10kWh LifePO4 DIY Battery Addition..... Here is my write up.

championc

Just to clarify, I think the CALB cells (which most on this thread have bought / will buy) are either rated for 2c or 3c.

I think it's the likes of Pylontechs that are 0.5c rated. They possibly only have small pouch cells inside.

reklamos

Even within CALB it does varies depending on the battery type. The 200Ah ones that most of us have bought are 0.5C(https://www.evlithium.com/CALB_Battery/42.html) other types go higher but DOD lifecycles for all of them are measured at 0.3C. Also max discharge rate is usualy 2x higher than charge rate.

G0ldp001

It would be great is someone put together as a kit for Ireland. I think lot of us are interested.

graememk

https://www.boards.ie/discussion/comment/119154378#Comment_119154378

Issue is by the time you get everything together for a kit, and providing support, a warranty? You'd be close to off the shelf batteries.

championc

https://www.boards.ie/discussion/comment/119154378#Comment_119154378

If you can use a screwdriver, a spanner and a digital multimeter, then this is ridiculously doable by all.

And I can assure you that all who have done it so far are from all walks of life. Probably most are average general DIYers

mrohare

quick question or 2..

1. What are peoples feelings on compression? - yes/no/how etc.
2. those of you who have built already - did you clean battery terminals/lugs etc. and how?

thanks.

dermotx

https://www.boards.ie/discussion/comment/119149575#Comment_119149575

Hi. I'm not sure I understand that comment. I intend buying from PWOD here https://www.aliexpress.com/store/5384082?spm=a2g0o.detail.1000061.1.6a841216Zqnnn0

Is the following the procedure?:

I buy the usual way on Aliexpress and pay for the batteries immediately. Before I pay, Aliexpress or PWOD will subtract the VAT.

They will give me a tracking number when the batteries arrive in Europe.

I don't understand the "be very careful" warning about contacting An Post.

Just as a precaution to make sure I am getting the batteries from PWOD and not some fake store, does anybody have a contact email for PWOD please?

Thanks

Dermot

championc

My "be careful" comment related to cheaper sellers and you trying to get refunds from these sellers when the batteries don't materialize.

The seller I tried to buy from kept insisting they they were at the post office for collection

BuzzFish

https://www.boards.ie/discussion/comment/119154378#Comment_119154378

I've been quiet since the original post as hit a very busy work period but the system is working away great. As others have said, a couple of simple tools, bit of planning and careful work and this is an easy assembly. There would be no value in someone building kits to sell on.

If anyone has specific questions, drop me a PM and I will reply in thread with your questions as I don;t get in here as much as I'd like and have missed multiple questions being asked.

dermotx

https://www.boards.ie/discussion/comment/119090548#Comment_119090548

Could I ask please where you picked up the Sofar me3000 inverter and how much it cost?

mrohare

https://www.boards.ie/discussion/comment/119167746#Comment_119167746

Fleabay used for £480.

Couldn't get it anywhere else.

dermotx

Thanks for that. Great price.

Mr Q

https://www.boards.ie/discussion/comment/119169899#Comment_119169899

You will struggle to get one for that now. There is currently one on the UK Ebay and he is looking for 1k GBP for it and it is used.

randombar has mentioned on another topic that wdsolar.nl sent him one even though they don't list Ireland as a delivery location. Seem to be one of the only places with stock.

Nelbert

Considering DIY myself for battery and solar so this is much appreciated guide.

To clarify my calculations 32 X 200ah (thanks for the mentions of the reliable Ali sellers) equates to approx 20Kwh (ignoring losses for charge and discharge)?

I see offers of higher ah rated batteries. Assuming you could find the right price Vs capacity value wise is there any thing different other than capacity?

My simple understanding is connect 16 in series to get up to approx 48 volts for inverter input and then another batch in parallel (groups of 16 in series essentially).

Can a BMS handle the initial balancing?

graememk

https://www.boards.ie/discussion/comment/119172565#Comment_119172565

It will take a long time for a BMS to do the initial balance, it can maintain it though.

You can get 16 at a time and go with that. The seplos can be daisy chained like that or go for a single bms and have a string of 16 pairs of paralleled cells (16s2p)

championc

Regarding higher cell ah's, those mostly appear to be the aluminium cased cells with quite small terminal posts and busbars.

I think that all of us with the 200ah CALB's would agree that the casings of them is far better and the terminals with M8 bolts and the multileaf copper busbars are a far better option

connesha

I'll soon start my DIY build of 20kwh CALB 16s2p, Seplos BMS, into a Solis Hybrid 5G 6kw.

A couple of questions on top balancing...

