Seplos BMS

graememk

https://www.boards.ie/discussion/comment/118403811#Comment_118403811

Short answer. Not really. unless i start using more in the summer or start charging the car from the batteries!.. and my night rate is 5.8c! And as you know I have more ordered.

Jan, Feb, March, Generally grid charging, and April I stopped. Started Grid charging in Oct i think a bit but been at 100 charge since Nov.

I can't make full use of my current set of batteries in the summer months.

I would be able to make use of it in the winter when grid charging though. but thats coming out at about 13.2c saving for every kwh i pass through the battery (Day: 20.27, night 5.83 +20% = 6.996 (for loss, i need 1.2kwh in to get 1kwh out) ) 13.2c/kwh saved.

Currently im running about 10.7 kwh in, 8.6kwh out and for the last month its 15kwh/day of day rate. 8 of it are already used by my current battery. so 7 left over.

Say 150 days that I can pull out that extra 7kwh from the battery.. 138 euro a year, from grid charging. Id say its touch and go for a 10 year payback. anything extra from solar is just a bonus!

Then i'll just merge all 4 sets and buy a new battery for myself :P

unkel

Problem is the ridiculous penalty for using "too much" night rate. 20kWh pack * 60 days per billing cycle is already 1200 units. that alone plus an EV will go well over the 2000 units before the punitive rate kicks in which essentially ruins any pay back perspective for a 20kWh battery

Now of course if this cap was to be abolished (it really should as it goes completely against any reason) and if the delta between day and night rate will go bigger rather than smaller (this is very likely in the near future), then the 32 cells will start to make total financial sense. Here's hoping!

graememk

https://www.boards.ie/discussion/comment/118403957#Comment_118403957

Only Energia have that cap I think. But yeah, add the ev into it and I'm over it. (About 500kwh/month)

I've not seen any other supplier do a similar rate yet. But the electric rates currently are nuts, and I don't see them coming down any time soon.

My meter is read every other billing cycle so I could give myself a bit of leeway in that aspect but you would nearly want to over report ahead of time than under report after the fact

SD_DRACULA

A second pack might still be worth it using something like BG's EV smart tariff that has like 4.6c/kwh at night, only problem would be that you might not be able to fill the whole pack even at 100a in the 3 hours you get that price for.

slave1

I’ve 32 and waiting on some parts before tackling, got them VAT free so perhaps I ticked the “dirt cheap” category. I’ve no intention in peak shaving over Winter as I breach the Energia cap already but let’s not forget the cap rate is still half the day rate so not punitive. It’s my intention to endeavour to be off grid as much as possible March- October via these batteries and additional inverter/two strings install. This intention is of course excluding EV charging.

It's not pure financial at this stage, I got some good pricing along the way so rather hit and run I want to put it back into more PV and also I’ll be squeezing the new panels into back garden and want to incorporate tilting capability.

championc

https://www.boards.ie/discussion/comment/118403610#Comment_118403610

They use FedEx, so you would have the regular 23% plus their handling fee

garo

https://www.boards.ie/discussion/comment/118403957#Comment_118403957

You are of course correct. it probably does not make financial sense for me. Like slave1 I got these VAT free as they were shipped from Germany so at 1037 paid landed it was a very good deal. The sweet spot for my current consumption is 12-15kWh of battery capacity. Maybe in a few years time I sell these on and replace with 280Ah or 300Ah cells.

Geeyfds53573

https://www.boards.ie/discussion/comment/118402097#Comment_118402097

Thanks Garo that’s great info.

Geeyfds53573

I have a few things I’ll need to resolve. One being the B+P+ on the 150A BMS with the 3 connections. I know I could source a 1/0 AWG (50 mm²) M8 lug to fit three 4 gauge wires but I will need to have a bit on length on these cables so any suggestions like 4 *M8 connection box I could use instead and just run one long cable from that.

