21 hours ago, jumper said:

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.

As a matter of fact, the user instructions (in chineese English) called for a RS232 link and provided such adapter with Pbmstools on a CD. The instruction told to jumper the packs with RS485 and link the master with RS232 to the computer. But that didn't work. I could only read the master. After I complained Averge corrected the instructions and provided the RS485 adapter. But that still didn't work with Pbmstools. Finally they provided the PmodbusToos to download and that works.

I downloaded that Battery monitor as per your instruction and configured the COM port. But it wont read the BMS.

Edited September 4, 20223 yr by Beat

1 hour ago, Beat said:

As a matter of fact, the user instructions (in chineese English) called for a RS232 link and provided such adapter with Pbmstools on a CD. The instruction told to jumper the packs with RS485 and link the master with RS232 to the computer. But that didn't work. I could only read the master. After I complained Averge corrected the instructions and provided the RS485 adapter. But that still didn't work with Pbmstools. Finally they provided the PmodbusToos to download and that works.

I downloaded that Battery monitor as per your instruction and configured the COM port. But it wont read the BMS.

My info from the seplos BMS via the parallel port on the LBSA battery, connected to Pi.

2 hours ago, Beat said:

As a matter of fact, the user instructions (in chineese English) called for a RS232 link and provided such adapter with Pbmstools on a CD. The instruction told to jumper the packs with RS485 and link the master with RS232 to the computer. But that didn't work. I could only read the master. After I complained Averge corrected the instructions and provided the RS485 adapter. But that still didn't work with Pbmstools. Finally they provided the PmodbusToos to download and that works.

I downloaded that Battery monitor as per your instruction and configured the COM port. But it wont read the BMS.

Thanks for the details, I don't know why there are always so many issues around battery comms, it seems even suppliers don't know what is going on, maybe they just can't keep up.

I guess your bms is either an older version that's incompatible with the software or it is not a seplos at all, thanks for testing it, much appreciated.

1 hour ago, Antonio de Sa said:

My info from the seplos BMS via the parallel port on the LBSA battery, connected to Pi.

Thanks. Do you have any SOC readings? Are your cycles counting accurately?

19 minutes ago, jumper said:

Thanks. Do you have any SOC readings? Are your cycles counting accurately?

@jumper Yes, I do as well as well as health status however, the cycle count is crazy, I queried LBSA and they told me that every time the SOC goes up or down pass 80% it counts one cycle. see attached.

57 minutes ago, Antonio de Sa said:

I queried LBSA and they told me that every time the SOC goes up or down pass 80% it counts one cycle

This is what I'm currently looking in to. I found a setting in the bms for the cycle count and it is set to 20%, so I think it is counting every time the cumulative discharge reaches 20% instead of 80%. It is not supposed to count the charge cycle at all when counting cycles according to the seplos manual. Have your son take a look when he gets a chance and see what he thinks.

16 hours ago, jumper said:

This is what I'm currently looking in to. I found a setting in the bms for the cycle count and it is set to 20%,

You incited me to look into it also. But I cannot find any provision for it in settings page:

1 hour ago, Beat said:

You incited me to look into it also. But I cannot find any provision for it in settings page:

My guess would be that not all settings are exposed by that custom software you got from Averge/Leoch, I suppose they don't want customers messing with the cycle count.

I can happily report that my cycle count didn't increase overnight, but I will wait for it to increase to fully confirm that it works. I checked my bms logs and the battery only gets down to 75% at night which would cross the 20% discharge setting and explain why it was counting 1 cycle per night. This means (if I am correct) that it should count 1 cycle every 3-4 days from now on so I will wait and confirm once that happens.

@Beatthe only suggestion I have to check if your cycles are counted correctly is to download the bms data and see how much you use at night and then see how often it counts a cycle and see if you can find a discrepancy there. There is always the possibility that you have a different bms without this problem or Leoch set it correctly at the factory.

19 hours ago, Antonio de Sa said:

I queried LBSA and they told me that every time the SOC goes up or down pass 80% it counts one cycle

I must say that imo this statement if very fishy. As a programmer it makes no sense to me to program something to count when it crosses the 80% barrier. I could then simply set my inverter to charge between 20% and 75% and never count a cycle, it just wouldn't work properly. I'm pretty sure it is programmed to add each time the battery is discharged and when that variable reaches a set threshold (80%), only then is the cycle increased. Then it would work according to what the manual says (cumulative discharge).