1) Is there any issue with top balancing all 32 cells together? (apart from it taking a long time). Intend to buy the power supply the OP here posted (https://www.amazon.co.uk/gp/product/B09C8LWV9W). I'm not in any rush, and have a few more bits and pieces to get still, so even it if takes a couple of weeks I'd be happy to let it sit there working away slowly.. and it'll save crawling into the attic a couple of times to change connections...

2) When the batteries are balanced, how long is it Ok to leave them sitting there before connecting to BMS/inverter? Do they drift after a few days/weeks if left unused? (or if keep the them connected in parallel after disconnecting the Power Supply they'll stay balanced?)

Thanks

championc

I certainly plan to charge them up to 100% first with my INVERTER, then disconnect them and then top balance them properly

reklamos

https://www.boards.ie/discussion/comment/119227898#Comment_119227898

1) It will take very long with 10Amp PSU. As @championc said top it first. You do not need to charge it to 100% just get to 3.5V on the cells. Also you do not need to connect to inverter. I have used DC PSU the could supply 58V and let BMS do the rest.

2) They do drift slowly but if you leave them connected the same way as you did top balancing they will drift equally. Leave them connected after top balancing overnight and on the next day connect to BMS.

spose

getting close to starting to put my battery together and looking for some help that isn’t too clear from the bits spread out across the different threads. My set up will be seplos and me3000. Once I have batteries set up and bms connected to battery do I need to configure the bms before or after connecting to the me3000? Once I connect it to a PC what exactly am I setting up in it? Do I need to do a firmware update or is it good to go?

on the me3000 then, anything i should watch out for on the set up of that or just step through the menus as it powers up?

last question then is I understand I need to do a charge and discharge cycle at the start but how exactly do I do that?

thanks for the help

Nelbert

I'm interested in this. Shed rebuild with an expanded roof area will be the place for panels.

I'm a bit confused though and reading conflicting things about BMS needed Vs not and what ones are compatible with the Solis Hybrid inverter on my planned purchase list. Does the Seplos BMS work and is there a reliable supplier anyone is aware of for one? Only listing I found had zero stock.

championc

@spose

The BMS is only powered by the batteries, so it will need to be connected to them to configure them.

Remember the small reset button which you may need to press to turn it on.

When configuring, you immediately need to set the interface to RS485 and the protocol to SOFAR . I may have the wrong names here but the items are side by side near the top right corner when in the admin screen.

Don't worry too much about the full charge and discharge. It only needs this to accurately calculate the capacity.

I think I posted a copy of my config file earlier in this thread, that you could use for values.

Once all setup, then configure the ME3000 for the battery type "General Lithium"

wonder1

Hi, Apologies if this is the most basic of questions, but what do I actually buy on this screen. I understand I need to buy a '4 cells option'. But what is that and where do i select it to add to cart?

Thanks (Im a complete newbie)

championc

The Colour is what they are using to select lots. You want 16 cells - so 4 lots of 4. Should be about €1300 after the reduction

CoffeeBean2

I am now committed to this adventure now as I have ordered 16PCS Lifepo4 3.2V 200AH. I'm currently in the process of putting together a shopping list and understand that the SoFar ME3000 is hard to get a hold of at the moment. With the high price, I may just go for the SoFar hybrid inverters as it would allow me to add some additional panels to the garage roof.

If I am going down the SoFar direction, I assume the best bet for the BMS is a Seplos 48V 16S LiFePo4 150A, at least reading messages here, that appears to be the route most have taken.

I read in your post @BlueFish that you purchased your Seplos BMS from Minerals Official Store on AliExpress, but I am unable to find that product within their store. I did find the below item, and while the webpage does not mention Seplos in the description, the photos do look like the Seplos BMS. Do you think it is the right one, or could it be a knock off?

https://www.aliexpress.com/item/1005003443741614.html

spose

https://www.boards.ie/discussion/comment/119237540#Comment_119237540

Thanks championc, I can’t seem to see that config file you posted any chance you could post again please

championc

Here's my XML file of settings for my Seplos. Huge thanks to @garo for guidance.

I have pushed the top end values to try and bring up some cells which were lagging behind at the top end when charging.

Parameter 20220402_1210.txt

ducky1981

Hey what is the best inverter to use for the battery setup I'm looking at a sofar or a Solis any recommendations or advice greatly appreciated

championc

Now that the Solis is confirmed as all ok with the new firmware on the Seplos, it would seem either.

From an automation and remote control of the inverter (telling it maybe to charge overnight or not, or charge to xx%), I think the Sofar is the clear winner, using a sofar2mqtt device and using passive mode on a Sofar Storage or Hybrid inverter.

ducky1981

It's the sofar hyd 6000-es I was looking at if I can get my hands on one at the moment so it should be good to go with the lifepo4 battery and the seplos BMS

Mr Q

https://www.boards.ie/discussion/comment/119282344#Comment_119282344

There are several used ME3000SP gone up on the UK ebay in the last few days. But they are expensive for used versions.

