. I could be wrong, but I only know to measure the drain on a battery to determine the remaining capacity.

I do have a smart charger I'm using that provides most of these functions, and I've got a resistive CCA meter.

Don't we all...

I've got my eye on a handful of properties along the N. Santiam river. Some of them have steep hillsides with a continuous stream of water pouring into the river. Wouldn't mind having a vacation rental or retirement house out that way. Paddled many miles on Packsaddle to Mill City, and drank as many beers.

Starlink really was one of the last "problems" to solve with living out in the hills. If I've got unlimited renewable energy, and a decent internet connection, there's not much else holding me back. I wouldn't be surprised if we see a reverse migration away from cities.

Would you have a few moments to talk about Geodesic Domes? :)

You know, passive superinsulated envelope with 'free' air conditioning to throw off heat from occupancy. OG Roman concrete.

One-track mind... :p

Always happy to discuss ideas. My follow-through takes ages though.

Also, can I assume this is your favorite commercial of all time?
https://www.youtube.com/watch?v=OBX02MGp8pg

https://ecomodder.com/forum/member-f...1-hausboot.png

Foundation is five lodgepole pine lashed together at the top, and spread apart to make pilings. Five compound curve hexagonal shells leaned together. Half-hex decks swing up to make shutters over the fenestration. Windmill at the top should be an hyperboloid Ugrinsky turbine.

Start whenever you can.

I'll start with repairing the 2 "extra" holes I put in the ceiling, and 1 in the wall, and build on that momentum.

Of course that would be cool, but if I were doing that I would also probably feel tempted to brew some alcohol, both for drinks and for motor fuel. And it would be also nice having a chance to grow some food.

Sounds good, you're invited.

From the blurb:
It does compute the CCA from the internal resistance. The formula used is
CCA = 3051.85 / R where R is in μΩ. Which you can do in your head.
This meter can measure the internal resistance of the battery, which you can't do with just an ohm-meter. I assume your resistive CCA meter is a smokin' hot load.

If the battery has a stated CCA you enter that and it tells you % of capacity. Which you can do in your head too.
-m

The two weak points in you initial experiments are going to be the inverter and the battery plant.

- I tried to run an efficient chest freezer on a good-sized portable inverter during a power failure. The inverter's electronic protection circuit immediately tripped out at every attempt. The inverter could easily have RUN the freezer based on Kill-A-Watt readings, but was incapable of STARTING it. Make sure an inverter is chosen with enough surge capacity to start motor-driven appliances if needed, such as a refrigerator or a well pump.

- Mixing and matching reclaimed batteries is a recipe for disappointment. When connecting batteries in parallel, a strong battery will discharge itself trying to "top up" the charge in a weak mate. That's why it is strongly recommended to always replace batteries in matched sets.

Sure, you could test pallets full of discards to find some equivalent batteries to mate, but do you want to spend the rest of your your life nursing batteries? The only upside is that you are getting them for free.

One cheap source for getting working but used deep cycle batteries for stationary use recommended online has been buying big 6-volt pulls from a golf-cart service vendor. I have not investigated this myself.

- Also, lead-acid batteries are not good for some of these applications. Running LED lighting with a steady resistive draw, OK. Please note that most deep-cycle batteries (not starting batteries) are rated at C/20. This means that a 100 amp-hour deep cycle battery should provide 5 amps for 20 hours to depletion. You cannot expect a 100 AH battery to provide 100 amps for 60 minutes.

Also, lead-acid batteries do not "come back" after repeated deep discharges. I looked at one premium manufacturer's graph for deep-cycle recovery, and if discharged to depletion (defined as about 1.75 volts per cell, or 10.5 volts on a 12 volt, 6 cell battery), the batteries could be expected to recharge only about 3 times! If lightly discharged, they would come back hundreds of times.

Most RVers and off-grid users set personal limits of only discharging deep cycle batteries down to 80% full or at worst 50% full in order to extend cell life. Stopping at 50% full, a 100 AH deep cycle battery provides 5 amps for 10 hours, or 2.5 amps for 20+ hours.

I don't want to discourage you, I myself fully intend to back up a semi-reliable grid connection with generator, battery plant, and inverter. That is 2/3 of a solar system. Just add PV panels and a charge controller. But go into this with your eyes open, and do your research.

Experiment on the cheap, but be prepared to spend for quality permanent components if you want to sleep peacefully at night. My "on the cheap" experimenting has started with a pair of 2kW portable inverter gennys that can be paired, and converted from gasoline to propane. I need to figure out how to get 240 volts for the well pump, either using a big transformer to step up the voltage, or maybe a smaller transformer to 'trick' the inverter gennies to output opposite phases for the necessary Line 1 and Line 2 hot outputs.

There are also new battery chemistries that are interesting. Lithium Iron Polymer (LiFePO) batteries support high current output and multiple recharges, but are still very $pendy. And the light weight of LiFePO cells is not a factor for stationary battery plants.

If a lead acid is below 11V its really not even on the scale anymore. Scrap them for lead for a good price. Its more than the $10/ battery core they give you. The local recycling place will take those batteries, aluminum wheels etc...

