Understanding the behaviour of ESS and Peek Shaving

[zyx360]

Hi all,

I’m fairly new to Victron and this forum.
I’ve configured my system and am currently validating (and trying to understand) the working.

My system;
3x Multiplus in 3phase topology
3x 15kWh gobelpower battery behind victron-lynx-bus
1x Victron VM-3P75CT at the grid point

The system is configured with;
ESS, minimum SOC is 40%
Nightly scheduled charging to 95%
Peek shaving
Peek shaving policy: Always
Limit system AC-import to 16Amps per phase

Could use some help understanding the decision the ESS/peek-shaving makes to use what power source.

I’ve started with this blog aricle;

Venus OS v3.30 - Peak shaving for ESS - Victron Energy

My vrm screenshot:

Looking at the screenshot i’m under the impression that one multiplus (phase1) is feeding another (phase2) over the DC bus to satisfy peek shaving.
This behaviour is documented in the blog article above, the thing i’m trying to understand is why it’s doing this?
I was (probably incorrect) under the impression that Peek Shaving would first use battery-power before any multi > multi power will be passed through the DC bus when the peek-shaving-policy is set to: always.

The screenshot shows the battery beeing discharged, but at really low rate.

Does anyone have any insight into the why? or am i may be reading the stats wrong?

Thanks!
P

[zyx360]

Don’t know if it helps but i did some more testing trying to figure out what’s going on.

I’ve discovered that loads behind the ac-out of the multiplus do not trigger this behaviour.

When i turn on a large consumer on ac-out the multiplus does the peekshaving from the battery, even when the battery SOC is below the minimum. (and the policy is set to always) After the grid load becomes smaller then the configured peekshaving value the battery immediatly gets (re)charged.

So only loads before the multiplus (ac-in) are not fully compensated from battery when the SOC is below the minimum value.

Some help would greatly be appreciated

Thanks!

P