Victron, Fronuis - ESS

Good Day all
My present setup( Fronuis grid tied 5kw primo )with 3.6kw pannels fitted.
I have purchased a Victron Multiplus 5000 ka 2 GX and intend building a ESS and micro grid. The intension is the fit a 11.4 kw LiFePo4 battery with above equipent in Ac Coupled GT inverter.
I believe 1 to 1 rule is satisfied. The question arrives about battery size. I have read that for AC coupled require 4.8kw per 1.5kw wp. As effectively only I only mange 3kw beacause of roof angle, will my system be acceptable and function as intended?

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(Add a small DC MPPT though).

Required for offgrid systems as well as backup systems that need to overcome extended grid failures.

Reason: recover from deadlock situation of AC-Coupling only situation.

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Many thanks, what size DC couple would you suggest?

To overcome the deadlock situation, it can be minimal, 150V/35A MPPT fed by 2 panels in series, preferably facing East.

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Noted, I will action

You can get away without the DC-coupled “black start” if you have some other means of recovering. For example a generator. But if you are still in the design phase, it is good to design for it with a small MPPT. The smallest one is sufficient, so as Phil says, a 150/35 with two panels, or even a 100/20-48 with a single panel, is going to be enough.

Manny thanks, will be utilizing a battery that is not on the compatibility list. Any advise?

Tell us which one?

Sometimes it just works because the battery maker works hard to be compatible with as many inverters as possible, because it is obviously in his best interests to do that. And sometimes you have endless problems and you get no support from either side. Depends :slight_smile:

KATBATT local brand from PE

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Never heard of her… sorry :slight_smile:

No issues, thanks all the same. I will document my Journey. Local company, Luiperdskop.
They have an good number installed but none with Victron to my knowledge.

CAN-bus comms? If it’s got that, it may just work. Hopefully they didn’t just copy the Pylontech protocol. Then you may definitely have issues. But there are ways around it.

They claim it’s compatible in the datasheet. The BMS looks like it might be Seplos, which does work with most inverters.

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Yes, this is why I purchased it, yet to arrive. The company has also promised technical assistance so I am cautiously optermistic

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Would you mind sharing a price? I am also near PE so very keen to see the options they have.


Its interesting the KATBATT’s recommended bulk voltage is probably the highest I have seen from a 16S battery at 57V (Seems like most manufacturers target 55.8-56.4V)

The Katbatt was approximately 58k including vat and delivery

Must admit I did not pick the voltage up when checking the Data sheet. Thanks, I will double check and enquire when setup time comes.

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Those voltages look in line with other batteries.
Someone should notify them that they might need to look at updating their datasheet on their website for the batteries.

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