Is there anyone here who can explain how to configure the system so that Victron respects the charging limits reported by the BMS?
My setup consists of three MultiPlus 5000/48 units, four MPPT chargers, and Seplos battery storage. The system works great except for one issue: the charge limit.
Victron correctly respects the discharge limit reported by the BMS, but it does not respect the charge limit and continues charging above the value set by the BMS.
Someone suggested that I should disable BMS control and configure DVCC manually. However, when I disable BMS control, the entire system switches to Pass-Through mode and stops charging the batteries. Because of that, I don’t know how to configure the system so that it respects both the charge and discharge limits.
Has anyone experienced something similar or knows what I might be missing?
Do you have DC Feedin enabled? Then, no DVCC Charge current limit is send to the MPPTs, they will run full throttle to allow feedin to be possible.
From the manual:
DVCC charge current limits are not applied to DC MPPTs when ESS is enabled with Allow DC MPPT to export. This is to get maximum output from the solar panels for export.
The system however will take care that your battery does not exceed it’s target voltage and switch to feedin, when required.
I would really like to understand this, or perhaps there is a manual that explains how the charging limit is determined and which parameters affect it. At the moment, I cannot figure out why the system is not respecting the charging current limit.
So, if I understand correctly, when I disable “DC-coupled PV feed-in excess is enabled with ESS”, the system will then respect the DVCC settings and the charging current limits provided by the BMS?
I think the BMS Limit is always obeyed. Just the (artificial) Limit in DVCC is not used, when DC-Feedin is active.
The values for DynamicESS are mostly important for scheduling. They will also act as maximums the local dess-delegate is allowing. They have no meaning for regular system behaviour.
I’ve sought for a similar setting and FINALLY I found it - in DESS. So if you use DESS (works at least for current beta version V3.80~33):
Go for DESS setup and configure the setup for maximum battery charge to your needs. DESS will obey the maximum charging load (typically a few % less than your setting) and send the remaining power into the grid. This happens for the full input from the PV as long as the limit for feed into grid isn’t hit.
For best result REMOVE any limits in DVCC or ESS, all is handled in DESS.
Amazingly this works now without a clear statement about the implementation for all the DESS settings - while DVCC works as specified - which comes as a surprise as the specification makes little sense for the user.
Ok, I’m finally happy with this solution, and like to share this possibility.
This would only work in some situations, i’m afraid. The DESS Schedule is not a 24/7 rate control, it may advice the inverters to “just do regular ESS” during times, especially during solar hours, when the forecast situation is unclear.
Then, no forced feedin that would keep your battery rate bellow the desired value would occur.
my problem is, that the battery get quite rapidly hot as the limits the pylon tech batterys indicate are quite high. I don’t like to get them to 35 C within 30 Minutes simply because a 3.5 kWh rated battery indicates a maximum input power of 1.7 and the PV is happy to put it in (instead of forwarding most to the grid).
The above said just worked permanently today with a lot of PV input that would heat up the battery much if not throttled. But the forecast in these days is quite clear. And if a forecast is unclear it is rather unlikely that there will be a lot of continuous power. Some high current input for a short time is a lesser problem, if the main issue is the said heat.
I still would like to have a proper setting that does the intended limitation in DVCC (or elsewhere) to reduce the batteries indication. But I doubt it will come…
thanks for the response. I’ve put already a fourth battery in. The limit adds up to 148 Amps - which can easily be delivered by the combined PV System and the inverter. And sometimes the DESS likes to do so.
The temp of 35 degrees might not be a big issue, but it limits battery life - actually for no good reason. Charging the battery slower would even help to gain more out of the system, as a fully charged battery can no longer take the overhead of PV which the inverter can not convert to AC, because of its limit is hit (and so the PV is throtteled).
