I frequently encounter this situation: BMS reports 100% SOC but only 50+V pack voltage and still charging. Floating charge is set on inverter to 52.5V. Packs are 100Ah LiFePh 10048 from Loech. What can I trust?

47 minutes ago, Beat said:

I frequently encounter this situation: BMS reports 100% SOC but only 50+V pack voltage and still charging. Floating charge is set on inverter to 52.5V. Packs are 100Ah LiFePh 10048 from Loech. What can I trust?

While still charging at 12A I feel they are not at 100% yet. Cell voltages also confirm they still have a bit to go.

Could it be that the BMS is configured to not charge higher in order to give more cycles?

3 hours ago, Beat said:

I frequently encounter this situation: BMS reports 100% SOC but only 50+V pack voltage and still charging. Floating charge is set on inverter to 52.5V. Packs are 100Ah LiFePh 10048 from Loech. What can I trust?

Often the SOC needs a calibration,Hubble had me drain to 0 then charge to reset,I was sitting at 0% SOC when there was around 30% left in the tank before recalibrating like that

This should be fully cycled from the factory to calibrate full capacity. Once fully cycled, 100ah will be changed to the real capacity that depends on your lowest performing cell.

On 2022/08/21 at 5:46 PM, PsyWulf said:

Often the SOC needs a calibration,Hubble had me drain to 0 then charge to reset,I was sitting at 0% SOC when there was around 30% left in the tank before recalibrating like that

I have discovered that this is a problem on the seplos bms used in the Hubble and in the shoto batteries and probably a few others. Perhaps Leoch also uses the seplos.

27 minutes ago, jumper said:

I have discovered that this is a problem on the seplos bms used in the Hubble and in the shoto batteries and probably a few others. Perhaps Leoch also uses the seplos.

Just watched this video from Andy and its pretty crazy how bad the Seplos is at balancing the cells.

 

12 hours ago, Nexuss said:

Just watched this video from Andy and its pretty crazy how bad the Seplos is at balancing the cells.

I find the title of the video a little misleading, in the end he admits it actually works, just a lot slower than he expected. I don't have a lot of experience with bms(s), but I would expect things to take time as we are dealing with cell chemistry which is not digital, so balancing things out could become quite finicky. The bigger problem I see with the seplos is that it seems to disconnect the charging circuit early due to the 'intermittent power supply waiting' error message which results in the top balancing being interrupted and the bms doesn't allow charging until the battery is discharged and after a while this behavior causes the soc calibration to go out. (This is where he has to connect an external charger directly to the battery in the video) I think this can be fixed with changing some settings in the bms software, but I'm still digging on that problem.

What I found the most interesting about the seplos is the ability to change the BMS protocol so it can emulate a pylontech and be used on an axpert with pylontech settings and direct bms comms over RS485... although this seems to only be available on later versions now... I guess the sales department was ahead of the technical department on that one 🤣

On 2022/08/31 at 8:44 AM, Nexuss said:

Just watched this video from Andy and its pretty crazy how bad the Seplos is at balancing the cells.

I could not get much intelligence out of that video. Anyhow, can anyone explain to me how balancing is technically done? The only way I can imagine is by shunting over-voltage cells with a resistor by switching transistor. That would require quit high power resistors and transistors.

Below the screenshot of my BMS at fully charged situation. BL apparently means balancing.

16 minutes ago, Beat said:

I could not get much intelligence out of that video. Anyhow, can anyone explain to me how balancing is technically done? The only way I can imagine is by shunting over-voltage cells with a resistor by switching transistor. That would require quit high power resistors and transistors.

Below the screenshot of my BMS at fully charged situation. BL apparently means balancing.

You are spot on on how cells are balanced on the circuits I have seen. Just a comment - some balancers balance at less than 1A so it can take many hours if not days if the battery is cycled/charged daily.

TIL the seplos will also activate equalization if in standby for a certain amount of time (10h default). Not sure we can go that long without load shedding, but interesting none the less. Here are the default settings fyi:

 

@Beatdo you know what bms your leoch is running, just for interest sake? I'm not sure if they make their own or not.

