Short answer: you can mount both under the carport and give the enclosure the narrower job. An IP65 inverter goes straight on the wall with 300 mm [12 in] of clearance all round, and an IP65 battery bolts up beside it to its own manual. A sealed 316L cabinet carries your AC and DC protection. It holds 40 C [104 F] inside at 35 C [95 F] ambient while its heat load stays under about 20 W for a 24 x 20 x 8 in box. A 5 kW inverter's 200 W of losses would ask for 10.8 m² [116 sq ft] of stainless wall in a sealed box, so the inverter stays in free air and the box stays small.
What a carport actually throws at the hardware
A carport roof stops vertical rain, and that is where its shelter ends. With two or more sides open, wind drives rain onto the wall at an angle, and a hosed floor throws splash back up the same wall. Add blowing dust, hours of sun loading a dark case, and a day-night temperature swing that breathes humid air through every gasket. Your gear faces four things out there: driven water, dust, sun load and the temperature swing. IP65 answers the first two and leaves the last two to you.
What IP65 covers and what it leaves open
IEC 60529 sets the code. First digit 6 is dust-tight; second digit 5 is water jets from a 6.3 mm nozzle delivering 12.5 L/min from 2.5 to 3 m [8-10 ft] for at least 3 min. Rain, a bucket of water and a garden-hose spray all sit inside that test. The next digit up doubles to a 12.5 mm nozzle at 100 L/min, and a pressure washer runs past both — hot high-pressure jetting is the IPX9 test. Neither 65 nor 66 is an immersion rating; the first immersion digit, 7, means 1 m [3.3 ft] of water for 30 min.
The code also says nothing about corrosion, sunlight or temperature, and it rates the unit exactly as its manufacturer shipped it, entries included. The same honesty applies to the boxes on this site: our enclosures are manufacturer-rated NEMA 4X-type / IP66 and not UL listed, and NEMA itself tests nothing. In US installs, NEC 110.28 makes the enclosure type the spec item, with Table 110.28 listing which types suit which locations. An IP code alone will not satisfy a spec that calls for a type, so read both lines on the datasheet before you trust the case. Every digit pair is broken out in the IP rating chart.
Three installs, by how open the carport is
- One open side, gear on the back wall: install it bare. The inverter hangs per its manual with 300 mm [12 in] of free space for convection, because its case is its heatsink. The battery bolts beside it with the clearances its own manual states. The rating decides, not habit — the same call as whether a drive can run bare.
- Two or more open sides, or a wall that takes weather: add a shroud. A back-plate with a small roof, open top and bottom so air keeps moving past the fins, breaks driven rain and splash while keeping the 300 mm clearance. Shade it or paint it light.
- Hosing nearby, salt air, vermin or public reach: seal it up. The inverter goes behind a door only with the heat arithmetic below or a heat exchanger, and the battery gets a compartment built to its instructions with a lock.
Whichever you choose, keep every disconnect reachable, and isolate both the AC and DC sides before you open anything. A 51.2 V bank feeds a fault as willingly as the mains do.
Sizing a sealed 316L box for a 5 kW inverter at 35 C ambient
Work it with these inputs, and swap in your own numbers where marked:
- Inverter: 5 kW off-grid, IP65. Full-load efficiency assumed 96 % — a worked-example number, so replace it with the efficiency or heat-dissipation line on your inverter's datasheet.
- Heat to move: 5000 W × (1 − 0.96) = 200 W.
- Ambient on the design day: 35 C [95 F].
- Inside limit: 40 C [104 F], the ceiling this site sizes electronics to unless a datasheet allows more.
- Wall: 316L stainless at k = 3.7 W/m²K, the reference value for a stainless wall.
- Candidate box: 24 x 20 x 8 in, outside 0.610 × 0.508 × 0.203 m.
In steady state a sealed box sheds heat only through its walls: heat passed = k × wall area × temperature difference.
Wall area = 2 × (0.610 × 0.508) + 2 × (0.610 × 0.203) + 2 × (0.508 × 0.203) = 1.07 m². With 5 C of rise available (40 − 35), the box passes 3.7 × 1.07 × 5 = 19.8 W, call it 20 W. Turn it around for the inverter: 200 / (3.7 × 5) = 10.8 m² [116 sq ft] of wall. The largest size in the 316L range, 60 x 36 x 16 in, carries about 4.8 m², so you would need more than two of the biggest boxes. Even letting the inside run at 45 C, a 10 K rise, still asks 200 / 37 = 5.4 m² [58 sq ft].
The decision lands on a threshold. Under about 20 W of losses, this sealed box holds 40 C at 35 C ambient, which fits the DC isolator, AC breakers, surge protection and a monitoring supply. At 200 W, passive sealing fails, and you pick one of two doors: the inverter stays in free air, where its rating was earned, or its cabinet gets an air-to-air heat exchanger rated for the full 200 W. A filter fan moves the air for less, but the assembly takes the filter's rating, commonly IP54 — a downgrade on a weather-facing carport wall. The full method lives in PCB heat in a sealed enclosure.
