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Energy optimize the property with the Victron ESS system

|10/10, 2022

Energy optimize the property with the Victron ESS system

There is no doubt that our most frequent question right now is how can I energy optimize my property? Here we clarify the concepts and give you concrete proposals for various ESS solutions (Energy Storage System).

Common challenges
There are several different challenges which an ESS addresses and depends onå installation and setup, each system is designed individually for maximum price/performance. Below we have summarized the most common gestures that come to us.

  1. We consume the most electricity in the part of the day when; it is the most expensive and we would like to have a solution instead of using cheap night electricity during the day.
  2. We have a recurring need for more electricity. mä what we can or want to secure the property for and would like to have a solution that can do; in and support incoming power when needed.
  3.  We are in an electrical area with frequent power outages and we would like a solution for to get an even electricity supply to the property even if the incoming electricity fails.
  4. We need to be able to operate our property without incoming electricity for a longer period of time period and would like to have a power plant solution that automatically kicks in when needed.
  5. We want to build a smaller solution to use cheap night electricity on; the day for certain selected loads but we don't want to build ourselves into a corner so it is important that the solution is able to scale up over time.

Fundamentals of Victron Energy ESS system< br>The solution has the function of storing energy in batteries from the relevant source / sources when it is available or reasonably priced to then be used when needed or during those hours when the price of the fixed electricity network is at its highest.

With Victron Energy, you are not locked to a certain battery make, but you can connect batteries from different manufacturers . Victron's Lithium batteries are mounted with advantage there; it is an integrated solution and the system is scalable.  The solution is also supplemented with components for system monitoring and remote configuration through Victron VRM portal.

ESS system parts
How to do to make the system more accessible, we have divided the included components into 7 main groupings (Inverter (inverter)/charger, DC distribution & Battery & monitoring, System & monitoring, Battery solution, Solar panels & regulators, Electricity and Ö others):

1. Inverter/charger
The inverter/charger is the main component of the ESS system and this is where we dimension how many phases the system should be able to handle or how large loads we want to be able to drive.

In this blog post we handle två types of Inverter/charger, but there are of course a number of different models to choose from.

Victron Energy Quattro-II
The Quattro-II series is a combined inverter and charger. It can also take twoå AC inputs (in our example we use the one for power plant) and automatically connects to the active source. Its many features include a pure sine wave inverter, adaptive charging, hybrid PowerAssist technology and a number of system integration functions such as three-phase or split-phase operation and parallel operation. Up to 6 Quattro-II can work in parallel to achieve; higher output current. Three-phase operation or operation with phase division is also possible; possible.

Victron Energy MultiPlus-II
MultiPlus-II is a multifunctional inverter/charger with all functions from MultiPlus, as well as an external current sensor as an option, which the PowerControl and PowerAssist functions. It also has a built-in function with protection against operation and the list of countries where it is approved for ESS is permanent. Up to 6 MultiPlus-II of the models up to 5KVA can work in parallel to achieve higher output current.

2. DC distribution & Battery monitoring
DC with high effects also has; a great need for powerful and well-functioning DC distribution and there are of course many different ways to solve this challenge. Victron Energy Lynx is a complete series of products for is just DC distribution and the system can be expanded as needed.

In an ESS system we usually recommend a system consisting of 2x Lynx Distributor and 1x Lynx Smart BMS alternatively Lynx Shunt VE.Can depending onå battery bank. The respective Lynx Distributor is placed before and after the BMS or Shunt, has four fuses and carries a positive and negative rail, which greatly facilitates the installation.

Lynx BMS or Shunt handles the battery monitoring and communicates with Cerbo GX så that you can follow this in VRM the portal, apps etc.

3. Monitoring System
Victron Energy has a monitoring platform called VRM where you can monitor, control and optimize your systems from Victron Energy while catching potential problems early by shutting down insert warnings and alarms.

The basis of the system är Cerbo GX which is a "communication center" for Victron Energy products and also manages it via apps and computers, we travel that an extra external screen is mounted connected to the system for easy handling even without a computer or phone.

 
4. Battery solution
An ESS solution's core and usually most costly component is the battery bank, which is used to store energy for later use, but before we talking about the size of the bank, there are a couple of additional choices to consider.

1. What technology should my battery bank have? To simplify the reasoning, we divide the batteries into Lead or Lithium and compare them in the categories below.

