Not compatible
COTEK SE400-112 + Fortress Power eFlex MAX 5.4
- Voltage doesn't match: the 51.2 V battery won't work with this 12 V inverter.
Checked automatically against spec sheets. Not yet confirmed in a real install. Last checked 2026-10-14. 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 | COTEK SE400-112 | Fortress Power eFlex MAX 5.4 |
|---|---|---|
| Voltage | 12 V accepts 10.5–16 V | 51.2 V |
| Current | Max battery current Not published | Max charge 100 A Max output 100 A Peak output 130 A |
| Communication | None listed | Sol-Ark closed loopGrowatt SPF/SPE closed loopOpen loop (no comms) |
| Cable connection | Stud size Not published | Terminal M8 |
Values come from each maker's documents. "Not published" means the maker doesn't state it.
Confirm with the makers before you buy
- Each product's current limits. One or both aren't published, so ask both makers.
- 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 (M8).
- 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
COTEK SE400-112
- No store links yet. The maker's site is below.
- COTEK (maker)
Fortress Power eFlex MAX 5.4
- 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.