MultiPlus 24/5000/120-100 not charging above 70A

Q&A and troubleshooting
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1

These are the settings.

Settings Summary

TAB: General
System frequency 50Hz
Shore current 50.0 A
Overruled by remote checked
Dynamic current limiter checked
State of charge when Bulk finished 98.0 %
Battery capacity 800 Ah
Charge efficiency 0.95
TAB: Grid
Country / grid code standard None: (feeding energy from DC to grid not allowed)
Accept wide input frequency range (45-65 Hz) checked
AC low switch mains off 180 V
AC low switch mains on 187 V
AC high switch mains on 265 V
AC high switch mains off 270 V
UPS function unchecked
TAB: Inverter
PowerAssist checked
Assist current boost factor 2.0
Inverter output voltage 240 V
Ground relay checked
Inverter DC shut-down voltage 22.00 V
Inverter DC restart voltage 24.00 V
Low DC alarm level 24.50 V
Do not restart after short-circuit (VDE 2510-2 safety) unchecked
enable AES unchecked
TAB: Charger
Enable charger checked
Weak AC input checked
Stop after excessive bulk unchecked
Lithium batteries checked
Charge curve Fixed
Absorption voltage 28.40 V
Float voltage 27.50 V
Charge current 120 A
Repeated absorption time 1.00 Hr
Repeated absorption interval 7.00 Days
Absorption time 1 Hr
TAB: Virtual switch
TAB: Usage
Virtual switch usage Do not use VS
TAB: Assistants
TAB: Assistant Configuration
Assistants not used

Here is a screenshot of the Charger settings.

MultiPlusStuckAt70
MultiPlusStuckAt70860×713 348 KB

I am used to it derating (presumably to IGBT max temp) to about 95-100 Amps after a while. But now , even if the system was off, it will never go above 70. Usually it stays at 65/66 Amps.
Ambient Temp is 28C… Temp of Air out of top of inverter is 35-40C.

Firmware version is 481.
The inverter is connected to a Venus GX with VE Bus.
DVCC is not enabled.

Should I enable DVCC ? I have not, since not all devices are supported .
AC Power source is a 5.5kW generator.

2

You would have to uncheck weak AC. And not have weak AC to charge from.

481 is pretty old firmware but won’t be the reason. Unless you have a very up to date GX.

You could also check of your battery cables and connections are ok as well.

DVCC might help if your battery bank has comms with the GX. But otherwise not really.

3

Thanks. That did remove the 70A limit. But now it ‘hunts’ as it ramps to quickly (i.e cycling between 40 and 120 Amps), bogging the generator down. I think I can get that under control.
I doubt DVCC will help, as I think all the chargers would have to support that.
And yes I have a smart Shunt on the batteries, so getting voltage and current should be fine.

4

So the issue with the charge is likely the stability of source. Maybe something has changed on the generator side.