How to access and change parameters of a battery with an unknown Smart Inverter BMS
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- Опубліковано 4 січ 2024
- Hi, in this video I am showing you how you can access your Smart Inverter BMS of any Wall mounted or server rack battery from China, even when you do not know what you really have.
My Battery: UNISUN Vss, LiFePo4 48V/200Ah
BMS: Unknown
This is the link to the adapter cable (non-affiliated):
www.aliexpress.com/item/10050...
Links for software:
Pbms: cdn.shopify.com/s/files/1/124...
Pbms Orient Power:
www.opsolarbattery.com/_files...
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Nice always good to see how other people do it.
Very informative. I think the pack voltage is what is causing the inverter receive a stop-charge signal.
You may be able to adjust balance current somewhere in the software, as well. I played with these values. I was not successful because defective cells would not hold the charge well even after balancing.
Hope you will get replacement for your bad battery. Good luck!
Thx a lot, this is what I was looking for. Same problem - even more, since I use a battery pack with 5 batteries - and the stupid BMS (sorry) does not do it´s job. In my case, one battery (one cell) runs into OV - so BMS logic requests lower and even no more charge current from hybrid inverter. Result: other batteries don´t ever have the chance to balance. Grrr. Will check the tool the next days. Thanks again!
Hi. Today, every device is called Smart, but at the end it's just setup by a dumm human and it causes more inconvenience then if it would be a well designed hardware device. You will have good results once you are able to change parameters. Thanks for watching
Another way to improve is to add a active balancer and a "voltage detection controller" who activates the active balancer above 3,4 volt resp. at 17 volt. Most BMS have way to weak balancing current. Active balancers have up to 5A. To activate just above 3,4 v is important, otherwise a always running active balancer destroys the top balancing. Here in Thailand these two devices cost in total about 20USD, well worth the little money ; D
@@topeye4202 yes correct. But there's always the question on how easy it is to add extra devices to your bought battery pack. It's very easy if your pack is build with prismatic cells and you just need to un-bolt a few bus bars and add the extra wire. My pack for example is build out of pouch cells. All connections are spot-welded and the only place where you could connect a balancer is directly at the connection into the BMS. You would have the choice to either cut wires and solder the balance leads to the clipped ones or build yourself an adapter, where you get the identical sockets and plugs to integrate the balancer cabling. Average users wouldn't do either way as you would definitely void any warranty or the job would just be to excessive. Not everyone is expert in electronics and electrical engineering as we are ;)
Setting a few variables inside parameters which could eliminate the problem, will probably be the top end of what people will do and feel comfortable with.
@@topeye4202 Shure, just want to avoid extra-work if possible. And regarding your "voltage detection controller": this is extra-work for the extra-work. The active balancer should know itself when it should be active.
@@ginnescamper7421 The active balancers are balancing if they think there is some diviation, but if they do that at low soc and in the flat area, the cells wont come back at the same point into the top balancing.
How to explain... difficult... It's similar to how disorientated people in desert who want to walk straight, but actualy walk in circles. The sensors are simply too imprecise in flat areas, small errors add up to a big error. The flat area of the charging curve is a bit wavy. SOC is not in a fix linear relation to the voltage.
Andy from the offgrid garage made many tests and came to the conclusion that no additional active balancer is better than one that runs all the time.
hello..(from Italy)
I set it with a maximum charging voltage of 3.40v per cell and I'm fine with very little unbalance
At charging, 3,40V is just right after the cells are coming out of the flat part of the curve. So, you shouldn't see much unbalance there anyways even if there is a little unbalance present. But if you are happy with discontinuing charging at that low level, I am good with it. No complaints from my side :) Greetings to Italy!
Great video. What is also possible, is to export the settings to a file in case one would like to revert to a previous setting. What I would really like to know, is the gap charge setting and the start current setting, (under system config) to what value it should be set. My supplier can not help me with the info.
- Chris
Hi. I couldn't find any information about those particular values and I can't really think about anything this is really used for. I would not really change anything inside system configs anyways.
It will as well a lot depend on the inverter as well, which of the setting will be used at all.
With the Deye Hybrid I have found that Protection and Alarm values are relevant only. And the way how the inverter is dealing with those triggers, seems to be set as hard values inside the inverter (like the absorbtion, it seems to be set to 100W). Many other values are just unused.
Nice vid roland! Are you using the middle RS232 port to read from the BMS as well as write to the BMS? I understand one can also read from.the RS485 port using this same software?