Geeyfds53573

https://www.boards.ie/discussion/comment/118407299#Comment_118407299

I saw an Anderson connection but anything else one could use safely.

garo

https://www.boards.ie/discussion/comment/118407299#Comment_118407299

You could get a busbar to connect all three posts and then just run one wire from it. As long as the connections are tight it shouldn't be an issue.

DrPhilG

https://www.boards.ie/discussion/comment/118403957#Comment_118403957

I wouldn't think that too many are emptying the entire 20kWh pack every day.

My battery is still at 50% most nights when I hit night rate. My total charge added in December was 363kWh. Even with January not being much better I'll still probably be below 700kWh charged, plus some of that figure was charged from generation on the few good days.

Add in my normal overnight usage of about 4kWh and that's still less than 950kWh of night rate in a 60 day period.

*its half 11 and I'm tired so maybe my calculations suck...

graememk

https://www.boards.ie/discussion/comment/118408640#Comment_118408640

Oh we know that, I'm chatting about raw payback 16 vs 32 cells, And what i was saying is that it will be night rate charging, for me will be the biggest end of my savings. As once april hits, im not charging at night anymore, And the batteries are carrying me to night rate. There diminishing returns on the second 10kwh.

Discharging on night rate will save me a bit, but at 5c /kwh at night, it aint much. I cant say what my unit rate will be come july again, when my fixed contract is up though. And I have another set coming anyway, even with that knowledge.

unkel

https://www.boards.ie/discussion/comment/118408640#Comment_118408640

You do know what that means, right? In case it wasn't obvious, the second pack will never pay for itself. Unless we get near zero FIT and peak electricity prices will hit €1 per kWh within the next year or so. Entirely possible of course.

bullit_dodger

As usual, your on the money there I think unkel.

I was giving this a little thought myself too. I've got ~9Kwhr battery but my daily consumption is in the ~35Kwhr range. Typically my daytime usage for those 15 hours of "daytime rates" is 21 units, so a full charge from night rate with my battery doesn't carry me through the day. Today my battery was empty at 16:35 as I also gabbed 2-3 Kwhr from solar panels.

Irrespective of if you buy off the shelf or do a DIY, the first pack is sort of easy enough to model the payback. Your usage is typically way more than the capacity, so it's easy to figure out what happens with the electricity you store. The second pack which gives you better coverage though ..... complicates matters

I was trying to model it in excel, but it's tricky as with the larger capacity, you might be able to "ride through" a dull days production. For example, let's say Saturday is a great sunshine day. Sun goes down at 8pm. You've filled up both your batteries (20kwhr) and used 4-5Kwhr before night rate kicks in. You can see from the forecast that Sunday is rain, so you decide not to discharge overnight, but use that charge the next daytime. It's hard to model those types of things......but to be fair I don't know how realistically often it happens?

Using the API's that most of the inverters have, and couple it to some weather forecasting, it's doable....but it might be just chasing €10's / years. Fun project if you get it to work, but perhaps payback isn't the way to look at a project like that.

DrPhilG

https://www.boards.ie/discussion/comment/118408911#Comment_118408911

I wasn't disagreeing with your point about payback on a second set. Just correcting the estimate of 1200 night units in a 2 month spell due to overnight charging.

Geeyfds53573

https://www.boards.ie/discussion/comment/118408206#Comment_118408206

Yep I know what you mean and would be fine on the battery side (hard to source also) but I want to be able to easily move this to a shed next year and easily extend the cabling- Anderson connector looks good but is it a standard used in Ireland or is there a terminal block/ junction that is the standard used by electricians

championc

Well I'm up and running :)

championc

Just some notes

The ME3000 Inverter to Battery cable works perfectly. It's an RJ45 to RJ10 (not RJ11). The pinouts are.

RJ45. RJ11

4. 1

5. 2

7. 3

8. 4

On the ME3000, select the battery type of General Lithium

Before turning on, the most important thing to do is to check that the BMS wires are linked to the cells correctly.

