Sunsynk Inverter Settings - how to change the charge voltage and current with a Seplos BMS
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- Опубликовано: 17 окт 2024
- Looking at where Sunsynk inverters get the battery charge and discharge values from a Seplos battery.
Battery charge voltage
Charge current limit
Discharge current limit
The confusing way a Sunsynk inverter pulls the battery figures from a Seplos BMS explained, and how to change them.
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Helpful video. I thought Jason Donovan was the presenter 🙂
Shhh, I was hoping to keep my failing media career on the quiet...... 🤣🤣
Exactly the info I was looking for, for ages. Thanks very much
I had the same problem finding info, so I'm glad this helped.
Hi did you connect two seplos batteries?
Yes, the batteries are both connected to a common DC busbar, and interconnected with each other.
How do l get software to change the battery charge voltage parameter?
You can download it from Seplos. Link below:
www.seplos.com/download.html?group_id=6318
To change any settings, you'll need to sign in on the program. User: admin Password: admin
When you go to install it, your computer will probably see it as malware. Mine certainly did. It doesn't seem to have a valid certificate, that's all. It seems to be fine though.
Although who knows, maybe I'm being watched by the Chinese government now. Oh well....
I'm starting my off-grid system with 2*5kW Sunsynk inverters and 2*14.3kW Seplos batteries with BMS 2. Everything working good, but I found that my batteries charging until 98.2% and stop. And BMS doesn't disconnect batteries from charging - maybe you have minds there I did mistake? Now I use 54.4V charging voltage, but batteries voltage is 54.32V... Or BMS do not need stop batteries charging?
I think your system is running normally, don't worry.
My first question is how long are you waiting to see if it goes to 100%? It can take quite a long time, and I mean hours.
The charge voltage starts to drop as the battery gets closer to the charging voltage, until at the end, it is just sitting doing very little and looks idle. This is normal. I find charging from the grid, my batteries will top out and reset to 100% maybe once every ten days or so. However, charging from solar, they will reset to 100% on most days.
This is because the grid is so stable that it just trickles the voltage in at about 1 amp, whereas the solar comes and goes, which means the battery discharges a bit and then all of a sudden the solar ramps up, and it throws 20 amps at the batteries. This extra amperage pushes the voltage over the charge voltage set, and the battery resets to 100% and switches to standby.
Your BMS line 14 is also the "reset to 100%" voltage command. So when the solar pushes it over, bingo, reset.
54.4v is a tricky one for the bms to handle, as the default passive balancing is set to start at 3.4v.
Obviously, 54.4v is 3.4v per cell, so the bms might not be able to balance (unless you have lowered the "Equalisation Opening Voltage" - BMS Line 8, in which case forgive me for saying....)
@@kindabusydoin I will try to ask Seplos about this problems... Problem is that when inverters try to charge to 100% some cells have big differences in voltage... :( Thank you for answers...
@@skrudzasss Let me know if you get an answer from Seplos please.
However, by charging to a lower voltage, you are never charging to 100%.
100% would theoretically be 57.6, and charging to this value is a problem for the passive balancer which is in the version 2 bms.
As you say, you get very big splits in cell voltage, as the passive balancer cannot keep up with the runaway cells.
That is why I use 55.17v.
At 3.45v per cell, the cells never diverge far enough to be a problem. As long as you top balance the cells to start with, the passive balancer will look after them very well at that voltage.
I never get more than 14 millivolts difference between cells. I have also set other Seplos batteries (version 2) for people to this value as well, and they are doing well.
All we are doing is changing what the battery calls 100%, and getting it to reset to this new "100%" at a lower value. That way you are never charging to 100%.
I hope this makes sense.
@@kindabusydoin sorry, one more question - how you use aux load. By manual Sunsynk do not recommend to use aux load when use inverters in parallel. But I saw in forums that many use this load stright from inverter. Another solution - to use contactors which connect to load, but this connector switch on/off by command from aux load...
No problem, ask as many questions as you like.
This is yet another video that I am in the middle of editing together.
The aux port is fine used in parallel. Deye have confirmed it's OK for them, but I don't think Sunsynk want to do the work to test and approve it
Obviously if Sunsynk say no, then you connect at your own risk....
And, maybe, you found solution how to charge batteries just until, like example, 95% from the solar? I don't need charge all time until 100%, but I didn't find to stop charging batteries by percentage :(
Unfortunately that doesn't seem to be possible with Sunsynk.
I'm charging to 55.17v, which i think is a good compromise
Another thought on your charge voltage..... and I'm going to put out another video on this, as I think it's interesting....
I have my BMS set to 55.17v, but Sunsynk rounds that up to 55.2v. So the inverter is sending .03v extra over top of the 100% reset value, and so it doesn't sit idle as much before resetting.
So if you're using 54.4v, then try setting 54.37v. It should round up to 54.4, and will help it to reset to 100%.
I'm also using Aux Load to divert as much power on solar as i can to other items, so this also helps to not charge the batteries to max all the time.
@@kindabusydoindo you really need to have the BMS connected to the inverter? Could you just set the battery as AGM that way you would have a more control. BMS could work standalone. Data could be logged through solar assistant.
You certainly can set it to AGM, and some people do.
The problem with AGM is that LiFePO4 batteries are not great being measured on voltage (mainly through the middle charge range), so the state of charge is not particularly accurate. That then causes issues with using functions like the Aux Load to use extra solar etc.
Sure, you can always find work arounds for this, but just tweaking the BMS settings and letting the inverter talk to the BMS is an easier solution I feel.
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