My energy back-up

Something I’ve not seen discussed here recently (or often) is having an energy/battery back-up. I think it’s probably fairly common for folks to have a UPS type backup for short outages. But what about hours or days? A couple of months ago we had a tornado pass through our area which had a direct hit on the main office of our local electric co-op and just a few miles away another hit on an electrical substation. I was one of the lucky ones and only lost power for 3 days. Others were out for many more days. It’s not uncommon in our area to have a short, multi-hour outage once a month and longer, day-long outage a couple times a year, usually due to severe storms with strong winds.

I’ve got a UPS for my MacMini that ensures a safe shut-down but for longer outages I decided I wanted a bit more and thought I’d share what I’ve come up with and what it will do for me in the case of day-long or multi-day power loss.

My budget was between $500 and $1000. The goal was to be able to power a few lights in the evening, keep the internet on and keep my iPad and iPhone charged and to do this for 2-3 days and with careful use perhaps 4 days. I use a well so this would not get me water, cooking, heating or cooling. The initial goal was just creating a base level comfort of lights in the evening and access to the internet and computing with the iPad and iPhone.
After a bit of research I decided to go with the Bluetti EB70 which sells for between $500 and $600. Currently $600.

At around 650 usable watt hours this backup will let me power a 6 watt string light, 10 watt bulb, 5 watt hotspot, 15 watt small table-top fan for a total of 36 watts per hour. At 5 hours a day that’s 180 WH per day, so 2 days is 360 WH used. So that leaves just under 300 WH for charging the iPad and iPhone. Three full iPad Pro charges would be around 120 WH and two full iPhone charges would be around 24 WH. That leaves just around 150 WH.

So, two days would be pretty doable. With more careful use I could probably stretch to three days.

One of the considerations in this kind of battery back-up is charge cycles. I went with the Bluetti because they are Lithium Phosphate cells which mean 2500 cycles compared to Lithium-ion which is are likely in the 700 cycle range.

In thinking about how many watts this category of device can output at any given moment, it’s important to note they’re usually 800 watts or less so no high energy device… no microwaves, coffee makers, etc. But it can handle quite a few low energy devices (up to 800 watts for this particular unit). So, if I only needed power for a day I could not only run a couple lights and charge my iPhone/iPad but my smallish energy efficient fridge only pulls around 40 watts so I could also run that for a few hours. Or, I could run my smallish TV, AppleTV, 2 HomePods.

In testing my set-up I plugged in several lights, the small fan, AppleTV, TV, 2 HomePods. I ran the lights during the afternoon and in the evening added the TV, AppleTV, AirPort Extreme and HomePods for 2 hours. That full load, all attached to a power strip, is only about 100 watts, so, not much, not even close to the 800 watt capacity. In addition to the 4 standard AC plugs, there are also 2 100 watt USB C ports, USB A, and a spot on top for wireless charging of a phone.

These units can be charged up via a standard wall outlet in 3-4 hours, a car takes several hours more or a solar panel. I opted to also get a 200 watt rigid solar panel

What does the solar panel get me in practical terms? The Bluetti EB70 will only take in about 150 watts from this panel which means on a sunny day it will fully recharge in 5-6 hours. This changes though based on cloud cover and time of year/angle of sun. They will, assuming at least a few hours of sun, give me indefinite (though still carefully moderated) power supply of 650 WH per day.

This panel cost around $220. I also added an extra 50 feet of cable so that I can charge without moving the battery so that’s additional cost. It’s just plug and play. I securely attached the panels to my south facing porch, plugged the cable in and ran that into my tiny house and plugged it into the Bluetti. 10 minutes.

Solar charging on a mostly clear winter day, around 2pm, 131 watts from the sun.


There are other solar panel options including portable folding panels. Bluetti offers two different folding panel options geared towards mobile use, both at significantly higher cost than rigid panels from other companies. As I expect to use this primarily at my tiny house I chose a rigid panel for lower cost.

My last consideration for a future change is that at some point I’ll need to replace my 2012 MacMini. I’d previously planned to replace it with another MacMini but now plan to replace it with a MacBook Air. The reason being that my general set-up is that the Mac shares internet: Hotspot to Mac via Wi-Fi which shares via Ethernet to the AirportExtreme which then shares to all my other devices via Wi-Fi. The MacBook Air would be a better solution during a power outage as it would not affect the internet at all even if some of the HomeKit devices would be offline. The hubs and a few lights would just continue with no affect at all.

Anyone else have additional energy back-up?


Just a note that an automotive inverter is even more budget friendly, if you have a car with a full gas tank (or the ability to get gas, like a more localized outage where gas stations 10 miles away may be open) and are primarily using devices with batteries.

Or a less elegant solution - a parallel set of deep cycle auto batteries and an inverter would likely result in more power per dollar spent and higher power output if necessary.

But that Yeti thing is definitely slick - and it’s a nice, done-for-you package. :slight_smile:

Yeah, I thought about a more DIY set-up. In that case I’d also have to add a charge controller and an inverter. The nice thing about these new units is that they have the controller and inverter built in. Also, the lifespan, safety, no maintenance of the lithium phosphate battery is nice. It is a pretty slick, plug and play package.

How long do they figure the battery is goid for, chronologically?

They say 2,500 charge cycles. Not sure if that’s what you mean by chronologically though.

