Is anyone using a powerstation as a home battery for savings with Economy 7?

nappy501

Is anyone using a powerstationa s a home battery for savings with Economy 7?

I'll explain why I am considering the above.  I have been camping for decades and a couple a years ago I bought a 300w, 300Wh powerstation, portable car compressor fridge and a foldable 100w solar panel.  It last about 2.5 days without sun, but then, I get enough sun to charge it up.  This isn't always the case though.

I am now considering getting a larger powerstation maybe 1000Wh, which would take away any anxiety about running out of charge.  Powerstation have come down in price. However, I'm not sure I can justify using it 4 to 6 times a year.

But then I thought, maybe I could use it at home everyday.  I could charge it up on the Economy 7 rate and then use it during the day.  I would create extra saving and unplug and take with me when I go camping.

So I have done some investigating;-
I'm with E.ON Next paying 25p day rate and 10p night rate.
10/1/2024 Annual day rate 630.7
                               night rate 478.6
                                  TOTAL  1109.3 kWh

7/1/2025 Annual day rate 555.5
                             night rate 457.2
                                TOTAL 1012.7kWh

111kWh/365 = 3.04kWh per day
 630kWh/365 = 1.73kWh used on day rate daily

With a discharge ot 20% I would need 3.85kWh powerstation for 24 hours or 2.2kWh powerstation to cover the day rate hours.

Is anyone else doing this?  They call it 'peak shaving' in USA.  I'm now hovering between buying a 1000Wh and 2000Wh powerstation.

Why am I not going for a fitted home battery system?  I intend to move in the next couple of years.  My house has slate tiles and is north facing, which is why I haven't considered solar panels in the past.  If it is fitted permanently in the house I can't take it camping.

The price increase from 2000Wh to 3 to 4,000Wh is a big leap. And I have no idea how to feed into the lighting circuit, so I wouldn't be running them from the powerstation.

I intend to move

Swipe

I looked at this and didn't feel confident plugging my fridge and freezer into it. So for general appliance usage plugged in directly, I calculated that it would be time for a new power station by the time I had broken even.

QrizB

There was someone a few years ago(2021 maybe?) who fitted a storage battery to his all-electric E7 flat, for much the same reason. I thought his idea had merit but (with electricity and battery prices as they were then) he was looking at a 7-8 year payback and the anti's were scathing.

We then had the energy price spike that we're still in the tail of. I suspect he will have broken even by now.

Anyway, back to your question. You might want to take a look at the EcoFlow Stream range of plugin storage batteries.

MforumSManE

Good idea in theory but.

What and how are you going to plug in everything that consumes power during the day, assuming you are not going to connect it to your main distribution board with a changeover switch as pictured, you’ll have extension leads all over the house and the manual plug in process per day. Also sounds like a fire waiting to happen not to mention the trip hazard.

nappy501

MforumSManE said:

Good idea in theory but.

What and how are you going to plug in everything that consumes power during the day, assuming you are not going to connect it to your main distribution board with a changeover switch as pictured, you’ll have extension leads all over the house and the manual plug in process per day. Also sounds like a fire waiting to happen not to mention the trip hazard.

The majority of my electricity usage is during the night rate, so those appliances would remain as is. My main oven, washing machine and air fryer are all used on the Economy 7 rate.  During the day rate is the electricity to the gas boiler, fridge, freezer and lights. The microwave may get used for 2 to 3 minutes during the day.  I am only thinking of one in the kitchen to start with.  The cable run would be about 2 metres.

nappy501

Swipe said:

I looked at this and didn't feel confident plugging my fridge and freezer into it. So for general appliance usage plugged in directly, I calculated that it would be time for a new power station by the time I had broken even.

I understand the worry regarding the fridge and freezer, but I feel more confident because of using my little portable compressor fridge with the powerstation whilst camping.  Initially, I was continually checking the powerstation and fridge that they were still on. Now I don't bother until the second day if there hasn't been much sun.

nappy501

QrizB said:

There was someone a few years ago(2021 maybe?) who fitted a storage battery to his all-electric E7 flat, for much the same reason. I thought his idea had merit but (with electricity and battery prices as they were then) he was looking at a 7-8 year payback and the anti's were scathing.

We then had the energy price spike that we're still in the tail of. I suspect he will have broken even by now.