7 hours ago, Beat said:

Anyhow, can anyone explain to me how balancing is technically done? The only way I can imagine is by shunting over-voltage cells with a resistor by switching transistor. That would require quit high power resistors and transistors.

I can't offer any technical specifics unfortunately, all I get is "BMS could balancing individual cell at standby and charging mode through power consumption circuit." Not very helpful I know, but if you can identify components from an image (I certainly can't) I'm pretty sure thy are here where the cells plug in. There is supposed to be voltage sampling and equalization happening there:

 

14 hours ago, jumper said:

I can't offer any technical specifics unfortunately, all I get is "BMS could balancing individual cell at standby and charging mode through power consumption circuit." Not very helpful I know, but if you can identify components from an image (I certainly can't) I'm pretty sure thy are here where the cells plug in. There is supposed to be voltage sampling and equalization happening there:

Thank you for your picture. I never dared to open my battery packs. It's just sharp enough to distinguish the rows of resistors and transistors. However their size tells me the limited power capability. As @Scorp007mentioned, 1A balancing current (= 3.5W) does not help a lot in the short time the fully charged condition prevails.

5 hours ago, Beat said:

I never dared to open my battery packs.

Same here, no way I'm opening a R25k battery and voiding the warranty to see the bms. I came close, but luckily figured out it was a seplos before I got that far. I got that image from the web. I think most people are in the same boat which is why info on which battery runs which bms is not so easy to find and manufacturers are happy to keep up guessing for the next 5-10 years.

Some more pics of the seplos for interest sake so you don't have to go digging:

I managed to identify the seplos by the front plate layout on my battery. It has 4 soc leds, 1 alarm led, 1 run led, then the dip switch, then CAN port followed by 2 RS485 ports (A&B) and a reset button, all in a straight line next to each other. If you have the same layout on our leoch, then there is a good possibility it is a seplos. That is the bare basics (as on my shoto), but it also has the capability to add LCD screen, cooling fan and on/off switch which different manufacturers seem to use in different arrangements.

6 hours ago, Beat said:

As @Scorp007mentioned, 1A balancing current (= 3.5W) does not help a lot in the short time the fully charged condition prevails

I totally agree, I think this stems from most of the applications for these batteries being telecoms and ups backups in server rooms etc. which stand around most of the time connected to the grid and only used in emergencies which is very different to our use in solar, especially with all our load shedding.

I must say I can't complain yet as my battery charges full and cells are balanced nicely without any comms to the inverter, albeit only 24 cycles old, we will see how it goes.

Better pic of the pcb:

Seems like the same bms used in the SHOTO batteries.

 

Looks like the chip shortage has caused some major issues with these units. Namely faulty Diodes. Looks like the Seplos BMS has made its way quite far. 

Ppl worry about voiding a warranty. What is that warranty worth with these? The Chinese market is flooding our markets with ODM products. Buy these products with your eyes wide open. 

Buy smartly & use machines, that you know how to get the best out of. 

The DIY market of cells and a BMS of your choice is in my book the best option right now when one sees things like this. 

2 hours ago, Nexuss said:

Seems like the same bms used in the SHOTO batteries

Yes it is, I have a shoto and it has a seplos.

1 hour ago, Steve87 said:

Looks like the Seplos BMS has made its way quite far

Yep and I suspect it is in a lot more batteries than people realize. I'm pretty sure it's in at least 2 'local' batteries, but don't have exact confirmation yet, I'm still researching.

1 hour ago, Steve87 said:

Buy these products with your eyes wide open. 

Buy smartly & use machines, that you know how to get the best out of. 

That is my intention here; to try to help people identify what is in that 'black box' they paid so much money for so they can better understand how it works.