I panic-bought a dual-fuel generator and a couple of propane tanks the last time we had a long outage.
I like propane because it doesn’t ‘go bad’ or need stabilizer like gasoline. If things get weird, I can also use gasoline or propane, whichever I can find.
I don’t as yet have a way to connect it to the house (people usually use dryer plugs or transfer switches), so it will be extension cords if/when we need it.

I also have a couple of UPSs (one, two) that are good for a few minutes (they have a lot of load, NAS, iMac Pro, monitors, etc.).

Not sure the weather situation where you are @Denny, but one of the problem we had when I was a kid is the power would go off, then the pipes would freeze because we had well water, and it was a whole big situation of replacing pipes, etc. that went on for days.


This hits one of my non-tech stress issues… Where I live (lower Delaware), the water table is so high that in any significant storm, our sump pump starts going. We have a pretty strong battery backup (it actually lasted about 12 hours through a power outage, running more than once a minute), but just knowing that a flooded basement is a very real possibility makes me periodically consider a generator solution.

I’d recommend the Interlock approach over the dryer outlet approach. Both work, but one significantly reduces safety risks. I’m not one to go over the top on safety measures, but 40A 220V power is no joke.


We bought a house a year ago that had a whole house generator installed by the previous owner. It’s powered by our natural gas connection. Since living here we had had 3 or 4 short outages of less than 30 minutes and two longer outages of more than 5 hours. One was a traffic accident and the other was storm damage.

With the backup you still have an outage of a few minutes while it starts up and switches power over. To handle those periods, most of our computer gear and internet connection are on UPSes that cover about an hour.

In one case we were out to dinner and returned to the generator running. It wasn’t one of the times when itself so we realized the power was out. I have one UPS setup to email me when there’s an outage but hadn’t checked my mail.


That’s the ultimate!
If we had that many outages, it would be more attractive. As it is, I bought our generator in Oct 2020, and it’s run a total of maybe 10 minutes when I made sure it works :slightly_smiling_face:

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Maybe tomorrow it gets a real workout! (I’m not hoping for it, but I’ve got mine gassed up and ready to go :wink: ).

Agreed that whole house is the ultimate - our friends that have them swear by them. In our case, it just didn’t make sense given how close we could come to all the advantages with the “portable” one we bought.

I have all my electronics on UPSs that last between 1-4 hours depending on the item. Our modem, router, and switch could run for about 3 days on the UPS I have for them. I also did the “surgeries” to remove the beepers from inside so they’re silent when they kick on. Then I put all the white noise machines and bedroom fans on battery backup as well.

Of course, the power hasn’t gone out since I did all this 2 years ago.


We’re getting an EV truck for that. Well, it’s not the primary reason but it does have multiple 120V outlets that we’ll be able to use in an extended outage.

At some future point it’s also supposed to have vehicle to house capability so that we can also use it like a generator. We’ve had multiple extended outages this year already so I’d love to have that sooner, not later, but we’ll settle for getting the truck first.


Yeah, I’m in mid-Missouri. It’s becoming less of a concern in terms of the longer stretches of very cold weather. But it’s on my radar. In a power outage I’d use/drain the water in the lines into a storage tank which would leave them mostly empty or near empty and, I think, there’d be much less of a chance of freezing/bursting in that case? Otherwise, I could run a small propane heater in the well house portion which would be the most likely to freeze during an outage. I’ve not had any issues (when I have electricity) as it’s all heat taped, insulated and the small well house itself heated efficiently (using a HomeKit temperature sensor and smart plug!).


Like a boss!


I’d love a MPU episode on this stuff…


Lithium Iron Phosphate batteries are dropping in price faster than just about any other component. Covid and supply chain issues have slowed things down a bit but the trend should pickup again soon enough.

I’m thinking about getting a backup system for the computing stuff but the ultimate goal will be backing up the entire house and my path will likely be PV/ESS mated to an EV with V2X (Vehicle to Grid/Home/Load) functionality.

In Arkansas we have the same 'nado issues that can knock out power at any given time and i’ve already dealt with irrigatation pipes bursting after a freeze. So i’m trying to fortify as much as I can.

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Does an EV actually have the power to run a whole home for an extended period of time? Or would that be for limited “essential” types of things?

A Tesla Model 3 long range has a 82kwh battery. If you can do without air conditioning, figure on 3-5 kw for typical stuff. Should hold you for 15-20 hours. If you drop usage to just refrigerators, lights, tv, computers, and internet then probably a couple of days.

The Ford F-150 Lightning (not out until May, and if you haven’t ordered yet you can’t get one…) can power a whole house for days.

It’s a “fun” approach, and helps justify the cost of the larger EVs, but it’s not justifiable economically for that purpose or for most people.

A tri-fuel generator that can power almost everything in your house (e.g.not A/C, not electric heat pump) is $800-900. Another $200-$800 (DIY or electrician) gets it connected to your panel. For under $2k (in some cases well under it) you can power all the essentials.

Plus you have the flexibility of either three fuel options (gas, propane, natural gas), or you can connect it to your NG line if you have one. Unless your battery powered generators are very large, and powered by solar (and you have lots of solar), they come out environmentally neutral or worse than standard generators.

I just want to add that I’m very pro-EV. We own one, and if I could have afforded/justified the Lightning or Rivian, I’d have gotten one in a heartbeat.

IF you’re buying one anyway, why not get the extra use out of it as a generator. BUT, while YouTube reviewers who get free ones love to praise battery-based generators, there’s just no comparison in cost, functionality, or longevity between battery based systems and more traditional generators.

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