Those bms default settings are the best I’ve seen, they must be learning. They are a good starting point. I’d probably lower the bulk in the inverter to 55.6 then you can just leave the start balance alone in the bms. Then just play with the current till it’s balanced. If the inverter decides it’s done with bulk/absorb early, you can temporarily raise the float voltage to just under the bulk(55.5) to keep it there till it’s done balancing. When done don’t forget to set your float back to 54.
JK bms with inverter Gootu
- Thread starter Danielchu45
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Danielchu45
New Member
so the settings in the bms are ok? Based on these setting what will the bulk and float voltage will be?
Danielchu45
New Member
can you explain a little bit more cause i am not that much expert
Yeah, just don’t change a thing for a while in the bms. Id set the inverter setting for bulk at 55.6 volts for simplicity. Higher bulk voltage only gains you 1% of capacity at the expense of battery life and potential BMS failure due to excessive cell protect disconnect. Many here only charge to 55.2 and that’s great too. Let’s just get it running for now. The inverter float of 54 or less is good.
Danielchu45
New Member
ok so i just want to ask a thing SOC is at 3.59v so it will be 57.44 so if i charge at 55.6 it will not be at 100% but that wouldn’t be a problem right?
the other thing i want to ask is if i want to connect the bms to communicate with the inverter do you have experience with this kind of inverters or if not i want to ask another thing if i succeed at the communication that mean i don’t touch the settings on the inverter and on the bms right?
That would be something that a techie at your site could do. A screenshot with parameters (V & A) to the forum would probably find an expert to offer opinion. I’m kinda doubtful that the inverter is at fault but it is a valid point.can you explain a little bit more cause i am not that much expert
Danielchu45
New Member
I don’t know the inverter is at a repair caused its in warranty but i hope after i get it everything will be ok
Good that you covered your bases
Danielchu45
New Member
yea i hope they fix it
Anything above 54.4 no load, the state of charge can be considered 100% You gain so little by going higher than 55.2 volts it simply isn’t worth it. As far as utilization the communication of the inverter type bms, I’d have to step back and let others answer questions.
Danielchu45
New Member
so as far i understand everything i don’t touch the settings on the bms when the inverter came here i adjust the bulk to 55.6 the float 54v and i charge it with about 10amp so they can balance and after its charge i can use it or i disconnect it from the inverter and leave it turn on for a few days so the bms can balance the cells?
in the settings the start balancing voltage is 3.45v if i charge it with 55.6 it will be 3.475v on cells so the bms will have enough voltage?
You got it.
Once you see a cell get too close to protect , back off the charge current.
You want the balance start voltage to be just under your bulk. The first cell that hits 3.45 and the bms will start balancing.
Danielchu45
New Member
so your telling if one of the cell get too close to protect 3.65 to stop the charging but doest the bms stop it when it get closer to the voltage to 55.6? if it dont should I reduce the current from the inverter, and if it gets closer to 3.65 from the BMS, should I stop charging from the bms or direclty from the breaker between the battery and the inverter?
Danielchu45
New Member
got it but if i charge it at 55.6 i highly doubt that will get at protection!
if i charge it at 10 amps where i limit it from the bms or from the inverter?
That I believe is a grid charge current setting. Not to confused with the combined solar and grid which you may or may not need to change depending on your system( panels or not)). You might have already charged the cells adequately when the bms gave up.
Danielchu45
New Member
now the cell are at 3.28v and i will charging only with solar.
A thing that come to mind now adon't know if it has anything to do with it at all, but I have to say it the day it was charging i did it with solar and grid it was ok with 60-70amp when i change the charging from solar and grid to only solar the charging got down to somewhere 10amps and a minute or two it was on fire.
Danielchu45
New Member
the cables are about a meter/3 feet
I had a similar failure with a cheap Chineseum off-grid AIO inverter. BMS (Ant SmartBMS) had a blown MOSFETs blown and inverter, the inverter had 3 faulty with one totally exploded however it worked fine with just solar and A/C diesel generator input but nothing on the battery charging or discharging circuit worked even after removing the pack with the blown BMS and running just on the good pack. Previous to this failure everything was running fine for 2 years. I don't know if the BMS or Inverter was the cause but I suspect the inverter was the cause. The load at the time was < 500w with the inverter rated at 48v 5.5KW. I changed the AIO to Growatt SPF series and BMS to JK, being off grid and unable to determine to the root cause I thought it best to use different and slightly better equipment. If you find out please update us on what failed in the inverter when it's returned.
Danielchu45
New Member
yea more of the chinese inverters are with the same board and functions and maybe they fail with the same thing and yea my inverter also work but there is a button on the side to turn on the power right if its off the inverter is showing the coming voltage and everything but as soon as i press the button to turn on and the relay close it goes to this error.
As soon as i get it it will inform you here
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