I am ready to configure the Multiplus and MPPT and need to get some feed back on the settings please, that I will use on the VE configure and and Victron connect. I have listed below. Multiplus. VE configure Tabs General
50 Hz AC1 limit 30A (2A below my RCBO on the feed)
Battery monitor 95% Bat Cap 186Ah Charge efficiency? No note in help on this. Grid
G99 do I need to put anything in code settings? Help is no use. Inverter
230V, Power assist 2.0, DC input 47V (not sure of this have set this for 2V above discharge end)
Do not restart after short circuit? Help no use.
Enable AES blank Charger
Enabled, Lithium enabled, Curve Fixed, Abs V 60.75, float V 60.00, charge A 60 max battery amps is 90 but fused at 80A internally, so should I go higher. Values entered are from BMZ data.
Stop charge ? Help is no use. Virtual switch
Do not use enabled Assistants
ESS selected, should I add any others? Tools ignored.
Further to the Multiplus above this is what I was proposing for the MPPT450/100 on Connect. SETTINGS
Battery V 48V
Charge Max A 60A but like previous battery max is 90A but it has an internal 80 A fuse so it could be a bit higher than 60A Charger Enabled. Yes Battery preset User defined Remote on/off Expert mode off. Charge Volts
Abs V 60.75
Float V 60.00
Equalisation voltage 32v does it matter what this is if Auto Equalisation is disabled? Temperature compensation Don’t know?? SOLAR Low temp cut-off Disabled? Partial shade detection Off I have no shade most of the year but some possible from a hedge in December. A search explains there is no real detriment in having it enabled. So On? Tracker Names as default Relay mode don’t know?? Display as default.
Battery monitor & Charge efficiency: Battery monitor is normally disabled IF an external BMS system is connected (You have a Cerbo & BMS communications?)
Grid Code is dependent on your location & regulator.
Do not restart after short circuit: Again, this is dependent on local regulations, depends if you want to have to manually restart the system if there is a short on the output. Shorts are normally cleared by a breaker tripping, but a major short may occur, and the inverter has the ability to try to restart. Under certain circumstances - like you start work on a “dead” electrical system without disabling the inverter, an auto start can cause a hazardous situation.
AES - enable this if the system spends a lot of time under very light load conditions, and there is limited battery capacity.
Assistants ESS: this will only work if there is a GX device with communications to the BMS.
MPPT settings: The critical settings here are the battery Absorption and Float voltages, also to a lesser extent the max charge current. All of these are determined by your battery parameters. MPPT should also be linked to the GX device.
Low Temp Cutoff is designed to prevent charging at low temperatures where a lithium battery cannot accept charge.
Relay mode: Depends if you want to use the relay to control a fan for additional cooling.
60.75V sounds high for a lithium pack, do make sure that this is set to ~200mV less than the manufacturer’s stated max voltage, this will avoid high voltage disconnects from the battery.
MP2s are rated up to 60VDC, so i doubt that you can set 60.75V as absorption, but ive not tried myself.
MPPTs could go higher than 60V, the default AGM profile includes 66V equalisation voltage, but again, pushing the battery up to 60.75V with the MPPT would go over the MP2s rating.
What kind of battery do you use, and is there a GX device in your system?
Thank you for your reply. This is a very thorough answer and it is much appreciated.
Yes.
I will just use G99 and leave at that?
Sound advice
Have both.
What is considered a low temperature?
It is LiNiCoAlO2 chemistry which may account for the high values. They have come out of the BMZ manual and repeated in the Victron notes on the battery.
This will be a fresh new start up and I will first power up from the battery and do the configuring on battery, What I am unsure of, what needs to be connected to the Cerbo other than the Multiplus and MPPT at this point, and should any be left off.
Ok on the grid code.
Low temperature charging does depend on your battery chemistry. See manufacturer’s recommendations.
On first start up: AC input and output breakers open. BMS connected to cerbo, Inverter: If your BMS does NOT have a soft start circuit, then you also need to wire up the inverter remote voltage sensing circuit to provide this function. In this case, the main inverter dc switch is left open while the battery / BMS & Cerbo are energised. The MPPT may remain connected to the dc bus at this stage, but with the PV turned off. Once the Battery voltage is stable, then the inverter precharge breaker should be closed, then the main breaker after 10 - 15 seconds. During this time, the Cerbo should reflect the BMS (battery) data.
IF the BMS does have a soft start circuit, then the inverter as well as the MPPT can be connected to the DC bus at start-up.
In both cases the inverter control switch should be in the off state. The VE-Bus (inverter data) should be connected to a Mk & laptop. The inverter control switch can then be turned on and the inverter programmed. then the VE-bus can be connected to the Cerbo.
Similarly, the VE-direct from the MPPT can be connected to the laptop, and programmed, then the VE-direct data connected to the Cerbo. Cerbo setup can then take place.
Thank you for an excellent answer again, looks like I am good to go now. It is all v well having detailed manuals but putting it all together in a procedure is seriously lacking particularly for someone who previously had a plug and go inverter with a stepped procedure.
Fortunately it does. It took me a while to confirm but it was in the BMZ manual all the time.
