Victron Blue Smart IP22 3 Outputs: How They Really Work

The Victron Blue Smart IP22 3 outputs question comes up under almost every video about this charger. If it’s a 30A charger, does each output get 30A, or is it split three ways? And how does it know when one battery is full? Victron’s manual answers both, and the answer changes how you should wire it.

A Blue Smart IP22 charger video.

Victron Blue Smart IP22 3 Outputs: The Short Answer

According to the Blue Smart IP22 manual:

Each output can supply the full rated current, so one output alone can take all 30A on a 12/30 (3).
The combined current of all outputs is limited to the full rated current. A 12/30 (3) never delivers more than 30A in total.
Current is shared automatically, depending on each battery’s voltage, state of charge and capacity.

So the outputs aren’t fixed at 10A each. A flat battery takes more, and a nearly full battery takes less.

Isolated Outputs, One Algorithm

Victron says the 3-output models include an integrated FET battery isolator. That lets one charger charge separate batteries at different voltages or states of charge without current flowing between them.

The important limitation: the outputs are not regulated individually. One charge algorithm, meaning the same charge cycle and voltages, applies to all three outputs. Victron says all the batteries must be compatible with that common algorithm, which typically means the same chemistry. Don’t put a lithium bank on one output and a flooded starter battery on another.

So How Does It Know When One Battery Is Full?

It doesn’t track each battery separately. The charger follows one charge cycle for the system. A battery that’s already full simply draws less current as its voltage rises, while the emptier ones take more.

Models and Current

Model	Normal mode	NIGHT or LOW mode
12V, 3 outputs	15 / 20 / 30A	7.5 / 10 / 15A
24V, 3 outputs	16A	8A

Source: Victron Blue Smart IP22 Charger 120VAC datasheet.

NIGHT and LOW modes cut output to 50% for quiet operation. Output also reduces as temperature rises toward 50°C.

Wiring Tips

Fuse each output cable near its battery.
Use the same chemistry on all three outputs.
Victron’s manual shows schematics for 3-output models with a Smart Battery Sense or SmartShunt for voltage, temperature and current sensing over VE.Smart Networking.

Want the source figures? The Blue Smart IP22 Charger page on Victron’s site has the datasheet.

Worked Example: Two Banks of Different Sizes

A boat has a 200Ah house bank at 50% and a 100Ah starter battery at 90%, both AGM, on a 12/30 (3).

At the start: the house bank sits at a lower voltage, so it takes most of the 30A, perhaps 25A or more, while the starter battery takes only a few amps.
As the house bank fills: its voltage rises and its current tapers, leaving more of the 30A available to the other outputs.
At absorption and float: both batteries sit at the same charger voltages, drawing only what each needs.

Illustrative split; the actual sharing depends on each battery’s voltage, state of charge and capacity. Charging about 100Ah into the house bank at an average of around 25A takes roughly 4 hours, plus absorption.

Worked Example: Three Identical Batteries

Three 100Ah lithium batteries in a trailer, each on its own output, all at 30%. Since they’re the same size and state of charge, they share the 30A roughly equally at about 10A each. Each needs about 70Ah, so the bulk stage takes around 7 hours (estimate: 210Ah total ÷ 30A). If you connected them in parallel to one output instead, the total time would be about the same, since the 30A total limit is what sets the pace.

When a 3-Output Charger Makes Sense

Separate banks that must stay isolated, such as a starter battery, a house bank and a bow-thruster battery.
Batteries of the same chemistry that suit one charge algorithm.
Simple installations where you want one charger instead of several.

If your banks use different chemistries, two separate single-output chargers, each set to its own profile, are the better fit.

Choosing the Model Size

Total battery capacity	Suggested model (est.)
Up to about 150Ah	12/15 (3)
About 150–200Ah	12/20 (3)
About 200–300Ah or more	12/30 (3)

Rule of thumb: roughly 10–20% of total capacity in amps; check each battery maker’s maximum charge current. Since the current is shared, size for the combined capacity of the banks that typically need charging at the same time.

Setting Up in VictronConnect

Connect over the charger’s built-in Bluetooth.
Choose a preset that suits all three batteries, for example Normal, High or Li-ion, or set custom voltages.
Enable NIGHT or LOW mode if the charger is in a living area overnight.
Pair a Smart Battery Sense or SmartShunt through VE.Smart Networking for real battery voltage and temperature, as shown in Victron’s 3-output schematics.

Mounting and Ventilation

The IP22 rating protects against dripping water falling vertically, so mount the charger in a dry, ventilated spot, such as a locker away from the bilge or an RV storage bay. Leave space around it for air to circulate, since output reduces as temperature rises toward 50°C.

FAQ

Does each output of the Victron Blue Smart IP22 give the full 30A?

Each output can, but the total of all three is capped at 30A on a 12/30 (3).

Can I charge lithium and lead-acid at the same time?

Victron says all batteries must suit the same charge algorithm, which typically means the same chemistry.

Are the outputs isolated?

Yes. An integrated FET isolator stops current flowing between batteries.

Can I use only one or two of the three outputs?

Yes. Unused outputs can stay unconnected; the connected outputs share the full rated current.

What’s the difference between NIGHT and LOW mode?

Both reduce output to 50%. NIGHT mode returns to normal output automatically after 8 hours, while LOW mode stays on until you switch it off.

Sources: Victron Blue Smart IP22 Charger 120V manual (section 4.7, Multiple isolated outputs); Blue Smart IP22 Charger 120VAC datasheet, victronenergy.com, accessed Oct 2026.