The battery compartment, sized by its manual
A 51.2 V, 100 Ah wall-mount pack stores 5.12 kWh, and IP65 versions are built to hang outside. Their own heat is small: one full cycle a day at 95 % round-trip efficiency releases 5.12 × 0.05 = 0.26 kWh across the day, about 11 W on average. Inside that 1.07 m² box, 11 W is a rise of 11 / (3.7 × 1.07) = 2.8 C. So the compartment you build is a sun, impact and temperature job, not a heat-removal job.
The battery's instructions set the numbers that matter: wall clearances, fixings, any venting path the maker calls for, and the charge-temperature window. Most lithium packs refuse charge below 0 C [32 F], and winter is its own design question (insulated battery box for LiFePO4). Give the battery its own space, away from hot electronics, built from the parts list in battery compartment enclosure. The vented-versus-sealed heat trade is worked through in outdoor battery charging enclosure: vented or sealed, and the wider rating-and-size picture sits in outdoor solar battery enclosure sizing.
Material, mounting and keeping the rating
Under a carport the cabinet lives in humidity and wet-dry cycling, plus salt near the coast. Go 316L for coastal or salted sites and 304 for sheltered inland walls. 304 can still pit under chloride deposits left sitting, which makes it a cleaning routine rather than a lost cause (why wet-dry cycling rusts 316L).
Mount the box on the wall that stays shaded through the afternoon, keep it clear of the floor's splash zone, and bring every cable through the bottom face with a drip loop below each gland. Fit glands their maker rates at IP66 with the supplied seals and torque. The assembly takes the lowest rating among its parts, so one cheap gland re-rates your whole cabinet. Day-night breathing and condensation are the outdoor question left over, and the vent or sealed box decision covers it; for a carport, bottom entries, a shaded wall and an intact door gasket carry most of it. Hang it the way mounting a weatherproof box without losing its rating shows.
What to put on the order
| What | Order this |
|---|---|
| Inverter | IP65 5 kW off-grid unit, bare wall-mount, 300 mm [12 in] clearance, shaded wall |
| Battery | 51.2 V, 100 Ah [5.12 kWh] IP65 pack to its manual, own compartment, lock on the door |
| Protection cabinet | 316L box, 24 x 20 x 8 in outside (H x W x D): hinged gasketed door, removable mounting panel; manufacturer-rated NEMA 4X-type / IP66, not UL listed |
| Entries | Bottom-face gland holes for PV, battery and AC cables, sizes fixed on the approved drawing |
| Material | 316L coastal and salted sites, 304 inland |
| Lock | Padlock hasp or keyed quarter-turn |
Custom cutouts go through the custom enclosures page. You set the material, every dimension and every hole, the box is built from one piece, and delivery is 10 business days from your approval of the drawing. Still weighing sizes? The enclosure selector shortlists by environment and DIN module count. One line to hold: the inverter and battery live on the wall under the carport, the sealed 316L box carries the low-wattage gear, and anything above 20 W inside that box gets a heat exchanger or stays in free air.
Enclosures in this article
| Enclosure | Material | Outside H x W x D / display | Rating |
|---|---|---|---|
| 24 × 20 × 8 in | 316L stainless | 24 x 20 x 8 in | Rated NEMA 4X / IP66 by the manufacturer; not UL listed |
Questions
Can an IP65 inverter sit outside under a carport without an enclosure?
Yes, on the wall with the clearance its manual states — typically 300 mm [12 in] all round for convection. IP65 means dust-tight plus 6.3 mm jets at 12.5 L/min, which covers rain and hose spray. Mount on the shaded wall, and clean it with a hose, never a pressure washer: that jet sits beyond both IP digits, in IPX9 territory.
Does an IP65 battery need its own enclosure?
Its case already passes the dust and jet tests, so what you add is shade, impact protection and temperature control. A 51.2 V, 100 Ah pack cycled once a day at 95 % round-trip efficiency warms its space by about 11 W, so the compartment follows the manual's clearances, fixings and charge-temperature window rather than a heat calculation.
Can the inverter and battery share one sealed cabinet?
Not passively at summer ambient. A 5 kW inverter at 96 % efficiency dumps 200 W, and a stainless wall passes 3.7 W per m² per K, so holding 40 C inside at 35 C outside wants 10.8 m² of wall — more than two of the largest 60 x 36 x 16 in boxes. Keep the inverter in free air, or fit an air-to-air heat exchanger sized for the full 200 W.
Is IP65 the same as NEMA 4X?
No, and one does not imply the other. IP65 tests dust-tightness and a 6.3 mm jet; Type 4X adds hose-directed water and an extra 200 hours of salt-spray corrosion testing that IP65 never runs. In US installs NEC 110.28 makes the enclosure type the spec item, and our cabinets are manufacturer-rated NEMA 4X-type / IP66, not UL listed.
What size box do I order for the AC and DC protection?
For a typical off-grid set, the 24 x 20 x 8 in 316L box carries the DC isolator, AC breakers, surge parts and terminals with about 20 W of headroom at 35 C ambient. Mount it so every breaker handle sits no more than 2.0 m [6 ft 7 in] above grade, the NEC 240.24(A) limit.
