The Busbar

Thermal · The Lead

AirPlus roof fan measures 495 CFM against a 1,765 CFM label — and the Maxxfan beats that on 12W

FarOutRide built a duct, pointed an anemometer down it, and ran both fans at 12.8V. The AirPlus tops out at 495 CFM drawing 22.8W. The Maxxfan reaches 561 CFM — more air than the AirPlus manages flat out — on speed 5 and 12W. The 1,765 CFM on the AirPlus box comes with no test conditions attached.

FarOutRide published a bench comparison of the two 14-inch roof fans most van builders are choosing between — the Maxxfan Deluxe and the AirPlus — with the page carrying an update stamp of 5 September. The method is worth stating because it is the part vendors skip: aluminium flashing formed into a Ø315mm cylinder to force the discharge through a known area, an anemometer in the duct, and airflow calculated as velocity (m/s) × area (m²) × 2,118.88. Everything measured at 12.8V, lid fully open, exhaust mode. Noise taken at 6in and 2ft.

The headline number is the gap between the label and the duct. The AirPlus specification label claims 1,765 CFM (3,000 m³/h). Measured flat out, it moves 495 CFM drawing 22.8W — about 28% of the printed figure. FarOutRide does not report finding any documentation of where 1,765 came from, and neither did we.

The more useful comparison is the one that needs no interpolation. The Maxxfan on speed 5 moves 561 CFM on 12W. That is more air than the AirPlus produces at its maximum, on roughly half the power. Flat out the Maxxfan reaches 809 CFM at 39W. Put in the units that size a bank: eight hours of AirPlus at full speed is about 182Wh; eight hours of Maxxfan at speed 5, moving more air, is about 96Wh.

One reconciliation we owe readers. We published FarOutRide's Maxxfan figures once already, in July, from the in-van Quad-Shunt: 45W at speed 10, 17W at speed 5, 2W at the lowest setting. The bench rig now gives 39W, 12W and 1.5W at the same three positions — consistently lower by around 15–25%. Neither set is wrong. The van figures include the real install's resistance and whatever the supply voltage actually sagged to under load; the bench figures are a clean 12.8V into free discharge. That the same fan, same tester and same speed settings produce a 6W spread at the top of the dial is the whole argument of this week's Background in miniature.

There is a trap in the per-setting tables that is worth naming. "Speed 5" is not an operating point — it is a position on a dial, and two vendors' dials have nothing to do with each other. Comparing fans setting-by-setting makes the AirPlus look efficient (4.47W for 314 CFM at its own speed 5). Comparing them at equal airflow reverses the result. Any fan efficiency claim that does not state the CFM it was measured at is not a claim about efficiency.

One structural detail raises the stakes. FarOutRide identifies the AirPlus as an OEM product — Jiangsu Sanjo, model 3J-PF — sold under ProBreeze, Plus Fan, Carbest Vanvent, Vechline, Belluna and GoCamp depending on the retailer. The 1,765 CFM figure is not one brand's overstatement; it travels with the tooling.

In fairness: this is one tester, one sample of each fan, and a free-discharge rig rather than a laboratory. FarOutRide chose the AirPlus for their own build anyway — it has a built-in blind, lights and a radio remote, and no history of motor squeal. Prices as of August 2026 run $300–$475 for the Maxxfan and $350–$390 for the AirPlus in the US. See this week's Background for why nobody is required to publish a number you can check.

Sources

Industry

Marine How To takes apart the word 'American' on a lithium battery sticker

The piece argues that most 'American assembled' LFP packs are imported cells in an imported case with an imported BMS, and reaches for the FTC's first Made in USA Labeling Rule enforcement — which landed on a battery maker.

Marine How To published "American Assembled Li-Ion Batteries WTF?", carried by its feed on 2 September (the page itself shows no date — see flags). The argument in one line, in the author's words: "You're buying Chinese cells, assembled into a Chinese plastic box, with a Chinese BMS, Chinese wiring, Chinese hardware, and a sticker applied in the United States."

The one hard, checkable anchor is real but old. In April 2022 the FTC brought its first enforcement action under the Made in USA Labeling Rule against Lithionics Battery and owner Steven Tartaglia, over an American-flag "Made in U.S.A." label on packs built with imported cells and BMS components. The settlement carried a civil penalty of $105,319.56 — stated by the FTC as three times the profits attributable to the claims — plus customer notification and ten years of compliance reporting. The news here is that Collins is using it, not that it happened.

