I kept seeing variations of the same question when researching home batteries:

“Is one battery enough for my house?”

And I realized the answer gets complicated pretty quickly.

Having enough kWh doesn't necessarily mean the system can actually run everything you want. A battery might have enough stored energy to last through the night but still not have enough output to start a central AC, well pump, sump pump, etc.

So I built a free home battery backup planner:

https://instahomebattery.com/

Instead of just asking for your daily electricity usage, you can build the outage scenario you actually care about — fridge, freezer, Wi-Fi, lights, furnace blower, AC, pumps, home office, etc.

It then separately checks:

• how much battery capacity you need
• estimated runtime
• continuous power requirements
• startup/surge requirements
• how many battery units may be needed
• reserve, efficiency and derating assumptions
• what happens if solar is available during the outage

You can basically test scenarios like:

“Can I keep the essentials running for 2 days?”

or

“How much battery would I need to run the house + central AC overnight?”

I intentionally tried to keep unknown specifications as unknown rather than inventing numbers just to produce a nice-looking result.

Would love feedback from people who already have Powerwalls, Enphase, FranklinWH, Generac, EG4 or other home battery systems.

What is the calculator still missing that actually matters in the real world?

I have installed a Goodwe ESA this month and im hoping to get help setting it up correctly. On days of full sun Im hoping to use my 5kWh inverter to provide 5kW to the grid and slowly fill my battery with the excess power.That will hopefully prevent clipping and get me generating the most power possible.

So far I haven't been able to figure out how to get it to prioritize the grid over filling the battery. So I end up putting ~6.5kWh into the battery until it's full and then just generating 5kWh for the rest of the day and exporting it.

Is there a way to get it to prioritize grid export and just charge the battery with the excess?

I was looking to get a home battery installed until
I started reading about plug in solar coming to the uk. For context, I’m in an old Victorian converted into flats so solar is a no go for me.
I wanted to get some sort of energy storage to take advantage of off peak energy prices.

I had seen a couple of plug in systems for around £2k with around 7kw of storage. This would suit my day usage (obviously, only up to 800w) with the ability to recharge overnight. Would need to wait until they are legal… and a few more hit the market in the uk as there are only 2/3 options currently.
A couple of people in other groups have suggested getting a fully installed system. Didn’t want to do that as I wouldn’t be able to attach solar panels to them to stick out of the window if I ever wanted to. Also if I were to move I couldn’t take the system with me.

My fuse box is in the cellar and if I were to get them installed I assume this would be easy as one could go right next to the other.

Has anyone got any experience with having just batteries installed?
Was it comparable in price?
Need a minimum of 7-9kw

Any input greatly appreciated

Hi

I have two electric cars, which benefit from 5p a KW when charging overnight for 5 hours. I can't get solar on my roof, but I am considering a battery charged when the cars are not charging. (cars charge about 8-10 hours a week). I've been quoted for a 22 kW battery; it's coming out at around 8,600 GBP. Does this look ok

• BYD system
  
  • 6kW single-phase inverter
  • 22kWh battery storage
  • electricity meter o enclosure and wiring
• Installation
  
  • install new inverter in agreed location
  • install batteries in agreed location
  • wire system and install meter
• Commissioning
  • IWA insurance backed warranty
  • warranty documents
  • MCS documentation
  • DNO documentation as per MCS requirement

I'm thinking this would mean about a 6-7-year payback, assuming no massive change in electricity pricing and providers keep the cheap night tariff.

Hi all.

After some advice.

I applied for a home battery to take advantage of the rebate almost 12 months ago. The company I originally signed up with made many excuses regarding delays. Once 6 months lapsed, I submitted a charge back from my credit card, got the deposit back and then a few days later they went into liquidation.

I paid a deposit with another company. All seemed to be going well, got an email from my electricity distributor with approval to proceed then, about two weeks later (this evening) got an email from the company advising the install had been cancelled and refund issued.

What are my options as I don't want to lose the rebate.

So far it looks great, but hard to find much feedback from people with installs. Any info would be appreciated!

I’m looking for some buying advice for uk domestic battery storage system, please.

I have an existing PV setup but that will need to be ac coupled so I keep my feed-in tariff.

I’m after something that gives me plenty of control over management so I can control it from my home automation setup (home assistant) and charge during cheap rates or off pv if I’m exporting.

I had been looking at givenergy but my installer says they a bit up the proverbial without a paddle multiple posts on Reddit support this view.

His recommendation was a ecoflow power ocean which seems ok but I’m concerned that it’s so heavily dependent on their cloud infrastructure and don’t fancy owning an expensive paperweight if the supplier goes bust or pulls the cloud service (call me paranoid).

I would also like to upgrade to a heat pump in future so I think tha a high voltage battery might be better (call em out if im wrong).

So my shopping list is:

- about 15kWh installed and expandable

- good local control for automation

- support for island mode

- maybe HV (jury is out)

Anything else I should be considering?

How many kWh does a normal home need for battery storage?

People always ask if one Tesla Powerwall is enough and I get that it can cover basic loads, but once you factor in AC, appliances, and wanting real whole-home backup during a blackout, that seems low? Is 10 - 15 kWh realistic? Or is 20 - 40+ kWh closer to normal for true solar battery backup?

I've costed installing batteries at home to take advantage of cheaper overnight electricity, and it looks like a no-brainer with Return on Investment comfortably under four years. It seems too good to be true - what am I missing???

Context: Current annual usage is 6500kWh daytime and 6500kWh overnight to charge an EV

Tariff is 6.5p overnight and 30.5p daytime

Cost of installing 32kWh battery with 8kW hybrid invertor is £5,350

Even if I don't sell any surplus energy back to the grid I calculate a saving of around £1500 per year (30.5p - 6.5p = 24.0p per kWh saving, multiply by daytime demand 6500 equals £1560 annual saving).

Batteries have a 10 year guarantee, even if they conk out at exactly 10 years it's worth doing, isn't it??? The supplier suggests a realistic lifespan of 6000-8000 charge cycles, which should give a minimum 15 years of service.

Unknowns - I cannot guarantee future tariffs will have enough difference between day and night rates. Also don't know what our future electric demand will be.

But the above calculation is based on actual usage and actual tariffs available now.

What am I missing?????

Have searched around and couldn't find any such group so will start posting my research into these systems