I used one of the sellers previously for an inverter and all was as described.

championc

Second set nearly here. From PWOD on AliExpress and proof for those unsure about taxes etc, you can see that they are commencing their trip from "Poland".

UPS website says I'll have them by Tuesday.

championc

And they have arrived

spose

Lost a week of progress to the good weather. Battery built and everything just about ready to switch on the sofar later today. Found getting the bms connected to the laptops a bit awkward but connected now. Thanks champion for the parameter file. One thing I’ve noticed though is it doesn’t seem to take the battery size and soc reading from the file. It still says 100ah and 75% soc. Any ideas why or does it even matter. I didn’t do a firmware update for the bms, should I?

championc

Just change the Capacity and SOC from on-screen and then click the Send All.

You may need a Firmware update if you are connecting it to a Solis inverter.

spose

Thanks to a lot of the help here I have my 32 cells up and running now with seplos and me3000 and pretty happy. Having some intermittent alarms on the bms so still trying to figure them out but seems to be charging and discharging ok for a few hours now

championc

Have you two separate strings, or 16s2p ?

spose

16s2p

spose

getting a lot of intermittent alarms for different reasons in charge/discharge. Mail sent to seplos but any suggestions welcome

championc

Why was it Charging at 22:04 ? And what SOC% did it discharge to ?

spose

The time stamps are wrong. Not sure where it’s pulling them from but it’s not linked to the laptop. Looks to be ~7 hours off. At that time it was reading 65% soc. Lowest soc it made it to at any stage was 48%. Have it powered off now. Part of the oddity is when the solar is generating the alarms reset themselves and the me3000 works again. When no solar is generating the me3000 doesn’t come back out of standby

championc

What version of firmware are you running on the ME3000 ? Did you set it up for General Lithium ? If you go into System Information, on page 4, does it show the battery as a SHEnergy v0.0.1 ?

reklamos

https://www.boards.ie/discussion/comment/119333642#Comment_119333642

That's a lot of errors. The errors suggest that you have some bad cells as you get 'cell differential' errors. I cannot remember exactly but the difference needs to be 0.3 or 0.5V for this to get triggered. Have you top balanced your cells? 'Output short' would suggest that someting on the inverter side but it could well be seplos.

The best way to get to the root of the problem is to constanly monitor seplos, each cell and inverter stats.

spose

Thanks both. Settings are as you ask champion. Cells were balanced but did have a week before they were connected. When running difference I’ve seen is on the seplos is 30mv typically between high and low. Taking one example when showing high voltage alarm the highest cell reading is 3.5 lowest is 3.384. For other high voltage alarms the individual cells are all below 3.5. From watching the alarms are definitely appearing on the seplos first and then registering on the sofar

spose

Feedback from seplos…these alarm information will definitely be sent to the inverter, and it cannot be prevented unless your inverter can make the BMS discharge and charge alarm value not reach, that is, turn off the charging before the BMS is charged to the highest, and turn off the discharge before the discharge is the lowest. , you can take a look at your inverter manual to see if this function is described.

reklamos

https://www.boards.ie/discussion/comment/119336274#Comment_119336274

3.5 and 3.384 is 116mv diference which is not bad but it seems to me that this not near the top of the charge as voltage is low. I have also some cells that start running away but this happens when soc is ~90% and the cells are at 3.45v

Check waht diference you get at the top and bottom charge. You can configure logging on PC so it dumps data to file and you do not need to eyeball it.

graememk

https://www.boards.ie/discussion/comment/119338026#Comment_119338026

For LFP 3.384 could be anywhere from 50-95% though. The cells could be a little bit out.. or a lot.

spose

the fact that it can give high voltage and low voltage alarms within 20 mins doesn’t seem right. Reading the reality one log all the voltages look ok even though low voltage alarm says voltage was 0.2v on cell 1. In a closed box and checked cables and all seem fine.

spose

So powered it back up this evening to see how it behaved and ran for about 2 hours with only 2 alarms. There was no solar for charging during that time. discharging ranged from low couple of amps to long enough periods of>50amps. To make it awkward the time stamps on the realtime log and the alarm log don't match. Real time log is actual time and alarm log is 7hrs 11mins ahead. For the last alarm (06:50) on the alarm log shows low voltage on cell 1 (0.2V) cell 2 (0V). All the previous low voltage alarms seem to also be 0.2V. The realtime log shows the voltage stable across cell 1 and 2 at that time (23:38) at 3.2V. Don't want to just keep resetting the battery and inverters just to see how it behaves but I'm WFH tomorrow so will try it while there's a good bit of solar production going on too

alarms3.xlsx

real time data3.xlsx

championc

Check or reseat the BMS cell monitoring cable connectors onto the board's connectors