Passthru state

Q&A and troubleshooting
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1

Hi,
I have a system

  • without ESS,
  • no grid meter,
  • no CAN devices connected,
  • no NET code used,
  • no LOM enabled,
  • The BMS allows the LFP battery to be charged and discharged

The Multi (II 24/5000) goes in “passthru state”. What does that mean? How can it be avoided?

Regards Edward

2

Passthru means theres Mains available and switched through to the load side as well as the battery is not being charged or discharged, so its likely fully charged. The Multiplus is a simple connection, from mains to load, the inverter portion is “off”/in standby

3

I expect it to be in float and in absorbtion for an hour once a week. It did that upto 24 of december actually . But not anymore since. (After beiing off grid (inverting) for a day and going thru a normal charge cycle (bulk, absorbtion, float)).

It does work in power assist now and then, but slowly let the SOC go down

4

Passthrough can also happen when bms comms are not within certain intervals and if the bms senda a do not charge or do not discharge signal.

If the bms is in control it can also be the reason why there is a slow decline in soc. Some are both current and voltage controlled and do not increase the CVL sent to the system

5

Goodmorning,

Thank you for the answer. I will ask the supplier of de battery for the update rate.

What will the minimum comms rate be? I see a normal update in VRM, so at least every 15 minutes.

Thanks Edward

6

I don’t know what the min rate is from the victron side.
But 30 seconds is in my opinion too long for decent control and information.
The gx will wait just over 2 or 3 minutes before logging a bms lost error. (Usually the time it takes to reboot the older slower devices and allow for programming tasks.)

7

Hi,

I guess it wil give a signal when it looses its BMS?

Edward

8

Yes when comms have been lost for too long.
The pass through thing is a bit more nuanced.