Solar PV battery options

unkel

That's it. No need to start the car's ignition, I have the HV DC switch in the car off, connect resistor to pre charge the caps in the solar inverter, then switch HV DC on. Then the solar inverter thinks it's a string of solar panels producing power (in the dark 😁) and starts drawing the maximum current it can (11A), and the car's HV battery is drained into the home at about 2.2kW or if more than I need it goes automatically towards topping up my empty home attached battery

First time I tried it seriously, I got the guts of 10kWh into the house one of the very bad dark rainy days a week ago or so. Next day was a fine day and the car's battery was fully filled up again from the sun via the Zappi on eco plus mode

10-10-20

https://www.boards.ie/discussion/comment/119791563#Comment_119791563

Ok, quirky; very interesting solution there.

But you do have a suitable (<20A) breaker on that cable - as close to the battery terminals as possible, right?

unkel

Yes, fuse on the normal HV connection from battery to the car's charger (I borrow this connection for the V2H / have made the charger detachable) and fuse on the pre-charge circuit

the_amazing_raisin

https://www.boards.ie/discussion/comment/119791563#Comment_119791563

That is hilarious, and genius 😂

I was assuming you'd gotten a high power dc-dc converter to convert the HV battery down to 48V, but using the MPPT would work as well

I've seen some 450V MPPTs around, so you could in theory do the same with the Tesla if you were willing to get your hands dirty 😁

the_amazing_raisin

Has anyone bought cells from NKON?

https://eu.nkon.nl/rechargeable/lifepo4/prismatisch/eve-lf280-prismatic-280ah-280a-lifepo4.html

They're a Dutch company form the looks of it. Prices for EVE 280Ah cells are good, almost too good, better than PWOD almost

However, they seem to have good reviews and a lot of them seem genuine, so either they're fairly legit or the review bots have gotten more sophisticated (I'd believe either at this stage)

unkel

Did you see the expected shipping date? 😂 You might have them in March...

unkel

https://www.boards.ie/discussion/comment/119793145#Comment_119793145

Wasn't my idea to use the PV inverter, so I'm not the genius here!

I was pretty happy though that I had a pair of MC4 parallel connectors lying about so I thought I'd share one MPPT between a solar string and the V2H. Might as well as I'd never use the V2H during the day, just at night when there is zero PV output. I also happened to have a perfect length couple of MC4 cables that I had terminated into an XT60 connector (I use those for everything) and I had just made the car's on board charger mobile with the same connector. So it all came together perfectly and the V2H setup didn't cost me a cent. Now that was the part that I enjoyed most 😁

the_amazing_raisin

https://www.boards.ie/discussion/comment/119793235#Comment_119793235

Well, I don't need them urgently, and if it saves a few hundred and I've an EU based distributor to harass when there's something wrong then it seems like a good deal

My guess is they're getting pre-orders in so they can order in bulk and get a discount that way. Seems like a smart way to doing things

unkel

If you've ever seen an aluminium cell like the EVEs up close and a plastic CALB one, you'd probably bite the bullet and spend the few hundred quid extra on the CALBS. These yokes are incredibly sturdy.

But yeah, EU distributor who you pay (with your card) is a good idea. That said, of all the problems I have ever had with parts from AliExpress, they have always paid up in full. AliExpress tends to side with the customer, not the supplier. And because of that, they keep getting me back over for more and more like a proper addict 😁

graememk

https://www.boards.ie/discussion/comment/119793145#Comment_119793145

The solis can work an mppt up to 520v

Not that I'd be tapping into my Niro! 😂

the_amazing_raisin

https://www.boards.ie/discussion/comment/119793376#Comment_119793376

Ah what could go wrong 😉

Seriously though, don't do it! 😱

Mr Q

https://www.boards.ie/discussion/comment/119793154#Comment_119793154

They're expensive in my view. I purchased some from Alibaba earlier this year and they were about 50 euro per cell less than that with customs, delivery etc.

