Solar PV battery options

garo

I am too far gone as are you 😀

slave1

Sometimes it’s the challenge and the economics are set aside

garo

Yes and thats why I am considering a second pack. I've already done the hard work of getting the BMS wired and running, done all the crimping etc. Adding a second set in parallel would be a doddle. Also if we think in financial terms, the number of hours I spent working on this, if my job were paying overtime, I would have probably made more than the cost of two battery packs.

slave1

https://www.boards.ie/discussion/comment/118550521#Comment_118550521

5 days later, all cells are between 3.6406 and 3.6408 so obviously works

graememk

Finally got the bathroom done... So Got some time this afternoon to tear the old battery pack down (Merging the 2 older packs for my dads set, and keeping all the new ones together.

top balanced them to 3.6, Its been nearly a week since that was finished, All are over 3.45 but some are 3.5x, Close enough, As long as they are above 3.4 I'm happy.

Also have moved from 2 rows of 8 (the 9th cell would appear high on charge and low on discharge due to the extra cable linking the 2 rows) to 1 row of 32 (16s2p)

slave1

Single row of 32, snap, using this as a guide

Jonathan

Might be of interest to some here. Popped up in my YT subscriptions earlier.

https://www.youtube.com/watch?v=O-VX32g3Aeo

championc

After a month running on the Seplos BMS, I finally had thing dialed in pretty well I felt, until the end of month showed that I had used 29 day units. Something was definitely wrong.

I went investigating and began homing in on the possibility that I was importing a small amount of power permanently, based on a misreading of the CT clamp attached to the mains, and the 30m run to my Storage Inverter.

I finally copped that I could use my MyEnergi app and look at the Grid graph. Sure enough, I was importing about 10 - 15w all day and night.

So at 14:00 today, I changed the CT clamp offset from +10w to -10w and then, around 18:00, changed it to -15w

slave1

I think I understand that, I too will have a similar setup by the end of the month so must check back on this CT offset which I've never heard about before

Alkers

https://www.boards.ie/discussion/comment/118538623#Comment_118538623

And excuse my ignorance but are those clamps wireless? Which cable to they go on?

championc

https://www.boards.ie/discussion/comment/118573121#Comment_118573121

On the ME3000, it is item 15 - CT Clamp calibration in the settings menu

championc

https://www.boards.ie/discussion/comment/118573489#Comment_118573489

Generally wired and go around the positive / live wire. Used to measure current. The MyEnergi ones can pick up enough current through induction to power a connected Harvi, to send data wirelessly with radio signals to a Zappi or Eddi

Alkers

So would I have to run s CT clamp cable from my main fuse up to the battery pack?

championc

It's the inverter which talks to everything. So a CT clamp would be connected from the inverter to the incoming grid connection

graememk

https://www.boards.ie/discussion/comment/118573636#Comment_118573636

Doesn't have to be the main fuse, it can be from the consumer unit, as long as it's on the main incoming grid cable.

There's also a second CT used to monitor the solar but that's more for stats, it only needs the grid one.

It would(generally) need its own cable back to the consumer unit

Big Lar

Just wondering how long folks have been waiting for these batteries from the OYE store, feel like I am getting the run around from them. Ordered 6th Nov last, they extended purchase protection at the start of Jan but still nothing.

slave1

I was 6 working days, @DrPhilG was deffo very long time

garo

https://www.boards.ie/discussion/comment/118573020#Comment_118573020

Interesting. I didn't see that with my Growatt/Seplos combo. But what I did see was the BMS/inverter combo being a bit slow to respond to sudden increases in demand when solar PV has a sudden drop. This also means that every day around sunset (or half hour before) I end up drawing from the grid for 10-20 mins.

The other issue I have is the inverter losing it's connection to the BMS when the battery is 100% full. I've had the inverter firmware updated and cut wires 7&8 on the CAN cable as suggested but no joy.

Jonathan

https://www.boards.ie/discussion/comment/118575407#Comment_118575407

https://www.boards.ie/discussion/comment/118575118#Comment_118575118

Merged this over to the DIY Battery thread.

graememk

https://www.boards.ie/discussion/comment/118575407#Comment_118575407

I got mine about 2 weeks ago, ordered in Nov. (From pwod)

When did you get your ups tracking number?

Big Lar

https://www.boards.ie/discussion/comment/118575826#Comment_118575826

https://www.ups.com/track?loc=en_ie&tracknum=1Z7235996837313271&requester=WT/trackdetails

They keep extending the buyer protection but I am getting at the end of my rope now with them.

championc

https://www.boards.ie/discussion/comment/118576865#Comment_118576865

Do you have the tracking number ?

