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

championc · 20-09-2022 10:10pm

https://www.boards.ie/discussion/comment/119643845#Comment_119643845

If you lodge a claim, lodge photos but add arrows and large text simple commentary, that an idiot can understand, because you have to make a clear undisputable case. You only get one shot, so you need to make it count.

I personally lost another claim because I didn't spell out what my photos were saying. I had blurb in my claim, but pictures speak 1000 words !!!

munsterfan2 · 20-09-2022 10:35pm

https://www.boards.ie/discussion/comment/119643845#Comment_119643845

It could also be that they are old / used 200ah cells and will deteriorate quickly as has happened to mine. After 2 months trying to run them as 140ah one of the cells died completely.

unkel · 20-09-2022 11:00pm

I've had a few claims before where I had to use video as evidence. I'm brutal at that sort of thing, but I was given plenty of chances to explain my videos and re-do some. I have got a full refund every single time I entered a dispute with AliExpress, in fairness to them. I'd say I've had at least 12-15 disputes over the last few years. I buy a lot of stuff over there.

Nelbert · 21-09-2022 6:40am

Is this issue confined to the OYE seller or has anyone used PWOD and been impacted?

Considering a DIY battery to avoid day rate over winter but this is worrying.

mrohare · 22-09-2022 5:50pm

They refused at first but now offered a refund, BUT I have to pay postage!! It is ridiculous as cost of return is huge. Cannot get talking/messages to a real human on aliexpress and the eve bot keeps saying it is buyer's responsibility to pay return on this sale. Scam.

munsterfan2 · 22-09-2022 6:23pm

Did you use paypal, if you did try to cancel your payment with them. You cant ship batteries back easily due to shipment requirements.

munsterfan2 · 22-09-2022 6:24pm

Make sure to leave a review on their store before the time limit on that expires

unkel · 22-09-2022 7:46pm

https://www.boards.ie/discussion/comment/119651743#Comment_119651743

I've been there with batteries. Simply tell AliExpress that it is illegal to ship any battery with lithium in it to outside of the country. Simples. They accept that (and it's not far from the truth)

mrohare · 22-09-2022 8:04pm

https://www.boards.ie/discussion/comment/119651858#Comment_119651858

Good call @munsterfan2. Lodged a complaint with PayPal this evening.

mrohare · 22-09-2022 8:06pm

Hi @unkel, how do I tell Aliexpress? I just get their chat bot. Cannot find a link to a human chat or email etc.

unkel · 22-09-2022 8:09pm

Keep telling the chat bot that you want to speak to a human. Or better, do it formally through the dispute progress, you can update it with your statements

unkel · 22-09-2022 8:10pm

https://www.boards.ie/discussion/comment/119652196#Comment_119652196

I would wait until a resolution with AliExpress is definitely not possible. If needs be, threaten AliExpress that you will start a claim procedure with the credit card company if they seem to refuse

mrohare · 22-09-2022 8:52pm

https://www.boards.ie/discussion/comment/119652219#Comment_119652219

But, I can't even get talking to Aliexpress. The seller agreed a refund but I have to pay return. There is no option to do anything (on the page) but enter return details. I have searched Aliexpress site for a live chat or email address but it is only an automated "Eve" bot that gives generic answers. If you have any way to get a message to Aliexpress, please let me know.

munsterfan2 · 02-10-2022 10:28am

Any progress with your claim @mrohare

S' · 05-10-2022 2:26pm

For those that went the DIY route and purchased from OYE or PWOD, are you happy with the capacity?

Looks like I got used cells from PWOD.

Top balanced to 3.65v

Resting voltage is 3.4v, all within 20mV of each other and battery voltage is 54v

When a 10A load is on them they all drop to around 3.25v and battery voltage is at 52v.

If I turn on the oven the BMS (seplos) low voltage alarm cuts in, this is when battery should be >90%.

unkel · 05-10-2022 3:22pm

When your pack is resting at 3.4V (fully charged) and you switch on the 3kW oven, you get a low voltage alarm from Seplos straight away? Something strange going on there. What is that reported voltage and do your inverter and the Seplos both reported the same voltage? What is the alarm level on the Seplos set for? Some of the default values in Seplos are way over protective imho.

With any battery, you will always get voltage sag if you apply a load to it that is a significant part of its total capacity. So a 60A load on a 200Ah pack will not go unnoticed 😁

E30M3 · 05-10-2022 3:44pm

https://www.boards.ie/discussion/comment/119704611#Comment_119704611

It sounds s if you have a BMS calabration issue currently. What BMS do you have and have you calibrated the battery capacity for the BMS?

S' · 05-10-2022 4:25pm

https://www.boards.ie/discussion/comment/119704922#Comment_119704922

Get a low voltage alarm after 20secs when I switch on the Oven. Pulls 80A on startup.

Yes, at the minute battery voltage is 55.3v on Solis inverter, Seplos BMS and on my fluke multumeter.

Inverter displaying 100% but the last few evenings when the battery is drained to 65% and then hits low voltage alarm when a load of around 11A is present during that time.

I loaded the following parameters to the Seplos and this firmware

Seplos BMS Modified Firmware.zip

Parameter 20220402_1210.xls

S' · 05-10-2022 4:30pm

https://www.boards.ie/discussion/comment/119705032#Comment_119705032

Seplos 48v 16s 200A BMS

https://www.aliexpress.com/item/1005003443741614.html?spm=a2g0o.order_list.0.0.21ef1802ZdxOvd

Seplos is unable to calibrate as it either hits low voltage alarm (discharging) or high voltage alarm (charging)

I have set the Seplos battery to 200A.

