My Victron ESS System, help me to configure it

[Zucca]

I finally started to play with the Victron toys I bought from you almost a year ago.
This epic delay is due to the solar companies which are struggling to understand what a Victron ESS system is.
It's basically a DC coupled solar ESS system, no feed into the grid.
I have a Lynx power in, shunt a and two distrubutors.
Three Smart Solar RS and two Quattro inverters for generating the 120VAC split phase.

To get everything up and running I am orienting myself on this guide
https://www.victronenergy.com/live/ess:start

However I would like to have your opinion on a couple of topics.

This is what I would like to achieve

1) Lynx Shunt
it provides Vbatt and batt SOC to the system.
Here I tend to ignore the SOC (since it could drift over time) and get the batteries charge state based on the DC Vbatt.
I could also setup a temp sensors but as a first implementation let's keep it simple, I don't wanna use it for now.
Please advice is I should use the SOC from the shunt or not.

2) Two Quattro Inverterts 10000 to generate the 120VAC split phase for the home
Setup

Vbat > 51.2V [SOC > 20%] Inverting, no power pulled from grid.

Vbat <50V [SOC < 10%] Battery charged from the grid (if possible) to prevent a severe empty battery state

between the above Passthrough, power pulled from the grid

Do you think it is possible to use the power assist function in the inverting state to get power from the grid if the home is demanding more than the inverter can deliver from the batteries?
Example:
Home is demanding 12KW from each 120VAC phase, 24KW total.
The two Quattros can deliver only 8KW each, 16KW total of max inverting power (ignore startup...).
The missing 24-16=8KW (4KW each phase) will be automagically pulled from the grid to make the home happy.

3) Three Smart Solar MPPT RS 450|100
They will be in sync with the same parameters.
Setup

Vbat > 53.2V [SOC > 80%] Floating, no energy flow from solar panels to the 48VDC bus

Vbat < 53.2V [SOC < 80%] Bulk charging, all the solar energy available will be delivered to the 48VDC bus

Do you think it is necessary to setup an ESS assistant to achieve the above?

I would very appreciate if you could push me into the right direction.

Many thanks in advance,
Should I post it in the Victron forum?

 

[drps10]

2) Two Quattro Inverterts 10000 to generate the 120VAC split phase for the home
Setup

Vbat > 51.2V [SOC > 20%] Inverting, no power pulled from grid.

Vbat <50V [SOC < 10%] Battery charged from the grid (if possible) to prevent a severe empty battery state

between the above Passthrough, power pulled from the grid

Do you think it is possible to use the power assist function in the inverting state to get power from the grid if the home is demanding more than the inverter can deliver from the batteries?
Example:
Home is demanding 12KW from each 120VAC phase, 24KW total.
The two Quattros can deliver only 8KW each, 16KW total of max inverting power (ignore startup...).
The missing 24-16=8KW (4KW each phase) will be automagically pulled from the grid to make the home happy.

Bump… looking for this exact answer. Planning stages for me. I want to know if I get a dual 5kva system, will grid assist the batteries when there is to much draw for extended period from hot water tank running and other high demand loads.

 

[Madcodger]

As I recall, when you are on "shore power" (AC) with Victron, that is your primary power - not a just in case "assistant". The Quattros can have the battery assist the AC if shore power can't handle the load, but it doesn't work the "other way 'round". But let's see what the Victron gurus say...

 

[Adam De Lay]

I know I have programmed my 5kVAs to enable AC IN when power output reaches a specific threshold, but I've never actually hit that threshold to see exactly what it does.

@sunshine_eggo can you enlighten us?

 

[sunshine_eggo]

There are multiple methods to accomplish fallback to grid. It can be based on voltage for any battery or SoC if battery communications are present. In general, any method must have both start and stop criteria.

The easiest way is Virtual Switch. You can have the unit start using AC input once battery drops to X level. AC input use will pass AC through to loads and charge with any surplus up to AC input limit. PowerAssist will engage to boost power for any loads that exceed the AC input limit.