Charged willingness
Lithium batteries has a very good willingness to charge, which means that it is basically just as easy to charge the entire battery from empty to full, while a lead battery starts to become slow to charge at about 80 %.  Good charging willingness is especially important if you want to reduce the time for charging or have limited access to charging such as solar panels.

Continuous voltage
Lithium batteries basically have a constant voltage from full to empty battery, while a lead battery has a gradually decreasing voltage after which the capacity is used. When the voltage drops, there is more current to generate the same effect, which in turn has a negative effect on the battery's discharge.

Utilization rate
Lithium batteries have a utilization rate of up to 99%, but in order to have a little margin, we usually say that we have 95% of the bank's size available for use. A lead battery has no more than a 50% utilization rate, while it is difficult to charge fully and the total capacity gradually drops, and we usually therefore see that a battery bank with lead should have a total capacity of 220% of one with Lithium for the same capacity.

Form factor
Lithium batteries have an unbeatable weight factor compared to Lead, for example ;gives a lead battery på 200Ah 12.8V 65Kg at the same time as a Lithium battery på 100Ah (same capacity) does not weigh more than 14Kg. It is often said that the volume is at least half in favor of Lithium, but the difference is usually much larger than that.  

2. How exciting should I be? my battery bank?
In boats, motorhomes, caravans and summer cottages, you normally use 12V banks and sometimes 24V. The reason is that a large part of the equipment used is adapted for this voltage, while charging from generators, solar panels, etc. is limited to space requirements or machine specifications. In these applications, the outlet is relatively limited and high currents are often available.

When applicable ESS system we work with large loads over long periods of time and if we were to use 12 or 24V systems, the necessary cable dimensions between batteries and inverter/charger would be unreasonably large and therefore you use usually 48V system.

3. How do I dimension my battery bank?
To make a more precise dimensioning of a battery bank, you need to take into account a number of factors such as maximum usage during the day; are the big users again and if they overlap etc. In our example below, we keep the calculation more general and start from one month's usage then if we assume that we want to be able to run 50% of the day with inverted power from batteries.

If we assume that we have a month's use on 1,800 kWh and that we have 30 days på a month we get one day's consumption of 60 kWh and if we want to be able to run 50% from the batteries, we need to be able to extract 30 kWh from the battery bank.

A 48V bank actually has 51, 2V (4x12.8) if we then divide 30,000 Wh by 51.2V, we see that we will need a battery bank on at least 586Ah etc.

5. Solar Panels & regulators
Usually, solar panels with associated regulators are handled as a tempting solution for charging the battery bank, which reduces or during certain periods completely eliminates the need for charging from the fixed electricity supply. tet. If Victron Energy's regulators with support for monitoring are used, these can be connected with Cerbo GX for monitoring and managing.

Note that the solar panels produce the least effect during the months (October to February) when the need for electricity is normally the greatest and that covered panels do not produce any effect at all.

The graph below shows how the effect varies throughout the year in the Stockholm area. 

6. Power plant
It is good to use most types of power plant all the way from small; with 1-phase to large powerful 3-phase power plants, however, connection differs depending on the installed system and type of power plant.

An inverter/charger is used of the Quattro type, the power plant is connected directly to intended entry and dependence on if it is a 1- or 3-phase solution for the power plant, it is adapted accordingly. Do you instead have a solution that is based on; MultiPlus (without input for power plant) you normally supplement the solution with a battery charger such as Blame TG (if it's a 48V system) which is then connected to the power plant, which in this case is 1-phase. 

With the help of Cerbo GX which is included under system monitoring can start the power plant automatically when necessary, for example if the battery capacity is on a Lithium bank is under 30% at the same time as the consumption of The AC side exceeds a certain value (provided that the power company has supported it). 

7. Other
Under other we include cabling, sealing rings, main switches or other installation material that can be difficult to estimate exactly before the actual installation and it can be wise to budget around 10,000 – SEK 15,000 for these components.

Example system
Below we have three different example systems that range from a 3-phase solution with power plant as a backup to a 3-phase solution without a power plant and finally a 1-phase solution intended to drive a specific load such as an air-to-air heat pump or the like.

Victron Energy 3-phase Quattro-II solution with power plant

Component list (excluding power plant, solar and installation material)

Victron Energy 3-phase MultiPlus-II solution

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Component list (excluding sun and installation material)

Victron Energy 1-phase MultiPlus solution

Component list (excluding sun and installation material)