Battery - to take advantage of 2am to 5am cheap rate electricity

Casati · 28-12-2023 2:11pm #1

Hi - I have looked at various threads and have no doubt this has been answered, but it's hard to find in all the detail!

Basically is it feasible to consider buying a battery (and whatever else is needed) to charge up nightly at 5.5 cent per kW, and then run the house from this battery during the day? i.e. The ambition being to effectely pay just 5.5 cent per unit for all electricity used - not considering getting solar pv or selling to the grid etc.

Any idea how much you'd need to spend on a battery of suitable size - i.e at a guess I would use 10kWh per day in winter so presume the battery would need to be at least that size or bigger?

SD_DRACULA · 28-12-2023 3:04pm

If you're handy at DIY currently that's the cheapest option to go for as I'm sure many folk here will confirm.

And for some shameless advertising, if you want a plug-and-play solution with warranty etc, I'm in the middle of going DIY myself and I will have 4 x B51100 5.12kwh Dyness batteries for sale after, about 1 year old 😉

Casati · 28-12-2023 3:10pm

https://www.boards.ie/discussion/comment/121543712#Comment_121543712

Sorry did you mean to give a link or something- what is the cheapest option?

Ubbquittious · 28-12-2023 3:19pm

I wonder how much longer those cheap EV rates are going to last. I am fully expecting "the good" to be taken out of them at some point

SD_DRACULA · 28-12-2023 3:22pm

https://www.boards.ie/discussion/comment/121543726#Comment_121543726

You'll find all the details on this thread: https://www.boards.ie/discussion/2058246061/10kwh-lifepo4-diy-battery-addition-here-is-my-write-up#latest

Calahonda52 · 28-12-2023 3:25pm

1: CapEx cost of kit

2: Lifetime/recharge cycles limit of kit?

2a: discharge rate of battery: eg will it cater for an elec shower at say 9 kW

3: Will battery allow deep discharge: a LI version is about 700-750 euro a kWh

4: 10 kWh/day or 3,650 pa seems a bit light, SEAI indicator is 4,440 IIRC

5: not my area but you must consider losses:

AC to DC to battery, and back

Casati · 28-12-2023 3:51pm

https://www.boards.ie/discussion/comment/121543769#Comment_121543769

Number 1 is really what Im interested in - if I DIY - which would obviously mean quite an education to get up to speed, what would it cost versus getting somebody who does this for a living. I really have no idea if it's anyway feasible at all.

I would need to check bills, but my guess is that yes I am using more than 10kWh per 24 hour period, but my assumption was I could continue to use my heat pump during the heat night hours, in tandem with charging the battery- but potentially this isn't possible I dunno

con747 · 28-12-2023 5:39pm

https://www.boards.ie/discussion/comment/121543855#Comment_121543855

A chap here selling ready made ones. I think he has sold a fair few. https://www.donedeal.ie/all?userId=2545070

Ginger83 · 28-12-2023 5:55pm

https://www.boards.ie/discussion/comment/121543712#Comment_121543712

Is it a stupid question to ask why you are changing the 20kWh of batteries after a year?

graememk · 28-12-2023 6:32pm

https://www.boards.ie/discussion/comment/121544183#Comment_121544183

Its an addiction/hobby at this stage... I dare say hes upgrading to about 30kWh (maybe 45?) but DIY.

https://www.boards.ie/discussion/comment/121543769#Comment_121543769

1) how long is a piece of string lol, really depends on what you buy.

2)LFP is usually rated for 3-4000 cycles? maybe 6000 cycles. but at that point the battery isnt dead, its just got 80% of its capacity.

2a)discharge rate, Thats more dependant on the Inverter not the battery, and your well into NC7 category if you can run a 9kW shower. Having a good DHW tank could be more suited there. (also a battery, that you can "charge" on night rate.

3)generally LFP you cycle between 20-100%, but you can push it to 15.. maybe 10 on occasion

4) Id agree, especially with more fully electric homes, its a bit on the lower side, but going to touch on this a bit later.

5) round trip losses are about 20%, Ive measured it over 2 different inverters, AC in vs AC out. Needs to take that into consideration.

Circling back to point 4. Assuming you have enough battery capacity.

The Limit on an NC6 for an inverter is 25Amps. The sunsynk 5kw has a max output of 25amps, (I think it used to be called the 5.5, but it seems to be back at 5 now, looking at the website.

3 hrs, the most* you can get into a battery is 15kWh (at 5kW), and get about 12 out.

Cost to buy €0.75, that will replace 12kWh of day rate at 41c, 4.92, €4.17 per day.

