DVCC issue - 150A limit exceeded with multiple MPPTs

DIY
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1

Hello,

I have a Victron system and I noticed a behavior related to DVCC current limiting that I’m trying to understand.

System configuration:

  • 3 × Victron MultiPlus 5000 (48V)

  • SmartSolar MPPT RS 450/200

  • SmartSolar MPPT 250/100

  • SmartSolar MPPT 100/45

  • DVCC enabled

  • Max Charge Current in DVCC set to 150A

Observed behavior:

When there is no load, the battery charge current stays exactly at the DVCC limit:

  • Battery charge current: 149–150A

However, when I add a load of about 2 kW, the battery charge current increases and stabilizes around:

  • ~157A

This value remains stable and does not drop back to 150A.

I also checked the solar chargers and they seem to be producing close to their configured limits. It appears that all MPPTs are contributing normally.

Questions:

  1. Is it normal for DVCC to allow a few amps above the configured Max Charge Current when there is system load?

  2. Could this be due to the distributed regulation between multiple MPPTs (RS + VE.Direct models)?

  3. Is there any recommended configuration to make the 150A limit stricter?

Firmware on all devices is recent.

Thanks

2

As an additional information, this happens when the water heater is on. If I use air conditioning, the charging current stabilized @ 150A as it should be.

3

It might have something to do with the ac load type and PF and the way the inverter reads it and powers it.
This is possibly due to the ve bus dc reading as well. Not sure just spit balling.
Do you have SCS on?

4

Yes, SCS on.

5

Hello Catalin, After reading your issue regarding DVCC limiting the amps to your battery bank that I find it very interesting. I have 9 MPPTs 4 RS 450/200. 4 MPPT 150/70 and 1 MPPT 250/60. After reading about DVCC and understanding the pro or con I thought there is too much automation. So what I did is to put limit on each Solar Charge Controller. My system is running for about eight months without any issue.The way Victron System is running I love it. I am not sure the way I put limit on the MPPTs is the right thing to do. The system is working great. Good luck.

6

I did the same from the begining, 150A for rs450/200 in order to have less than 6-7A on each pv string. When is needed i can go up to 13A per string on winter or so.

7

Try with it off

8

Do you have DC feed-in enabled?
That will cause ignoring, the current limit.

1 Like
9

I’m totally offgrid, no ess.

10

I checked again today and confirmed that the behavior occurs only when the water heater is on. With other loads, the charging current stays exactly at the DVCC limit. So I assume the behavior is induced by resistive load.