To revert to inverter operation, you have have it "ignore AC" once the battery raises to a given level. This can also be triggered by many other trigger criteria.

Conceptually, there is no "assist" from grid. Once on grid, it's all grid all the time until grid is terminated.

This thread is about ESS. ESS is most appropriate for an integrated system where grid backfeed is also present with potential interface with a grid tie inverter where one may be trying to limit grid usage to off peak time and/or optimize how customer generated PV is managed and batteries are charged. In other words, ESS is complicated and hard for the new user.

If grid is simply present for fall-back purposes when battery gets low, ESS is overkill. There are easier ways to make that happen.

 

[drps10]

Thanks for the reply’s. Why would it be overkill?

If grid is simply present for fall-back purposes when battery gets low, ESS is overkill. There are easier ways to make that happen.

Sorry to hijack. I don’t want to use AC to charge the battery (unless a storm might be coming and solar didn’t top it off), so I don’t want to rely on SOC to switch it back. I will be doing critical load panel and move over the heavy loads too (hot water, mini split condenser and possibly pool heater). With everything running may overload each inverter.

In my head, the grid will assist the inverter and allow everything to be running mostly from solar/battery and just squeeze out the remaining needs from grid.. Or does it not work like that??

Once on grid, stays 100% grid? If so, what would make it come off grid and back to battery/solar. Once one of those loads turns off or does it need manually done? I know it can be done with SOC, but if the charge is still high enough and “hot water” is done, will it go back to battery?

 

[sunshine_eggo]

Thanks for the reply’s. Why would it be overkill?

Have you read the ESS manual?

Sorry to hijack. I don’t want to use AC to charge the battery (unless a storm might be coming and solar didn’t top it off), so I don’t want to rely on SOC to switch it back. I will be doing critical load panel and move over the heavy loads too (hot water, mini split condenser and possibly pool heater). With everything running may overload each inverter.

Okay. You need to be very specific about how you want things to work.

In my head, the grid will assist the inverter and allow everything to be running mostly from solar/battery and just squeeze out the remaining needs from grid.. Or does it not work like that??

Your head is wrong. No inverter works like that. The Victron is one of the few off-gird inverters that can boost grid if grid is insufficient (maybe your breaker only allows 30A, etc.).

Inverter/chargers are both, but can only be ONE at a time. If you have AC power coming in, it's using the big transformer to convert AC to DC to charge the batteries, and it passes the AC through to the loads (it's impossible to invert at this time). If on DC power, it's using the big transformer to invert DC to AC to power loads. It can't do anything with incoming AC in that mode in normal operation.

In the "boost" mode where loads threaten to overload the AC input, it synchronizes its output with the incoming AC, stops charging and adds DC to AC inverted power to the incoming AC much like a grid tie inverter does.

Once on grid, stays 100% grid? If so, what would make it come off grid and back to battery/solar.

Whatever criteria you choose.

Once one of those loads turns off or does it need manually done? I know it can be done with SOC, but if the charge is still high enough and “hot water” is done, will it go back to battery?

Example on/off criteria:

Switch to grid when load > 4500W for 15 seconds.
Switch back to inverter when load < 1500W for 30 seconds.

Switch to grid and charge when battery voltage is below 48V for 30 seconds.
Switch off grid when:
battery voltage is > 51V for 5 seconds
has been on grid for 30 minutes ("when no VS on condition for 30 minutes)

Here are the various VS ON conditions:



and the VS OFF conditions:


Virtual switch (VS):


by setting the above, VS ON = use AC input. VS OFF = ignore AC input.

This is a new experimental feature aimed at mobile installations on shore power:


It will run off AC, but it will only charge from AC if below the voltage specified.

 

[drps10]

I love the forums! Thank you sunshine! I will read the ESS too. Thanks for educating myself on this. Very new to this and trying to learn and understand every angle.