3 hours ago, georgelza said:

One say AGM based, one Lithium based ? - both 48Volt,

You can of course run two Mutipluses, both feeding power into the same AC network (like grid-tied inverters) from separate battery banks charged by separate PV arrays. You can't put one Multi on the output of another though (not an officially supported configuration), so if the grid fails you will have two islands, each with their own loads on the output.

With the external control function you can even implement your own control system, (using modbus-TCP), eg make the one Multi charge while the other one feeds into the grid, passing power from one battery bank to the other.

I've often considered doing something like this for the fun of it. I have a 24V 3kva for the house, and a 12V 3KVA on the test bench. So exactly this scenario: Two battery banks, two inverters. It would make sense to use the test bench inverter to offset peaks and to recharge it when there is surplus, using a clever software mechanism of some sort. This is the tricky bit 🙂

3 minutes ago, plonkster said:

You can of course run two Mutipluses, both feeding power into the same AC network (like grid-tied inverters) from separate battery banks charged by separate PV arrays. You can't put one Multi on the output of another though (not an officially supported configuration), so if the grid fails you will have two islands, each with their own loads on the output.

With the external control function you can even implement your own control system, (using modbus-TCP), eg make the one Multi charge while the other one feeds into the grid, passing power from one battery bank to the other.

I've often considered doing something like this for the fun of it. I have a 24V 3kva for the house, and a 12V 3KVA on the test bench. So exactly this scenario: Two battery banks, two inverters. It would make sense to use the test bench inverter to offset peaks and to recharge it when there is surplus, using a clever software mechanism of some sort. This is the tricky bit 🙂

Do they not go out of sync if the one fails before the other one? I was under the impression that it would cause problems.

16 minutes ago, SilverNodashi said:

Do they not go out of sync if the one fails before the other one?

They tie with the grid. When the grid drops, they both Island. It's the same in principle as if you and your neighbour both have a grid-tied inverter and you happen to be on the same phase. The difference is that it's a battery hybrid, and they happen to be on the same premises, but it works the same: Both work together to reduce your consumption when the grid is on. When the grid fails, then you end up with two islands instead of one.

You might of course opt to put your emergency/backup loads on only one of them and use the other one purely for peak shaving.

Edit: In fact, now that I think of it, I've had a customer like that. Someone had a system in his main house and in the pool house... 🙂

Edited March 29, 20197 yr by plonkster

4 minutes ago, plonkster said:

When the grid drops, they both Island.

So, if I was to install 2 x 3kva grid tied inverters, would that still fall within the 63amp breaker regulations?

6 hours ago, The Terrible Triplett said:

So, if I was to install 2 x 3kva grid tied inverters, would that still fall within the 63amp breaker regulations?

Nope, of course not.

But a 3kva and a 1.2kva... they can tie 2.5kw and 900W, just about on the limit.

2 hours ago, plonkster said:

Nope, of course not.

My bad ... did not think it through. (facepalm)

22 hours ago, The Terrible Triplett said:

T105RE's has been renamed to SPRE_06_225, as has all the ranges.

Am not aware of them being discontinued.

Sorry, should have been clearer. I didn’t mean that they are not making that size and spec battery, I meant the models/branding have all changed. SPRE line is now rated at 1900 cycles at 50% DOD as opposed to 1600 previously..