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

johnbk

I did top balance and also noticed the imbalance. I took this photo as soon as I turned it on. Interestingly they evened out after 20 minutes. Was wondering if the Seplos can balance? I have seen on videos that this is the Achilles heel of the Seplos.

I’ve no way to load the battery so I’ll come back to it once I have the inverter installed and the battery connected.

I also need to get a better isolator.

unkel

Seplos only has passive balancing (it just burns the high cells and wastes energy) and only by a few hundred milliamps. So basically it hasn't a hope of balancing cells that are more than a tiny bit out of balance. I wouldn't worry about your cells just yet, the voltages in your pics are very high, so even a 100 millivolt difference means very little and it will always happen on the last stretch up to being fully charged. Just keep an eye on it.

jumpin jack

https://www.boards.ie/discussion/comment/120164462#Comment_120164462

Hi there,

The 8 batteries arrived by DHL and look really good, I had to pay VAT only on the purchase. Better than waiting 3 months to come from China?

jumpin jack

Hi there,

Would anyone know where I can buy a short pre terminated battery cable like this or just the connectors, I can't find them anywhere.

Thabks

jumpin jack

https://www.boards.ie/discussion/comment/120189962#Comment_120189962

It's a 25Mmm power cable

jumpin jack

The cells arrived from the UK and look perfect. The cost was £119 + €30 transportation and VAT at 23%.

graememk

https://www.boards.ie/discussion/comment/120189932#Comment_120189932

I suppose you didn't pay vat at purchase? (If you did you possibly could get them to refund it as it was exported)

unkel

@jumpin jack - "The cells arrived from the UK and look perfect. The cost was £119 + €30 transportation and VAT at 23%."

GBP119 = €134 + €30 shipping is €164 + 23% Irish VAT = €202 per cell. That's close to double what we pay landed from AliExpress. They sure look like brand new cells and it is good to have a relatively local company to get back to if something is wrong, but double the price means it will take twice as long for the batteries to have paid for themselves.

slave1

https://www.boards.ie/discussion/comment/120189298#Comment_120189298

I'd advise changing the "cycle" parameter on the Seplos, it defaults to 20% so every time you use 20% of the battery pack it will record as a full cycle.

THE ALM

https://www.boards.ie/discussion/comment/120189962#Comment_120189962

These are for 25mm cable, other cable thickness available so check, need a fairly hefty crimper also. Think mine took less than a week to arrive.

SLPPA25BSR / C10-730186-200 | Amphenol Industrial, Surlok Plus RADSOK Electric vehicle connector Plug, 120A | RS (rs-online.com)

jumpin jack

https://www.boards.ie/discussion/comment/120190936#Comment_120190936

Thank you very much for that, I've been searching everywhere!

poker--addict

30e postage per cell or for the pack? Looks cheap no?

jumpin jack

https://www.boards.ie/discussion/comment/120192147#Comment_120192147

Hi, €30 for 8 cells plus VAT at around €300.

Cells are really well packed and brand new.

I was delighted and will definitely order more, cheaper than buying directly from EVE factory. $160 per cell plus shipping and VAT here.

jumpin jack

https://www.boards.ie/discussion/comment/120190083#Comment_120190083

Hi there,

Actually I bought 8 cells at £119 ea, Shipping cost was €30 and VAT was around €300 which I can claim back. The cells arrived perfectly packed and delivered in 2 days from the UK.

Mr Q

https://www.boards.ie/discussion/comment/120190006#Comment_120190006

They have the QR code and everything as they should. Did you scan them all for manufacturing dates and info?

johnbk

Got the Solis inverter connected today. 32amp mcb on my rcd row on the consumer unit wouldn’t work. Rcd kept tripping. Electrican then went with an independent 32amp rcbo which worked fine.

To get the battery to connect and clear inverter error codes I had to switch from pylon (default) to AoBO on the Solis and change the Seplos bms CAN to Sofar.

First thing inverter did was to recharge the battery up to the bms high voltage disconnect, it then changed the status of the battery from 90% to 100%.

If this sounds simple it wasn’t and all this was done over the course of three hours while scrolling through the forum here for answers.

I got the kettle going to put a load on, but the battery isn’t really delivering any significant amount. I know I have a lot of learning to do but any suggestions on settings would be appreciated.

unkel

You should really post that in the Seplos thread. Tl;dr there are a lot of settings in Seplos you need to change and controls that need disabling, or it will have your battery more off than on.

You might also need to employ someone who can translate from Chinenglish to English 😂

johnbk

Noted, thanks. I’ll switch to the Solis and Seplos accordingly. By the way, switched the ct direction setting on the Solis and I’m up and running. (A lot easier in my case than switching the ct as it was a tight squeeze) 100% home battery powering the house now!

unkel

Nice one, well done! I've reversed the wires at the other end of the CT clamp in the past when I couldn't be bothered changing the CT clamp itself. As you say, tight fit. Or in my case I had two of them in my consumer unit. Not just tight in there, but I just won't go in it myself. I'd do anything else electrical, but not that.

johnbk

I didn’t envisage the Solis 6kw inverter pulling this many amps. I wired the battery for 125amps so I’m glad I did. 100 amps would have been cutting it fine.

