What Is an Off-Grid Inverter?
An off-grid inverter is a battery inverter that converts DC from a battery bank into AC for household loads, with no connection to the utility grid. It is the component that turns stored energy into usable power.
Unlike a grid-tie inverter, it does not export or synchronise with the utility. Unlike a hybrid it does not manage solar charging, that belongs to a separate charge controller. Its single function is DC to AC conversion, which makes it the simplest and cheapest way to bring AC power to a remote site.
Types of Off-Grid Inverters
Off-grid inverters are grouped by how much of the system each one manages. Some handle conversion alone and leave charging to other components. Others absorb the charger, the transfer switch and the solar controller into a single unit.
Battery inverters
A battery inverter converts DC to AC and works alongside a separate solar charge controller and battery bank, so each part is sized on its own terms and can be replaced without touching the rest of the system. This is the simplest and least expensive way into off-grid power, and it is the category the Victron Phoenix series covers at Volts Energies.
Inverter-chargers
An inverter-charger combines the inverter with a battery charger and an automatic transfer switch. When a generator starts or shore power is connected, the unit charges the bank and passes power straight through to your loads, then returns to battery supply when the source disconnects.
All-in-one systems
An all-in-one unit brings the inverter, the battery charger and the MPPT solar controller together in a single pre-wired enclosure. Fewer components need sizing, mounting and wiring, which shortens installation and reduces the number of connections that can fail. Victron EasySolar is the example in this range.
System voltage
Every off-grid inverter is built for one battery bank voltage, and the two have to match. A 12V unit suits RVs, vans and boats. A 24V unit suits seasonal cabins. A 48V unit suits full-time homes, where the higher voltage carries the same power at lower current and allows thinner, cheaper cable runs. Voltage is fixed at purchase, so moving from 12V to 48V later means replacing the battery bank and the inverter together.
Off-Grid Inverters vs Hybrid Inverters
Both run loads from a battery. The difference is what else they manage.
Solar charging. A hybrid has MPPT built in. A battery inverter needs a separate charge controller.
Grid interaction. Hybrids can import, export and switch between sources. Off-grid inverters do neither.
Cost. A battery inverter plus a controller usually costs less than a hybrid of the same output, and each part is replaceable on its own.
Scale. Hybrids suit whole-home 48V systems. Battery inverters start at 250W.
Choose a hybrid if the property has grid service or you want one box managing everything, see hybrid inverters. Choose off-grid if there is no grid and you are building in parts.
What Size Off-Grid Inverter Do I Need?
Inverter size is set by peak simultaneous load, not by daily energy use or battery capacity. Add the running wattage of everything that may be on at the same time, then add headroom for surge.
Running watts and starting watts are different numbers
Anything with a motor draws several times its running wattage for a moment at start-up. A compressor fridge that runs at 150W can pull 600W or more the instant it kicks in. Well pumps and power tools are worse. Continuous rating covers steady load; surge rating covers that spike. Check both on the datasheet.
Add 20 to 25 percent headroom
Size above your calculated peak, not at it. Running an inverter near its ceiling shortens its life and leaves nothing for the appliance you add next year.
RV, van or boat — 300W to 800W
LED lighting, phone and laptop charging, a vent fan and a compressor fridge. Matching models: Phoenix 12/500 at $187.06 or Phoenix 12/800 at $304.57.
Weekend cabin — 800W to 1200W
Lighting, a compressor fridge, a water pump and occasional power tools. Matching models: Phoenix 12/1200 at $376.52 or Phoenix 24/1200 at $425.68.
Full-time cabin — 1200W to 3000W
The above plus a microwave, kettle and larger tools, run one at a time. Matching model: Phoenix 24/3000 at $1,396.95.
Off-grid home — 3000W and above
A full household appliance set, well pump and workshop equipment. Matching model: Phoenix 48/3000, or an inverter-charger if a generator is part of the system.
Do not oversize by habit
Every inverter draws standby current continuously, and a larger unit draws more. On a small bank running unattended, an oversized inverter quietly eats capacity. Size to the load, plus headroom, and no further.