The negative is the bottom pin on each bank. So measuring it and the first pin up will give 3.3v (or so), next up will be 6.6v, next will be 9.9v and so on. Jump over the temperature probe pins. Then check the second bank.

Get these wrong and you will blow up the BMS

And for those wondering about the BMS wiring, while the Seplos diagram is a bit confusing, it is essentially like this, with the first cable from each of the two connectors going to a negative on cells 1 AND 9, and the remaining 8 battery cables from each connector connect to the positive on each cell

And both the negative AND positive main cables go through the BMS

I also mounted the unit upside down in order to not have the main battery wires crossing

unkel

Nice work championc! Liking the cork there 😂

championc

Obviously, the Seplos isn't the handiest for keeping an eye on your battery cells, so the solution may be to read the cells via RS485 into maybe a Raspberry Pi and then into Node-Red or whatever.

Here is a document with the data format, which I got from Seplos

SEPLOS BMS Communication Protocol_V2.0.pdf

reklamos

https://www.boards.ie/discussion/comment/118414645#Comment_118414645

This is at the top of my list. Just w once my batteries arrive :)

SD_DRACULA

Now we need someone to get the Seplos working with a Solis hybrid :D

championc

I missed the most important part - which was to set the correct protocol on the Seplos BMS. It meant that the BMS was not "talking" to the inverter fully. So I had set my Capacity for 190Ah but my Sofar ME3000 still thought I only had the default setup of 100Ah. You must Login (admin / admin) and then the CAN option appears. At 100% SOC, glad to see just a 17mV difference between cell voltages

E30M3

Re the wiring harness on the SEPLOS, would it be possible to utilise that as it is if planned carefully or is it simply too short for that purpose? Thought it would be ideal re minimising work and risk to avoid extending if possible but probably not.

Again GARO and CHAMPIONC and indeed everyone on the forum who has shared info I'd like to add my thanks for the amount of time and information you have shared here. It has given me the confidence to order batteries which are en route hopefully.

Geeyfds53573

Awesome championc was there a specific firmware you have to use for the sofar? Also Rj45 to RJ10 to a USB connection to laptop I assume? How did you figure out the pinouts?

Great info and great job.

Geeyfds53573

sd_dracula I see pylon on the drop down? Should be good for Solis.

Geeyfds53573

https://www.boards.ie/discussion/comment/118425675#Comment_118425675

Online I see the BMS leads are tight on smaller batteries so yep they will need to be extended.

graememk

https://www.boards.ie/discussion/comment/118425862#Comment_118425862

The battery connector on the sofar is a rj10. That's what the cable was for.

Although for balancing you'll not see any real imbalance until the cells are > 3.4v

If you log the voltages just before the charger stops you'll see if there is any difference. Once they hit 3.4 they rise to 3.6 quite quickly

championc

https://www.boards.ie/discussion/comment/118425862#Comment_118425862

Having not spotted the CAN protocol selector, I upgraded the firmware from v2.5 to v3.0 last night. But I think v2.5 would have worked. It just needs the battery type of General Lithium.

Cabling wise, the BMS leads are tiny, so everyone will need to extend then. I stripped two lengths of Cat5, and kept the colours in the Cat5 order, so Wh/Or to cell 1, Or to 2, Wh/Gr to 3, Bl to 4 ......... Wh/Br to 15, Br to 16.

The Canbus cable is RJ45 on the Seplos side to RJ10 on the Sofar ME3000. Pinouts are

RJ45 RJ10

4. 1

5. 2

This cable is pre-supploed with all Sofar ME3000 Storage Inverters

The software gui is accessed using a USB to RJ485 adapter (purchasable optional extra). It's an RJ45 on the BMS into the adapter, with pin 6 Gr to RS485 Gnd, pin 7 Wh/Br to A+ and pin 8 Br to B-