Depends on what you're going to want to run on said generator. But, if you could get a whole home inverter that would start a 240v range or ac plus about 500 watts running at the same time you would have it (typically about 5000-6000w. Then you would just need a string of batteries connected that could handle the peak load, and then probably just charge the batteries from the generator.
Or you could get the 240v appliances figured out. A variable refrigerant flow hvac unit would be able to run in reduced capacity mode all day long depending on programming greatly reducing the compressor starting spikes in load to maybe even just one for a said period of time. A clothes line would solve the dryer issue. a Single burner induction stove top would solve the range oven issue, Then if you have a grill you could bake with it if needed. Gas water heater etc...

With all of the new advancements in technology now i would love to do a $375 homestead credit house out in the woods outside of the city (by say 20 minutes). Stick to 120v appliances, an external intake and exhaust wood stove, a 120v vrf hvac unit, a 2000w honda generator, a heat pump based 120v water heater, a whole home inverter, some batteries to weather a set amount of days without sun, and a small amount of solar panels and you are there.
You would have to figure out rain water and septic systems as the authorities hate you drinking rain water or doing any sort of septic system outside of one on land that passes a perc test and has the inground tanks($$$)
(outhouses are not approved lol)

The only thing I have that takes 240v is the oven and AC (luxury appliance I rarely use). Even the range is gas (weird they didn't go gas oven). Everything else could be run from a 3,000 watt inverter, and possibly smaller. TV and lights is probably 200 watts. Fridge is a hundred typically. HVAC is 700 watts for the blower.

So, I don't need 240v.

It was nice to have dual energy sources during the power outage. Never really thought about it before, but it builds another layer of resiliency. If I had installed the right carburetor on the genset my dad loaned me, the house could have been 100% powered from the natural gas line.

I have all of the equipment to do what you've said you want to do. I have a 2kw inverter/charger with a support/generate function. It works like this... You program the inverter with the amount of generator/shore power available down to 10 amps. This works perfectly with my 1200 watt Honda. The generator is running and powering everything through the inverter bypass. If you say press start on the microwave and the house requires more than 10 amps the inverter will draw from the battery to support the load and supplement the generator. When the load drops the surplus is then used to charge the battery. This inverter was not an inexpensive piece of equipment like the inverters you cite. Mine is meant for boats and RVs with limited shore power.

In your case I would find a large 12V alternator and engine to charge the batteries as needed. Add some solar if you like to help keep the fuel consumption down. Under normal grid conditions you can use the solar with a zero-export inverter to power household loads.

What inverter are you using?

I'm curious too.

I got this 4,000 watt inverter but haven't tested yet. Still sorting out the battery situation.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

4kw @ 120v =33.3333 amps then add some for inverter losses so under 50 amps. 4kw @12 volts =333.3333 amps power in. Like > 2 gauge fairly short battery connections and some serious battery storage like a volt battery pack. Bet it cooks itself at those loads

Hmm, but no mention over on the diysolar site of this. Must be chineseium

yikes that a good point on the 12v amps being no bueno. I've also heard the chinesium ones can be much lower on actual efficiency when tested as well. Some times like around 80% efficiency but it all depends on load and duty cycle. Sounds like a 48v system makes a lot of sense if you get into larger stuff.

My inverter/charger is a Cotec that was discontinued. The Victron MultiPlus looks to be a good choice. https://www.victronenergy.com/invert...48v-800va-3kva

I went 24V with my inverter/charger and build a 7S battery from a Ford CMax Energi battery.

I like that cotec. Thats a nice product for a smaller system.

https://www.invertersupply.com/media...1203153059.pdf

Don't you have a garden tractor?

https://blogger.googleusercontent.co...20/ygyugui.JPG
justacarguy.blogspot.com/2023/03/i-admire-pirelli-company-they-actively.html

Who, me?

Parents have several. Dad has a 240v PTO generator. He can power things via gasoline, natural gas, diesel, or possibly even battery (has an EV).

https://ecomodder.com/forum/attachme...5&d=1554246263

Nevermind.... I guess.

When I was at a car show at the Lane County Fairgrounds in the 80s or 90s where some kids from a North Eugene high school shop class were showing their invention. It was an impeller that dropped into the bucket with hydrualic lines to spin it.

It made a concrete mixer that you could maneuver around between the piles of materials and the form or slab. I thought it was genius. Never have seen anything like it since.

These days it's all about the pump truck. I was the "hose man" for a day for my buddy who was shorthanded. They gave me the least skilled job, which still required a fair amount of skill. Pour the continuous stream of concrete from the hose to just ever so slightly more than the form, so the guys with the screeth had enough to work with, but not too much they were overwhelmed. I don't know how much I "helped".

Whole House Generator $1,700.00 and Portable
 

12,500 watt Westinghouse from Home Depot "DUEL FUEL" Generator 50 Amp power cord found a 50' cheaper than shorter ones. 50 amp plug box added to Junction Box with a 50 amp fuse with power cut off slide plate. Converted Duel Fuel to Nat Gas with an additional valve for Nat Gas hose goes where Propane hose went. Watch Florida Guys vids about fuel requirements per day and you will see why you want to convert to Nat Gas. Plenty of Utude vids to show how to do this for your house. All you lose when moving to new house is Junction box plug and 50 amp breaker less than $200. Luckily have not had to use it since "Snow-ma-gedon" in Texas!