This SOC lark on the Seplos is driving me mad. The lowest the Solis settings will go to is 5% SOC so as soon as the Seplos tells the Solis the battery is at 5% the Solis stops drawing current despite the battery having loads of capacity left and stopping the Seplos from calibrating. I am however gaining a little each cycle.

unkel

Don't worry, your Solis will soon throttle down to 60A or so 😁

It says 100A continuous in the spec sheet, but doesn't deliver on that...

johnbk

Also, to keep information in one place regarding battery calibration, this video will save someone a lot of time trawling through threads looking for information. I found it very informative and helpful

https://youtu.be/oBRSvSFVt74

slave1

https://www.boards.ie/discussion/comment/120203020#Comment_120203020

I’d put something thin over those batteries, anything metal falling onto them could do damage

johnbk

The Seplos bms is really quite clever. It is getting more accurate by the day on the capacity.

I have the load shifting set up now on the Solis. The last few nights, I have got over 12kwh put into the battery at night rate which has kept a busy house going until around 8pm the following day before the 12 kWh are all used up from the battery. I am paying 11.5c per kWh hour less for the night rate. On load shifting alone, the battery would pay for itself in 5 years in my case. Am I correct on this? (11.5c x 12kwh x 365 days x 5 years €2518)

The one thing to take off would be the losses of running the inverter I think. Maybe an extra year would allow for this.

Thanks

unkel

You're still using quite a bit of day rate electricity then, @johnbk. Maybe consider getting more battery? And don't forget it's February now, the days are getting much longer and we are getting a lot more solar PV. You will run out far earlier in December and January than 8PM

Pay back periods are a bit of a gamble as nobody knows what way electricity prices will develop, but personally I deem it inevitable that the difference between the cheapest and the most expensive rates will get bigger, not smaller. The more renewable generation we get as a country, the more it becomes abundant at some times. And with our hugely increasing electricity consumption as we move away from fossil fuels, I can see electricity becoming quite expensive at peak times. I wouldn't rule out getting electricity for free or even being paid for it (like Octopus do in the UK) in the early hours of a very windy night. Nor would I rule out electricity at peak costing €1 per kWh (in Texas the highest recorded charged rate was a staggering $10 per kWh during a heatwave a year or two ago). If you expect the difference to go bigger than it is now, the expected payback period for batteries will get shorter.

slave1

https://www.boards.ie/discussion/comment/120214879#Comment_120214879

Your losses can be reasonably put at 20% in/out

DC999

https://www.boards.ie/discussion/comment/120214912#Comment_120214912

I'd hold the very same view on where pricing for electricity will go. We're going to use loadssssss more electricity in our homes, businesses, shops.....

Our Winter electricity usage is 3 times higher this year than last year. Changes are 1) added an EV and 2) doing a large amount of heating from electric rads (our gas usage not gone but dropped hugely). And outside winter, the EV has almost doubled our house usage.

I don't mind mind paying a high peak-time TOU if there is a similar cheap rate I can max out.

unkel

My winter electricity use is way smaller this year than last year, as I can no longer afford to heat my house exclusively from 100% efficient, but very expensive, electric heaters 😁

Still doing as much as I can, as my night rate electricity is a lot cheaper than gas per kWh, daytime electricity also (from battery), but I do go over the penalty threshold and then it costs as much as gas and even more if gone through the battery. Still trying to use as little fossil fuels as I can.

DC999

https://www.boards.ie/discussion/comment/120215246#Comment_120215246

Yeah, deffo dangerous cost wise if people are just leaving electric rads on a lot. I’d a ‘credit’ on my meter that I only started to use from Oct. So suits us to use electric rads a fair bit for now.

Electricity costs more than gas as we know. 2.5 times more for me per kWh on 24hr tariff (still on that for good reason, but will move in time). Did some back of the envelope maths for me… It’s only about 1.6 times more expensive for me when I take our 15 year old boiler efficiency into consideration. And likes of the boiler pump running and using maybe 200w (pure guess). That gap will get wider on next electricity renewal as rates as higher of course. But we’ve a small house that heats fast (loses heat fast but small size means it warms fast).

We’ve the gas heating coming on 3 times a day (morning, when kids get home, kids bedtime). And some days it won’t come on at all or for less – controlled by temp on a Nest. Rest is covered with 2 electric rads downstairs. Temp downstairs is nice, not cold. Well, the hall is freezing but that’s fine 😊

unkel

@DC999 - "Electricity costs more than gas as we know. "

Well, that depends on your plans. I pay 8c night rate, 28c day rate and 15c gas. So a unit in and out of the battery costs about 10c after efficiency losses, so still a lot cheaper than gas

And the cherry on the cake is that crypto mining with 8c electricity is actually borderline profitable with efficient GPUs, so basically if you sell the coin, it would cover the electricity costs, so free heat essentially :-) The only problem is that I go over the 2000 units per billing period at the cheap rate and then I pay as much as gas, or even more if it has to go through the battery