How to Choose an Off-Grid Inverter
What is your peak simultaneous load? Add the wattage of everything that may run at once, then add 20 to 25 percent for motor and compressor surge. That sets your minimum continuous rating.
What is your bank voltage? The inverter must match it. Higher voltage carries the same power at lower current, so cable runs are thinner and cheaper.
Do you need charging and transfer? If a generator or shore power is part of the setup, an inverter-charger handles both automatically. A battery inverter does not.
What are you powering? Pure sine output is required for compressors, variable-speed motors and sensitive electronics. Every inverter here is pure sine.
Do you need remote monitoring? Phoenix models include a VE.Direct port for Bluetooth monitoring through VictronConnect. Add a Cerbo GX for remote access via the VRM portal.
Off-Grid System Components
A battery inverter is one part of a complete system. Every off-grid build also needs:
Charge controller. Regulates panel output into the bank.
Battery bank. Sized to carry the site through low-sun days. See LiFePO4 and AGM.
Battery monitor. Tracks true state of charge. Victron SmartShunt and BMV series.
Cables and protection. Correctly gauged cable, fuses and disconnects. See power cables and fuses.
Generator backup. Most year-round Canadian systems pair with a generator for December and January.
Frequently Asked Questions
What is an off-grid inverter?
A battery inverter that converts DC from a battery bank into AC for household loads, with no connection to the utility grid.
What size off-grid inverter do I need?
Add the wattage of everything that may run at once, then add 20 to 25 percent for surge. A cabin with lights, a fridge and a laptop typically needs 800W to 1200W. A full home needs 3000W or more.
What is the difference between an off-grid inverter and an inverter-charger?
An off-grid inverter converts only. An inverter-charger adds a battery charger and an automatic transfer switch, so a generator or shore power charges the bank and passes power through to the loads.
Off-grid inverter or hybrid inverter?
Choose off-grid if the property has no grid service and you are assembling the system from separate parts. Choose hybrid if you want solar charging, grid interaction and inverting managed in one unit.
12V, 24V or 48V — which should I pick?
12V for RVs, vans and boats. 24V for seasonal cabins. 48V for full-time homes. Higher voltage carries the same power at lower current, so cable runs are thinner and cheaper. The choice cannot be changed later without replacing the bank and the inverter.
Do I need a pure sine wave inverter?
For compressors, variable-speed motors, medical equipment and sensitive electronics, yes. Modified sine output can cause overheating, buzzing and premature failure. Every inverter in this collection is pure sine.
Does an off-grid inverter charge my batteries?
No. Charging is handled by a separate solar charge controller, or by an inverter-charger if a generator or shore power is part of the system.
Do I need a solar charge controller as well?
Yes, if solar panels are charging the bank. The controller regulates panel output; the inverter converts stored DC to AC. They do different jobs.
Can I run an air conditioner or well pump?
Only if the inverter's surge rating covers the start-up draw, which is often several times the running wattage. Check the motor's locked-rotor amps against the inverter's surge specification.
How much power does an inverter use when idle?
Every inverter draws a small standby current continuously. Phoenix models switch to a low-power search mode when load drops below a set threshold. On a small bank, idle draw matters over a long unoccupied period.
Do off-grid inverters work in cold weather?
Victron inverters are rated from −40°C to +65°C. Batteries are the cold-sensitive component, not the inverter, lithium banks in particular should not be charged below freezing without a heater or low-temperature cutoff.
Can I monitor an off-grid inverter remotely?
Phoenix models include a VE.Direct port for local Bluetooth monitoring through VictronConnect. Adding a Cerbo GX or Color Control GX enables full remote access through the Victron VRM portal.
Can I connect two inverters for more power?
Some models support parallel operation. Check the datasheet for the specific unit, not every Phoenix model supports it, and paralleling requires matched units.
Do I need a licensed electrician?
12V RV and marine installs are commonly owner-installed. Permanent AC wiring in a dwelling requires a licensed electrician and inspection in most provinces, even with no grid connection.
What warranty applies?
Terms are set by the manufacturer and listed on each product page. Volts Energies supports installation and troubleshooting for Victron products. Order coverage is in our return policy.
Does Volts Energies ship across Canada?
Yes. Free shipping applies on orders over $297, with terms and conditions.