E30M3 · 05-10-2022 4:46pm

https://www.boards.ie/discussion/comment/119705261#Comment_119705261

Did you do a controlled Calibration as per the instructions initially? Both of those things will happen but in a controlled way.

S' · 05-10-2022 5:06pm

https://www.boards.ie/discussion/comment/119705332#Comment_119705332

No, I didn't. Can you point me to these instructions?

championc · 05-10-2022 7:18pm

Personally, I charged my cells to 3.65v, one by one. When I finally finished with cell 16, I went back to the beginning again, since all were below 3.5v.

I previously read that LiFePO4 does NOT lose voltage.

So re-commencing charging, I once again charged each up to 3.65v. This time, each settled around 3.60 - 3.62v. Some cells took quite a while on this second round, so I am quite sure that there is definitely extra capacity which I would have lost had I finished after the first round

E30M3 · 05-10-2022 11:28pm

https://www.boards.ie/discussion/comment/119705410#Comment_119705410

They should have been written on a leaflet stuck to the inside of the box the BMS was delivered in. Did you see this note on the box?

Calibration instructions also discussed on the SEPLOS BMS thread

poker--addict · 14-10-2022 9:15am

Before I look at some videos of top balancing on YouTube, can anyone bring me up to speed in simple terms why batteries only giving say 60% of capacity until this step is completed? And why we use a bench power supply - like why doesn’t the inverter or BMS eventually sort it out? ( yes I’m starting looking at thus from a low bar 😂, at least until I see a cheap relatively trustworthy powerwall)

graememk · 14-10-2022 10:31am

https://www.boards.ie/discussion/comment/119742458#Comment_119742458

To give an example, of how I think of it.

Battery pack is made up of usually 16 cells.

If them cells are thought of as buckets, that hold water for instance. Each bucket is slightly different size.

They are all holding different amount of water too. One could be at 50%, another at 75% and another at 25 %to give a extreme example.

When they are put in a string, they all fill and empty at the same rate. When any of the buckets get full, the bms stops all charging. So not to "overflow(overcharge)" that bucket

When empting the bms will stop discharge so not to " over empty (over discharge)" a bucket

Top balancing gets all buckets completely full so they all hit "full" at the same time. So that was they are all at the same state of charge. And all move as one.

The bms can balance cells, but it's like a slow drip out of the highest cells. It will get there eventually but it takes a long time.

It's good enough to keep it in check though.

There is active balancers that can balance at 4 amps (the neey for example) and they can move power instead of just burning it off.

poker--addict · 14-10-2022 11:15am

Plain as mud thank you.

poker--addict · 14-10-2022 11:20am

10kw or 20kw of batteries?

8kw of panels on the roof. Day night esb meter for now. Intend to get an EV once the car to house/grid tech is more widespread and doesn’t cost a fortune to hook to house- and that will be the cheapest large house battery anyone could want. So do I stick with 10kw, or is there any logic in 20kw? I am cash flow poor post panels so happy with avoiding 20kw cost unless there is strong roi reasons to pay up. Houses uses a lot of power, heat pump draining battery quickly probably isn’t ideal so I am thinking 10kw to manage shoulder peak hours is the way to go, pump uses grid at night, charge battery before sun rise. 20 might actually be counter productive as I write about it - as it will just get trashed by heat pump?

unkel · 14-10-2022 11:26am

It's insane that decent €200 BMS have only passive balancing (which is plainly sh1t - not fit for purpose and lossy / inefficient as it just burns electricity from cells that are too high) doesn't have the built in active 4A balancing that a €40 balancer has. The active balancer takes electricity from cells that are too high, stores it in a capacitor and then sends electricity from the capacitor to the cells that are too low

I installed a balancer myself a couple of days ago (had it for years, never tried 🤣), the results are astonishing. And I don't even have to qualify that with "for such a cheap device"

Here's your man from the off grid garage about them: (summary: "you should get one")

https://www.youtube.com/watch?v=1SRUhgBdy_g

DC999 · 14-10-2022 11:44am

https://www.boards.ie/discussion/comment/119743013#Comment_119743013

What about no battery for now. And get an EV. You’ll save a grand a year on petrol (give or take) for ~15000kms a year. And tax is 200 quid. Charge on the cheap night rate so it’s the cheapest cost to ‘fuel’ it. And get the 600quid grant for the EV charger. Get the cheapest charger you can, not a Zappi that can take power from solar (as you get paid more in FIT that cost of cheap rate juice).

I got a 2nd hand Leaf a few months ago and it's brill. It's our only car now. So don't need to spend a fortune on EVs. Can if you have the deep pockets - we didn't :)

poker--addict · 14-10-2022 12:33pm

DC999 all valid points. I am waiting however because with two small kids and their belongings we “need” an SUV size EV. Straight away that means fairly large outlay, and not all of them make vehicle to grid/house power transfer easy. The two way power I think adds significant value to EV ownership ( currently, unless doing big miles, I think a lot are over priced). I think the lack of 2 way power from car to house will change rapidly now that big names like VW are getting there, and we should I feel get to a point where the house charger is not 1000s to support that two way power too. Happy to be corrected if wrong, sorry off topic.

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

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