If that 12 kWh is enough to get you through the day great, But you could be needing a good bit more of day rate. if you need more, energia has a higher ev rate at 8c, (and over 1000kwh /2 months, its something like 9c) and a day rate of 36.

4hrs would get you 20kWh, 16 out, saving per day is €4.16 but cost per day is €1.6

Load shifting on DN is viable too (9hrs of night rate), but all ready depends on your use.

*you can get 58V chargers that could run in parallel to your inverter, to up your charge rate but thats delving more into DIY

Casati · 29-12-2023 9:56am

A lot to consider there for sure, need to do a lot of calculations. Is there a fire risk with these batteries?

slave1 · 29-12-2023 12:55pm

there is no need to look at your bills for usage, just manually look at your meter and write down the units, then look again after 24hrs and this will give you your daily usage, simples

no fire risk with lifepo4 battery

slave1 · 29-12-2023 12:57pm

..and I'd sit back for a while, FIT is very new, has surprised us all with it's high rate, it may settle down over the coming year and your decision becomes financially in the red

Casati · 30-12-2023 1:21pm

https://www.boards.ie/discussion/comment/121546726#Comment_121546726

Ah yeah didn't really think of that. I did some quick calculations and think it would be difficult (but not impossible) to run everything off a battery e.g I've a 14kW heat pump and also have one electric shower and electric heaters in an outside room so I'd end up consuming a lot of power some days at 41 cent per unit

graememk · 30-12-2023 1:25pm

https://www.boards.ie/discussion/comment/121549844#Comment_121549844

If you have a smart meter already, you can pull up your data on the esb networks website, See how much you actually use.

Casati · 30-12-2023 1:27pm

https://www.boards.ie/discussion/comment/121549857#Comment_121549857

Still on the day / night meter but I have a reasonable idea of those bills. I'm going to watch this space closely mind

graememk · 30-12-2023 2:26pm

Can still be done with the DN meter, just the payoff isn't as quick.

What would your average day use be, per day?

MakersMark · 30-12-2023 2:33pm

I think the idea is admirable, but doesn't make sense financially.

You'd be better off taking the 10 to 15k you'd spend on batteries and investing it in the markets.

There's far too many variables associated with load shifting as an economic investment.

Muahahaha · 30-12-2023 3:04pm

Is it fair to say too that batteries should come down further in price as the supply of lithium catches up to its shortages?

graememk · 30-12-2023 3:08pm

https://www.boards.ie/discussion/comment/121550089#Comment_121550089

Who's spending 10-15k ?

14 kWh of a kit is about €2300, (but you will have to travel to NI to get it, they don't deliver to the republic) + 800 for an inverter will get you a basic system.

graememk · 30-12-2023 3:11pm

https://www.boards.ie/discussion/comment/121550178#Comment_121550178

Hard to know. But the price of bare cells, from 2020, has rose and only now has fallen below 2020 levels.

1300 would get you 10kWh.

Can get 14kwh for 1200 now.

irishchris · 30-12-2023 3:13pm

https://www.boards.ie/discussion/comment/121550089#Comment_121550089

That is open to debate. But depending on battery storage sizes you can get large batteries and a storage inverter for far less than 10-15k.

I went the DIY route myself but there are still ready made packs for good prices. Recently fitted a gobel 15kw battery to a family members system. 2700k including delivery and all taxes/duties to your door. It is up ready to go with just the positive negative and can cable to connect. Grand total of about 15 mins setup. Many other options out there too so worth pricing around.

MakersMark · 30-12-2023 3:28pm

OP indicates full system is needed.

What would be the cost for a full 10 to 15KWh setup,(not just a battery), assuming not going DIY?

I'm not seeing much change out of 10 grand.

How long do you think companies will offer 5.5c rate?

Not looking for an argument here, but as an economic investment there are easier ways to make money.

bullit_dodger · 30-12-2023 4:17pm

https://www.boards.ie/discussion/comment/121550266#Comment_121550266

I'd sort of agree with you there Makers, although there's more to it than simply ROI and making money back. A fair chunk of the rationale of me going solar & battery a few years back was that I wanted a way to contribute to decarbonization of my own lifestyle. Part of the reason the suppliers can offer these cheap rates at 3am is that there typically is an abundance of power verses consumers. Makes sense to fill storage be it pumped hydro or batteries when there is abundant power.

Incentivizing people to go/use these rates is a good step. I'm still on D/N, but every month of winter my 8.2Kwhr battery saves about €30-40 by topping up at night and using during the day - but yeah, I'm sure you could equally find some commodity/stock returning similar if not better - but if your "in about the races", I think it's right way to go.

graememk · 30-12-2023 4:22pm

https://www.boards.ie/discussion/comment/121550266#Comment_121550266

Battery only? buying new? I suppose going with a 5kw Inverter too

Hard to get prices in Ireland for the gear but

https://www.itstechnologies.shop/products/sofar-5kw-hyd-5000-es-hybrid-inverter-for-solar-battery-storage-trade-prices €900

Lets assume the gobel, 15kwh, €2700,

install? 500-1k? (cable from inverter, to CU, Isolators, DC/AC, DC possibly redundant as theres ones on most batteries.

