Please forgive me for a beginner’s question, and probably for having chosen the agm battery tag, too, in my ignorance!
I am trying to commission D ESS for the first time on our two-year old installation: the configurator is asking me to give figures for ‘Maximum charge power’ and ‘Maximum discharge power’. The installation was custom made, but not by me, and I have no idea what figures to input, or where to begin to look for them!
Can anyone help, please?
Many thanks,
Ben
Hello Ben … and welcome to the Forum 
… You know … there are no stupid questions 
Why don’t you give us some details about your setup and your batteries… the number of batteries, and maybe a photo as well… The technical specifications are usually printed on the batteries themselves.
On top of that, AGM batteries naturally have different charging and discharging characteristics than LiFePo batteries.
Thanks for the prompt reply!
Our battery system was built by a small local concern, and is 16KWh capacity. Our PV panels have been installed for same years - we couldn’t re-use the inverter as it wasn’t a hybrid; also, changes to UK regulations meant that we couldn’t replace the older one in the same physical location - the loft. So we installed a second, hybrid inverter.
Having got our Feed-in Tarriff arrangements sorted out, and moved to Octopus, our energy supplier, I am keen to explore DESS.
I shall try and add some pictures.
I guess what I could benefit from is a tutorial guide to walk me through the initial set-up!
Ben
I forgot to record that our PV array is just under the 4KW limit on FiT in the UK.
Ben
I misunderstood that in the translation… I was worried you were planning to use an AGM battery for DESS now.
But everything’s fine It looks like a 16S system with a JK-BMS.
Has the “regular” ESS been working normally for you so far?
You should definitely start by reading up on the basics of DESS and understanding the core functions.
Tags fixed and moved to the right category.
Sorry about the translation - the query-writing software insists on the user supplying two tags, and I’d used one already, leaving AGM as the only option!
Yes, I admit to not knowing enough about the standard ESS, and it’d probably be a good place to start - any pointers as to where a beginner should look?
Many thanks,
Ben
Then be sure to start by adding the basic functions of an ESS system to your system.
Of course, it’s important that your current system is working properly.
Are the readings from your 16S battery displaying correctly, and do your components have the latest firmware?
You could update the Multi since you haven’t installed the ESS Assistant yet… because it gets deleted when you do a firmware update… So go ahead… take the plunge with ESS
… and feel free to ask questions or use the search function… because the same questions keep coming up all the time… but they’ve already been answered countless times.
You could write a little more about your system… How is the PV integrated? MPPT or an external PV inverter… A quick sketch or a system diagram often makes things easier.
Already most helpful, thank you!
As a retired systems engineer I felt the need to understand how it would integrate with the original PV sub-system - I have a diagram somewhere which I shall find, but basically it is AC coupled. Oh, to add to the mix there is an air-source heat pump, along with a legacy Solar iBoost - which doesn’t seem to get much of a look in - we have several subsystems which have no communications interface, other than observing AC flows within the system.
Ben
I’m trying to update the inverter firmware, and am being warned to do this only when PV is limited by light levels or by isolation the panels. Given that our system is AC coupled and that there are in fact two inverters sitting on the AC line, should I be observing any special precautions?
Thanks,
Ben
That shouldn’t be a problem in the evening or after dark
So it would be great if you could provide a diagram of your setup… Where and how are the various components installed in your system?
As long as there are no PV inverters connected behind of the Multi, that shouldn’t be a problem…
The numbers refer to what the battery can be charged with “best case”. So, there are two factors influencing this:
1.) The battery itself.
2.) Since the charge-figure is mostly important for charging energy from grid (solar is dc ↔ dc), the second factor is your inverter power. So, knowing how much inverters and which model you have would allow to conclude the maximum there - which in most cases is the limiting factor except for very very small batteries or much inverter-power.
Here is an attempt at a diagram - bus/monitor & things omitted, unless anyone would: (a) like to see them (b) not know better than me how they interconnect!
system diagram.pdf (41.6 KB)
For a (D)ESS to function properly, you’ll naturally need meters that must be integrated into the Victron system.
At a minimum, you’ll need a grid sensor, a meter for your (non-smart) PV system, and a meter to monitor the AC load for the hot water tank… if the IBoost can’t be integrated via protocol.
Only then can your system determine actual consumption and perform zero-point control, since your AC PV is also part of the system and your battery should also be charged when there is a surplus.
Once that works… next step: DESS
Thanks. Our installer is going to visit this week and give me some education as to how the parts fit together, so I hope to make progress following that.
Ben
