PowerAssist and PowerControl are two features built into every Victron MultiPlus and MultiPlus-II that solve a common problem: limited shore power. PowerAssist supplements weak shore power with battery power during peak demands, while PowerControl prevents you from tripping the shore power breaker. This guide explains how to configure both.
What Is PowerControl?
PowerControl limits the amount of current the MultiPlus draws from the AC input (shore power or generator). If you set the input current limit to 10A, the MultiPlus will never draw more than 10A from the source, even if your loads demand more.
Why it matters: UK campsite hookups are typically rated at 10A or 16A. If your total load exceeds this, the campsite breaker trips. PowerControl prevents this by limiting the MultiPlus's input current to the supply's capacity.
What Is PowerAssist?
PowerAssist goes one step further. When your loads exceed the input current limit, instead of simply refusing to supply the extra power, the MultiPlus takes the extra power from the battery via its inverter.
Example: You're on a 10A hookup (2,300W). You turn on a microwave (1,200W) while the kettle is boiling (2,000W). Total demand: 3,200W. Without PowerAssist, either the campsite breaker trips or loads go unpowered. With PowerAssist, the MultiPlus draws 2,300W from shore power and supplements the remaining 900W from the battery. No breaker trip, no interruption.
How to Configure PowerControl
Via a GX Device (Cerbo GX)
- Navigate to Settings → System Setup → AC Input Current Limit.
- Set the limit to match your shore power supply:
- UK campsite (standard): 10A or 16A
- Marina berth (typical): 16A
- Home mains (UK ring main): 13A per socket
- The MultiPlus will never draw more than this from the AC input.
Via VEConfigure (MK3-USB Adapter)
- Connect the MK3-USB adapter to the MultiPlus and your computer.
- Open VEConfigure software.
- Go to the Grid tab.
- Set Input current limit to your desired value.
- Optionally, set a Dynamic current limit which allows the limit to be adjusted remotely via a GX device.
Via the Digital Multi Control (DMC)
The Digital Multi Control is a physical panel with a rotary dial that lets you adjust the input current limit on the fly. Useful for installations where the shore power capacity varies (different marinas, different campsites).
How to Configure PowerAssist
PowerAssist is enabled by default on all MultiPlus and MultiPlus-II units. When the AC load exceeds the configured input current limit, the MultiPlus automatically supplements from the battery.
Fine-Tuning PowerAssist
In VEConfigure, under the Grid tab:
- PowerAssist boost factor: Controls how aggressively the MultiPlus supplements from the battery. The default (2.0) means it can deliver up to twice the input current limit in total power. Reduce this if your battery bank is small.
- PowerAssist sustain: Controls how long PowerAssist can operate before reducing load. With a large battery bank, you can sustain longer peaks.
For most installations, the default PowerAssist settings work well. Only adjust if you're experiencing issues like the battery depleting too quickly during peak load periods.
Practical Example: UK Campsite Setup
You arrive at a campsite with a 10A hookup (2,300W available). Your MultiPlus 3000VA is set with an input current limit of 10A and PowerAssist enabled.
| Scenario | Total Load | Shore Power | Battery Supplement | Result |
|---|---|---|---|---|
| TV + lights | 100W | 100W | 0W | All from shore |
| Kettle only | 2,000W | 2,000W | 0W | All from shore (within 10A) |
| Kettle + microwave | 3,200W | 2,300W | 900W | PowerAssist engaged |
| Kettle + heater | 4,500W | 2,300W | 2,200W | Heavy PowerAssist (check battery) |
During PowerAssist operation, the battery discharges briefly. As soon as the high load ends (kettle finishes boiling), the MultiPlus reverts to shore power only and recharges the battery. For a 200Ah lithium battery, even a 2,200W supplement for 5 minutes only uses about 1.5Ah — negligible.
Setting Different Limits for Different Locations
If you regularly visit campsites with different hookup ratings, you have several options:
- Digital Multi Control panel: Rotate the dial to change the limit instantly.
- GX device: Change the limit in the settings menu whenever you arrive.
- VRM remote access: Change the limit remotely via the VRM portal or app.
- MultiPlus-II: Has a configurable current limit that can be adjusted without any additional hardware, via a GX device.
Common Issues and Solutions
"Shore power breaker still trips"
If the campsite breaker trips despite PowerControl being set correctly:
- The input current limit may be set too high — try reducing it by 1–2A below the breaker rating.
- There's a brief inrush before PowerControl can react. Some sensitive breakers trip on this transient.
- Check that no other devices are connected to the shore supply outside the MultiPlus (e.g., a direct hookup to a water heater bypassing the MultiPlus).
"Battery drains quickly while on hookup"
If PowerAssist is engaging frequently, it depletes the battery between charging cycles:
- Reduce simultaneous high-power loads — don't run the kettle and microwave at the same time.
- Increase the input current limit if the supply allows it.
- Reduce the PowerAssist boost factor in VEConfigure.
Summary
PowerControl limits the current drawn from shore power to prevent breaker trips. PowerAssist extends this by supplementing from the battery when loads exceed the shore supply. Together, they let you run high-power appliances on limited hookups without interruption. Set the input current limit to match your shore power supply (typically 10A or 16A in the UK), and PowerAssist handles the rest automatically.
