Hmmmm... Our #solar battery provider is offering to upgrade our unit.
Going from 2kWh to 4.8kWh.
Total cost including installation will be £2,900!
That's expensive. But cheap for a battery of that size.
Our old battery is about 8 years old, and getting a little temperamental. But still basically works.
But bigger capacity would mean being able to export more when energy prices are high.
They're here!
2x US2000 batteries and a smart controller - ready to be installed.
Will more than double our #solar storage capacity.
And, come winter, we'll be moving on to a smart tariff which will charge them from the grid when electricity is cheap - and discharge when it is expensive.
Hopefully these will one day be cheap enough to store a full day, week, or even month of juice.
New Moixa #solar battery installed.
Should be able to store 4.8kWh.
Ethernet connected (WiFi too, if I want) so it can receive instructions on when to activate.
Little info screen showing basic data.
Currently soaking up the sun, ready to power our home after sunset.
@Edent That would be good. If you could write a review about your battery experiences, that would be great. I'm always looking for decent, open solar systems. I couldn't find one, so I bought separate parts - battery, charge controller, inverter and connected them together myself. So far my choice of inverter has been the most disappointing.
@Edent@solar Until now I hadn't realised your roof was east/west. We have an east/west orientation and I'd always assumed we wouldn't generate enogh to be worth it, but you get rather more than I expected. I should probably take another look at getting some.
@Noneeeed Yup!
There is an efficiency hit. But you probably use more electricity in the evenings, so you get to use more generated by the west aspect.
Some installers are a bit sniffy about it - but it works perfectly for us.
@Edent That's a really good point about the evening western aspect, I'd not really thought about that. We need to have our roof replaced (terrible 1960's asbestos slates that are failing) so this might need to wait for next year once the finances recover.
@Noneeeed
Personally, I'd get it done at the same time.
A large part of the install cost is scaffolding and labour.
Our panels are inset - they removed tiles so they'd fit. So it is possible to replace simultaneously.
Obviously, I don't know your finances - but I think it is worth investigating.
@Edent I did think about that. Organising a roofer to turn up has been hard enough, getting them and a solar installer (plus the electics) to all coordinate might actually break me :D Worth investigating though.
Battery got to about 95% full yesterday.
Started discharging at about 20:00.
This morning it is 30% full.
That's consistent with our home's ~250W idle usage.
Our electricity costs for last night are £0.00. Which saved us about a quid.
At current prices, this battery will pay for itself in 7 years (obviously it is a lot more complicated than that.)
@Edent Only 250W? When you say “idle” you mean with the lights off and nobody home, all electronic devices in standby mode? I thought the fridge would use more than that.
@ratkins All devices in standby, and us tucked up in bed.
The 250W is an average. We got the most efficient fridge/freezer we could. I'm sure it occasionally spikes higher than that, but only briefly.
@johnmclear@ratkins
I have a server running 24/7, smart home bridges, zigbee bulbs, fridge/freezer, separate freezer, various consoles on standby, alarm system, etc.
I'm not exactly living a frugal life.
Took 6 hours to charge the battery from 35%-100%.
Fairy standard WFH day - lots of computer use, but no domestic appliances.
Going to use the oven and see how quickly the battery responds to increased power use.
Hopefully eating #solar cooked pizza tonight 😆
@Edent I wish for EU legislation (sorry, I know, too soon with Brexit) that forces companies who run devices on local networks to open up their protocols, so you can still use/own your devices once the company cloud services close. I can’t connect to my EV charger at all other than through their sucky app (https://gist.github.com/tomayac/754284dd79e20147f482d932ed89f2a1), and my solar panel gateway is accessible locally, but gated on a cloud login (https://github.com/tomayac/enphase-solar).
@tomayac TBH, I think that's a consumer thing. You should have purchased a device which met your needs.
That's why I chose a specific solar inverter - because I knew Fronius had excellent local support.
I could have paid extra for a battery with a direct API - but I'm happy working around that.
@Edent Partly agree. With the solar material and installer shortage (at least here), it was a bit of a compromise between getting reasonable stuff now, or your dream configuration never-ish. Also not all installers are happy to install “not their” stuff. The EV charger was a bit of a surprise “gift” from Hyundai that came with the Kona, so no choices there.
@Edent
We are new to the solar and battery world, but I can already see that the batteries are crucial to reducing our energy costs
Being able to charge the batteries for 1/3 the cost of normal grid electricity is a huge advantage when there isn’t enough solar generation for all our needs
@Edent Now that I’ve actually used our Solar PV setup for six months, we could easily get away with a 5kWh storage installation, because our import rarely exceeds that.
Many companies were quoting us for twice that capacity when we were looking at a combined installation.
@Edent is that in a porch or similar external-ish place?
I’ve been thinking about getting battery storage (and solar) installed, but have some safety concerns about having a big lithium pack in the house! Do you know if having them somewhere outdoors-ish has any adverse effect on the battery performance with ambient temperature fluctuations?
Do home insurance companies care about you having battery storage?
@edward
Ours is in a porch because it makes noise. There are fans, relays, and an inverter all humming away.
Batteries don't like getting too hot or too cold - depending on the technology used.
You can get weatherproof outdoors batteries.
I don't know what your home insurers think - speak to them directly.
@Edent I have a 5kwh battery set with a 4.2 kwp panels. I am considering getting one more unit to have 7.5 kwh batteries.
We do a mix of partial charge during cheap night tariffs and export in the afternoon once battery is full. More battery would mean I might not need to import anything outside of the cheap night tariff when sun's visible lots.
@Edent What's the trajectory on the price per kWh of batteries? Do you think waiting a year to stretch out the last legs of your current battery would give you a better deal going forward?
That's a fairly substantial improvement to payback.
As far as return, I guess you have the data to work through. With a 9.5kwh battery we've been able to move pretty much everything to a go off peak window.
Personally would have said 8-10kwh makes more sense than an upgrade to 5
@Edent We have an 8KWH battery, and although we only have a few (very sunny) weeks of data, it does seem that the bigger the battery the better chance you have to push back to the grid.
@Edent presumably this would then grant a new warranty (assuming it's new hardware)? I would go for it, given the expected lifetimes of current battery technology
@Edent Could 4.8kw do you through the day (7:30am -12:30am) in the winter? If so you could switch to economy 7 (or similar) and charge the batteries overnight. Current rates are 17p and 47p. Will probably wear the batteries out quicker.
@Edent indeed. Octopus Flux is also a good deal. Maybe see if a modular battery (like pylontech) is available/compatible. Would allow a rack which you can slowly fill.
@fishidwardrobe That's the thing with complex electronics. Could last another decade, could have a bad capacitor tomorrow.
Battery tech seems to be getting cheaper though.
@Edent Right, so. Pick a number of years. Say, three. Guess how much cheaper batteries will be then. Compare it to how long it will take to earn back the cost of this one?
That's what I'd try to do.
You at least know how much the current system will earn in that time. Multiply that by two (or, 1½ to be pessimistic.)
@Edent Do you have any statistics about whether your battery gets completely charged/discharged daily? (or how often, or how much are the daily exports/imports)
@IvanSanchez it's set to fully charge during the day (mostly from solar) and discharge in the evening.
Depth of charge is 80% on the old one and 90% on the new one.
@Edent I should rephrase as "how large is your daily surplus?" If it's more than 2kWh (meaning, it does fully charge and then you're forced to dump into the grid) then I'd be inclined to say "upgrade".
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