Basic Solar Question - Consumer Unit

QrizB

I’m not convinced by the PW3. 13kWh for £7k, when you can get a 32kWh Fogstar for less than half the price.

Just to note that £3300 to Fogstar will get you a 32kWh battery:

https://www.fogstar.co.uk/collections/solar-battery-storage/products/fogstar-energy-48v-32kwh-battery-heating-fire-supression

... but most people don't want to rewire their house and replace all their appliances to run on 48V DC. You'll also need a suitable inverter and fitting.

The best fitted price I can find for a 32kWh Fogstar system and inverter is about £6k.

https://www.itstechnologies.uk/collections/sunsynk-installed-packages/products/installed-solis-5kw-ac-coupled-ai-optimised-fogstar-energy-eco-16-1kwh?variant=57873708908925

You might be able to find a better quote (I didn't spend long searching and I ignored anyone who wanted me to submit details or phone them) but it's not "half the price".

NedS

https://forums.moneysavingexpert.com/discussion/comment/81942869#Comment_81942869

Indeed, and that's with a cheap 5kW inverter whereas the PW3 includes a built in 11kW inverter, so less than half the rated output. Many will find a 5kW limiting whereas 11kW provides much more headroom to run multiple appliances at once (e.g, from our own personal experience, 2.7kW electric cooker, 3kW kettle, 1.5kW microwave, 1kW ASHP can all be on at the same time when we are cooking Sunday dinner). Try telling the wife to stop drying her hair whilst you boil the kettle to make a cup of tea!

Doesn't provide full home backup in a power cut. I won't even ask the LRA rating, required to kickstart a heat pump from battery.

I also wouldn't want to install that inverter and battery outdoors on an exposed wall where we often see driving rain and trust it to still be in good shape to 10 years. Maybe you have a sheltered location or a garage, but mine is outdoors and exposed to the elements.

In summary, you can buy a bigger capacity battery cheaper, but that's about it. If all you care about is capacity, then the Fogstar ticks that particular box.

SimonSeys

https://forums.moneysavingexpert.com/discussion/comment/81942869#Comment_81942869

https://forums.moneysavingexpert.com/discussion/comment/81942869#Comment_81942869

I seem to have touched a nerve with the Tesla fans!

Fogstar have been around for a while (a pal has a motor home electricity system designed around them plus Victron) and the plummeting battery prices mean that house batteries are now much cheaper than even a few years ago. It’s a shame Tesla haven’t dropped their prices.

There are a lot of Straw People arguments in those posts. I don’t think anyone has suggested rewiring the house to 48V. And quoting for a 2x16kWh system when the 32kWh battery I linked to is significantly cheaper is disingenuous.

I agree I need an inverter. My 9kW inverter was around £1k. For an extra couple of hundred I could have had a larger inverter if that met my needs. I thought about it but the house will never use that amount of power so I decided against it (more the size of the cable to the garage). I also paid someone to install it too.

I’m not convinced by the laptop analogy I’m afraid. This is infrastructure rather than a consumer good. A battery system is very much install it and then forget about it for me.

All in my 32kWh system was only two thirds of the price of the purchase price of a 13kWh Tesla system. My system has islanding. I have two ovens and an induction hub and it runs those fine. I can charge my EV any time of day for 9p/kWh. Currently on Octopush IOG for import and IO Flux for export. Estimated payback is around 4.5 years.

I’m very happy! And money saving!

QrizB

I seem to have touched a nerve with the Tesla fans!

I'n not a Tesla fan (although I'll accept there are times when the PW3 might be the best option). My battery is a Fogstar, my inverter a Sofar. But your post was erroneous, which you now seem to accept:

All in my 32kWh system was only two thirds of the price of the purchase price of a 13kWh Tesla system.

Two thirds is not less than half.

SimonSeys

https://forums.moneysavingexpert.com/discussion/comment/81945230#Comment_81945230

Oh let it go…

A 32kWh Fogstar is less than half the price of a PW3…

Qyburn

https://forums.moneysavingexpert.com/discussion/comment/81945189#Comment_81945189

According to Octopus you can't be on IOF for export only, it has to be both. The action of applying for IOF switches both export and import in one go. How did you swing it? I'm currently on IOF but if I could combine IOF export with Go import that could be a dream both Summer and Winter.

With that combination do you find Octopus only force charges your battery during off peak slots, or is some at day rates?

NedS

https://forums.moneysavingexpert.com/discussion/comment/81945470#Comment_81945470

As you say, IOG and IOF cannot be used simultaneously as they are two distinct tariffs.

Perhaps they mean combining IOG for mainly import in winter with IOF for mainly export in summer?

JKenH

https://forums.moneysavingexpert.com/discussion/comment/81945189#Comment_81945189

Hi, it wasn’t clear if your figures included installation.

The £7k price for a PW3 is installed and includes the back up Gateway which enables you to run solar panels when the grid is down. I appreciate that isn’t something that happens often and as a result you may feel it to be a waste of money but, like insurance, is something you buy in case it does. Perhaps not of relevance in your situation the PW3 also includes a 3 string solar inverter. If, like me, you wanted to add extra solar panels at the same time as a battery it is a consideration.

I’m not knocking Fogstar but I felt that a PW3 better suited my needs. If I was more hands on, like @QrizB, then I can see the attraction of a Fogstar which offers more storage capacity for less money.

NedS

https://forums.moneysavingexpert.com/discussion/comment/81945597#Comment_81945597

Exactly, they are very different offerings targeted at different market segments. It is not a simple like for like comparison.

pete-20-11

https://forums.moneysavingexpert.com/discussion/comment/81945470#Comment_81945470

There is a small group of people trialling IOG import and IOF export with specific types of home batteries.

Hopefully not a secret! It's being discussed in the Octopus agile forums.