question

perma-batteries avatar image
perma-batteries asked

ESS Maximum inverter power not limiting with lithium

We've noticed on a ESS system comprised of a Multi-II 5KVA + MPPT 150/100 with 2x Pylontechs US2000, that even if we activate "Limit inverter power" , the current drawn by the US2000 will still be ultimately determined by the DCL and BMS and NOT overriden by the "limit inverter power" option, which is worth noting (-68A sudden burst from 2x US2000, inverter power activated at 1200W).


So my guess is that the limit inverter power function is only working when you've got non managed (ie : lead acid, etc...) batteries with an ESS....





ESSPylontech
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

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

Hi @perma-batteries,

That parameter in the ESS menu should not be considered very strict.

It is an additional target used by the ESS algorithm to determine what should be powered by what and when.

As this is all subject to some delays (varying depending on the energy metering, models used, load type, etc) in some cases surge loads that exceed that value will still be delivered by the inverter, with batteries or solar.

If the load is continuous, you should see the ESS system adjusting to limit the inverter power to that value, and the remainder coming from the grid. Note that is also subject to a superseding limitation, the AC input current limit. If that that is set, the inverter will supply the load as a priority, even if it exceeds that Maximum inverter power level (and before it breaks the AC input current limit).

1 comment
2 |3000
Toggle Comment visibility. Current Visibility: Viewable by all users

Up to 8 attachments (including images) can be used with a maximum of 190.8 MiB each and 286.6 MiB total.

dcsonka avatar image dcsonka commented ·

Hi Guy,


I have a question on your remark above: "Note that is also subject to a superseding limitation, the AC input current limit. If that that is set, the inverter will supply the load as a priority, even if it exceeds that Maximum inverter power level"

Does this mean, that I can even overload my inverter in case there is enough solar+battery power?

I saw this behavior on my installed base (3phase Multi+ 2 3K 48V with DC PV 5kWp, 32A ACin limit).

My consumption was 3.5kW constant for about 10min on one of the phases and I noticed, that it was fully coming through the inverter. I expected that the Mult+ will limit the inverter power to its nominal 3kW value and would compensate the extra needed power from the grid. At least this is how it is done when for example the battery is below the SOC limit, the inverter combines PV and grid power towards ACout.


I am a bit concerned that I would be able to burn the Multi in case I am not watching out for the output power.

Can I safe guard it by setting the inverter's output power say 2.8kW?

I just want a smooth operation without overloading anything, especially the Multi+.


Thanks


Dezso

0 Likes 0 ·