Solar PV battery options

irishchris

https://www.boards.ie/discussion/comment/119167140#Comment_119167140

These are the battery control parameters within the Solis

graememk

https://www.boards.ie/discussion/comment/119167221#Comment_119167221

I'll check Dads in the morning.

irishchris

https://www.boards.ie/discussion/comment/119167391#Comment_119167391

Cheers appreciate that Graeme 👍

graememk

https://www.boards.ie/discussion/comment/119167396#Comment_119167396

Soi have the max charge voltage set to 57.

irishchris

https://www.boards.ie/discussion/comment/119168486#Comment_119168486

Cheers Graeme I notice your equalising voltage is lower at 57.5 and will change mine to that.

Sorry I'm little bit confused as to where you have max charge set to 57v? On the Solis settings or bms?

graememk

https://www.boards.ie/discussion/comment/119168503#Comment_119168503

The bms set at 57v

graememk

https://www.boards.ie/discussion/comment/119168519#Comment_119168519

The max charge voltage of the bms is set to 57* .

irishchris

https://www.boards.ie/discussion/comment/119168519#Comment_119168519

Perfect graeme thanks, will log in to BMS now. Is your dad using a seplos also? Does he run into many high voltage alarms on his?

Is it the monomer high voltage alarm I set to 57v on BMS or what setting is it in your dad's that is set to 57v on the seplos. Apologies for the million questions 😱

graememk

https://www.boards.ie/discussion/comment/119168551#Comment_119168551

Both of us are using the zeva, but settings should be settings and how the batteries behave.

championc

Like you see on Euronews ........ No Comment

Pylontech Teardown

[YouTube]t25kCIIpEQ8[/YouTube]

irishchris

https://www.boards.ie/discussion/comment/119172158#Comment_119172158

jeez just goes to show you dont know what is underneath the shiny casings of these off the shelf batteries

reklamos

Looks like the older model of Pylontech. I would say there is more than just one bad cell in there as all 3 packs are swollen. Having good voltage does not mean that the cell can hold charge. Something has trigered this process could be temperature, maybe they were sitting for too long with low/high charge. Could be also faulty BMS that pushed them too much.

championc

One cell failing means the the charging voltage is therefore split across 14 rather than the original 15 cells. If cells were around 3.45v and one failed, it would add 0.25v to each other cell, and if the BMS failed to trigger shutdown based on one cell and only shutdown based on total pack voltage, it could keep charging !!!

fuse

I'm getting quotes at the moment.

Started with "I must get a battery" then saw that it's not necessarily the best option with an E/W orientation where I'm working from home. But I figure I should get a hybrid inverter to keep it ready for a future addition.

For a 4.8kW system, in a house using around 15kWh per day is it worth an extra 1750e to add a 2.4kWh dyness battery. Should I be trying to match the system size with battery or is there any harm in using a 2.4kW batttery on a 4.8kW system?

reklamos

https://www.boards.ie/discussion/comment/119173356#Comment_119173356

I understand that part. The BMS in these batteries is pretty good from what I've seen. Each cell is monitored and each cell has temperature probe also, so it should have noticed that one is a runner i think there is more to it.

https://www.boards.ie/discussion/comment/119174395#Comment_119174395

Get the biggest battery you can afford. 2.4kWh is nothing. With 4.8kW system running at full blast it will only take half an hour to charge it fully. My daily consumption is close to yours. I do work from home for over 10 years, have 4.5kW system and 10kWh battery was not enought for me hence I upgraded to 20kWh.

championc

Me too. I've 3.9kWp and filling 10kW most days.

The reality of WFH is possibly a laptop and external monitor each day, at maybe 100w per hour. You'll use more power boiling a kettle for 5 mins that the laptop for the guys of a day

yankinlk

https://www.boards.ie/discussion/comment/119174395#Comment_119174395

I have east west, 6.6 and a 5 kw battery. I work from home and use about 20kw a day.

Even wfh I recommend a battery. Without a battery u will never get any work done, cause every time sun shines u will run around trying to turn stuff on...and when a cloud passes over you will run around turning it all off. Good luck.

yankinlk

IMHO and it is just an opinion. The battery should be roughly half the consumption size. System size is not as important... cause you will likely increase it anyways if you build too small.

scunermac

I wanted to build a system that was ‘future proofed’ with the ability to add a battery down the line. However I just found out the company I got a very good quote from, only install single phase inverters. with the excess going to my hot water.

I know you could install a battery later into this system which would have a built in inverter. But there is an added cost. One I checked was €7K for a 5KW battery which had a built in inverter.

how much of a deal-breaker should I consider this? Anyone have a single phase inverter and wish they had gone with a hybrid inverter instead?

