Seplos BMS

championc

https://www.boards.ie/discussion/comment/119793110#Comment_119793110

In the discussions with them, it seems that you can toggle through 01, 02, 03, 0x

Go figure :(

Gareth79

I'm just setting up a pretty standard setup here: ME3000SP with 16S EVE 280Ah cells and a Seplos.

All mostly ok, but during charging Cell 9 reads approx 0.1V higher than all the others. Putting my multimeter across the terminals, the cell voltage is within a few mV of the others, whether or not it's charging.

All my balance/sense wires are the same length and seem connected up ok. One thing is that cell 9 is connected to cell 8 through about 80cm of cable (25mm2) and 2x pairs of Anderson connectors (I have 2x packs of 8 cells), could that affect the readings? I don't exactly know how they calculate it all.

I have contacted Seplos support but at the moment their advice is to check the connections.

graememk

https://www.boards.ie/discussion/comment/119814301#Comment_119814301

Yep that's voltage loss over the cable. I've seen it too.it will be the opposite on discharge.

When charging, put the multimeter on each end of the cable and you can measure it.

Very hard to eliminate it but can be mitigated by putting more/heavier/shorter cables in.

graememk

Just to add a bit more to this:

The bms measures the voltage between the positive of cell 8 and the positive of cell 9 and everything in-between

So the lug, wire, the connector, the wire, another connector, wire and finally another lug.

The heavier and shorter you can make that cable the better.

You'll not eliminate that voltage difference, but you can reduce it.

And if you measure the voltage between the positive of cell 8 and cell 9 (when charging!!) You will see the same value the seplos sees.

Gareth79

https://www.boards.ie/discussion/comment/119814881#Comment_119814881

Great info many thanks, I had assumed that it only measured each cell individually using the sense/balance wires, but guessed that it being the first cell after the link cable was no coincidence. My cable route is definitely is longer than it could be, also I have a "link cable" between the packs which adds 2x sets of Anderson connectors which I can eliminate by just having a longer flying cable out of the pack. I can run a test later by rerouting the cables a bit and plugging the packs without the link cable, and will buy in some 50mm cable and connections to replace them.

Gareth79

So I removed the link cable and that alone reduced the different to 75-80mV, so I think replacing the cable with some 50mm² and rerouting them should help. The rest are 25mm but I assume that will just affect the overall pack voltage, and not be so critical (by presumably causing the charge to shut off too early).

One question - if the cell is always a bit higher will the BMS be permanently attempting to balance it?

graememk

https://www.boards.ie/discussion/comment/119816929#Comment_119816929

Only during charging, discharging it would try and balance everything else.

But now that you have reduced a voltage drop from 0.1 to 0.02 which is big reduction.

Although the amount the seplos can balance isn't much anyway

andyr24

Is this a case of charge them up with inverter. Split pack and top balance.

spose

https://www.boards.ie/discussion/comment/119816987#Comment_119816987

Do you know how many Ah you are getting before it hits the 2.9v? Have you seen how close they are when approaching full?

graememk

https://www.boards.ie/discussion/comment/119817120#Comment_119817120

I also want to add a full charge is when every cell is above 3.5/3.6v

andyr24

https://www.boards.ie/discussion/comment/119817120#Comment_119817120

Had charged to 100% overnight at 30amps set on inverter. Only 3 or 4 cells hitting 3.6v. Battery was at 37% soc when cell 14 bottomed out.

andyr24

At 100% this morning according to BMS only 3 cells above 3. 55v

C1 3.436v

C2 3.442v

C3 3.463v

C4 3.431v

C5 3.639v

C6 3.572v

C7 3.438v

C8 3.435v

C9 3.458v

C10 3.427v

C11 3.418v

C12 3.455v

C13 3.426v

C14 3.476v

C15 3.415v

C16 3.65v

garo

So charge back up to 100%, split and then top balance. Since all cells are above 3.41 at 100% you should be able to top balance in a day.

andyr24

Will do that in the morning a see how things go. Working smoothly just not getting full capacity.

garo

Yeah without a top balance now it will take months of passive balancing from the Seplos for you to get 100% capacity.

championc

https://www.boards.ie/discussion/comment/119817593#Comment_119817593

As I have previously mentioned, I would suggest now charging each cell to 3.65v individually and let them sit, then do them all a second time.. They were all paralleled when I did this.