I am now starting to think that they haven't mixed up 20% SOC and 80% DOD when setting up the bms, I actually think it is a legacy default value from lead acid because for lead acid 20% is the generally accepted DOD.

@jumper I've done an experiment this week, I've selected my system parameters as follows :

SBU.

Back to mains at 51,2 V = 20 % SOC.

Once it reaches that level inverters change over to mains and start drawing +_ 1.8 Amps from the battery, ( inverters no load power ) eventually by about 6:00 AM the battery SOC is at +_ 11% 

At that time sun comes out and my batteries start to get a bit of charge from PV,  BMS counts one cycle.

Very strange results, It counts one cycle every 24 hours.

Today I'm going to set inverters to SUB and run it for a few days to see the results.

See dashboard. 

9 hours ago, Antonio de Sa said:

by about 6:00 AM the battery SOC is at +_ 11%

Thanks for testing this Antonio. From this it looks like you are using more than 80% of the battery capacity before it starts charging, so the cycle count of 1 per day would be correct.

At first I thought it was strange that it was counting at the same time every morning, but then I figured you are using only solar to charge the battery (OSO) or it would charge when you go back to grid. So from that it means the bms would be in 'discharge' status until you go back to grid and then it stays in discharge while it runs the inverter until the first bit of light hits the panels (around 6am) and the battery starts to charge and it is most likely when the bms status changes to 'charge' for the first time that it will add to the cumulative discharge, do the cycle count check and increment it if necessary. It wouldn't make sense to do the cumulative discharge sum while the battery is discharging as it could go lower, most likely the status change to charge mode is when the function is triggered... this is just my theory from the data provided.

9 hours ago, Antonio de Sa said:

Today I'm going to set inverters to SUB and run it for a few days to see the results.

I think it would be a good test to change the OSO setting if you have that on and also use grid to charge the battery. That should cause the battery to start charging when you go back to grid and possibly increment the cycle then, instead of 6am on the first charge after hitting 20% SOC. I would test this, but I have no grid.

BTW my cycle count did not increase again today, so it looks like it is working as I think it is, but it could be that your cycle setting was correctly set by LBSA if you are going down to 11% SOC each night and it is counting 1 cycle per day.

17 hours ago, jumper said:

Thanks for testing this Antonio. From this it looks like you are using more than 80% of the battery capacity before it starts charging, so the cycle count of 1 per day would be correct.

At first I thought it was strange that it was counting at the same time every morning, but then I figured you are using only solar to charge the battery (OSO) or it would charge when you go back to grid. So from that it means the bms would be in 'discharge' status until you go back to grid and then it stays in discharge while it runs the inverter until the first bit of light hits the panels (around 6am) and the battery starts to charge and it is most likely when the bms status changes to 'charge' for the first time that it will add to the cumulative discharge, do the cycle count check and increment it if necessary. It wouldn't make sense to do the cumulative discharge sum while the battery is discharging as it could go lower, most likely the status change to charge mode is when the function is triggered... this is just my theory from the data provided.

I think it would be a good test to change the OSO setting if you have that on and also use grid to charge the battery. That should cause the battery to start charging when you go back to grid and possibly increment the cycle then, instead of 6am on the first charge after hitting 20% SOC. I would test this, but I have no grid.

BTW my cycle count did not increase again today, so it looks like it is working as I think it is, but it could be that your cycle setting was correctly set by LBSA if you are going down to 11% SOC each night and it is counting 1 cycle per day.

@jumper  Last night running on SUB my battery went down to 69% due to the inverters "no load power " +_ 2 Amps, strange thing still counted one cycle at 6:00 AM.see dashboards

Thanks @Antonio de Sa, that is strange. You are only using 30-35% of the battery and it is still counting a cycle. The fact that it always counts at 6am is even stranger.

What does your dashboard show for PV Watts around 6am?

1 hour ago, jumper said:

Thanks @Antonio de Sa, that is strange. You are only using 30-35% of the battery and it is still counting a cycle. The fact that it always counts at 6am is even stranger.

