Solar PV battery options

redmagic68

pylon tech are there 2.4 and 4.8 both priced on the website with others

unkel

All batteries and pretty much all inverters are made in China. For the "asian total DIY job" most of us use 200Ah CALB cells, which are of far better quality than the cells that go into any purchased batteries. Take my word for it. Or don't and DYOR watching tear downs of these packs on YT. Personally I can't wait till Will Prowse gets his hands on a Pylontech 😂

poker--addict

I hear you unkel. I am just wondering what the middle ground of not doing any work with wiring and balancing - it is another language to me, one we can all learn quickly no doubt but time all the same. Something plug and play, without paying a premium to an installer, might generate some savings too?

Manion

Same as above. I'm tempted to get a hybrid invertor as a middle group. Is it pretty much a standard connector for batteries or do you have to match invertor to battery type?

micks_address

hey folks - apologies as i know this has been asking but im struggling to see answers.. im thinking about solar (who isnt) and im wondering about a battery... 5kw seems to be about 5k to add to the system.. is the idea you charge the battery from the solar when its producing and hopefully there's enough power in reserve in the battery to run the household until you get more light and solar recharges the battery?

if thats the case.. what kinda battery size makes sense? or is it better to not bother with the battery save the cost and export to the grid and get some payment for that you can offset from grid consumption?

bullit_dodger

It's hard to recommend get a battery/don't get a battery. 12 months ago, when they were cheaper, we had €600 specific "battery grant" and there wasn't a FIT in place with the suppliers, it was a no brainer for me. Get yourself a battery.......and a biggish one at that!

Now with FIT paying you, the removal of the grant and the increase in prices (although also an increase in rates) the economics are debatable. I think many houses would still do well with a battery but only a small-medium one. The feasibility fiscally though VERY much depends on your usage. If you are a low usage household (under 4000 units/year) I'd say pass on the battery, but if you have the usage then that could swap the needle in it's favour.

Basically you'll have to do the math with your consumption and see if it's feasible for you.

Metalpanic

Anyone have any experience or insights running a solar PV battery system in a house with A2W heat pump installed?

DrPhilG

If your installer is charging €5k to add a 5kWh battery, get a different installer.

micks_address

For my last two months used about 500 units.. have an EV but get complimentary charging at work so use that when I can..

bullit_dodger

https://www.boards.ie/discussion/comment/119573794#Comment_119573794

You need to look at the big picture, get your yearly figures. 500 units in the middle of summer may not be applicable for 2 months in the middle of winter as you can imagine. It sounds like you are a low usage if you use 500 units - although that's pure speculation on my part.

Also, I'd encourage you to do the math yourself. Don't take some random persons advice (even if it's mine :-) ....it's a big sum of money, you should be sure of if it's right for you.

DC999

Adding to that @micks_address, do you have an EV? That's the largest battery you'll even be able to afford. Or plan to? If that's parked in the driveway a lot of the time it sucks up the excess. Which means the house battery would be very much a 'nice to have' in Year1.

I reckon if the battery is slowing down your decision to get solar, then take it out of the mix for now. All the solar options can be paralysing at the start (I was one of those souls) - and the battery one is very house dependent. Can always look to get it in Year2 or later when you know more about your usage.

Ask the companies quoting to suggest if they feel it would help, and get the prices with it in and out. Then you can decide. With the decent FIT at moment, you're not really 'losing' by not having a battery.

What others have done here is get more panels on Day1, so their 'engine' is bigger. Means they produce more (and get more FIT) and reduces the need for a battery. Panels are cheap, labour is high. So they are on the roof anyway, so can add more panels quickly. But again, that can all happen in later years too if the budget won't stretch.

micks_address

https://www.boards.ie/discussion/comment/119573846#Comment_119573846

Yes we have an EV..our electric consumption probably won't change much over the winter as we use gas for heating and water and have an electric shower..

poker--addict

https://www.boards.ie/discussion/comment/119558485#Comment_119558485

Hi bullit_dodger, thank you very much. would you have the opposite graphic/data, ie the number of day KW units carried into the evening with battery. Presumably the objective in this case is to drain the battery between sunset and night rate start time, and the calc is Day KW saved- FIT lost out on...

championc

Everyone's evening consumption is different, but yes, it's all about not buying expensive units.

People in the UK on Octopus Agile charge batteries from 13:00 till 16:00 because of the peak rate from 16:00 till 19:00

What becomes difficult is deciding if you discharge overnight or use the grid and don't charge nor discharge.

Despite the sh1te day on Saturday, I had the battery to last from sunset on Friday evening till sunrise on Sunday morning, and got my batteries fully charged by late yesterday afternoon. But with a smaller battery, I would have been possibly charging to 100% on Friday night given Saturday's forecast.

bullit_dodger

https://www.boards.ie/discussion/comment/119575068#Comment_119575068

Unfortunately I do not have that data as it's sort of complicated to generate. Not impossible mind you, but it would require a bit of work, and it would also be very specific to my consumption. My basic load 24x7 is about 1Kw, and I have automation to turn off/on cryto miners based on the available energy coming from my panels, the time of day, what percentage is in the battery, etc. ..... basically not your average house! Applying that data to someone elses house would be a mismatch.

However, over in another thread though where we were discussing the feasibility of expanding an array, similarly here I'd simply just work out two figures. The money saved with day rates, and then the money saved with night rates. This is your "range", and then obviously your actual savings would be somewhere in between those values. For my own house, I basically rough ball park it at 80% of the battery I use at day rate. Sometimes it will last to 1am if it was a bright evening, and also since I sometimes put the washing on during the day, that energy saving can't be classed as a battery saving as I simply could have turned it on at night time without battery usage, so ballpark for me was 80%

Again, I'm sort of an unusual case. I try to outline the arguments for "normal" houses though, but in some respects people with a heat pump wouldn't be too far removed from me.

