Using an ESS system (1 or 3 phase) with Victron Multiplus 2, connected to grid, it is not possible to hookup a generator since the Multiplus only has 1 AC-in instead of the Quattro. But is it possible to set up a separate Multiplus just for Generator input?
A client of me wants to install a generator that automatically starts when grid fails, and then have it charge the batteries.
I know I can use a Multiplus for this and set the AC-in to Generator, but I am not sure if it is possible to implement it into the grid tied ESS system.
Yes, but you can only connect it to the battery, donât connect the AC out.
The new multiplus would be used as a dumb charger, controlled by a relais on the old system. Be aware there is only limited (unsupported) integration with GX and VRM. Also make sure you look into the caveats of monitoring DC loads.
As stated above an automatic transfer switch would be the better solution, a single multiplus has limited DC charging output and converting AC-DC-AC is not very power efficient.
No, you cannot simply use a transfer switch if you have a grid-tierd system. The problem lies in the grid code setting. The Multi monitors the grid conditions and automatically disconnects from the grid if they are poor. Most standard generators do not supply grid power in such conditions. As a result, you also have to change the grid code in VE Configure to ânoneâ, when you are switching over. More about grid code: VEConfigure: grid codes & loss of mains detection
To over come this problem Victron built the Quattro series.
Long story short, to use a Multi as DC-charger is the right way, if you have already a Multiplus system, but if you are in the planing phase then maby think about a Quattro.
An automatic transfer switch would be not an option as the generator used will only be a small hand started generator (max 2000W).
I understand that the multiplus would only function as a charger and that the efficiency would not be great, but this would be for emergency use only.
Yes, I know that I can use a second Cerbo, but the whole point is to integrate it into the existing ESS system without using a second Cerbo.
I tried the search before, but all I can find is for large generators that provide enough power to supply an entire house, not a small generator that is only used to charge batteries in case of grid failure and low battery SOC.
The system is already running, so changing over to a Quattro is not an option anymore.
If victron had larger 48V DC Chargers, that would have been an option too, but I can only find the Skylla-TG charger which is more expensive than a Multiplus.
The question about the generator and ESS comes up 3-4 times a week in all languages. The topic has been discussed thoroughly from all angles. And a little initiative is also required here.
MK 3 and Flatpak are already the solutions.
OGPS
(Ed @ Off-Grid Power Systems - offgridps.com)
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I understand the solution and I understand the desire to point people to search. I resist the urge to do it nearly every day. But, this isnât something thatâs necessarily easy to search for. It would require some understanding of what to search for. So my advice is resist the urge and just donât say anything or give a link to where they can find more information, which you did do. Thank you for that.
The problem is that I never heard of flatpack and I had no idea I had to seach for âmk3â, hence why the search option only gave me vage topics that were not really related to my question. I guess this is also the case for many other users, which is why this questions keeps on getting posted multiple times.
12.3.1. DVCC effects when there is more than one Multi/Quattro connected
Only the Multi/Quattro (which can be a single device, or multiple together configured for three-/split-phase as well as parallel) connected to the VE.Bus port will be controlled via DVCC. Additional systems, connected to the GX device using an MK3-USB, are not controlled by DVCC and will charge and discharge according to the configuration made in those units.
This applies to all types of systems with DVCC enabled. For example a system that does not include a managed (CAN-Bus) battery, and uses only the DVCC charge current limit: that charge current limit is only applied to the Multi or Quattro connected to the VE.Bus port.
I am doing something similar with my 3p microgrid; I have an additional RS6000 connected to the grid and some leftover solar panels. Charging from the grid is enabled depending on SoC. The advantage using the RS6000 over the Multiplus is the additional 2 MPTT trackers you get for free, and I use it to dump up to 5KW back into the grid once everything is full.
If you have the option to trade in or sell the MP2 and swap it for a Quattro, that would be the best option for a single phase ESS with single phase genset.
A transfer switch will probably not work as expected as the genset is not likely to be within spec of the grid code.
In a three phase Multi or Quattro ESS with a single phase generator, my choice would be to add a MP2 to use just for charging.
You could use its output for special loads that you donât want on the main ESS system.
As people have stated, you need to be careful when programming the âchargerâ Multi, so it doesnât overcharge the batteries.
Or get creative with Node Red.
Some kind of safety mechanism that switches the charger Multi to âIgnore AC Inâ if an error pops up would seem useful.
If youâre still looking at this in about a year, Victron has announced a couple of new options on the IP43 charger line, including a 48V charger. Might be a good fit for your 2000W scenario, but likely wonât be available for 9-18 months.
Iâm setting up three extra MultiPlus 3000/35 units that will be used only for charging my battery bank. I added these three units to VRM as a separate system, but Iâm using the same SmartShunt for monitoring.
The reason I chose three smaller MultiPlus units instead of one large charger is because my generator is three-phase. If I used one big charger, it would pull all the power from only one phase of the generator. I donât think the generator would like that, so using three chargers spreads the load across all three phases.
and yes a generator has to hy Hz (51) so i have to chance the grit code to none the chargers only have to charge the batteryâs (48V)
