Hello All,
Rookie here, so please go easy on me. I have a strange situation...
Multi RS Solar, without PV solar panels, used as an UPS, with 3 x US2000C Pylontech batteries.
Multi RS connected with the batteries' BMS through a Cerbo GX.
Both inverter and Cerbo with latest firmwares. (1.15 and 3.13)
Multi RS "internal" ESS configured as Keep Batteries Charged.
Without any consumption from AC-OUT, the batteries consumption is 0 (zero), batteries being all the time in IDLE state.
On the picture below, you can see that the BMS considers to replenish the batteries once at about 9 hours to keep them charged.
Before replenishing, batteries voltage dropped to about 49.8V and after recharging is 52.4V, 2.6V difference, all normal here.
What I don't understand, is that after I begin to draw power from AC-OUT, the batteries consumption begins to be 0.2A (!!), also seen on the graph below...
Of course, the batteries are not on idle anymore and therefore, this leads to a much often recharge of the batteries, once at about 1 hour.
Also, the voltage excursion is from 50.4V (before recharging) to 52.4V (after recharging), with only 2V difference this time.
Why is that? Why a consumption from batteries when power is drawn from the AC-OUT?
For sure a 400W average consumption from AC-OUT will not warrant a battery "help"/consumption, isn't it?
Again, the inverter is set as "Keep the batteries charged" and Victron makes it clear "Utility grid failure is then the only time battery power is used".
I confirmed all of the above with a DC clamp meter, to be sure that is not a glitch... It's true, the current draw from batteries increases when AC-OUT consumption is present.
Thanks in advance for any help/advice!