Then, if you used RS232 to read and write, how did you find the pinout config ? Assume you made your own cable as these pinout configs can differ per BMS
Lastly, i see the battery is set to address #1. What were the dipswitch settings for this battery?
I ask these questuons as our battery has the exact same Pace BMS and we have the software too, just trying to get to know it better
Hi. When using the RS485 port, you will definitely need a cable supplied by the battery manufacturer, as there, pinout configs can vary.
When using the RS232, this seems to be one standard for all these "Pace"-style inverter BMSes. RS232 seems to be the standard comm port for read/write.
I just bought that USB to RS232 cable, named to be used for these Pace-BMSes, and it just worked.
When using RS232 there is no need to set any Dip switches. Mine where at Zero, and they still are...
@@RolandW_DIYEnergyandMore Very helpful thank you!
Something else I was wondering, we noticed on one of our batteries the charging MOSFETS must be defective/faulty. Despite the cell o/v voltage being set to a maximum of 3.65v, we were able to witness cells reaching over 3.72v!
We didnt want to continue it charging like this of course due to potentially damaging the cells. The charge voltage was set to 57.6v, and 'full pack voltage' was set to 56V, yet 2 cells climbed over 3.7v and didnt seem to want to stop. Have you ever experienced this?
Also, if MOSFETS were indeed faulty and those cells just kept climbing high and higher, what would happen? is there an additional fail safe that would prevent that ticking time bomb from exploding?
I understand there is also a 'Pack o/v protection voltage' setting, but if MOSFETS are defective Im assuming this wont protect the battery either (because the individual cells are not being protected themselves at that level either)
@@dalepurdon8948 I usually do not care about pack voltages. I only let cell voltage limits control the whole pack. But of course, that isn't relevant if the BMS cannot disconnect if a limit is reached. If you really have bad mosfets then you cannot continue using that pack. Cells which go over 3,7V will be irreversibly damaged. They will start swelling and in worst case blow out electrolyte. LFP is considered quite save if it comes to fires.
So yeah. Either fix the BMS or replace it by a new one.
@@RolandW_DIYEnergyandMore Thanks again!
But normally a BMS is not reaching OVP right? The max over all charging voltage is limited by the charger (3,55Vx15) and normally no single battery voltage is peaking more than 200mV right? My batteries have max 20mV diviation when they pass 3,45V. I thought its not good when the BMS needs to interrupt charging, for several reasons, most important of them is to have redunancy, so the BMS as a second control device can step in, only if the charger fails in limiting the max charging voltage, or if last top balancing failed as in your case.
No. That was in the "inverter centric" world, where we just set our usual voltage targets at the inverter. We had to set them in a way that they would in general fit to the battery profile, and the BMS would really just interrupt in emergency.
But here with this Inverter BMSs the table has turned. The inverter only acts on signals coming from the battery via communication link.
And the signal to reduce current to start absorb is the value of OV-Alarm, and the signal to finally stop charging is the value set in OV-Protect.
Without those signals the inverter will just keep going on till the value it is given as maximum total pack voltage. but that voltage would be much to much for individual cells inside the pack if there is imbalance.
So yeah. What if the BMS does fail to give the Stop signal? And this is why it is so important to have access to the parameters, so you can set much more conservative values.
You could still use such a battery without communication in the traditional form. Just set the inverter to control its operation by voltage or percentage calculated by its own.
Its all just a new, different perspective. But you are totally right. Where is the redundancy?
@Everyone and Roland, the JK BMS devices seem to have a serious flaw (as Andy over at "Off-Grid Garage" has confirmed on the 8th January 2024) where the saved parameter values will reset to factory default setting, if the BMS is off for a few days. The JK BMS does not permanently save the values (something along those lines), and will default to LCO (LiCoO2) values (such as having 4.2V for Over Voltage Protection).
Andy over at Off-Grid Garage has recommended to avoid using the JK BMS and remove from your system as soon as possible. They can not be trusted.
Here is the video Andy had recently uploaded on the 8th January 2024: ua-cam.com/video/9sUXwdT_Nto/v-deo.html
Ok, it's been 4 months. How are the batteries doing? Did they balance out?
Hi. Yes, It took around 2 months and they balanced to the last millivolt. Now balancing is only triggered very rarely as the 20mV differential to start balancing is hard to reach.
So yeah. New batteries do not require all to much balance currents. It just takes a correct setting of parameters and time.
