Seplos BMS

Do all the BMS leads need to be of the same length when extending i.e. do you have to extend them all even though some will not require extending?

https://www.boards.ie/discussion/comment/118426231#Comment_118426231

Gonna start of saying Mine aren't.

Technically yes they should be the same length. Due to voltage drop on the cables.

Practically, it won't matter as the margin of error on the voltage will be bigger than any voltage drop as there should be no current flowing when it's reading the voltage.

I've been looking at the code for the zeva bms and it stops balancing when it polls the voltage.

I'll check the voltage drop with my multi meter tonight.

What is throwing mine off a bit is the cable between the pair of rows of my cells (when there is a high current flowing it's about 50mv so that cell looks low on discharge but high on charge. When rebuilding the pack I'm going to put it on 1 row.

Geeyfds53573

Thanks men, Ah I see so Sofar has a rj10 as the battery connection and the software connection to laptop will be the same for all. That make sense. On the firmware side did support@seplos.com provide? They sent me a link to docs I have read some but obviously a lot more to read. Those who ordered on 11/11 before me let me know when/if you hear the batteries are on the European side please.

https://www.boards.ie/discussion/comment/118426231#Comment_118426231

Checked from the shortest to the longest, all was sitting at a voltage drop of 1.6mV

48v 150A 16S lithium iron phosphate lifepo4 bms monitoring system battery management system with LCD Screen (seplos.com)

Grand, I have my Seplos but still waiting on the cables and LCD screen which were missing from the package, when they arrive I'll be able to progress

E30M3

Is enquiring and buying direct from SEPLOS the best approach or are there other suppliers folks have used?

i.e.

Thank you

https://www.boards.ie/discussion/comment/118428859#Comment_118428859

A guy David Schad on the Sofar FB group is a distributor in the UK

E30M3

https://www.boards.ie/discussion/comment/118413223#Comment_118413223

Just to check championc have you 2 Positives going to the BMS and from the BMS to the inverter? appears to be 1 in the pic and I'm wondering did you use a busbar on the board or am I missing something?

I did just 1. The two points on the board are joined together and I'm only coming from one battery terminal - so totally pointless

https://www.boards.ie/discussion/comment/118451027#Comment_118451027

It could split the load on the mosfetts more easily. But the bms shouldn't need to shut off the current. The inverter should be doing that anyway

garo

https://www.boards.ie/discussion/comment/118452571#Comment_118452571

True but if your inverter is limited to 3kW you won't be drawing more than 62A so one wire is enough.

Full disclosure: I did 2.

Finally got me BMS cables and LCD screen so will be extending cables and starting to top balance next week or so...

I have 32 batteries so will top balance 16 at a time.

How soon to final install should one top balance? Reason I ask is that I'll be waiting on electrician and likely unpredictable availability

Sparks needed to do what ??

https://www.boards.ie/discussion/comment/118463219#Comment_118463219

Once they are top balanced they should stay that way for a while.

How long.. not too sure unfortunately but the cells will drift down to 3.3x within a few hours anyway. This does not mean they are discharging. It's just the nature of LFP.

https://www.boards.ie/discussion/comment/118463295#Comment_118463295

Hook Sofar up to Consumer Unit

Folks, I am nearing the end of Top Balancing so set this weekend aside for extending my BMS cables.

I am going for a 16S2P straight line setup which I have mocked up below and how I am intending to bus bar all together.

As I have one Seplos I am trying to figure out how to connect up the BMS cables and finding the Seplos instructions very confusing.

@graememk looks like you have 32 batteries in a row like me, so how did you hook up the BMS cables.

For example, working from left to right, A1 to C1N (Cell 1 Negative), A2 to C1P but where the hell do A3 and A4 go? I'm quite confused on this being honest.

So after finding another Seplos BMS Manual online (I think the first one was incorrect) I have mocked up below what I think is the correct layout of the BMS cables along with the main power cables...

Thoughts???

https://www.boards.ie/discussion/comment/118586803#Comment_118586803

Not sure what way the seplos is configured

But my first wire went to the most negative and then each positive of each cell.

https://www.boards.ie/discussion/comment/118587073#Comment_118587073

While the Seplos diagram was very confusing - pitting the links onto each busbar, but on alternative positive and negative sides, to make things look neat, the simple way to look at it is

Connect the black wire to the 1st and 9th negatives, and then put a red wire on each positive in each set of 8 cells. Connect to the same place on each busbar so you don't get confused.

To verify, you need to measure the voltage on the Seplos connectors. With a meter on the black wire pin, measure to the reds and ensure that you get a voltage reading on each red pin, incrementally increasing. This is what your BMS will see and use, so it's important to do this, and take your time

garo

You have your A's and B's in line but your cell interconnections are the wrong way around. The positive of the first pair of cells from the left should connect to the negative of the second pair and so on. As currently configured A2 is you most positive voltage. The correct config is A1 as the most negative and B9 as the most positive. Just flip the connections between the cells.

Think I got ya, I'll redo the mock up tomorrow, all a learning curve

Okay, I believe this is what is required.

A1 is the Negative terminal of the pack and B9 is the Positive terminal of the pack. Battery 8 (15+16) and Battery 9 *(17+18) are linked to allow the BMS to see the two halves of the pack

reklamos

So hooked up my first batch of batteries today and ran into a problem. Getting alarm on my inverter batName-FAIL. The inverter deos see SOC, voltage, current etc. but the Alarm is still there? Anyone with Solis inverter ran into this? I have Pylon selected ofn BMS and on inverter.

https://www.boards.ie/discussion/comment/118591777#Comment_118591777

Try the LG setting, that uses SMA. The only difference between pylontech and SMA is the battery name.

https://www.boards.ie/discussion/comment/118591777#Comment_118591777

CAN-Bus-protocol-PYLON-low-voltage-V1.2-20180408.pdf

SMA CAN protocol.pdf

Some light Reading :P (also if you want to listen into the battery its very useful)

reklamos

Same problem with LG

irishchris

https://www.boards.ie/discussion/comment/118591777#Comment_118591777

Strange one as that alarm means that the inverter realises the model of battery detected doesn't match the model name you have selected. First time have read of someone with this and the DIY batteries. I know drphil has a Solis with these connected but from memory think he selected lg too as his battery on it?

DrPhilG

https://www.boards.ie/discussion/comment/118592400#Comment_118592400

Yeah I got an error when set as Pylontech, changed to LG and it worked fine.