DrPhilG

https://www.boards.ie/discussion/comment/119199476#Comment_119199476

You're mixing up your terminology here. Single phase vs 3 phase refers to the power supply at your house. 3 phase inverters are hugely expensive, and there are only a tiny amount of homes in Ireland who have a 3 phase supply.

What you're referring to is a standard inverter vs a hybrid. A hybrid is a bit more expensive most installers use them as standard.

championc

But all is not lost. You can add a separate Storage Inverter onto which you can add batteries. Look at the Sofar ME3000, onto which you can also attach a DIY 10kW battery bank for about €1500 (see other thread)

DrPhilG

https://www.boards.ie/discussion/comment/119199526#Comment_119199526

Or he could just clarify what he's getting from the installer and go with a hybrid which is most likely what's already on offer.

If he already had the system and didn't have a hybrid then it might make sense to go with a separate inverter. But if only at the quote stage, I wouldn't see much value in going for 2 inverters now.

scunermac

Thanks both.

You are right, I’m mixing up my terminology. What I meant was that my installer is going to provide a standard inverter, not a hybrid.

Which I suspect is why the price is reasonable ~€5.5K (after grant) for 4.9KW system plus eddi.

But it sounds like even if I go with a standard inverter that I could easily add a battery later anyway, albeit with an extra piece of kit like a Sofar ME3000. Is the €1500 you mention the total price for sofar + battery championc? Or just the battery?

championc

€1500 for the battery and BMS. The ME3000's are currently a bit scarce so you could be looking at €750 for it - but the ME3000 is super controllable from externally (Node-Red), so real load shifting and weather compensation opportunities.

I think there's still one on Adverts currently

John mac

https://www.boards.ie/discussion/comment/119201243#Comment_119201243

€900 is the cheapest ive been able to find , from The Netherlands , nothing on adverts.

Jonathan

https://www.boards.ie/discussion/comment/119203112#Comment_119203112

Is @graememk's sold?

graememk

https://www.boards.ie/discussion/comment/119203444#Comment_119203444

Yeah, was on my way to update that post. Just finalised it today.

Taxburden carrier

General question: is there any issue with locating your battery with the inverter in the attic. Thinking of temperature swings but newbie so any advice welcome

DrPhilG

https://www.boards.ie/discussion/comment/119203810#Comment_119203810

I have insulation built around mine for winter. Kept it at a cosy 18 degrees even when the attic dropped to 3 or 4.

Keeping it cool in summer may be more challenging, but I've found recently that just a standard table fan blowing at the inverter has been enough to drop the core temp by a good 10 degrees on a hot day.

irishchris

Temperatures in summer can get high and my Solis in garden shed was reaching 60C+ on many days of high production. Got wall mounted fan blowing down on inverter heatsink. Set to come in with homeassistant at 30c and off at 25c. Temps now sit most days at 25ish

graememk

https://www.boards.ie/discussion/comment/119205637#Comment_119205637

Link to said fan?

irishchris

https://www.boards.ie/discussion/comment/119205686#Comment_119205686

https://amzn.eu/d/5vilUqQ

This is the one. I have it connected to smart plug linked to home assistant and automated then to come on depending on temperature readings pulled from the Solis inverter

DrPhilG

Better weather today, checked the Solis core temp and it was 54°.

Turned on the fan and 2 hours later its 33°.

Battery is 22° and nearly full.

SD_DRACULA

Ordered one of these bad boys myself https://www.amazon.co.uk/gp/product/B08GP622YS/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Will set it to max speed and let HA control a smart plug with this plugged in based on the inverter temp.

I was going to go for a DIY project and build one of these esphome fan controllers https://github.com/patrickcollins12/esphome-fan-controller but don't wave the time for that 😔

bullit_dodger

https://www.boards.ie/discussion/comment/119201033#Comment_119201033

Again you are mixing up things a little there scunermac.

Standard Inverter : Can take power generated from your panels and give to your house (including EDDI hot water)

Hybrid Inverter : Can take power generated from your panels and give to your house (including EDDI hot water) and also, if you have a battery present, it can charge and dis-charge a battery.

You don't have to have a battery installed with a hybrid inverter, but if you install a Standard one, then you are effectively closing the door on adding a battery down the road without either replacing the standard inverter with a hybrid, or adding a 2nd inverter such as a "ME3000"

If you are unsure or don't have the money right now for a battery, but feel that it's likely you will add a battery down the road, I'd ask for a "hybrid inverter". They are perhaps €200-300 more expensive than the standard one, but you'll keep your options open.

DrPhilG

Agreed.