I'm not a shoto or seplos fanboy, it is just what I happen to have bought and it looked decent enough to me, but I don't think we should be too quick to judge brands by some minor issues (to me) or by the products that make it to our market because it looks like shoto is a pretty big company that produces some impressive products that we will never get to see in this country. The SDA 48-100 that we get is just one battery they produce which happens to be from their telecom line and is actually meant to be on grid, but it is part of their high temp range, so that works well for me, I guess, although it is part of their 'floating' range and not their 'cycling' range.

We only get what is imported and that will only be what fits the South African price point. Maybe we will get to see more in the future if eskom continues on their path.

Some examples of the things they produce which I don't think could be sub-standard or they wouldn't be in business:

Home Energy Storage System: http://www.shuangdeng.com.cn/view-103-491.html

Household Energy Storage System: http://www.shuangdeng.com.cn/view-108-2756.html

SHVP lithium battery for IDC: http://www.chinashoto.com/view-3014-20218.html

IDC HVC-Li Battery System: http://www.shuangdeng.com.cn/view-102-2766.html

Microgrid: http://www.shuangdeng.com.cn/view-500-2758.html

I'm not trying to sell anyone on shoto or seplos, I just find it interesting the 'view' we get of China from over here as it is very distorted, I had no idea of any of this stuff until I started digging and actually changed the website to the chinese version and used google to translate the page and it is a completely different world with different products and not always the 'cheap crap' we are used to.

15 hours ago, Steve87 said:

Looks like the Seplos BMS has made its way quite far. 

Below a picture of my Leoch battery packs:

These are rebranded Leoch from China by the importer Averge. They could very well contain that Seplos BMS. But what about the built in display? And yes, this type of packs are designed for telecom application. It's that type in black version that often get stolen from cell phone towers and thrown on the black market.

Otherwise I'm pretty happy with them after more than 2 years and over 600 cycles. I figure that telecom companies choose their equipment carefully concerning quality, they do not buy chunk. The SOC little discrepancy compared to pack voltage is merely a cosmetic one. The charge is entirely controlled via the pack voltage by the inverter settings. I have no coms between the packs and the inverters. I'm even afraid, such comms could mislead the inverter concerning SOC.

56 minutes ago, Beat said:

But what about the built in display?

19 hours ago, jumper said:

but it also has the capability to add LCD screen, cooling fan and on/off switch which different manufacturers seem to use in different arrangements

Here's an example of a diy bank running the seplos with LCD screen: https://community.victronenergy.com/questions/70005/seplos-48v-100ah-energy-storage-battery-compatibil.html

Still very much a possibility, although I think it is an older version than mine, being 2 years old and on the new one that RS232 port is a CAN port and on the newest version it is what they are calling RM485 which can do direct bms comms to axpert inverters with pylon setting using RS485. FYI that port is the only one that can be used to directly connect to an inverter for BMS comms

The other 2 RS485 ports are used for comms between batteries and the RS485A port of the master can be connected to a PC to read out the BMS data with the seplos app from my screenshot above, very much the same as pbmstools, just on RS485 protocol.

If you are inquisitive like me and want to know if it is a seplos, you can connect to the RS485A port with a R30 USB-RS485 converter and if the software works then you know, but only bother if your RS485 port pinout (hopefully in your manual) matches. The finer details of connection and software download can be found in another post I made here if you need them: 

 

1 hour ago, jumper said:

If you are inquisitive like me and want to know if it is a seplos, you can connect to the RS485A port with a R30 USB-RS485 converter and if the software works then you know, but only bother if your RS485 port pinout (hopefully in your manual) matches.

I do have this RS485 connection to my laptop, as you can see from my posted BMS readouts. I even spliced an extension cord to it so I can read it in my office some 6m wire length away trough a concrete slap and a double brick wall. The packs are RS485 jumpered so I can read each pack individually.

The PmodbusToos software, jumper cables and RS485 adapter were provided by Averge.

Edited September 3, 20223 yr by Beat

1 hour ago, Beat said:

I do have this RS485 connection to my laptop, as you can see from my posted BMS readouts.