But I think most waited about 10 weeks

Geeyfds53573

All 16 batteries charged to 3.59 - 3.62. Doing the math they were at a very low SOC. Hopefully Sunday I’ll get time to put some of it together.

DrPhilG

https://www.boards.ie/discussion/comment/118575407#Comment_118575407

Ordered in March, landed in August.

graememk

I'm back up and running now again with 20kwh storage.

Also picked up a second ME3000, thats being controlled via nodeRed. I can now charge/discharge at 6kw.

Jonathan

https://www.boards.ie/discussion/comment/118580351#Comment_118580351

How is that working? Are you setting a static discharge rate on the first to cover your base load? And allow the second to vary using the CT clamp?

slave1

https://www.boards.ie/discussion/comment/118580351#Comment_118580351

23kWh gross, you limiting by ~15% to get to 20kWh usable?, I was going to go 20%, 15% bottom, 5% top

garo

How do you get 23kWh gross? Using 3.2V nominal I get 20.48kWh. 3.2*16*200

slave1

But do these batteries not charge to 3.6V

graememk

https://www.boards.ie/discussion/comment/118580439#Comment_118580439

I have CT on the Battery feed, at the consumer unit. Connected to an emonTX so its external to the whole system. - I had thought about it for a while, I have come up a relatively simple algorithm.

When the load on that passes 1.5kw (charge or discharge) I set the secondary ME3000 to charge/discharge at half of the load on the battery CT. That updates every 10 seconds which is good enough. when the load drops below 1500w, it goes back into standby.

Picked the second hand one up for £280 delivered to a depot in NI.

I have read, that I could wire up a ct in parallel to to the grid CT that is around the output of the secondary ME3000, and then the Secondary one has its own grid CT.

Both will kick in when it sees a load, but the primary will quickly take over from the secondary until it is maxed out. Then the secondary will be able to make up the difference.

I have the 2 inverters connected to the same 20kwh pack.

https://www.boards.ie/discussion/comment/118580923#Comment_118580923

https://www.boards.ie/discussion/comment/118580983#Comment_118580983

The capacity is calculated on the "Nominal" voltage so 3.2v. Planning on going 100-20 or 15% Not sure yet, but only doing a max charge of 56/57v (3.5-3.55V)

Edit:

garo

https://www.boards.ie/discussion/comment/118580983#Comment_118580983

But nominal voltage is 3.2 so that's how you usually calculate capacity. Also you really don't want your batteries at 3.6V for long periods. That's the charge voltage i.e. voltage applied by the charger and not the voltage of the battery at rest and certainly not the voltage you see when you are drawing current.

graememk

Again... As a reminder... Check all the bolts on the terminals are tight..

And don't spend ages wondering why a cell was running high on charge and low on discharge. When I had tightened "every" bolt.

optip

thank you to all who have contributed to this thread - it's a fantastic resource.

I've taken the plunge & ordered 32xCALB 200 cells from a previously mentioned supplier to upgrade my existing Victron + BYD 5kWh Solar/Battery system. (6kW of solar)

project is for 1) fun/hobby/learning, 2) to have options in a power cut / grid instability, 3) this won't save money - except over very long term - although my personal belief is that grid unit costs will skyrocket over the next few years and I'll be glad to mostly consume EV rate grid power and keep the monthly bills reasonable (~40kWh/day winter consumption).

My intention is to switch smart rate suppliers/tariffs yearly, using the ev rate power=>big battery + solar to minimise peak rate usage. I already automate my 5kWh battery system to control night-charging the battery using OpenHab/mqtt control of the Victron system (using cloud forecast to decide how much to charge while trying to avoid exporting unnecessarily). On a good day now, the battery is empty by 4-5pm - but that's my first peak rate consumption of the day (outside of surges, etc). My hope with this project is to reach 11pm (/end of peak rate) still on battery for most of the year... should be fun 😀

graememk

https://www.boards.ie/discussion/comment/118601580#Comment_118601580

Do you already have a smart meter installed? If not standard day night tariffs are better value right now

optip

https://www.boards.ie/discussion/comment/118602095#Comment_118602095

I do - was installed about a year ago out of the blue. I've just been on a standard tariff until recently - doing a bonkers switch every year. Hopefully, there will still be value in regular switching with the smart tariffs.