Round it to 4500.

3 hrs, most you can get into a battery is 15kWh (at 5kW), and get about 12 out.

Cost to buy €0.75, that will replace 12kWh of day rate at 41c, 4.92, €4.17 per day. (this is accounting for loses)

If you cycle it every day, thats, €1500/yr, Pinenergy Cooline is a 2yr contract and the 5c is a discounted from the day rate, day rate goes down, ev rate goes down. (energia's tariff workings is in an earlier post) but each persons use would be different, possible payback in 4 years.

DN rates, cheapest night rate is 17.17c, 35 day, Is only 1.63/day.

Full DIY? Id say I could get the parts together for under 3k, maybe 2.5 if i can get a bargin on the inverter.

Edit: I know solar and batteries because its grew into more of a hobby and I like building stuff, and it actually paying its way is a bonus. I am still on a DN myself as Ive put in a heatpump and wanted to see how that effected things before jumping on the 3hr plan!

Also, If someone had 5k to play with. What would be an investment that you would recommend? And after 5 years what it would be worth?

MakersMark · 30-12-2023 4:43pm

https://www.boards.ie/discussion/comment/121550417#Comment_121550417

I hear you, but the OP says he's not putting solar in, just wants to load shift to reduce bills.

If you're not going the whole thing DIY, including connection, I dont see it as an economical choice.

MakersMark · 30-12-2023 4:47pm

https://www.boards.ie/discussion/comment/121550434#Comment_121550434

I'm a big proponent of US mutual funds that can get close to S&P500 performance.

My returns for this year are below.

I think US markets will see 10 to 12% growth next year.

listermint · 30-12-2023 4:50pm

https://www.boards.ie/discussion/comment/121550266#Comment_121550266

Multiple people have answered this already with pricing but you've ignored all of their responses...

graememk · 30-12-2023 4:58pm

https://www.boards.ie/discussion/comment/121550536#Comment_121550536

I know very little about investments, and I have 5K to put in, Not have to look at it again for 5 years. What would you recommend/ what would you expect that 5k to be at in 5 years? (stock markets can rise and fall, your capital is at risk etc etc).

MakersMark · 30-12-2023 4:58pm

https://www.boards.ie/discussion/comment/121550547#Comment_121550547

No, a DIY cost for batteries was given.

Until the last post, no one mentioned an inverter, or cost of an electrician to safely hook everything up.

I guess you're only interested in your own echo chamber point of view.

Unlikely the OP will save a cent unless he complete DIYs the whole job.

That's the reality,but hey, knock yourself out if uou want to load shift.

Make sure you tell your insurance company that you're DIYing 15 kWhs of batteries from China too!

All the best!

Casati · 30-12-2023 5:11pm

Thinking about it, I wouldn’t probably go DIY route so would want something I could get signed off by my spark. I’m on around 17 cent night and 34 cent day, so comparing savings to 34 cent rather than 41 makes it harder again to see an immediate return. Hopefully with car battery supply not as constrained as it was we will see reduced prices in future and it might become a no brainer

listermint · 30-12-2023 5:17pm

https://www.boards.ie/discussion/comment/121550577#Comment_121550577

Ah yes echo chamber..

Famously the reserve of people who think 'the markets' solve all of life's ills.

Gud look

DC999 · 30-12-2023 11:55pm

https://www.boards.ie/discussion/comment/121550204#Comment_121550204

Never heard of the Gobel pre built battery. Where did you source that?

unkel · 31-12-2023 2:18am

https://www.boards.ie/discussion/2058328605/battery-to-take-advantage-of-2am-to-5am-cheap-rate-electricity

That's exactly what I do. My night rate (between 2AM and 5AM) is 5c / kWh and it is all the electricity I ever buy (busy 5 person household with 2 EVs too). Everyday my graph looks pretty much exactly like this:

My systems are big and almost fully DIY. As others have said, it's become a hobby now. With the pleasant side effect that the money invested is paying back very quickly for itself, probably already has done.

unkel · 31-12-2023 2:23am

https://www.boards.ie/discussion/comment/121546726#Comment_121546726

Good to be prudent. Seems unwise to base decisions on investments of several thousand on the situation that applies now. And yes the feed in tariffs are far higher than any of us expected. Who knows what is to come