It makes no sense to me to get a standard inverter now and then be faced with an upgrade or a second inverter later.

Much cheaper and easier to get a hybrid now to future proof.

John mac

Also Check if the inverter is Tied to a battery , will lessen any oprions later ..

graememk

https://www.boards.ie/discussion/comment/119207547#Comment_119207547

The solis hybrid inverters are nearly double the price of standard inverters (700 vs 1300 + vat)

Its not hard to swap out inverters, but it's still more work than just putting in a battery.

scunermac

https://www.boards.ie/discussion/comment/119208666#Comment_119208666

Yep exactly. It doesn’t mean you can never add a battery to a system that has a standard inverter installed. It just means there is a bit of extra work (and cost) to do it.

The dilemma I had was trying to justify the cost increase now for a hybrid inverter ‘just in case’ I wanted to add a battery later. I decided to save my money for now by just going with a standard inverter, with the understanding that the system could still be upgraded later if needed (with an additional cost at that time).

Plus, the installer I decided to go with only install standard inverters (they operate a very fixed model). So it would have meant changing to a different installer with a higher price. I was very happy with the installer I’ve gone with as they were brilliant during the initial planning stage. I’m now just waiting until the second half of this year for the system to be installed.

championc

The important thing is that keeping with the original install keeps that warranty and support intact.

I do feel that a separate storage inverter gives several benefits over hybrid, the most useful being being able to install both in separate locations (maybe PV inverter in the attic and a Storage Inverter in the shed with the batteries)

Galego

https://www.boards.ie/discussion/comment/119207951#Comment_119207951

That's it. The Solis hybrid inverters are compatible with loads of batteries. Polyntech batteries will become relatively "cheap" once stock is back.

The Solis hybrid is only 400eur dearer than their string inventer model. I think it is a total non-brainer.

CoffeeBean2

I have been lurking for a while and have read most of the posts of the last few months. Thanks all for some really great information! I am planning to build a DIY 10 / 20 kWh battery system using either 16 or 32 of the standard 200AH Lifepo4 cells at the end of the summer. I'll probably play it safe and just go with a 10kWh 16p1s system now.

Some stores on AliExpress have a sale on at the moment to celebrate 618. I see most people mention OYE Store and PWOD Store when it comes to LifePO4 cell purchase. Has anyone used OOzing Store? Comparing the VAT inc price, OOzing are about 300 euro cheaper than the other two stores for 16x '2022 200AH Lifepo4 4-32PCS 200ah Battery High Capacity Battery Pack NEW Lifepo4 Battery For RV Golf Cart Battery EU US duty free'.

Good value or too risky?

championc

I'm not aware of anyone actually receiving cells from anyone other than PWOD and OYE. Several of us have bought and received refunds from other sellers

Mr Q

https://www.boards.ie/discussion/comment/119225101#Comment_119225101

I purchased mine from Docan Power on Alibaba. Very easy to deal with and all arrived.

But like you I also purchased some from Aliexpress which did not arrive and had to wait for a refund.

the_amazing_raisin

On a slightly tangential topic, what are people using as enclosures for DIY batteries?

If I go the DIY route I'll probably end up putting the battery downstairs in the utility room as it's reasonably convenient for the CU and cable runs from the panels

This opens up the possibility of the kidderlings messing with the wires or trying to lick the busbars or something

So something which is fairly secure like a metal cabinet seems like the best approach (small server cabinet springs to mind). Or maybe a lockable box made from fire rated plywood?

Anyone have any other ideas?

Also how much ventilation to the cells need? Would a few temperature activated exhaust fans on the enclosure do the job?

con747

Lick the busbars 😂

https://www.boards.ie/discussion/comment/119228026#Comment_119228026

championc

If you put under a table or bench, you could get a piece of wood as a door, hinged along the bottom / floor edge, with a bolt or lock keeping it closed

the_amazing_raisin

https://www.boards.ie/discussion/comment/119228089#Comment_119228089

Never underestimate the amount of trouble kids can get into 🤕

the_amazing_raisin

https://www.boards.ie/discussion/comment/119228220#Comment_119228220

I was thinking of putting a kitchen cabinet in and putting the batteries inside with a padlock across the door

I would probably line it with fire resistant material since modern furniture is basically kindling

Bit worried about ventilation though, the utility room gets fairly warm and inverter plus batteries will only add to the heat. Maybe a few vents in the bottom and top of the cabinet would be enough? Plus some temperature activated fans to assist in warmer weather?

munsterfan2

Got a battery capacity tester from Aliexpress, working through my cells, but here is a sample output. Tested down to 2.6v.

A few more to test as was away on holidays. Will get on to OYE store again then.