Geeyfds53573

I somehow had September in my head as a big Alibaba month for battery sales - I know 11/11 but is that the next big sales event?

the_amazing_raisin

Has anyone who has built a DIY battery tried doing any sort of capacity testing on the cells?

I've seen some battery testers on Ali express for around €60 which are basically a fan heater that will discharge the battery and measure the energy produced

I might be reading into it too much but I was thinking of getting one with the battery cells. If I'm spending thousands on cells then less and €100 on a tester to ensure they're in good condition when arriving seems sensible

unkel

I had one of those capacity testers, I think I picked it up for about €30 or so. Sold it on unused after a few years. Wish I hadn't. Will take a long time to capacity test all 32 200Ah CALB cells if your were to buy 20kWh like many of us have though 😁

Good idea to test them though. If you have one bad cell and you have 16 of them in series, it will take the capacity of the whole string down. And if you video the capacity test, it will be very easy to get your money back from AliExpress, as they nearly always side with the customer (if you can provide the proof they are looking for)

championc

https://www.boards.ie/discussion/comment/119577943#Comment_119577943

Just be aware that if you do find an issue, they will happily take it back and replace it, but the cost to return it is likely to exceed the cost of buying another.

If you look back a few pages, someone has already been down this road

the_amazing_raisin

https://www.boards.ie/discussion/comment/119578093#Comment_119578093

Thanks for the heads up, I guess my main worry would be a single cell dragging down the whole pack's capacity. If I know that I've got a bad cell and need to get a new one then that's half the battle

the_amazing_raisin

https://www.boards.ie/discussion/comment/119578092#Comment_119578092

Yeah that was kind of my thinking, and yes I'm thinking of getting the 32 200Ah CALB cells 😁

I could probably test 2 cells a day if it takes ~5 hours per cell, so 2 weeks to test the whole pack

I guess I could get 2 BMS's and make 2 packs so I can assemble one while testing the other. It'd add a few hundered but also gives me some redundancy if I've a bad cell or BMS failure

championc

I wonder would there be 8 or 16 of us would would buy one cell each as a spare ? I think I would. So buy a 8 or 16 and split it up.

the_amazing_raisin

https://www.boards.ie/discussion/comment/119578844#Comment_119578844

I suppose a group of people could buy some spare cells as insurance and then sell on any spares that don't end up being needed

Could go a step further and see if there's enough interested people to put in a big order for cells and get some sort of discount

VinLieger

Question about possible blackouts, ive seen conflicting info about being able to run your house off your battery in the event of a blackout? How does this work and is it possible, ie do you have to ask the installer to set it up in a specific way? Im intending on having solar attached to to the battery that helps answer.

bullit_dodger

https://www.boards.ie/discussion/comment/119584209#Comment_119584209

Yes, it's possible with varying degrees of effort/cost.

So inverters that we install are "grid tied", meaning when the grid goes dark......the inverter ceases to function. It won't charge the batteries from solar (assuming it was during the day) and it won't supply the house, at least not directly.

You can however power "some" things from the battery. The easiest way is to use the EPS (Emergency Power socket) which most inverters have. This you can wire to a 3pin socket and from that you can run say an extension cable down to your living room and run the tv etc. While it would be fine for that, you won't be able to run the full house from it.

If you had a more sophisicated (costly) setup, you could wire switch overs which depending on how your house is configured, you could wire that EPS output into your fuseboard, but generally most (99%) people will never have a need to go beyond the extension lead I think. Maybe I'm wrong.

VinLieger

https://www.boards.ie/discussion/comment/119585222#Comment_119585222

Well my question is obviously specifically about the coming winter and maybe a few to follow, right now its looking like any outages would be at peak time and id ideally like to be able to switch over during this time if it was necessary, is the EPS solution basically a switch that you can isolate yourself or the inverter from the grid to avoid the issues of it trying to send or pull from the grid while its out of action?

bullit_dodger

https://www.boards.ie/discussion/comment/119585340#Comment_119585340

is the EPS solution basically a switch that you can isolate yourself or the inverter from the grid to avoid the issues of it trying to send or pull from the grid while its out of action?

Not sure your gettng it. But basically it's an outlet/socket from the inverter. I can't remember the specific connection type, but it's not a regular one. From that you could then wire up a 3pin socket something like this lad has done (not mine)

Then things you plug into that specific socket would come from the battery, even during a power cut. You could simply run a cable from your inverter to the living room and then power the telly etc. via

Masterplug 50 Metre 4 Gang Heavy Duty Cable Reel | Woodie's (woodies.ie)

Simple solution.

Alternatively you can do something more sophisticated with change over switches and power a specific circuit such as downstairs sockets/lights using that same output but you need to be careful here that you correctly and properly isolate your house from the external grid or you run the risk of grid feedback which is a no-no.

the_amazing_raisin

https://www.boards.ie/discussion/comment/119584209#Comment_119584209

You need to ensure your house cannot feed electricity back into the grid in the event of a blackout.

The idea is that if an ESB Engineer is working on the line and expecting it to be deenergised then they might get a shock if your house is powering the local grid

You need to discuss it with your installer, they should be able to install an inverter that had a built-in anti islanding switch

Murt2

https://www.boards.ie/discussion/comment/119509458#Comment_119509458

Hi,

I don't suppose you still have that battery available?

connesha

Hi. I'm afraid not. It's going to another boardsie.