question

@Craigeng

You can install 3 Multiplus-II units setup as 3 phase system.

How big MP-II you need to buy depends on your house power requirements.

The automotive lead/acid start batteries will last very short time since they are not meant to be deep discharged but you can play with them to learn the system.

I would encourage you to use victron's battery balancers with 48V banks. It will give the best use out of them.

They are poor for an ESS as depth of discharge is not great, they don't like supplying larger loads and will have a limited life.

I have an assortment of victron gel batteries in the field, at just over 2 years now, they are all wearing out and that was with a max 40% discharge.

The difference between an ESS with Lithium and one with LA is chalk and cheese.

You are more likely to decently recharge a lithium bank in your "cheap" power window than you will LA, with its long charging cycles. ESS systems are way more effective when not using old style batteries.

So I guess there is no 3 phase unit?

Would I just wire the units as if I were feeding 3 separate single phase supplies?

Would there need to be three separate banks of batteries?

Thanks in advance, Craig

Just wanted to Clarify the LA batteries I have are deep discharge motive power batteries taken from electric vehicle

Craig, if you have not done this before, 3-phase and parallel systems are complex.

Get a professional to help you or you will have issues.

There is a lot of reading and training available.

Start here:

https://www.victronenergy.com/live/ve.bus:manual_parallel_and_three_phase_systems#parallel_split-_and_three_phase_vebus_systems

There are no 3-phase products, you configure multiple devices into a 3-phase system, with shared batteries and comms.

This community is not a substitute for qualified installers and there are many newcommers here, some who end up hopelessly out of their depth having jumped into the deep end.

I was an aircraft high voltage engineer.... I do appreciate your valid concerns about newcommers, but although I am a newcommer I dont imagine I will end up out of "my depth"

Not sure where you are located. A small number of the inverter/chargers have a UL rating but the Multiplus II and Quatro II aren't there yet last time I checked. You'd probably need UL to pass local inspections.

There really isn't a Victron solution for the US if you want to set up an ESS system and feed excess energy into the grid. Besides the UL rating, you'd also need the power company's approval for feeding energy to their grid. Other countries have different levels of approval and many have appropriate approvals for Victron units.

Tesla PowerWall might be a less expensive solution if you need to invest in a large battery bank. But in your case, salvaging the LA motive batteries may make your initial investment less using Victron inverter/chargers. Do the math to see.

Be sure to read all the documentation available on multi-phase and parallel systems. There's also training at professional.victronenergy.com. Building a multi-phase system isn't rocket science but there are critical things to insure the system is safely installed and configured.

Hi there,

Am in UK.... I find it hard to believe no one produces a dedicated 3 phase inverter charger that will accept LA or lithium????