The Busbar

In two videos published 9 and 13 July, Will Prowse capacity-tested twelve Battle Born 100Ah batteries bought in December 2017 and run gently indoors their whole life — all twelve measured between 26.8Ah and 60.2Ah — then tore two down and found most of their parallel cells sitting at 0V. The data lands mid-lawsuit: Dragonfly Energy's trade-libel case against Prowse is still active, and none of these results have been independently verified.

SolarAssistant, the $15 one-time-license Raspberry Pi monitoring layer that sits on top of Deye, Growatt, EG4, Sol-Ark, and Voltronic-clone inverters, released v0.2.0 of an official Home Assistant integration on 2 July alongside a beta firmware build adding REST, WebSocket, and Cloud APIs — replacing a lot of the MQTT workarounds and custom decoders DIY builders have been hand-rolling for years.

Victron announced the Nucleo GX on 3 July — a lower-cost, faster GX communication centre ($266 MSRP) built for ESS and off-grid installations around the Multi RS. It's explicitly not for boats: no VE.Bus, tank, or temperature inputs. A faster Cerbo MK3 aimed at marine installs is coming later this year.

ARCO Marine announced the Zeus Omega on 24 June — a new alternator control system that splits the traditional single-box regulator into a lightweight Control Module near the battery and a sealed Alternator Drive Module bolted directly to each alternator. One Control Module runs up to six ADMs. Pricing starts at $889 for a complete single-alternator system.

On 12 June, Renogy rolled out a new line of N-Type (TOPCon) bifacial solar panels in 100W, 200W and 400W ratings, sitting alongside its existing 250W and 590W bifacial models. The pitch is higher cell efficiency — around 25%, on 16-busbar cells — plus rear-side generation, with Renogy claiming up to roughly 14% extra energy from the back of the panel versus conventional PERC and an 80% bifaciality factor. It's aimed squarely at off-grid, RV and overland users. How much of that rear-side gain you actually see, though, depends entirely on how the panel is mounted — which is the subject of this week's Background.

On 2 June 2026, Dragonfly Energy — the maker of Battle Born Batteries — filed a trade-libel suit against YouTuber William Prowse in Nevada's Second Judicial District Court, alleging his monetised videos misrepresented the design and safety of Battle Born's 100Ah LiFePO4 battery. The complaint claims Prowse removed internal structural parts and tested damaged units outside specification, that he praised the same product before disparaging it, and that he took more than $200,000 in affiliate and advertising payments from Dragonfly over the years before publicly denying the relationship. Dragonfly seeks damages and an injunction. These are unproven allegations in a civil complaint, and the suit escalates the terminal-failure dispute we covered in April into a courtroom.

Rod Collins (MaineSail / Marine How To) reports that the DIY LiFePO4 house bank he built from GBS prismatic cells in 2009 — date-stamped May 2009, in service on his boat since early 2010 — has just turned 17 and still meets roughly 100% of its original rated capacity on a calibrated capacity test. By his earlier accounting the bank had passed 2,500 cycles, most around 80% depth of discharge, by 2023. It's one documented bank, not a study — but it's a rare long-horizon data point on LFP calendar life, and the practices Collins credits are the usual unglamorous ones: never park it full, no float, conservative voltages.

Venus OS v3.73 landed on 19 May. The headline fix for existing installs: a Dynamic ESS bug that caused the Multi RS to throttle solar production while charging from the grid is resolved. The release also adds support for the VM-3P5A energy meter, Carlo Gavazzi EM530-RG and EM530-MV meters, and three new Bluetooth tank senders (Mopeka Pro-200B, Garnet SeeLeveL SOUL and 709-BTP7). A point release, but the DESS fix matters to anyone running a Multi RS on Dynamic ESS.

Governor Wes Moore signed HB 1532 (the Utility RELIEF Act) on 12 May, putting Maryland's plug-in solar provisions on the books. Residential customers may run portable PV up to 1,200W per utility meter from 1 October; devices rated 391W or less are exempt from UL certification; systems above that must be UL-listed (or by an equivalent national lab). No utility fees, no interconnection process — but customers must notify their utility and may be required to pay for an automatic locking disconnect switch. Maryland is the fifth US state to legalise plug-in solar, days before Colorado's HB 26-1007 (1,920W cap) follows.

REDARC has its biggest North-American product week of the year. The RS3 pure-sine inverter range — 1200W, 2000W and 3000W with integrated automatic transfer switches, RV-C compatibility, and full output to 104°F — is now listed and priced on the US site, with the 3000W variant at $1,319. The RS3 family debuts at Overland Expo West in Flagstaff (15–17 May), alongside the new REDWorks pre-wired Power Panel range (Scout 25 to QuickFit 100A) and a stripped-down REDVision Essentials Display. The combined launch is REDARC's strongest US-installer pitch in years.