question

Anita avatar image

ESS: VE Bus state & charging behaviour??

I have a new client with existing system with ESS. Although I have read up extensively about ESS, I have no previous actual experience with it, since all my clients are off-grid.

I have 2 questions:

1) VE Bus State:

I notice that the VE Bus state is always in Bulk, and never in Invertering state, even when using power from the battery. See photo attached.

Why is this? Should it not be in Invertering state, when using battery power?

All my off-grid clients are permanently in Inverting state.

2) Inverter charging behaviour:

Is it possible to setup the inverter to charge the batteries, when they are at the Low DC voltage, and then stop charging when full?

I only see Sustain Voltage and the Scheduled charging times. With Scheduled charging time, what if Low DC voltage is reached outside of a Scheduled charging time? When outside of the Scheduled charging time, it just stays at the Sustain voltage.

So basically to charge like in a normal grid-interactive system.

I hope my questions makes sense....

System consists of 10kVa Quattro, SmartSolar 250/100, 330Wp panels, GX, BMV & Sirius Supercapacitors.

Regards,

Anita

ESScharging batterysmart solar set-up helpVE.Bus
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1 Answer
Lucian Popescu (Victron Energy Staff) avatar image

Hi Anita, for the first question the answer is no, in ESS, as long as the system is connected to the grid, will never display inverting. That is just for off-grid. For the second question, I'm not sure I understand what you need. If you want to charge the battery from the grid, you can select "keep the battery charged" or schedule charging. Or the system will automatically recharge the battery when needed using sustain. So what else do you need? ESS assistant was designed to use the power from the sun as much as possible, not from the grid

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@Lucian Popescu (Victron Energy Staff),


1) Thank you for answer. So even while using battery power (and no grid), if would not show inverting. Thus the only time it would show Inverting, is when the grid is off?

Where can I get the meaning of all the different states of the VE Bus?

2) Initially client complained that there was not enough power taken from the batteries. State of charge remained above 90%, voltage around 50V. The Sustain voltage was set at 50V, at that time.

Then we changed the Sustain voltage to 45V. The supercaps' minimum voltage is 44V. So we wanted to get maximum out of batteries. But then, once the batteries reached 45V during the night, the inverter would not recharge it up to 100%, but just sustain voltage at 45V.

During the day it is not a problem, because then it recharge the batteries from solar. The problem is at night. Their loads are quite high, and the current storage capacity is not enough to last through the night. So if the inverter just sustain the voltage at 45V, there would be no power available if the grid should fail.

So basically what we want, is that the inverter recharge the batteries to 100%, once it reaches 45V. Then when it is full, it would stop charging and used the battery again.

Hope it is clearer now.


Regards,

For 1, in that case the system is off-grid, not ESS.

For 2, you can't use the battery as much as possible and in the same time to be prepared for a grid failure. Either you increase the battery capacity or you keep it charged.

Anita avatar image Anita Lucian Popescu (Victron Energy Staff) ♦ ·

@Lucian Popescu (Victron Energy Staff),


Thank you very much for your explanation.

It now makes much mire sense.


Regards,

Anita