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simon-jukes avatar image
simon-jukes asked

What Components needed to connect AC PV to a battery?

Hi

First time here.

I am in the process of deciding on a battery storage system to add to my existing AC coupled PV system, 4kw, east west split system so max geraration as anyone time is 2.5kw. UK with feed in tarrif meter

Thinking of getting the Multiplus II inverter, however, i am a little confused on what other modules I need to take into account for costing purposed, other than batteries. There seems to be shunts, battery monitors etc. Planing on using the system to maximise the amount of generated solar as I currently export a lot to the grid during the day whilst a work and then importing from grid at night

Other than the inverter, what other compnents would i need to control the system and to automatically monitor current excess solar and use it to charge batteries and then draw off the stored power when solar is low / unavailable. Also interested in monitoring system via smartphone app

Grid is very stable in my area of the UK so not thinking of configuring the system as emergency backup in event of power cut, purely storage / use of excess generate solar

Thanks in advance

Simon



Multiplus-IIESS
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2 Answers
seb71 avatar image
seb71 answered ·

A GX device (such as Cerbo GX) for sure.

Have you decided on the battery type/model? This would influence some other devices you might want to buy.

Although you say your grid is stable (for now), you should look into adding even a small MPPT charger with some PV panels, to be able to charge the battery directly from the Sun in the event of a discharged battery and no grid.

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simon-jukes avatar image simon-jukes commented ·
Hi Seb


Re batteries, I was thinking of a couple of Pylontech US3000C (3.55Kwh) to start off with and then adding a third if I found I was consistently filling them

Cheers re the pointer re the GX device

I assume the only sensor I would need is the CT clamp included with the inverter, and this would measure import / export levels at the main incomer of the grid, only problem I can see with this is, somewhere, I have seen the cable can be extended to a max of 5mts, however, as I am aiming to install the batteries in the garage as I already have a fuse board in there with spare ways to connect to invertor to, I would actually need to be at around 8 / 10 meters. Worst case I suppose is I use a meter and then a length of shielded 2 core.

Thanks for all your info

Have a good day

Simon




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Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi @Simon Jukes,

The kind of system you are trying to set up is called an Energy Storage System (abbr "ESS") in the Victron world.

There are some good resources to get started understanding how it works and what is required. I would suggest to start with the video and go from there;

What is ESS training video

ESS Quick Installation Guide

ESS design and installation manual

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simon-jukes avatar image simon-jukes commented ·

Hi Guy

Thanks for the pointers to the info, off to have a read

Have a good day


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