Afyer the second run, they all sat at about 3.61v, whereas after the first, they almost all dropped down to 3.4v ish

andyr24

https://www.boards.ie/discussion/comment/119818039#Comment_119818039

I had top balanced them before I put the pack together and this makes a bit of sense. As I was short on busbars I did 1 run of 8 in parallel to 3.65v. I made up a few in the mean time and then ran them again in 16p to 3.65v. So half them got 2 charges to 3.65v and there are 8 cells pretty well balanced and seem to keep their balance at both low and high state of charge.

tatoviola

hello everyone, has it happened to anyone that the display becomes in Chinese? it was originally all in English. thank you

spose

https://www.boards.ie/discussion/comment/119867663#Comment_119867663

Ya happened me by accident. Hold down the top button for a couple of seconds and it changes back.

tatoviola

https://www.boards.ie/discussion/comment/119867849#Comment_119867849

it happened by chance. i don't know how to set EN language as it was before. if I press the button at the top it goes to the home but remains in Chinese.

spose

You need to keep the button pressed for a few seconds

tatoviola

https://www.boards.ie/discussion/comment/119867849#Comment_119867849

I was wrong, I did it as an indicator from you and now the display is back in English. thank you

ducky1981

Right Im nearly there with my DIY 10kw battery build but I have a question or two as I can't figure out what the seplos manual is saying to do due to the Chinese English that it comes in. Firstly the dip switches do I need to change any of them. And secondly how do change the battery parameters as it's saying I only have 123ah of battery instead of 200. I'm using a Solis 6kw hybrid inverter. Battery is set to aobo and the seplos BMS is set to victron it's the only way I could get them to work together

championc

For a single standalone BMS, all switches should be left as is - which is OFF

You need to click on "Login" and use admin/admin, and at that point you can modify the battery parameters

Jamo99

IMG_20221116_122026.jpg

Permenant Standby?

Hi been reading here for a while but need to tap into users knowledge now.

Hi Jimmy from Wexico.

Setup is Seplos 200a 16s bms 280a cells, victron charge controller, inverter not connected yet.

Bms appears to be balancing slowly (cells already top balanced)

Problem is no current is flowing into the battery from the charge controller which is set to lifepo4 and is energised. Green light on bms is flashing intermittently, no warnings, no red light but strangely no state of charge leds are lit.

With the charge controller disconnected the BMS only allows 3v from the pack which quickly drains down to nothing?

Stumped!

J

Jamo99

Ok jury is out on this as an actual fix but energy is flowing into the battery through the BMS now.

This morning there was a red warning light flashing. In the BMS software it said it was an overvoltage warning.

Here's what I did.

1. I re-set the BMS from within the software to the factory defaults (I hadn't made any changes).
2. I disconnected the solar from Victron charge controller and switched off the BMS at the push button switch. This cleared the warning light. The battery busbars on the inverter side of the BMS were now energised from the battery with the MPPT turned off but the voltage was lower than the battery voltage by about 1.2v when I checked with my multimeter for some reason?
3. I reconnected the solar to the Victron charge controller and it moved to Bulk mode.
4. Energy flowed into the BMS! MMPT Voltage is set to 55.2 (Absorbtion) 53.6 (Float) 45amps was the most I saw before it began to ramp down slowly. During charging the capacity led's were lit.

Hope it helps someone else. Obviously going to keep an eye on things.

J

tim9321

I've been watching this thread for a while and took the plunge and ordered a Seplos BMS 16s 200A to go with my Solis 6kW.

The steps in this helped me get everything running, CAN protocol of Sofar and AoBo on Solis and everything worked a treat. Today was the first day I've witnessed it hit 100% (night charges been finishing at 4am and I'm too lazy to get up) but a decent solar day so I plugged in to monitor it charging.

It hit a 100% but seemed to kick off the overvoltage protection and a few warnings. Not entirely sure if it's a concern or anything to worry, I haven't done a full capacity test but numbers generally look good. All the cells were top balanced prior to building. In normal running I only see about 5-10mV cell difference.

Any advice on settings to tweak to stop hitting the overvoltage protection would be welcome - which I think is still default at 57v.

championc

Monomer = one cell

What you may want to do is to up the recovery voltage. Once it hits the top, it's equalizing a tiny bit but then dropping. But the default value for me was too low. I set Monomer High Pressure Recovery and the Overvoltage Recovery to 3.4v, with the Equalization Opening voltage at 3.35v

poker--addict

I have a 6kw solis too. Cells on the way.

this 100% issue seems like a major ball ache!

tim9321

Thanks for the help, recovery voltages were already at 3.4v, but I’ve dropped the Equalization Opening voltage at 3.35v.

looks like sun will be out tomorrow so I’ll probs hit 100% again, will let you know.