What does your dashboard show for PV Watts around 6am?

@jumper very strange indeed. at 6:00 AM was 0 W, it looks like Seplos BMS has an internal clock counter ... lol.

2 hours ago, Antonio de Sa said:

very strange indeed. at 6:00 AM was 0 W, it looks like Seplos BMS has an internal clock counter ... lol.

This is quite bizarre, I'm not sure now if LBSA has changed the code somewhere because my battery has still not counted a cycle since I changed my setting to 80%. I'm expecting it to count tonight/tomorrow morning, but if it doesn't I'm going to have to try and drain the battery to 19% SOC as see if it counts then.

The other thing you could test is what happens if you don't use the battery for 1 night, if it still counts a cycle at 6am... that would be an interesting one.

Just want to report that my battery counted a cycle this morning, after changing the cycle setting to 80% on Sun (4 nights ago). It would have lasted 5 nights which is correct for the usage, but I ran some extra loads yesterday to try and catch the cycle increase while I was watching. I checked the bms data and it increased the cycle at 7:23 which corresponded with a battery status change from 'discharge' all night, to 'standby' for the first time as I had suspected. The panels 'wake up' around 6:10am, producing 30W and at 7:20 it produces 90W+, so the count happens when the battery status changes, not when the PV starts.

@Antonio de SaI had a thought: could your count always happening at 6am be an artifact of your dashboard coding perhaps? Could it be that the dashboard only runs the cycle increase check once a day at 6am? Would be a waste of resources running code every few seconds to check something that only changes once a day.

@BeatI'll make a more applicable topic relating to the shoto and seplos specifically to save you all the notifications 😉

1 hour ago, jumper said:

I'll make a more applicable topic relating to the shoto and seplos specifically to save you all the notifications 😉

No, no, don't do that. I think all BMS related issues should remain together. And I like to be notified.

On 2022/08/21 at 2:30 PM, Beat said:

I frequently encounter this situation: BMS reports 100% SOC but only 50+V pack voltage and still charging.

I thought this would be relevant here as it pertains to the reliability of the current measurements the bms performs when used specifically with an inverter. If the charging and discharging amps are measured incorrectly then that will affect the SOC value displayed. I found this at the bottom of an aliexpress link to the JKBMS that @WannabeSolarSparkyposted in another topic.

TLDR: measurements across the shunt resistor can be unreliable when the battery constantly fluctuates between charging and discharging. I'm pretty sure this applies to all bms using a shunt to do current measurements.

Protection (Current Sensor Anomaly)

This problem exists when the inverter is used, because the current direction is uncertain,
This kind of alarm will appear when the sun is not big or small, because at this time,
the battery fluctuates frequently between charging and discharging,
and there are uncertain factors, so this problem occurs.

A pure sine wave inverter does not draw a constant current. The current from the battery follows a sine wave shape.
It ramps from zero current up to peak current in 1/4 of a cycle.
The peak current is actually about 40% more than the average current.
Then the current will ramp back down to zero at the 1/2 cycle time. At this point, the inverter reverses polarity,
and ramps the current back up again, hitting the peak at the 3/4 cycle time. The battery current is positive again,
and the inversion happens in the inverter circuit. The the current ramps down back to zero again at the end of the cycle.
The process them repeats for every cycle.

If you measure with an averaging meter, you will just see a fairly steady current that should be close to the true RMS current.
I use a True RMS Fluke meter, and it is able to give a vey accurate reading on this odd waveform.
The current reading in the BMS just measures the voltage across a shunt resistor. This reading is only taken periodically,
and it is not synced the the changing current from the inverter. It might take a reading at zero current, or at the peak current,
but most likely, it will fall somewhere in between.
Due to the shape of the wave, the reading tends to bounce a bit above and below the true RMS current.
It is not perfect, but over the long term, it is "good enough" for the BMS to calculate the amp hours charged in or discharged out of the battery.
This works because if you average the readings over a full hour, the high and low readings will average out.

 

Edited September 12, 20223 yr by jumper

11 hours ago, jumper said:

TLDR: measurements across the shunt resistor can be unreliable when the battery constantly fluctuates between charging and discharging. I'm pretty sure this applies to all bms using a shunt to do current measurements.