Oh, I see, I thought you were getting this from the RS232 port as I've only seen this software work via RS232 in the past. I was wondering about the name of your software when I saw the screenshot, it's the only one I've seen, I think it is a modified version of pbmstools and they left out the 'l' when they translated it, it looks exactly the same.

If you already have the RS485 cable then all it means is downloading the seplos software and trying to connect, just change the baud rate to 19200. No need to install, just download the software and run the exe here: https://drive.google.com/drive/folders/1pAZ_i8w6QFbBYsoweEd93eP94szeZjKW

Back to your original post of Are BMS reliable? I would say the Seplos BMS is a good BMS, however, one needs to know it's limitations & weaknesses. 

The Pros: 

Pylontech Comms protocol used. Ability & software via LBSA to interrogate the BMS. Ability to daisy chain them in stack of master & many slaves. Local support, well let's say limited local support because LBSA might not fully support you if the product is not one of theirs. 

The Cons: 

Limited support. A known diode component flaw, however, easily fixable in the right lab or workshop. LBSA carry this out out of warranty for batteries bought through them. Poor cell balancing function. However, it is still present, but limited to passive balancing. 

All in all, the discovery of the Shoto being a Seplos is a good thing. 

The largest issues I have seen in installing any battery Shoto or for that matter any battery. Is the lack of understanding of how to get them to current share equally. You can hook up the BMS the correct way but the physical & mechanical fundamentals will always apply. The wires lengths must be the same. A very useful document is Wiring unlimited by Victron. I'm not sure if I can upload it into the Downloads section. I will try but the file size might be crazy. 

10 hours ago, Beat said:

Otherwise I'm pretty happy with them after more than 2 years and over 600 cycles.

On the subject of cycles, I actually think they have confused SOC and DOD in my settings as it is counting 1 cycle per day, but there is no way I am using that much as I don't live there at the moment and it is only running 1 fridge which uses max 10% at night, probably less. 53V down to 52.5V by morning (16S).

The manual states "When the accumulated discharge capacity is equal to 80% of the design capacity. The cycle count increases.", but the bms setting for "cumulative cycle capacity" is 20%, so I think it is counting 1 cycle as 20% DOD instead of 20% SOC. I'm going to try change that tomorrow and see how it counts over the next few days. Something is not right.

8 hours ago, jumper said:

On the subject of cycles, I actually think they have confused SOC and DOD in my settings as it is counting 1 cycle per day, but there is no way I am using that much as I don't live there at the moment and it is only running 1 fridge which uses max 10% at night, probably less. 53V down to 52.5V by morning (16S).

The manual states "When the accumulated discharge capacity is equal to 80% of the design capacity. The cycle count increases.", but the bms setting for "cumulative cycle capacity" is 20%, so I think it is counting 1 cycle as 20% DOD instead of 20% SOC. I'm going to try change that tomorrow and see how it counts over the next few days. Something is not right.

That sounds alot like what the Hubble AM2 users are experiencing in regards to counting cycles. It will count a cycle every time you go past 50% SOC . So if you do a test and discharge from 100% to 0% and charge back up to 100% it should count one cycle but it counts two. This may not sound like a huge problem but when they use the cycles for warranty purposes you would want it to count correctly. IMO it would be better to leave cycles out of the warranty completely and rather guarantee 70-80% capacity left in the battery after 5/10 years . So if you are buying a battery make sure how its BMS is counting cycles if its tied to the warranty.

37 minutes ago, Nexuss said:

That sounds alot like what the Hubble AM2 users are experiencing in regards to counting cycles.

Yeah I saw that, it seems everyone thinks it is counting charge and discharge, but it might be that this is set to 50%. My battery is sold as a 90% DOD, so technically it should only count 1 cycle after that and not 80%.

43 minutes ago, Nexuss said:

This may not sound like a huge problem but when they use the cycles for warranty purposes you would want it to count correctly

I agree, unfortunately counting cycles is the only way to judge real usage of a battery imo and not just time as everyone uses it differently. I think it's fine as long as it counts correctly. I've changed the setting now and will see, if it counts 4 cycles today I'm in trouble 😅