Anyway, back to your question. You might want to take a look at the EcoFlow Stream range of plugin storage batteries.

Thank you.  I'm off to have a look, but I didn't think they were portable?  I would still want a powerstation for camping.

wrf12345

Wiring a separate circuit, 0ff which you can run appliances and table lamps might be the solution, if the amperage in total is less than 13amps you can just plug the circuit into your existing circuit when the battery runs out. Really depends if you can group everything along one wall (even if the kitchen is on one side and the lounge on the other) and do a single run with max wattage of everything at less than 3000 watt (an 800W microwave probably uses closer to 1500W, BTW), or at least remember not to use everything at the same time. Cost for the circuit would be less than twenty quid including new sockets etc and would not be classed as a new circuit as it would be connected to the mains circuit as an "extension lead" when not connected to the battery.

QrizB

nappy501 said:

.  I'm off to have a look, but I didn't think they were portable?  I would still want a powerstation for camping.

I.mean, you can pick them up and put them in your car. So by definition they're portable.

The AC Pro has a 240v UPS outlet, haven't checked the other models.

I guess it depends whether you'd rather have a camping power station that you can use at home, or a home one you take camping. I was imagining that you were looking for one to use at home for 40 weeks of the year and camping for 2 weeks, which would bias me towards something like the EcoFlow Stream. If I've misjudged your needs, yes you should look elsewhere.

Ectophile

If you buy a 1000Wh battery, then even if it is 100% efficient - and it won't be - you'd shift 1kWh from day to night each day.  That's 15p.  How many lots of 15p do you need to buy a new power bank?

But it won't be 100% efficient.  You'd be lucky to save more than 10p per day.

mmmmikey

nappy501 said:

Swipe said:

I looked at this and didn't feel confident plugging my fridge and freezer into it. So for general appliance usage plugged in directly, I calculated that it would be time for a new power station by the time I had broken even.

I understand the worry regarding the fridge and freezer, but I feel more confident because of using my little portable compressor fridge with the powerstation whilst camping.  Initially, I was continually checking the powerstation and fridge that they were still on. Now I don't bother until the second day if there hasn't been much sun.

Hi - I've done this, sort of. I had a campervan with a 2kWh of Lithium batteries, inverter and charger which I kept when I sold the campervan and now use for home use. Does it save money? Yes, a little bit. Would it ever pay for itself if I had bought it for this purpose? Not a hope in hell. Sorry to be so negative, but best to be straightforward about a few things. There are a number of pitfalls, for example:

1. The fridge you are using while camping sounds like it is a 12V model if you use it in the car? If that's the case, and assuming you're using a 240V regular fridge at home, you're not comparing like for like. The powerstation battery will likely happily cope with the inrush current when either of them kick in, but there's a good chance the surge current will trip the inverter (i.e. the thing that converts the battery voltage to mains voltage) if you use it with a domestic fridge. Not necessarily the case, but the powerstations with big enough inverters to cope with starting up a fridge compressor are the big expensive ones. 

2. Following on from the above point, in terms of efficiency, you have to think about the inverter standby energy, which could easily be as much as the energy of the fridge - about 300Wh per day each for fridge and inverter in my case (although I do have an efficient fridge so yours might take more). This makes small powerstations horribly inefficient for running something like a fridge because you need the inverter to be on standby permanently so it's there ready for when the fridge kicks in. By the time you've added in the inverter overhead, you can find yourself using 600Wh per day to run something that uses 300Wh per day - i.e. 50% efficiency. Depending on your tariff you can still save but it crushes the economics to the point where you may only be saving 1p or 2p a day or maybe £5 or £10 a year.

3. If you're on an "extreme" TOU tariff like Agile which has very high highs and very low lows you can improve the economics. And you can also improve the economics by not using the inverter. For example, you might be able to power a broadband router using a 12V supply and appropriate voltage regulator. This is one of the things I do, and coincidentally my broadband router also uses about 300Wh per day.

So it can be a fun project if you're into that kind of thing and if you've got one anyway you might as well take any saving you can get. But the bottom line is that this isn't likely to save you an amount that is of significance in relation to the cost of the powerstation.

Hope this helps in some way - if you have any specific questions, do ask. 

EDIT: for clarity, I have no knowledge or experience of the EcoFlow Stream products so what I'm talking about is the "Jackery" type units that are typically used for camping.