The rest is his opinion and is presented as such: criticism of Battle Born cycle-life claims and internal current paths, and a claim that Solid State Marine ships semi-solid NMC rather than solid-state cells, with a 16.8V charge requirement he reads as incompatible with a standard 12V marine system. None of that is adjudicated, and Dragonfly Energy's suit against Will Prowse is still live. On the chemistry point he is walking the same ground as our solid-state background.

Worth noting on that last point: Prowse published his own Solid State Marine video on 31 August, two days before this article, asking the same question about the same company. Two critics who are not on speaking terms arriving independently at the same conclusion within 48 hours is not proof, but it is more than one person's opinion. See On the Bench.

Sources

Solar

New Jersey legalises 1,200W plug-in solar; ninth state by our count

Governor Sherrill signed the Garden State Balcony Solar Act on 1 September. No permit, no utility approval, landlords barred from blocking — but 14 days' notice required, and it does not take effect until roughly March 2027.

Governor Mikie Sherrill signed the Garden State Balcony Solar Act on 1 September. It covers plug-in systems up to 1,200W combined output connected to an ordinary 120V outlet, on a balcony, patio or in a yard. Residents do not need a permit or utility approval, and landlords, municipalities, HOAs and housing co-ops are barred from prohibiting installation — provided they are notified at least 14 days in advance.

The law takes effect six months after signing, so the protection is live around March 2027, not now. The 1,200W cap matches Maryland's, which we covered when HB 1532 was signed in May; by our running count New Jersey is the ninth state to legalise plug-in solar after Utah, Maine, Virginia, Maryland, Colorado, Connecticut, Vermont and New Hampshire.

The mobile-and-off-grid relevance is the same as it was in May: this is the demand signal pulling hardware that also suits vans, boats and cabins into the US market, and it still runs ahead of the certified product catalogue. The first US microinverter certified to UL 3700 shipped only in July.

Sources

Inverter

EcoFlow puts a residual current device inside the PowerRock 4000 at IFA

3kWh, 4kW continuous, 7.2kW peak, and a built-in RCD that EcoFlow calls an industry first for the category. Available in Europe from 4 September. No price, no cycle life.

EcoFlow used IFA 2026 in Berlin (4–8 September, Hall 2.2, Booth 166) to launch the PowerRock 4000 and the RIVER Gen4 series.

The PowerRock 4000 is the interesting one. 3kWh of storage, 4kW continuous output, 7.2kW peak for up to 100 seconds, 38kg, 80% charge in 48 minutes and full in 60, three-year warranty. EcoFlow describes a built-in residual current device as an industry first for the product class. On a jobsite or a boat that is a genuine functional difference rather than a spec-sheet number — earth-fault protection normally has to be added downstream, and portable units are used exactly where nobody adds it. Whether the RCD is Type A or Type B, and its trip rating, are not stated.

The RIVER Gen4 pair is conventional: RIVER 260 Gen4 at 256Wh and 300W (600W with X-Boost), about 3.0kg, 80% in 42 minutes; RIVER 520 Gen4 at 512Wh and 500W (1,000W X-Boost), about 4.6kg, 80% in 50 minutes. Both LFP, both with a 140W bidirectional USB-C port.

EcoFlow published no prices and no cycle-life figures for any of it. Europe gets the PowerRock from 4 September, with a wider distributor rollout given as November 2026.

Sources

EcoFlow / PR Newswire — Breaking Boundaries: EcoFlow Unveils RIVER Gen4 and PowerRock 4000 at IFA 2026

Battery

Bluetti launches four power stations at IFA and publishes almost no specifications

The Pioneer 5000 gets 5kW continuous and an 18kW surge, IP65 and IK10. Capacity, chemistry, cycle life and price are absent from the release, as they are for all three Elite mini models.

Bluetti announced four units at IFA under a "From Balcony to Everywhere" banner: the Pioneer 5000 and the Elite 30 mini, Elite 100 mini and Elite 200 mini, alongside its Balco 500 balcony system from May.

What the release actually states about the Pioneer 5000: 5kW output with an 18kW surge, IP65 ingress protection, IK10 impact resistance, and a wheeled chassis. That is a jobsite specification and the ratings are the point — IK10 is a 20-joule impact test, which is not something portable power stations normally carry. Trade coverage of the launch puts the pack at 5,120Wh LFP; Bluetti's own release does not say, so we are not asserting it.

For the three Elite mini models the release offers "multi-port output, UPS backup, and app control" and a lightweight frame. No capacities, no output ratings, no chemistry, no prices, no dates. Four products, and the only numbers in the entire announcement belong to one of them.

