Leave it 24 hrs and then see what the cell delta is for each battery. Your worst battery pack is currently at 10mv delta, no need for a top balance if tomorrow you see the same or even slightly worse. Just setting balance at 3.45v will keep them on target. Its a pain telling the SI to go back to acid and then back to Lithium and having to reset the shunt setting every time.
Top Balancing using SI-6048?
- Thread starter Disturbedfuel15
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Disturbedfuel15
New Member
Right now I have the RCV at 3.6 and they are all sitting at just about the same as pictured:
I feel like I should go to 3.64, and if they are still good once current reaches 0, call it balanced?
I feel like I should go to 3.64, and if they are still good once current reaches 0, call it balanced?
Disturbedfuel15
New Member
Aha! I think I found something after calibrating the BMS voltage. I needed to increase each one by about .2v to get it correct with what the actual voltage was. No current is flowing right now, even though they aren't at 57.6v--they are currently at 57.4v and nothing is changing. I looked at the data from SI and it reports the voltage is 57.6v. The SI is now .2v > the actual calibrated voltage. Hmmmmm makes me wonder.
The BMS should be reporting real time data to the SI. However, I wonder if the newly calibrated BMS voltage values being sent to the SI never got updated? In this case, I wonder if power cycling the SI or the BMS would cause the voltages to fall in line == ? I do know one thing, nothing is happening right now. They are all sitting at the same exact readings I posted earlier.
Oh, one more thing. I thought I had posted this, but I guess I did not.
I found a setting that allows you to limit the charge current, so I have that set on the SI as well as the BMS (already knew about BMS). I have it set to 10a, 2a per pack while 'top balancing':
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Assume you have one BMS set as 1 on the dip switch and the rest as 2, 3, 4 etc, so 1 is the only BMS sending canbus messages to the SI, check the RCV it's set to and compare it to the SI. It may need the SI to be put to standby and restarted.
Disturbedfuel15
New Member
Yeah, I think I'm going to do that. And actually you are correct, but technically I have the first DIP switch on 0, with 1, 2, 3, 4 following. If I started at 1, there were no communications! Really it seems JK has left it up to the community to find out how to use these.
Either way, it seems my cells are balanced... they are all within 0.010 of each other, every cell, every pack, while sitting charged at 57.7v (3.603/cell). I know it seems like it did not take long, but I have had them up and RCV of 3.45, balancing at 3.4 for a couple days before this. Unless someone feels differently, I think these are top balanced. I'm far from an expert, however.
I went off of the forum's Top Balance Tutorial, Appendix D: Top Balance using an active balancer:
Still only got one battery/BMS, parts for second are on route. I have mine set as 1, only setting I can get RS485 to work so assumed that would work for setting up 2nd battery. Then after 2nd battery was set up it would be set to 2 and linked to 1. Will have to try 0 tomorrow.
Set my BMS to 0 on Dip switches, windows software connects but goes straight to parallel tab showing real time data for multiple batteries but as I only have one the rest show as disconnected and cannot get access to any of the other tabs as they are greyed out. If you select device 0 when connecting it changes to device 1 when you connect which is not what the dip switches are set to.
Bluetooth App connects and you can go into settings and change them, Device ID shows as 0.
So totally confusing, to change the settings using the Windows app you need to set the dip switch to 1, only then can you change settings and upload new firmware. To get the batteries to have comms between batteries you set one battery to 0 and the rest as 1, 2 etc.
Bluetooth App connects and you can go into settings and change them, Device ID shows as 0.
So totally confusing, to change the settings using the Windows app you need to set the dip switch to 1, only then can you change settings and upload new firmware. To get the batteries to have comms between batteries you set one battery to 0 and the rest as 1, 2 etc.
Disturbedfuel15
New Member
What odd behavior, but not unexpected. You know, I have five of the old reliable b-series jk bmses. I wanted them on hand in case this didn't work. I'll probably be selling them soon it seems because I am happy with the functionality of these, although I am scared to death to do any updates now on both the SI or the BMS. I don't want to break anything!
I am curious what RJ45 port you are using to connect to the BMS? Reason I ask is to eliminate all variables between your experience and mine. I'll be curious once you get anther BMS in. Here is where I did firmware update/connected to PC: https://diysolarforum.com/threads/jk-pb2a16s-20p-no-communication.78801/post-1010240
I completely reset my sunny islands, setup as new systems. I was hoping it would fix the SOC being stuck at 99% and the batteries forever-charging. It did go to 100% for a bit, but it's back at 99% and it is holding the packs at 55.2v (RCV 3.45v*16). I do not believe it is healthy for the cells to stay at this voltage. I would like them to be released and brought down to float voltage, 3.35. I do not know how to accomplish this.
