Question about the Victron SmartSolar 150/45
If I set absorption time to 5 minutes and tail current to 7 A, but after those 5 minutes the current is still 8 A, what does the controller do?
Has anyone tested this in real conditions?
The MPPT should stay in Absorption mode, until the current drops to below 7A, or for 5 min which ever occurs last.
Not tested.
Hi Mike, but what would be the point of putting 5 mn and tail current that continues after 5 minutes? I think the maximum time is 5 minutes, if the tail goes down just before it goes into float… or not?
Sorry I got the logic wrong: the change to float comes on the first of either tail current or time.
Looking at one of my MPPT’s the absorption time can be set at up to 6hrs, not 5 min.
The reason for the timing logic is this:
If there is a DC load on the battery, that the MPPT cannot sense, then the absorption time changes to float, despite the current being high, this stops a lead acid battery from being over charged.
If you are using lithium batteries, then unless there is very little dc load, leaving the battery at close to absorption voltage for a prolonged time is of limited consequence - it’s not going to cook the battery, like it would with a lead battery.
Then I use life and at 56.30v now charged and in balancing I can’t leave them for so long if not the delta of the cells goes up and the bms can’t balance. So the calculated 5 mn end with the battery now full, but I wanted to associate the tail current in order to avoid reaching the pre-established maximum time, that is, if the absorption current drops a little earlier thanks to the tail current it goes into float, on the contrary if the current between loads or other is higher than when defined and 7 a the time of 5 mn intervenes as a limit.
This is why you need your BMS to be able to control the charge current & voltage from the MPPT.
Yes, the battery pack delta will increase as the first cells saturate at full charge. At this point the cell voltage rises rapidly, and the charge current needs to be reduced to the level determined by the BMS. You cannot do this without dynamic control of the Charge voltage and current. Depending on your battery chemistry, and if you are 15S or 16S, 56.3V may not be appropriate. This is high for 15S and a bit low for 16S. Once dynamic control is established, the first cell to get to e.g. 3.55V for LiFePO4, will control the charging voltage & Current, then the remainder of the cells will catch up as the balancer does it’s job. The exact voltage at which this happens is a variable depending on the state of the 14 or 15 other cells.
in fact Mike , my package is a 16s of the basengreen with tianpower bms … On another package with jbd bms I can keep more , which is why my question is addressed to the times and current tail , so it is important to know how it works . Normally if ipacco connected to a hybrid scc, I could control the current of cavity, but with smartsolra 150/45 no because it will not be able to determine who withdraws current or the load or battery . Of one thing I am sure that having connected the smartshunt from 3000A , I manage to filter the demand for current , as the two-way smartshunt knows that at that voltage the battery will come to pick up what I have declared , but will not be able to carry out the current tail , unless I could create a network between my 2 victron scc and the smartshunt .. I would not know theoretically without expressing something that I do not know
If the charge current / voltage is under BMS control, then tail current and absorption time do not apply.
I find this confusing:
Of one thing I am sure that having connected the smartshunt from 3000A , I manage to filter the demand for current , as the two-way smartshunt knows that at that voltage the battery will come to pick up what I have declared , but will not be able to carry out the current tail , unless I could create a network between my 2 victron scc and the smartshunt
If you have a Lithium battery system with a BMS, the BMS should measure the individual cell voltages and calculate the max permitted charge current and voltage. These 2 parameters need to be communicated to the charging system. This is normally done by a GX device (Cerbo) and VE direct / CAN bus to the Charge controller. The BMS normally broadcasts the charge data on a CAN bus, which is connected to the GX device, forming a closed loop system.
Trying to charge more than 4 lithium cells in series without a closed loop control is asking for trouble.
Hi Mike sorry but the English translation is not clear. Anyway I saw that the only solution to make the tail work from the victron is to buy a gx to allow you to send the data from the smartshunt
You can run the venus OS on a raspberry pi or similar, but need additional interfaces.
Using just a smart shunt won’t work - it does NOT measure the individual cell voltages - you have BMS systems - you need to access the data from those systems to control the charging. Some systems have relay outputs to control charging / discharging. These can be used with the remote control input on most Victron gear, but it is a crude on / off control.
If you feel your English is not sufficient to express what you need to say, then use your native language - the on line translations are normally very good.
Ok , se victron forum lo permette … si quindi volevo dire che per utilizzare il tail current su smartsolar 150/45 che proviene dallo shunt occorre un servo gx per poter gestire via ve direct l scc . In ble non lo fa perché la connessione potrebbe non essere stabile .
OK, so no problem with the language, and yes, it is allowed.
So, EVEN with a cerbo smart shunt and MPPT in a system, the Cerbo can make the MPPT aware of the battery tail current.
However, THIS IS NOT WHAT you need to regulate the charging of a lithium battery bank,
Your BMS also can read the battery current and communicate that to the Cerbo, so to an extent an additional shunt is redundant.
What is needed: The BMS measures the highest cell voltage and should compute the max charging current / Voltage from that cell reading. This current is determined by the balancing network and may be from 50mA to several amps, depending on the BMS. This charge current / voltage data is what is required by the GX device to control the DVCC - the dynamic charge voltage & current loop. This is a feedback system driven by the highest cell voltage, not the total battery voltage or the battery current.
quindi , mi sembra di capire che il comportamente sarebbe simile a quello di un scc ibrido che collegato via 485 alla batteria ricava i paraemtri dal bms .
Comunque Mike volevo ringraziarti per le informazioni che mi hai fornito come espewrienza , più imparo e meglio è !!! Ti auguru il meglio !
Happy new Year to you…