Obviously USD rates have changed since then but not by that amount.

the_amazing_raisin

https://www.boards.ie/discussion/comment/119796289#Comment_119796289

I agree, but battery prices seem to have shot up in the past few months, so earlier this year might as well be last century

For comparison PWOD seem to be €1k more for what appears to be the same cells (no idea since they don't list manufacturers)

I know OYE might be cheaper but I'm not quite willing to roll the dice given a few people have had bad experiences. I'm a bit more willing to take chances with an EU seller since I have some basic buyer protection at least

championc

The CALB,'s from PWOD have only changed by the Dollar exchange rate swing all year. Yes, a few 100 for 16 cells, but that's all

the_amazing_raisin

https://www.boards.ie/discussion/comment/119797634#Comment_119797634

But those are 200Ah cells, it's currently about €2k for 16 of those from AliExpress

The ones I posted are 280Ah x16 cells for ~€2,900

So it's around €10 per Ah regardless, don't see how it's a bad deal...

championc

So the 200ah are listed at €1870 right now, which is about €1550 after removing the VAT at the checkout - so €1550 delivered to your doorstep.

200AH 3.2V Lifepo4 Battery DIY 12V 24V 48V High Capacity Lithium Iron Phosphate Cell for RV Vans Home Solar Off Grid System

https://a.aliexpress.com/_msr02hE

unkel

A good bit less capacity but a good bit more quality for roughly the same money. I'm all about value for money but in this case I would pick the CALBS. I'd say they have higher resale value too. Not that you are thinking about that now, but it is quite possible you will. I bought my first 10kWh of them in late 2019 and less than 18 months later I bought a new batch of 20kWh and sold my first batch. For more than they cost me new.

ELM327

Asking a very stupid question but it doesnt make sense to me and some googling doesnt help.

How do you know the capacity? It's 3.2v? Surely it needs to be 48-52v?

E30M3

https://www.boards.ie/discussion/comment/119798942#Comment_119798942

3.2 V X 16 Cells

ELM327

See I knew it was something stupid and I knew there would be some series involved.

So do you just assume they are 16 cells?

E30M3

https://www.boards.ie/discussion/comment/119798979#Comment_119798979

15 or 16 depending on the Battery and BMS configuration.

unkel

The capacity of what?

One CALB cell has a capacity of 200A (and is 3.2V nominal), a pouch cell as used in a Pylontech is also 3.2V nominal - all LiFePO4 cells are - and has a capacity of 25Ah

If you put battery cells in series, the voltage increases, but the capacity stays the same. Examples:

1. The famous DIY 10kWh pack that many people in this forum built. It uses 16 cells in series (16S1P), so has a capacity of 200Ah and a nominal voltage of 16*3.2 = 51.2V. The pack has a capacity of 51.2*200 = 10.24kWh
2. A Pylontech US2000 which is a very popular proprietary pack in Ireland. It uses 15 cells in series and 2 in parallel (15S2P) of 25Ah pouches. So the pack has a nominal voltage of 15*3.2 = 48V and the capacity is 15*2*25*3.2=2.4kWh

Hope that helps!

Galego

Question for the experters.

Is there need to install a fused isolator between a Pylontech battery and a solis (or any) inverter?

Someones is telling me "the manufacturer instructions show they need external short cct protection, and it's the easiest way of getting the fuses installed, and no more expensive as a fuse carrier only than as a fused isolator"

I thought I just had to plug in the battery to the inverter and off you go!

Mr Q

https://www.boards.ie/discussion/comment/119797068#Comment_119797068

Mine came from China but I have got emails since then saying they have EU stock now in Poland. 294USD per box of 2 batteries including all costs was the last price I seen.

They are listing them as 111euro a piece from China before other costs.

unkel

https://www.boards.ie/discussion/comment/119799439#Comment_119799439

I'm no electrician, but any cable coming from the positive terminal of any battery, should have a fuse imho

(That said, there is probably a fuse on the positive terminal inside the Pylontech, can't remember. But I'd put one in the cable anyway)

Geeyfds53573

Another 16 on the way

€1421.72 today from PWOD

€ 475,37 32％ Off | 3.2V 200AH LiFePO4 Rechargeable Lithium Iron Phosphate Battery Pack For Golf Cart RV Boat Solar Battery Energy Storage System

https://a.aliexpress.com/_mrupNYg

graememk

https://www.boards.ie/discussion/comment/119859651#Comment_119859651

Dont forget bus bars!

unkel

That's not a bad price these days, but when I click on it I get just under €3000 (before VAT) for 32?

Geeyfds53573

https://www.boards.ie/discussion/comment/119859957#Comment_119859957

Not too bad and I played all the games (-:

JHet

Some decent prices today:

That's €1,794.20 for 14.4 kWh

and €1,344.44 for the 10 kWh CALBs.

unkel

Sweet. Thanks @JHet. A good bit cheaper again than yesterday I think. Couldn't resist any longer, got myself another 16 😁

Geeyfds53573

https://www.boards.ie/discussion/comment/119862946#Comment_119862946

Now that is a great price - we’re they cheaper actually on the day?

