Battery Powered Furnace

[marko]

Interesting/ironic thread for me. People here talking about how to keep their furnace running when the electricity goes out.

In my neck of the woods the serious talk is about how we need to remove our gas/oil furnaces and replace them with electric heat.

 

[ncbill]

You could make this work. The biggest obstacle seems to be figuring out how the system is powered so you can attach a single source to power it.

You can buy a hundred amp hour lithium battery, a pure sine inverter, and a charger for the battery so you can charge it off the generator if you need to go additional nights. It might be cheaper to buy the small generator and make a weather tight / theft proof place for it to sit and run.

Instead of futzing with separate: battery pack made up of raw cells, charger, inverter (remember, any raw lithium-iron battery pack will also require a BMS for safe operation) I would buy a pre-assembled solution like:

https://smile.amazon.com/EF-ECOFLOW-Expandable-Generator-Emergency/dp/B09D7N1ZV8/

Use it overnight so you can shutdown & move your portable generator inside to prevent theft then recharge the above during the day.

 

[joesxm3]

Several posters seem to have missed the fact that I already have an 8000kw generator wired in to be able to flip the transfer a switch and select which circuits I want to run.

I live in an area where kids cut catalytic converters off of cars and one time stole the tires off a car in the middle of the afternoon with the people home. I had my house broken into as well.

I guess if you live on a ranch and have a backhoe and lots of bags of lime, thieves think twice

 

[old medic]

I guess if you live on a ranch and have a backhoe and lots of bags of lime, thieves think twice

Well I do have a backhoe....

 

[travelover]

Instead of futzing with separate: battery pack made up of raw cells, charger, inverter (remember, any raw lithium-iron battery pack will also require a BMS for safe operation) I would buy a pre-assembled solution like:

https://smile.amazon.com/EF-ECOFLOW-Expandable-Generator-Emergency/dp/B09D7N1ZV8/

Use it overnight so you can shutdown & move your portable generator inside to prevent theft then recharge the above during the day.

The battery I linked had a built in BMS. All the device you linked has are the same components in a plastic box at a much higher price.

 

[street]

Several posters seem to have missed the fact that I already have an 8000kw generator wired in to be able to flip the transfer a switch and select which circuits I want to run.

I live in an area where kids cut catalytic converters off of cars and one time stole the tires off a car in the middle of the afternoon with the people home. I had my house broken into as well.

I guess if you live on a ranch and have a backhoe and lots of bags of lime, thieves think twice

Sorry, I did miss or forgot about the Gen you mentioned. No need for a backhoe and lime here. We live here the old fashion way, by trust, honesty and integrity. Lol

Good Luck and hope you find your answer.

 

[ERD50]

Originally Posted by ERD50 View Post
First step - find out how much current the furnace draws on average, and max. Then you can size the battery and inverter to match. Those pumps and maybe a fuel pump and electronics probably don't draw all that much.
-ERD50

I would be more concerned it would draw more. you most likely have at least 4 120V pumps,pushing water not air, the burner ignitor and fuel pump. Add a 12 volt transformer for the thermostat and controls on top. If thats all running off one breaker in the panel then your idea could work. Personally would go the generator route.

No, not at all. The fan in a home forced air furnace is typically ~ 3/4 HP, maybe ~ 7 Amps @ 120V, ~ 750 watts after efficiency, and the size of maybe a 2 gallon can?

I recall seeing the pumps on my folk's hot water system, they were small - the links I found showed them to be 1/25th HP, and < 100 Watts.

Water holds so much more heat than air, you need to move less of it - and in a closed system, it's just the friction losses. The fuel pump is likely in that range and ignitor (runs a short time) and thermostat are minuscule.

-ERD50

 

[Out-to-Lunch]

No, not at all. The fan in a home forced air furnace is typically ~ 3/4 HP, maybe ~ 7 Amps @ 120V, ~ 750 watts after efficiency, and the size of maybe a 2 gallon can?

I recall seeing the pumps on my folk's hot water system, they were small - the links I found showed them to be 1/25th HP, and < 100 Watts.

Water holds so much more heat than air, you need to move less of it - and in a closed system, it's just the friction losses. The fuel pump is likely in that range and ignitor (runs a short time) and thermostat are minuscule.