Sources

BLUETTI / PR Newswire — BLUETTI Expands Smarter Energy Solutions from Balcony to Everywhere at IFA 2026

The Background · Standards Explainer

There is a standard for measuring fan airflow. Nobody selling you a roof fan uses it.

The obvious reaction to a fan that moves 28% of its labelled airflow is that the category has no test standard and vendors can print what they like. Half of that is true. The standard exists, and it has existed for most of a century.

What AMCA 210 is

ANSI/AMCA Standard 210, published jointly as ANSI/ASHRAE Standard 51, is titled "Laboratory Methods of Testing Fans for Certified Aerodynamic Performance Rating." The current edition is 2025 — the eleventh revision, on a lineage running back more than eighty years. It sets uniform laboratory methods for determining a fan's airflow rate, the pressure it develops, its power consumption, air density, rotational speed and efficiency, explicitly "for rating or guarantee purposes."

Note what it measures together: airflow and pressure and power, not airflow alone. That is the whole point, and it is what a single CFM number on a box cannot express.

Why one CFM number is not a specification

A fan does not have an airflow. It has a curve. Move air against zero resistance and you get the maximum the blade can shift; add resistance and flow falls along the curve until, at the fan's shutoff pressure, it moves nothing at all while still drawing power. A free-air CFM figure is the single most flattering point on that curve, and it is the point no installed fan ever operates at.

In a van, the resistance is not hypothetical. There is an insect screen. There is a lid at whatever angle it opens to. There is the make-up air path — a cracked window, a floor vent, or nothing, in which case the fan is pulling against a sealed box and the curve collapses. Two identical fans in two different builds are at two different operating points. This is why the honest question to a vendor is not "how many CFM" but "how many CFM at what static pressure, and what were you drawing at that point."

It also explains the trap in this week's Lead. Per-setting comparison tables put two fans at unrelated points on unrelated curves and invite a conclusion about efficiency that the data does not support. Compared at its own speed 5, the AirPlus looks frugal. Compared at equal airflow, it needs roughly twice the watts.

The gap

AMCA 210 covers air-moving devices broadly but carves out air circulating fans — ceiling fans, desk fans — where there is no defined flow path. A roof vent fan moving air across the boundary of an enclosed space is not that; it is a ducted-type application, and the standard is applicable in principle. We could not find an RV or marine roof fan sold with an AMCA-certified rating, and we could not find a vendor in the category that publishes a pressure point alongside its CFM figure at all.

The contrast within our own recent coverage is sharp. Two weeks ago Bergstrom published the OpenAir PLUS with its current draw given as a 16–60A range and a 10A average and the ISO 5151:T1 conditions that average was measured under. That is a datasheet. A week before that, the Velit V3 shipped with no published continuous amp draw whatsoever. The roof-fan category sits at the Velit end: a maximum wattage measured at one operating point, and a CFM figure measured at a different one, printed side by side as though they described the same moment.

What this costs a builder

Practically, it means the two numbers that matter to a DC system cannot be derived from the marketing. Watts size the bank and the wire. CFM decides whether the van is habitable in August. Neither is trustworthy in isolation, and the ratio between them — the only figure that would let you compare fans — is not published by anyone.

Which is why a builder with aluminium flashing, an anemometer and an afternoon produced more decision-useful information this week than the vendors did. FarOutRide's rig is not AMCA 210; it is free-discharge through a known area, without a pressure sweep. But it applied one consistent method to both fans, which is the minimum condition for a comparison to mean anything, and it is precisely the thing the industry declines to do.

Sources

Community Pulse

What the forums are talking about this week

A neat coincidence on r/vandwellers this week: a builder designing a system whose only load is an AirPlus Deluxe fan asked whether a DC-DC charger is worth adding at all. The plan is 400W of solar on an Unaka rack, a 200Ah LiFePO4 bank and a Victron MPPT 100/30, and the reasoning is that the fan draws so little that alternator charging would be redundant cost and labour. This week's Lead supplies the missing number — that fan is 22.8W flat out — which makes the arithmetic a genuine question rather than a guess, and shifts it to where it belongs: not "is the load big" but "how many consecutive grey days do you intend to survive."

Elsewhere, a straightforward switching question worth reading for the answer rather than the problem — whether a 12V Seaflo water pump can be run from two locations by wiring a second switch, and whether a dimmable switch would damage anything driving a pump motor. And a thermal one: a 12V system with 900Ah of lithium weighing a conventional mini split against the semi-truck units, which cool but do not heat.

We could read only the opening posts — the forum bodies are not reachable from this environment — so treat these as questions asked, not answers reached.

