question

@Johannes123

Not sure where you found the ratios?

With 6x 5kva the issue is more discharge support, since the PV is lower than the MP2 inverting amps.

6x 5000 is 30 000.

30 000 ÷ 48v is 625A nominal.

What is the nominal (not peak) of the battery discharge?

If it is 100A then you need 6 batteries minimum, 7 to be comfortable. Not sure what model Pylon you are referring to but that is the basic maths...

Hello Alexadra,

the Pytes V5 has same details for charge and discharge:
- 75A Standard
- 100A Maximum
- 150A for 15 seconds

The rule is written here at 3.2:
https://www.victronenergy.com/live/ac_coupling:start

3. Minimum battery capacity

Besides the relation between installed PV Power and the inverter/charger VA rating, it is also important to have a sufficiently sized battery. The minimum battery capacity depends on the type of battery, lead or lithium.

Note that, besides the minimum battery capacity, the mentioned sizes are often also the most economical battery size. In case used for self-consumption purposes that is. In case the goal is to increase autonomy, of course installing a large battery increases the system autonomy in case of a grid failure.

3.2 Lithium batteries

1,5 kWp installed AC PV power requires 4.8 kWh of battery storage:

So this 1:1 rule and 1,5:4,8 rule should prevent the whole system from crashing when the net-power-supply is cutted away, as then the power from the solar inverter is directed into the batteries.

This is why I was naming the charge power.

With 25/1,5*4,8 it is about 80kWh lithium battery needed by this basic rule, but for daily use I would be fine with about 40kWh (8 Pytes V5 batteries) - 60 kWh (12 Pytes V5 batteries).

But as it is under the 1,5:4,8 rule I like to confirm whether it will be fine with less Pytes V5 batteries and their 150A peak charge than the 1,5:4,8.

Best regards
Johannes

Can someone tell me whether the 3rd party batteries with high charge power also need to apply the 1,5:4,8 rule?

Hello johannes

Can you share your conclusion for your batterie dimensionning ?

I am also thinking about 6 x 48100 pytes batteries with a 11,9 kWc of bifacial PV. I Will probably have 6kWp on a fronius primo 5 (or 6) kw in AC in on a MultiplusII 5 kVA and the other 6kWc on a mppt 450 - 100.

I also wanted to Check if this rule still apply in a mixed ESS system with half the power on AC in…

I don’t understand the reason of this 1.5 ratio recommandation

Thanks for your feed-back !

Regards

Julien