Jonathan

Will Prowse's latest two videos are interesting.

https://youtu.be/oXBT8lSC25M

https://youtu.be/1U6E1bvjDYQ

optip

https://www.boards.ie/discussion/comment/118602189#Comment_118602189

very interesting... I hadn't given much thought to paralleling my existing battery with the new DIY battery. Another fun rabbit hole of research :)

Alkers

Does anyone know if you apply for the €600 solar PV battery grant before the deadline of 15th February, can you still get an install after that date or does the install need to be done before the 16th?

graememk

https://www.boards.ie/discussion/comment/118606308#Comment_118606308

Once you get approval I think you have 6? Months to install and claim.

But you need to nominate a company in the application form to do the work.

slave1

What ye're letting yourselves in for, 32 cell battery and Seplos BMS dry fit

Evd-Burner

https://www.boards.ie/discussion/comment/118617931#Comment_118617931

Im learning/researching this at the moment. I didn't realise you could go with 32 cells. Can you send your wiring setup and what the capacity will be?

Also as a general question to everyone, is it possible to have 2 battery only inverters installed and working together? I've seen a lot quote a sofar battery inverter. I was thinking that I would like do a 10kw battery but wanted to make sure if I ever wanted ot was possible to expand that.

championc

32 cells in 16s2p will give you about 20kW of storage.

Look back a page or so at the diagram I posted for wiring the Seplos BMS

graememk

https://www.boards.ie/discussion/comment/118618333#Comment_118618333

32 is nearly the practical limit that you can do per bms (but really any multiple of 16)

A 32 cell pack is what is called 16s2p (16 in series, with 2 in parallel)

You need 16 cells to get the 48 volts required for the inverters.

With the seplos bms, it's also stackable afaik so you could have multiple sets of 16 (in whatever configuration) connected to the inverter.

It is possible to have multiple battery inverters. But it's not straight forward.

Method 1 : primary inverter is on auto with secondary on complete manual control via a external source, eg the me3000 has a passive mode where it's controlled by a rs485 connection.

Method 2, CT trickery.

Primary inverter has a CT on grid and a CT on the input to the secondary inverter are in parallel with each other.

So this would "add" the CT's. There could be a very brief transient when both inverters will start a charge/discharge but the primary will quickly take over until it can't anymore, that's when the secondary kicks in.

Evd-Burner

https://www.boards.ie/discussion/comment/118618475#Comment_118618475

Found it, cheers.

https://www.boards.ie/discussion/comment/118618858#Comment_118618858

Thanks for the detailed reply, looked at championcs wiring and some YouTube videos, I think im starting to understand the setup now.

Looking at the Seplos features it looks like it can connect banks in parallel to each other. I want to make sure that whatever I do is future proofed for expansion. I would assume to add another bank they would have to be similar batteries and SOC?

graememk

https://www.boards.ie/discussion/comment/118618972#Comment_118618972

Will prowse has a couple of videos recently about it

https://youtu.be/oXBT8lSC25M

https://youtu.be/1U6E1bvjDYQ

They are about server rack batteries but principle still applies.

slave1

https://www.boards.ie/discussion/comment/118618333#Comment_118618333

Re expansion, anyone who gets 16 battery’s wants to move to 32….only a matter of time before the 32 crew expands

Evd-Burner

https://www.boards.ie/discussion/comment/118619076#Comment_118619076

Yeah that's exactly what I'm thinking re 16, so when I seen the 32 together it definitely peaked my interest.

I currently have 1 EV with another on order for around July. I'm putting in a DIY e/w solar setup of around 4.6kW on the shed which will only cost about 3.5k. In spring of 2023 (remortgage dependant) we will be getting an attic extension where we could get another 6kW on a south facing roof, id look to have the battery setup by that so to get the summer out of it.

munsterfan2

I got mine today, ordered late November, of course they arrived when I am away for a week. 4 boxes, so I assume there are 4 batteries in each box. (From OYE). I got my tracking number about 3 weeks ago, before they arrived in Poland. Poland - France - Finglas - ME took about a week. ( €1229 for Grade A 16PCS CALB 3.2v 200Ah LiFePO4 )

BuzzFish

https://www.boards.ie/discussion/comment/118634707#Comment_118634707

Ordered on the 21st Jan from OYE and have had no contact since. I know they were away for Chinese New Year but they are back now so surprised that I've had no update at all. Was this the same for you.... no comms until the batteries arrived in Poland?

championc

Check your order in AliExpress. They generally attach the UPS number reasonably quickly to it. But you'll only see that number going active in maybe early March