I have a Multiplus 2 GX, 3000, 48v inverter set up with a bank of pylontech US5000 batteries which i have set up as a dedicated UPS.
Works beautifully.
What i would like to do next is enable a generator input to recharge the batteries when they reach a set level in their state of charge.
I have the colour control GX also, so its easy to integrate a generator control.
However, im thinking that when the generator starts, i would need to integrate an auto transfer switch so that the inverter doesnt see the generator supply as the āgridā or shore power supply.
ideally, id like the generator to suppliment the inverter and charge the batteries while the inverter is in UPS state, and not cause the inverter to revert back to grid or shore power supply.
Failing that option, I will just fit a manual transfer switch and use the generator to power up the inverter when the batteries soc is low.
It would be great to have it all fully automated.
From 30% to 100% usually takes around 4hrs of charging time.
Hence if you need to recharge from generator instead of grid, then you will need an external transfer switch.
Its possible to get a switch with auxiliary contacts that can be wired to a Cerbo - Iām not sure if the GX has digital inputs, However, you can also wire this to an AUX input of the multiplus, and load the Charge current control assistant. This can then be used to set the charging limits. The transfer swithc is best left as a manual switch, rather than an Auot mains fail type switch.
I have a new manual changeover switch, its huge but I figured bigger is safer. I do like the UPS feature, especially if im away for any extended work commitments, knowing all my critical systems like home security, Internet and combi boiler are kept alive - but to be fair, any power cuts have only really lasted a few hours at most.
Eventually I will add solar and extra batteries, and run the system that way through an mppt.
I wasnāt sure if an mppt would be usable for generator feed rather than solar - enabling drawing from the batteries while simultaneously charging a certain percentage of the pylontechs.
To accept a common generator the grid code must be set to ānoneā which us not compliant to
most grid operators. Changing grid code can only be done via VeConfigure.
Solution would be changing generator AC via a telco 48V PSU to DC. Common PSUs are Eltec Flatpack2 and Huwei. Voltage and max current can be programmed and even controlled via CAN-bus. Not by VenusOS but EspHome/NodeRed/Home Assistant.
Hi @BjoernK there are a lot of posts and questions about generator backup for ESS systems at the moment.
Could you please make a detailed description how to use and control a Telco PSU?
The other solution, with additional MK3 and MP as charger only device (Seach at the Cerbo Manual for MK3 for more details) i posted many times in the last weeks.
Itās not possible to integrate DVCC.
You have two chooses.
A) Fixed voltage and current limit
Get a PCB which plugs into the back and provide convenient access to AC in, DC out and CAN-bus. Some boards include a potentiometer to set VDC and MAC current
B) CAN-bus control via NodeRed or Home Assistant
Else use an ESP32 with a EspHome software:
This can be integrated into HomeAssistant or via NodeRed into VenusOS
There are more projects on GitHub to interface with Flatpackās CAN-bus.
I hope this helps.
I personally abandoned when I decided not to got with one MP2 in an 3-phase setup but build a full 3-phase system covering the entire house.
@Ciderman I guess you could simply put a charger on the output of the generator and directly charge the batteries without having to deal with external changeover switches. That way you keep the mains wiring original and simply provide a charging facility for your batteries. Yes it does incur the price of a charger but saves the hassle of changing the mains wiring.
Thank you. I was also wondering the same thingā¦. In fact, I was thinking of adding a second identical inverter and using it purely in charger mode. That way, I can link the system and the inverter/chargers can talk to each other for the BMS etc.
Put simply, I like the UPS function, but if used I can get 4 days of emergency back upā¦ which then requires 4+ hours of charging from the grid.
So it got me thinking, it would be nice to save a few quid and run the system and top up using my generator which is dirt cheap to run.
Ideally I will eventually add solar and leave it on permanently, but retain the grid power option for complete flexibility.
I do love the victron range of products, its all so interchangeable, compatible and virtually plug and play.
@Ciderman that sounds like a good plan. If the multiplus is compatible witht ehe xisting you could just runt hem in parallel and have mains into the input of the existing one and the generator into the input of the new unit.
Itās a constant voltage and constant current DC source with a wide range of AC input. For TelCo application they are exchanged preemptive early, though cheap on used equipment market.
They have fans included and are designed for 24/7 operation. No need for extra fan. 60C was mentioned for self designed adapter board bringing the 3000W/60A DC output out of the case. Though design the board with thick copper layer.