This confirms very much what I posted in the SOH thread.

I just had a demonstration, how reliable BMS are. Yesterday my batteries got fully charged the first time after this winter. As I monitor the BMSs closely, i noticed the following:

At full charge with floating voltage reading on the inverter, two of the four packs BMS showed 92% and 95% SOC while the others show 100%. The packs are parallel connected with 25mm² cables. During the floating process of the inverters some BMS show significantly lower pack voltage than the inverters, the latter confirmed with multimeter within measuring accuracy. Different pack voltage on parallel connected packs and rather low current is physically not possible. It looks like some BMS go crazy in this situation. I would rather hesitate to connect such BMS to the inverter as I fear of misleading the inverter with unreliable information from the BMS. I think the battery voltage is the most reliable parameter for the inverters to control the charge, correct settings prevailed.

On 2022/09/21 at 12:03 PM, Beat said:

Different pack voltage on parallel connected packs and rather low current is physically not possible.

Been thinking about this and I'm new to using lithium, but could it be possible to have different voltages on parallel packs because the bms has the capability to disconnect the charging circuit on the full batteries? The current would then only be able to flow to the other batteries. With regular LA (no bms), the batteries would automatically 'balance' the voltage between them because there is no circuit to disconnect them from each other... not disagreeing with your findings, just thinking out loud.

On 2022/09/21 at 12:03 PM, Beat said:

I think the battery voltage is the most reliable parameter for the inverters to control the charge, correct settings prevailed.

I'm also running without battery comms, using voltage settings and the bms handles things perfectly on its own, I see no need to have the inverter intervene and add another point for things to go wrong, but I have nothing that actually runs off SOC values so it works for me. I see bms-inverter comms as having positives and negatives; it is easier to set up if you can just plug the battery in and it sets all the inverter battery settings automatically, no need to find battery specific settings to enter manually, which probably works for most people. I personally prefer to have control over the charging voltages as I don't use the manufacturer suggestions and I have seen some bms set crazy high charge voltages over 57V... once you plug in that cable you have no control.

15 hours ago, jumper said:

Been thinking about this and I'm new to using lithium, but could it be possible to have different voltages on parallel packs because the bms has the capability to disconnect the charging circuit on the full batteries? The current would then only be able to flow to the other batteries.

I don't see that possibility. The BMS has no control over current proven by its reading that goes out or in through the terminals, whether it goes to other packs or to the inverters. But sure, parallel connected packs equalize themself by means of internal voltage and internal resistance of the packs. I have observed this repeatedly.

I think that different pack voltage readings result from the adding up of cell voltages that somehow get screwed up.

4 hours ago, Beat said:

The BMS has no control over current proven by its reading that goes out or in through the terminals

I'm not sure of exactly how much control it has, but my bms definitely has the ability to cut the current in to the battery once it reaches 100% SOC. Once full, the bms charging circuit is opened and the amps are cut to zero and the inverter ramps down PV input and idles. In this state the bms will only allow the battery to discharge until it reaches 96% SOC (adjustable in settings) and then it will open the charging circuit and allow current to flow in again. I have read that the bms is supposed to be able to step down the current as it approaches 100% SOC, but I've not sat and observed if this actually happens.

1 hour ago, jumper said:

I have read that the bms is supposed to be able to step down the current as it approaches 100% SOC, but I've not sat and observed if this actually happens.

Hi @jumper  there is no way the bms can limit the current,  but it can instruct an  inverter to limit  the charge current, via suitable bms comms  connection. Example i have seen  these limits from a livoltek battery,  most of charge current limit is 100A, then it  throttles the inverter to a 10A limit at the tailphase of charging cycle. 

3 hours ago, BritishRacingGreen said:

Hi @jumper  there is no way the bms can limit the current,  but it can instruct an  inverter to limit  the charge current, via suitable bms comms  connection.

Thanks, I was aware of the ability to tell the inverter to limit the current via comms (and that's where I got confused), but wasn't sure if the bms could do it by itself. It makes sense now that if it can only open and close the charging circuit then it can only limit it to the input current or zero, nothing in-between. I'm also not sure where it would be putting all those amps without turning into a small house fire lol🤦‍♂️