Thank you 👍. I have the sungold Powerwall. you're right mine only balances during charging. Not while in idle/standby mode. Full status. It definitely seems wrong. To only balance for a minute or two during charging. Thanks for the help
Do you have the part number or full item tittle fot the BMS lead as you link to aliexpress does not work
CH340 USB RS232 to RJ12 6P Modular Plug for Pace Bms Batteries Inverters 200A 15s 100A Console Config Cable
interesting. When I press the link, it works. strange
Thanks for that, link failed as out of stock, tried another firm Lazanda Singapore but there mailinh system has a bug when trying to enter tel,postcode to UK
@@janetmorris6792 as far as I know Lazada don't ship internationally
Roland, around the 4:02 to 4:22 timestamp, your recording device was picking up high RF interference. Temporarily affecting the audio.
yes, thank you. the screen capture shots at the battery i unfortunately had to make with my 10 years old laptop and its forwardfacing microphone. I still hope everyone undrrstood well .
@@RolandW_DIYEnergyandMore Was still understood.
Is this the same with USB TO RJ45
hi. No, RJ45 is a 8-pin connector (LAN cable, etc). When it comes to batteries, they might use only a few specific pins of the connector at the battery and others at the inverter. So you would really need a cable supplied by the battery manufacturer to be able to use that. And it as well might not work to access the BMS controller via the RJ45 to read/write data. Usually that is done via the RJ232 socket...
The program wont connect to the serial port?
Usually it does. As well it finds the Port by itself...
You got the same cable that I have (USB CH340 to 6pin RS232) and checked if it was recognized be the windows OS? You have to find a CH340 device in connected devices.
If the device if connected but the USB port is not automatically found by PBmsTools, then try to select a few USB ports manually and check if it can connect.
If you are trying on the RS485 serial with a cable from the battery manufacturer then it won't work like this.
For that you have to follow the instructions which you get from the supplier.
My battery only has the USB port, no RS232 port. SRNE EOC 5Kwh. Any suggestions?
Hi. And you didn't get any cable with the battery? I am afraid you would have to look for the solution provided by the manufacturer... but still, similar as RS232, USB is a defined standard other then the RS485 where the pin layout could vary by the manufacturer. So you could try use a USB cable and see if the PBmsTools software can read it. But chances are that the battery is using a different protocol then PACE and it won't work. Just give it a try if you have a fitting USB cable at your hand...
@@RolandW_DIYEnergyandMore It didn't recognise it. The cable that came with the battery is only RS485 for inverter to battery connection
@@1982757 right, yeah. Some manufacturers don't want to let you manipulate the firmware parameters. Looks like SRNE is very serios about that :(
Does the battery cause any problems like building up imbalance?
@@RolandW_DIYEnergyandMore I am new to LiFePo4 battery, so I wouldn't know if the battery is building up imbalances. If you could please explain further?
@@1982757 Usually battery manufacturers will set their battery parameters to the LFP absolute limits when they ship out their product. This is all well if the voltages are managed by the Inverter/Charge controller. Then the BMS will only kick in if a limit is breached. Furthermore, balance trigger points are usually set very high.
With the Inverter-BMS, where the battery is now commanding the Inverter, the maximum limits do not really matter anymore, as those values are not suitable to control charging and discharging anymore. Thats why we want to set different parameters in the first place in this sort of setups. But now most scenarios will never trigger any cell balancing. So with time, you will notice cell voltages running away from each other.
Hi, I have a problem with the password for the software, isn't "123456", can you help me please?I'm from Italy
Do you know the battery maker or brand of BMS? Reading out the BMS data is working normally?
@@RolandW_DIYEnergyandMore the battery is Easun power 5kwh 100ah
@@stefanoschiavon82 and you are using PBms Software and are able to see the BMS data including Parameters when reading it out? Youi just cannot overwrite the Parameters because the BMS stays password locked, correct?
@@RolandW_DIYEnergyandMore yes, the parameters are locked and I don't know the correct password
@@stefanoschiavon82 ok, I can try and search the internet. Easun is a brand and should have support. did you try to ask them if they could tell it to you. I can tell them you would keep it confidential ;)
It will never balance the cell voltages because these BMSs do not have a balancer.
Every BMS has integrated passive balancing. It uses resistors to burn off energy, albeit with very small currents. But usually those little inputs will be enough to keep a pack (especially with new cells) in a balanced state. Most important is to keep this happening with every cycle. If the pack is out of balance, it will be very hard to get it back together just with the passive balancer.
I've experimented with the TDT, Gobels, and Pace BMS, and none of them seem to balance effectively, or if they do, the efficiency is so minimal that it's practically imperceptible. It's surprising to see that battery packs now only consist of 15 cells, and the nominal 51.2 volts are no longer achieved.@@RolandW_DIYEnergyandMore