Checked as a single pack, which covers this inverter’s charge current on its own.
Full specifications: Schneider Conext SW 4048 and Fortress eVault Max 18.5kWh.
The four checks
Voltage window: Overlapping window 44.8 to 58.4 V
The inverter operates from 44 to 64 volts and the battery cuts off outside 44.8 to 58.4 volts. Both stay inside 44.8 to 58.4 volts, which covers a normal LiFePO4 charge and discharge cycle with margin at both ends.
Charge current: 105 A into a 133 A limit
The inverter tops out at 105 amps and the battery accepts 133 amps, so a default install cannot overrun the pack. Adding batteries in parallel raises the accepted current further.
Surge rating: 200 A surge for 5 s against a 142 A peak
The inverter surges to 6800 watts, about 142 amps at 48 volts, and the battery is rated for 200 amps for 5 s. A compressor or well pump start has room inside that rating. Compare the durations as well as the amps, because the ratings are only equivalent if the pack can hold its figure as long as the inverter holds its own.
Closed-loop communication: No shared protocol
The inverter speaks Modbus and the battery speaks CAN, RS485. There is no common protocol between them, so closed-loop operation is off the table regardless of cabling.
What this means when you install it
Set the inverter charge current to 105 amps or less. That is the inverter maximum, which this bank can absorb. Protect the battery run with a 100 amp Class T fuse and 2 AWG cable.
The inverter speaks Modbus and the battery speaks CAN, RS485. There is no common protocol between them, so closed-loop operation is off the table regardless of cabling.
Figures side by side
| Field | Schneider Conext SW 4048 | Fortress eVault Max 18.5kWh |
|---|---|---|
| Voltage window | 44 to 64 V | 44.8 to 58.4 V |
| Charge current | 105 A delivered | 133 A accepted |
| Peak draw | 6,800 W surge | 200 A surge |
| Usable capacity | n/a | 18.5 kWh |
| Comms | Modbus | CAN, RS485 |
Manufacturer documents
Schneider has no public document library this site has been able to verify. Every figure on this page therefore needs checking against the paperwork that shipped with your unit.
Manufacturer documents: Fortress Power document library. Figures here should be read against the revision that covers your serial number, because manufacturers revise specifications without changing the model name.
Both units, current pricing
Prices on these move week to week, and the battery is usually the line item worth watching.
Schneider Conext SW 4048 on AmazonFortress eVault Max 18.5kWh on AmazonComms cableAffiliate links. As an Amazon Associate this site earns from qualifying purchases, at no extra cost to you. Prices and stock change often, and a listing appearing here is not a statement that the pairing above is approved.
Other pairings for the Fortress eVault Max 18.5kWh
EG4 18KPV with Fortress eVault Max 18.5kWh
Partial match, some fields unverified.
Sol-Ark 12K with Fortress eVault Max 18.5kWh
Specs align on every checked field.
Sol-Ark 15K with Fortress eVault Max 18.5kWh
Specs align on every checked field.
Victron MultiPlus-II 48/5000 with Fortress eVault Max 18.5kWh
Specs align on every checked field.
Questions people actually ask
Will the Schneider Conext SW 4048 work with the Fortress eVault Max 18.5kWh?
Specs conflict on at least one field. Checked as a single pack, which covers this inverter’s charge current on its own. The four checks below show which field produced that result.
What does this pairing cost to wire up?
Beyond the two units, a 100 amp Class T fuse and holder, 2 AWG battery cable cut to matched lengths, and a busbar if you are running 1 packs. A comms cable if you intend to attempt closed loop, and the pinout is rarely the same between brands.
Where does this pairing go wrong in practice?
The inverter speaks Modbus and the battery speaks CAN, RS485. There is no common protocol between them, so closed-loop operation is off the table regardless of cabling.
What charge current should I set?
The inverter tops out at 105 amps and the battery accepts 133 amps, so a default install cannot overrun the pack. Adding batteries in parallel raises the accepted current further.