-ERD50

I have one-pipe steam heat. I could probably run it for weeks off a couple of disposable consumer batteries!

 

[ERD50]

I have one-pipe steam heat. I could probably run it for weeks off a couple of disposable consumer batteries!

I only recently learned how one-pipe steam heat works. At first, it doesn't make sense, you need a loop for circulation, right? Wrong! Well, not wrong, but there are different ways to create a loop.

Basically, the steam flows up, it condenses as it cools, and the water flows down (passing the steam on its way up, in the same pipe). So two-directional flow in the same pipe. Pretty clever.

-ERD50

 

[Out-to-Lunch]

I only recently learned how one-pipe steam heat works. At first, it doesn't make sense, you need a loop for circulation, right? Wrong! Well, not wrong, but there are different ways to create a loop.

Basically, the steam flows up, it condenses as it cools, and the water flows down (passing the steam on its way up, in the same pipe). So two-directional flow in the same pipe. Pretty clever.

-ERD50

Yup, you nailed it!

If anyone ever needs to take a deep dive on this, I highly recommend this book: "The Lost Art of Steam Heating" By Dan Holohan. (https://www.amazon.com/Lost-Art-Steam-Heating/dp/0996477241/)

 

[ncbill]

The battery I linked had a built in BMS. All the device you linked has are the same components in a plastic box at a much higher price.

Higher capacity battery, though it's also more expensive because it's designed to recharge quickly from multiple inputs, including directly from solar panels (w/o the need for a charge controller)

A homebuilt system would also need wiring (@12VDC that means expensive, heavy-gauge wiring) plus all the appropriate disconnects (both circuit breakers & t-type fuses)

 

[CaptTom]

You could make this work. The biggest obstacle seems to be figuring out how the system is powered so you can attach a single source to power it.

Typically there's one circuit breaker for the boiler. (You have a boiler, not a furnace.) There should be a shut-off switch too, often at the top of the cellar stairs if it's down there, and/or near the boiler itself.

Assuming that was all done correctly, that should be your one source which powers the boiler burner, zone pumps and zone controller. The thermostats are likely 24 VAC from a transformer, either separate or in the zone controller.

You most certainly could power the boiler circuit from a suitably-sized battery bank and inverter for a little while. I'm not sure it's worth the effort though. Building a doghouse for the generator seems like it would be easier and cheaper, with less maintenance and a longer lifespan.

The biggest benefit I can see for battery backup would be short-duration outages, especially at night. It would buy you time before you had to go out and fire up the generator.

The ideal would be an inverter/charger with a built in transfer switch so you don't have to go mess with plugs or transfer switches. That's what we do in boats, not sure if that would be code compliant in a house.

 

[Sunset]

..... No need for a backhoe and lime here. We live here the old fashion way, by trust, honesty and integrity. Lol

...

We don't live near you.

We had a lawn sprinkler stolen off the hose because I left it out one night.
We put our vehicles in the garage at night, so we are not one of the nextdoor folks complaining about someone stealing things out of the car, or just stealing the car.

At my cabin for decades myself and neighbors would leave boats & motors tied up to the dock for a week when gone, and of course all summer long when there.

Last few years someone has stolen a tied up boat right from a person's dock, or a boat put up on land for the Winter is gone the next Spring.

Unfortunately, I think for pretty much everyone, the culture is changing and not for the better.

 

[Texas Proud]

That sounds like a good idea. A dedicated plug would make it totally safe unless the battery somehow explodes.

My friend said that the battery costs about $1000, plus the inverter and electrician.

The advantage compared to having to haul my generator out onto the driveway in the middle of a blizzard would be obvious. Having a permanent automatic generator would provide the save convenience. I paid $1400 for the 8kw generator and $800 for the electrician to do the wiring. Maybe it would have been better to just have bitten the bullet and paid the $6000 for the big generator setup back then.

According to how big a generator you wanted... my sister and I both bought 20KW ones... hers was $10K and mine $12k for generator... I had a lot longer gas run... I also had to cough up some more money to have a gas step down installed for the hot tub since I had to get a high PSI gas meter... from what she has heard from friends getting quotes now it is more expensive...