fshr

The musings of a grumpy hairless ape

Solar & Battery

The Beginning

We’ve been wanting to get a solar system installed for a while now. Both from the point of self-generation to reduce electricity and gas bills a little, and also to try and do our bit for decarbonisation of the energy we use (particularly around gas).

Solar however isn’t a cheap investment, and I prefer to avoid borrowing money as much as possible, so it’s largely been something to do “in the future”, with little hope of actually being able to do it. However, the unfortunate passing of a family member has left us with a small block of money to spend on home improvements, of which solar is one item.

The System

I looked at a few options for solar, and there’s now a few different options on the market, but we ended up going with Heatable. Heatable work by being a “front end” to a network of installers who do the work on their behalf. You discuss options with them, decide on the system you want, they do the design, and they then monitor and guarantee the work done. It does work out a little more expensive than other suppliers, but from their YouTube channel and website, they seem to have a clue about what they’re doing and aren’t just “box shifting” kit to get it on people’s homes and get paid.

I’d been through said videos and did some research myself, but Heatable also schedule a design/consultation call to go through requirements, etc. This was actually quite useful, as the design in my head was somewhat “over-engineered” and got scaled back and simplified somewhat! From that, they provide 3 options with pricing and you simply pick the option you want, pay the deposit, and you’re started!

From the options we had, we ended up picking a system comprised of:

15 × 450W REA Power solar panels (450W each), with
15 × Enphase IQ8HC microinverters (380W each)

paired with:

2 × Enphase IQ 5P Battery (5kWh each)

That’s spec’d to give us a 6.75kW solar system with 10kWh of attached battery storage. That’s estimated to give us a total estimated annual output of around 5,250 kWh (obviously depending on weather). While that’s more than our (current) estimated electricity usage, our generation across the year isn’t going to align perfectly with our usage.

For one, we’ll generate more in the summer than winter, and more during daytime than nighttime; whereas our usage is likely to be skewed the other way, more usage over the winter and during the morning/evening. Hopefully the battery can help “correct” the day/night skew a little by charging in the day, and discharging at night, but we’ll also need to make good use of an export tariff to sell some of the excess daytime power to offset any we buy back at night. Also, we also intend to install a heat pump which will decrease (or remove) our gas usage, but at the cost of increased electricity usage.

One other advantage of the Enphase] hardware is that it has an out-of-the-box HomeAssistant Integration which should mean that both the solar and batteries will integrate nicely into my existing HA setup. It’s also a (mainly) local integration, with all of the communication taking place on the local LAN between HA and the Enphase Gateway (it does still require a once yearly connection to Enphase cloud to get an auth token however!). This should mean quicker and more reliable updates and control in HA as it’s nt doing a round-trip out to t’Internet and back (this is also one reason why I went with Enphase for the batteries as well as the inverters).

The Install

The solar install took place over (around) a week during June 2025. Out of that week, we had about 3 days actual install time, with the remaining 4 days covering the weekend and setup / removal of the scaffolding.

We have a house which faces roughly east-west, so we distributed the panels across the front and back of the house, with 8 panels on the front:

and 7 panels on the back:

The control gear for the solar system annd batteries themselves are all installed as a set on the side of the house by the electricity and gas meter cabinets:

As both solar and battery systems are from Enphase, they have a single controller (it sits in one of the white boxes) which connects to our local WiFi for management and monitoring. it does come with the now obligatory cloud portal for monitoring, but also has a local “Envoy API” which you can connect to over local LAN without needing cloud access (excepting a yearly refresh of a local API key). This then makes it relatively easy to then connect the system into…

Home Assistant

As noted above, there is a native (now Platinum) integration for Enphase which provides information on both the solar and battery parts of the system. Installed and connected to my Envoy, this gives me devices for the Envoy itself, the 2 batteries, and each of the 15 microinverters on the solar panels:

Across the devices, you get a set of entities mainly covering the power and energy stats for the devices:

Inverters - Output (W)
Battery - Charge (%) and Power (W / VA)
Envoy - Power (W / kW) and Energy (kWh) for the system as a whole, for Consumption and Production, and for Now, Daily, & Lifetime.

If you’re a bit of a data nerd, this then opens up a whole set of datapoints to play with, and colorful dashboards to build:

Once we’ve got a couple of months of solar under our belts, and hopefully (soon) some exports set up, I’ll post some more stats and info on how it’s doing.

Posted 4 March 2025

In SmartHome Solar Battery