Geeyfds53573

https://www.boards.ie/discussion/comment/119859887#Comment_119859887

Good point will I need 16 more? PWOD store also?

graememk

https://www.boards.ie/discussion/comment/119865091#Comment_119865091

Yep 16 more.

ECO_Mental

Hi

I am doing some basic sums here on whether I would get a battery or not, but also it's for a thing in work where I am giving a presentation on my experience of my own PV system over the past year. I know most of the talk on here is DIY is the only solution but how much are commercial batteries. I have made some enquires but people are slow to get back with prices.

How much would a 10 kWh or even a 20 kWh commercial system be, I have number in my head of around €10k to €15k...

Thanks

micks_address

https://www.boards.ie/discussion/comment/119880835#Comment_119880835

the givenergy 9.5kwh battery is listed here at 4192 sterling plus vat https://midsummerwholesale.co.uk/buy/giv-energy/giv-9-5-batt

ECO_Mental

https://www.boards.ie/discussion/comment/119880897#Comment_119880897

Need to get that fitted and set up as well so another grand or two I suppose..

micks_address

yeah and what im not sure of.. does say the givenergy battery work with any invertor? mine came as a package deal with hybrid invertor/battery/panels

graememk

https://www.boards.ie/discussion/comment/119880835#Comment_119880835

I think 5kwh off the shelf batteries are coming in at 2-3k each.

+ Then getting a storage inverter/upgrading to a hybrid inverter

The givenergy ones are actually 10kwh batteries "under the hood" but they allow discharge to 0% instead of stopping at the usual 20%

ECO_Mental

Here is a complete package 8kW inverter and 18.4 kW of storage £14,625 or around €16,500 eek! that's not even fitted or delivered....

As everyone says DIY is the way forward but just checking as not everybody is up to DIYing something like this....

https://midsummerwholesale.co.uk/buy/storedge/solaredge-3ph-8k-bat-bundle

ECO_Mental

https://www.boards.ie/discussion/comment/119881078#Comment_119881078

https://midsummerwholesale.co.uk/buy/huawei-storage/huawei-6kw-hv-kit

The previous one was a 3 phase system so more expensive here is a 15 kWh single phase 6kW inverter one for £11,000

ELM327

You'd also have vat and customs

ECO_Mental

https://www.boards.ie/discussion/comment/119881147#Comment_119881147

😯 Oh S**t they are wholesale prices EEK!!! forgot about that

I knew the payback on commercial battery systems were bad but just wanted to confirm and run the numbers as I will be giving a small presentation at work about domestic PV systems

ELM327

The best way for payback is to buy calb cells and busbars and wiring etc on aliexpress. The next best is to buy from an installer that meets the price guidelines (1k euro for each 2kWh of battery)

championc

Commercial in many cases means 3 Phase and therefore leads you into totally different inverters

unkel

The only way I would ever even consider buying a commercial / pre made battery is if it is the smallest you can get and if the install is giving you the SEAI grant. And if I didn't have the time nor the inclination to DIY.

It's simply not for everyone. There is something to say for a system that is owned by someone else who will fix it when it goes wrong, etc. This will of course cost you significantly more and could easily double or treble the payback time of your entire system

Gerry

After reading 20 pages plus of this thread I'm sorry that I'm none the wiser.

If I want 5 or 10kw and I am happy to DIY, what is my best option?

Get CALB cells from a specific seller on aliexpress

Get a BMS

Am I likely to have cells bulging or not having full capacity in 12 months..?

Alternatively, if I buy a rackmount system from aliexpress, for more money, is that likely to be less reliable?

ELM327

https://www.boards.ie/discussion/comment/119882382#Comment_119882382

Calb cells from PWOD. BMS. At least that way you know what you're buying.

If you buy a rack mounted system you cant know what is inside, but if going this way watch the will prowse video of the battery

unkel

And don't buy a battery that Will Prowse or David Poz haven't yet reviewed, like a certain battery very popular in Ireland and the UK. I mention no names 😂

cjxfh

This may well have been covered earlier but have you folk advice on installing a solar pv system without a battery now but when batteries improve sufficiently adding a battery to the system. How realistic feasible and cost effective is this approach?