Threads

On the Bench

YouTube picks: builds, teardowns, firmware walkthroughs, and reviews

⚡ Must Watch

Solid State Marine Batteries: False Advertising?! Fire Risk?

DIY Solar Power with Will Prowse · 31 August 2026

Prowse takes on the same company Marine How To went after two days later, and on the same grounds — whether a pack marketed as solid-state is actually semi-solid NMC, and what that chemistry means in a boat. The convergence is the reason to watch it: two independent critics, no coordination, 48 hours apart.

Teardown

New V22 JK-BMS - The Budget-BMS with new Balancer and Wifi on the Testbench.

Off-Grid Garage · 5 September 2026

Bench run on the V22 generation of the budget JK BMS, with a reworked balancer and onboard WiFi. Continues the JK firmware thread we have followed through V19.31B and V19.34.

Firmware Deep-dive

First Full Charge of the Battery Shelf after Winter. How bad is the cell drift after 6 months?

Off-Grid Garage · 2 September 2026

Six months of storage, then a full charge, and a measurement of how far the cells actually drifted apart. Rest-state drift over a winter is the part of pack behaviour that almost nobody instruments.

Product Radar

New and notable components announced or launched this week

AirPlus 14" Roof Vent Fan — Jiangsu Sanjo (model 3J-PF; sold as AirPlus, ProBreeze, Plus Fan, Carbest Vanvent, Vechline, Belluna, GoCamp)

Thermal

12V brushless reversible roof fan with ten speeds, built-in blackout blind, LED lighting and a radio remote. Fits roof thicknesses from 1in to 3in.

$350–$390 (US, August 2026) Shipping through multiple van-gear retailers

Measured at 495 CFM and 22.8W flat out against a 1,765 CFM label. The fan is not bad — the number on the box is.

Maxxfan Deluxe — MaxxAir

Thermal

12V ten-speed reversible roof fan with integrated rain lid. Measured by FarOutRide at 809 CFM / 39W flat out and 561 CFM / 12W on speed 5.

$300–$475 (US, August 2026); around $500 in Canada Long-standing retail product; newly relevant as the reference point in this week's test

Listed for the measurement, not as a recommendation. Note separately that MaxxAir N-Series Maxxfan PCBs are the subject of six RV-builder recall campaigns tracked here since July — an unrelated defect on the same product family, and one no aftermarket fitter is covered by.

PowerRock 4000 — EcoFlow

Inverter

3kWh portable power station, 4kW continuous and 7.2kW peak for up to 100 seconds, 38kg, 80% charge in 48 minutes, full in 60. Built-in residual current device, described by EcoFlow as an industry first for the category. Three-year warranty.

Not published Europe from 4 September 2026; wider distributor rollout given as November 2026

The RCD is the reason it is here. Trip rating and RCD type are not stated, which is exactly what you would need to know before relying on it.

RIVER Gen4 series (RIVER 260 / RIVER 520) — EcoFlow

Battery

LFP portable power stations. RIVER 260 Gen4: 256Wh, 300W output (600W X-Boost), about 3.0kg, 80% in 42 minutes. RIVER 520 Gen4: 512Wh, 500W (1,000W X-Boost), about 4.6kg, 80% in 50 minutes. Both carry a 140W bidirectional USB-C port.

Not published Announced at IFA 2026; no date given

Bidirectional 140W USB-C is the only part of this that changes anything — it makes the unit a charger for a laptop-class device rather than only a socket.

Pioneer 5000 — Bluetti

Battery

Wheeled power station rated 5kW continuous with an 18kW surge, IP65 ingress protection and IK10 impact resistance. Capacity, chemistry and cycle life are not stated in the launch release.

Not published Announced at IFA 2026 (4–8 September); no date given

IK10 is a 20-joule impact rating and is genuinely unusual in this category. It is also the only substantive number Bluetti published about the product.

NOVA Core 2 — Wattstunde

Battery

12.8V LiFePO4 in 100Ah, 150Ah, 180Ah, 200Ah, 320Ah and 500Ah. Integrated heating mat allowing charge from -30°C, discharge to -30°C/+60°C, Bluetooth 5.0 and CAN-Bus as standard, ≥6,000 cycles at 80% DoD, seven-year warranty.

€621 (100Ah) / €924 (150Ah) / €1,092 (180Ah) / €1,680 (320Ah) at German retail Already shipping at European retail — listed as newly relevant, not newly announced

Included because CAN-Bus and a heating mat as standard equipment across a 100–500Ah European range is a meaningful line for winter camper builds. We could not establish a launch date, so this is not being treated as news.