That said, what is near certain is that we will be offered flexible rates, like they have in countries a bit ahead of us like the USA, the UK, the Netherlands, etc. Where you know the rates for the coming day for each half our slot. Rates can then easily vary between -€1 and +1€ per kWh and to make matters even more confusing, you could be paid for using electricity or you could be penalised for supplying electricity. Bring it on 😁 One day you could be paid €100 for storing 100kWh into your battery, cars, hot water and the next day you could be paid €50 for dumping 50kWh that you stored in your battery into the grid

graememk · 31-12-2023 2:42am

https://www.boards.ie/discussion/comment/121550622#Comment_121550622

I don't see any massive drops coming,

Cars are generally using lithium ion, but storage use lithium IRon phosphate, LFP, or LiFePO4.

Some Tesla's and BYD are using LFP now.

https://www.boards.ie/discussion/comment/121552751#Comment_121552751

Fully welcome fully flexible tariffs, even negative export. It would be harder to manage but doable with the right automations.

unkel · 31-12-2023 2:48am

https://www.boards.ie/discussion/comment/121552775#Comment_121552775

Tesla megapacks come standard with built in software to maximise profits in importing and exporting, given a set of parameters the owner can set. But these cost a few million each, so aren't aimed at consumers 😁

In the UK and the Netherlands, there are already companies that provide the hardware and software to do the same job for people who have solar and / or battery and / or EVs. Typically they provide everything for free, but take a cut (like 30%) of the profits. Not a bad deal. But I'd like to be in control myself. It's a game, why would I let someone else play? 😁

irishchris · 31-12-2023 1:44pm

https://www.boards.ie/discussion/comment/121552331#Comment_121552331

https://youtu.be/MbBr_EoV2OE?si=3hq9Fh2zlBylWcSl

Originally saw it in the above video from Andy.

Family member ordered it as didn't want to go the DIY route and arrived after about 6 weeks. Ordered from here

https://www.gobelpower.com/gobel-power-gpsr1pc200-512v-280ah-lifepo4-battery_p114.html

graememk · 31-12-2023 1:54pm

https://www.boards.ie/discussion/comment/121553577#Comment_121553577

How much was shipping? Did that bring it to 2700?

irishchris · 31-12-2023 4:46pm

https://www.boards.ie/discussion/comment/121553606#Comment_121553606

Yep with freight shipping brought it up to €2710. DPP so no extra charges and courier dropped to door. Prefer the DIY battery myself as similar to others here was good hobby and nice bit of learning.

But for someone who isn't into it this is I suppose as plug and play as you get for the price. Came with the neey balancer in it and cells are averaging 304ah instead of the advertised 280ah so very impressed by the quality.

con747 · 31-12-2023 5:36pm

https://www.boards.ie/discussion/comment/121554310#Comment_121554310

Seems to have a discount coupon on it now, was that there when they ordered?

Subtotal €2,026.33 Shipping Caculated Next Step Import Tax Free Tax Max Discount -€303.95

Cart Total: €2,026.33

€1,722.38

The coupon is restricted to certain products.

Coupon Code: PACKSAV10

Discount: 15%

Minmium Order: $1000

Valid Products:

graememk · 31-12-2023 9:17pm

https://www.boards.ie/discussion/comment/121553577#Comment_121553577

do we have to "consult with sales?" lol

jasgrif11 · 31-12-2023 11:03pm

Is the expedited shipping hand carrying it via air from China to your house :)

irishchris · 01-01-2024 1:53am

https://www.boards.ie/discussion/comment/121555253#Comment_121555253

https://www.boards.ie/discussion/comment/121554577#Comment_121554577

Discount code was there before but off a larger base price.

That air shipping is ridiculous but when ordered it in October there was option for sea freight delivery. Assume if you contact them via WhatsApp they would invoice for sea shipping unless they no longer provide that service?? Always find them quick and helpful via WhatsApp for sales and tracking.

The below was the option I used when ordering:

Sea Freight (DDP Terms) (Shipping to IE): €603.13

Casati · 01-01-2024 1:57pm

https://www.boards.ie/discussion/comment/121554310#Comment_121554310

What else would be need to get this up and running - inverter? Also does it need to be located near to the circuit breaker in the house?

ddonq1412 · 01-01-2024 2:44pm

When you do you get 14kw cells for 1200 euro. And what grade would they be.

irishchris · 01-01-2024 2:49pm

https://www.boards.ie/discussion/comment/121556860#Comment_121556860

Yes a hybrid inverter if adding solar with it or if just using the battery for night cheap charging then a storage inverter like the me3000. I see an me3000 new selling for 700 on adverts.ie at the minute.

You would need power cable and ethernet from your circuit breaker to where your storage inverter is