However, I found a parameter that may get me by for now:
Lmt battery state of charge for connection to grid (GdSocTm1Str) Could set this to 95% so grid disconnects once battery SOC is 95%
Lmt battery state of charge for connection to grid (GdSocTm1Str) Could set this to 40% so grid connects once battery SOC is 40%
Keep in mind I do not have any PV setup yet. Just battery backup right now. I'm not sure if it would do what I want, but I'm trying to figure something out.
I am PV only and off grid so can't answer you on grid queries.
The ports that work with the Windows App are two marked RS485-2, these are the greyed out Uart-2 in the app that are fixed to JK-BMS RJ45 Modbus V1.0. So one can be used to connect to PC and 2nd to next battery.
To drop your charge voltage use the app to change the RCV from 3.45V to your preferred lower V 3.35V, I can leave mine at 55.2V as using PV it takes until 3 or 4pm before I get there and then the sun intensity drops so the voltage drops naturally. The float function volts settimgs in the BMS does not get to the SI so until that is fixed you need to change the RCV using the app.
I have an HiFlying Elfin EW11 connected to the RS485 port on the BMS to send the data to my Wifi and then use a virtual serial port on my PC 25 yds away to connect to the JK so I can change settings in comfort.
I am on Firmware 15.17, if further updates come that break functionality you can force a firmware upgrade to an earlier working firmware but you need an added code which you get from here.
https://mirofromdiro.github.io/JK-firmware-code/
The ports that work with the Windows App are two marked RS485-2, these are the greyed out Uart-2 in the app that are fixed to JK-BMS RJ45 Modbus V1.0. So one can be used to connect to PC and 2nd to next battery.
To drop your charge voltage use the app to change the RCV from 3.45V to your preferred lower V 3.35V, I can leave mine at 55.2V as using PV it takes until 3 or 4pm before I get there and then the sun intensity drops so the voltage drops naturally. The float function volts settimgs in the BMS does not get to the SI so until that is fixed you need to change the RCV using the app.
I have an HiFlying Elfin EW11 connected to the RS485 port on the BMS to send the data to my Wifi and then use a virtual serial port on my PC 25 yds away to connect to the JK so I can change settings in comfort.
I am on Firmware 15.17, if further updates come that break functionality you can force a firmware upgrade to an earlier working firmware but you need an added code which you get from here.
https://mirofromdiro.github.io/JK-firmware-code/
Disturbedfuel15
New Member
When setting the RCV last night, I accidentally hit the "li-ion" button, which immediately applies all default parameters for lithium ion without any other confirmation. One slip and you're done.
Well, I got all the settings back to where they were before. Now bms is showing 69% charge. The aggregate SOC sent to SI is now 92%. I really hate the design of these bms. That one slip of my finger just screwed up the entire system. I'm not sure how to get it back to 100%, like the rest. Obviously it is 100%... The BMS is just miscalculating. Frustrated with these bms for sure.
Disturbedfuel15
New Member
Thanks for the advice. I figured out it will reset to 100% once it hits the SOC 100% setting. Older BMS did not have this setting. So I set the RCV to 3.5, let the battery hit the SOC100% and now it is back at 100%. Now I will float at 3.4. I am wondering how often I need to charge at absorption voltage, or if I can just leave it at 3.4 for extended periods of time. Reason being, I'm hooking up my critical loads panel, and the batteries will get used. Therefore, do I only want them charging to 3.4 after use or do I need to manually change the RCV from absorption to float every time I charge the batteries? I am not sure how often I need to charge at absorption voltage. I need to read more about it.
Until the float function works via the Canbus comms if you need a float V and an adsorption V then you need to be changing the RCV to suit. As to whether a set of well balanced cells needs a period of absorption is not something I have looked into, being PV charged I get that by default anyway every day I get the batteries to 100%. Going by the weather this week its not going to happen for a few days and I have no concerns and the cell delta is staying well under .010V. I think its more important to have the info and be able to change the settings if you see the cell delta go out of line
I can confirm that Float works, had a really sunny day and the battery was at 55.2V for some time and then the target voltage on the SMA dropped to 53.6V which is -1V from the JK float setting Vol RFV I have of 3.415. I have an RCV time set of 1H so that must have elapsed and the float started.
This was using Deye Canbus on the JK, not sure of the significance.
This was using Deye Canbus on the JK, not sure of the significance.
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