I have three feature requests for the Victron SmartShunts which according to my knowledge could all be realized in firmware:
I propose to implement a switch to operate the SmartShunt in reverse. The reason is in my system the cable routing would be much easier if I could connect the load to the right terminal and the baterry to the left, but currently it is required to be the other way around. I guess this switch would just have to negate the measured power, so it should be quite easy to implement.
I propose to increase the precision of configuration values, in particular the “Charge Efficiency”. According to my measurements the charge efficiency of my system is 99.5%, but in the SmartShunt I can only configure 99% which is too low or 100% which is too high.
I propose to add the ability to turn off the tail current condition for the automatic synchronization entirely, so that the automatic synchronization happens only basen on battery voltage. The reason is that in my system I have loads that are automatically turned on when the battery is fulland often this is faster that the tail current condition of the automatic synchronization, so it is not triggered.
I hope this is the right place for my proposals.
Thank you very much and best regards.
on the weekend I took some time to learn the VE.Direct HEX Protocol and implement it into my Ve.Direct-DTU, so now I can trigger a synchronization via MQTT from my Homeassistant which means that I no longer need the third requested feature.
Nevertheless, the first and second features I requested would still help me a lot, so I was wondering whether I can do something more to get them implemented besides posting these here. Is there another place where I could propose them where they might get more attention by the developers?
Because it would count charging the battery as discharging it and vice versa. Thus, an empty battery would correspond to 100% SOC and a full battery to 0% SOC which would cause problems with the automatic synchronization which sets the SOC to 100% if the battery is full. Here also the tail current condition of the automatic synchronization would cause problems as charging the battery would correspond to a negative current, so the tail current condition would always be fulfilled.
So far all of these problems can be mitigated in my software, but there are some further problems I am unable to solve: In the calculation of the SOC the charge efficiency and peukert exponent would be applied wrong and since you cannot set the charge efficiecny higher than 100% or the peukert exponent lower than 1 it is not possible to avoid running into miscalculations here.
Looking back I guess I completely misunderstood your proposal - You proposed to turn the Shunt around physically, right?
I guess that would solve this problem, however the port for the plus cable and VE.Direct port would point backwards which would make routing these cables more complicated and less important it would look ugly. XD
In the end I don’t see any reason why a seeting to reverse the Shunt is not there yet - I assume a skilled programmer would be capabale of implementing such a feature in few minutes and if I had the necessary information on the firmware I would have already done it myself.
3 should be solvable by setting the tail current to an absurdly high number, this will always satisfy the condition of charge current must be below set tail current value.
Hi Gregor,
this is the approach which I have used up to now, but unfortunately, it is limited as well, because the maximum configurable tail current is 10% of the batterys capacity, so for my 100Ah battery it corresponds to 10A, however, I can get charge currrents of 40-50A peak with enough sun. Furthermore, there is also the “Charged Detection Time” setting which sets for how long both the voltage and tail current condition have to be fulfilled for an automatic synchronization to occur which has to be set to at least 1 minute. Together, there is no reliable way to ensure that the automaitc synchronization occurs exactly the instant when a set voltage is hit because it takes at least this 1 minute.
Like I already wrote, I have fixed this problem in a different way: Since I implemented the VE.Direct HEX protocol into my data transfer unit, I am able to trigger the synchronization from my Home Assistant instance which means I don’t need the automatic synchronization anymore, so I just disables it my setting the voltage condition to an unreachable volatge.
The Voltage in the MPPTs can be set in 0,01V steps, whereas in the Smartshunt it can only be set in 0,1V steps.
If I configure the MPPT to an absorption voltage of e.g. 14,4V the SOC will never reach 100% as the measured voltage at the BMV flickers between 13,39 and 14,40…
Why do you care that much about automatic synchronization happening exactly “that instant” ?
If the SmartShunt decides to sync a little bit before the battery is actually full-full (somewhere >99% SoC) then the charger would not care, but simply continue its job until the battery stops taking charge… while the SoC in the SmartShunt is stuck at 100%, until discharge begins.
Yes, in particular for point 3 there are some solutions that serve as a workaround, however that feels unnecessary janky to me, because I see no reason why the firmware should not allow us to set values from amuch wider range than it is currently the case.
That is a question of temperature compensation, the SmartShunt has the option to connect a thermal probe and the ability to send this information to the charger(s) through VE.Smart, so they (and the Shunt) can adapt the voltages… which will also protect the lead-acid battery in the summer from overcharging.