This site is now in read-only archive mode. Please move all discussion, and create a new account at the new Victron Community site.
Hy guys.After a certain load,usually usually 3500-4000w the MPPT stops and everything runs only from battery.I have a pylontech US3000C with BMS that i keep only for backup with small loads at night.But daytime I want to use as much solar power as I can.Discharge current on console is 37A but my BMS deactivates the MPPT ....whats going on ? UPDATE : I have added another US3000C to the system but nothing changed.
You appear to have AC disconnected, with one battery that is terribly undersized. The system has to lean on the battery for load transitions, Unbalanced systems, no grid etc will cause instability with undersized batteries.
There should be at least 3, preferably 4 for systems like that.
Mppt's are slow and the bank needs to be able to supply/sink large load variations, one US3000C will not be up to that job.
It is a great way to damage a battery.
Did you consider using ESS instead?
https://www.victronenergy.com/media/pg/Energy_Storage_System/en/index-en.html
In off-grid the discharge current can't be limited, the Inverter is pulling from DC what is needed to supply the AC load.
Maybe you have a cell imbalance? In VRM go to advanced and there you can add a diagram of the highest and lowest cell voltage.
Or you look in the remote console -> device list -> Pylontech -> details -> there you can see the highest and lowest cell voltage in real time.
At parameters you can see the current CCL and DCL coming from the battery.
Finally I got ESS working,and also added a second Pylontech US3000C to the system.But nothing has changed,if the total MPPT load is higher than 65A the MPPT will receive a stop signal.( i presume from the BMS..).Funny thing...no errors ...no alarms,nothing.MPPT just stops and starts...If i got errors or alarms it would be better....Clip attached with the system running ESS and having the same problem.
Thats just my unqualfied idea, so it might be totally off.
One US3000C is rated with 35A continuous load. You have two, so we say 70A.
The MPPT peaks a couple time to 3500W, which at 50V means about 70A.
As with VS and ESS alike the Grid can go away at any given time and needs about 30-60s to connect back once available. Could it be that the BMS uses the continuous load to caculate when to protect its tush? Not the peak load (which should be able to handle 140A for 60s (peak1) and 200A for 15s (peak2))?
Very weird behaviour, but my guess is the same as others. It trips over 30 amps on the pv side, but that translates to way over 70 on the battery side. And since bms controls the mppt, it shuts it down. I never encountered this problem in the past when i had only one 5kw array, but maybe because i had minimum 200Ah, 4 50Ah pylons. Now i have 12kw pv, i m willing to test it myself. When i get a sunny day i ll plug in the water heater and disconnect all the batteries except 1 us5000. I ll let you know what i get.
I have 3 Pylontech US3000C,so thats 3x37A which is 111A that can be tolerated on the battery side,and MPPT can put out 100A max.The bigger problem is that i dont have any errors what so ever,when i look in the pylontech menu the is no overvoltage,no overcurrent....absolutely nothing.Everything is ok,the battery says its ok.And i dont think the MPPT should behave like that,shouldnt it throttle up/down?.This stop/start is not right.If battery menu says charge rate 111A in real time...why is the MPPT stopping at 60-70 ? And i repeat,the is no overcurrent alarm on the battery,because if there was i should see it.
Can you go into mppt settings and look up max charge current?
I have no other ideas, 3 x us3000 should be more than enough for the job. Maybe talk to your distribuitor to open a ticket to victron about your mppt, it s worth a try
