Not compatible
Tigo EI Inverter 3.8kW + Fortress Power eVault Max 18.5
- Voltage doesn't match: the 51.2 V battery won't work with this 400 V inverter.
Checked automatically against spec sheets. Not yet confirmed in a real install. Last checked 2026-10-22. We don't track firmware versions.
Size the battery cable and fuse for this pair in the build tool, from your run length.
Published limits, side by side
| Spec | Tigo EI Inverter 3.8kW | Fortress Power eVault Max 18.5 |
|---|---|---|
| Voltage | 400 V | 51.2 V |
| Current | Max battery current 11.1 A | Max charge 180 A Max output 180 A Peak output 230 A |
| Communication | None listed | Sol-Ark closed loopOpen loop (no comms) |
| Cable connection | Stud size Not published | Terminal M10 |
Values come from each maker's documents. "Not published" means the maker doesn't state it.
Confirm with the makers before you buy
- Whether one battery can take the inverter's full current. The inverter's max battery current is 11.1 A. This battery is rated for 180 A charging and 180 A output. Ask how many batteries to run in parallel.
- Which firmware versions support this pairing. We don't track firmware.
- That your cable lugs fit the inverter's battery studs (Not published) and the battery's terminals (M10).
- How to install both safely, from each maker's manual and your local code.
This result checks two things: the battery's voltage suits the inverter, and the inverter maker lists this battery for closed-loop communication (the battery tells the inverter how to charge it). It doesn't check current limits, charge settings, firmware, cable sizes, or safe installation. Confirm those with both makers before you buy.
Sources
This result comes from the documents below. We haven't yet found an outside source that confirms it, such as a forum report or a video of a real install.
Where to buy
Tigo EI Inverter 3.8kW
- No store links yet.
Fortress Power eVault Max 18.5
- No store links yet. The maker's site is below.
- Fortress Power (maker)
Spot a mistake? Email errata@offgridstacks.com with this page's link.