Panbo's Ben Stein adds a second battery to his rolling LiFePO4 cycle test and projects WattCycle's 100Ah Mini at 3,000–4,000 cycles vs the 5,000-cycle marketing number. Dragonfly Energy lands its first Japanese patent on solid-state electrolyte work. OffGrid Benchmark goes public with a no-sponsorships review platform. A 74-foot motor vessel rebuild illustrates how badly an inverter install can be done.
Battery · The Lead
Panbo's rolling cycle test passes 1,100 — WattCycle 100Ah Mini on track for ~3,000–4,000 cycles, not 5,000
Ben Stein's LiFePO4 cycle-life test on the Panbo bench has passed 1,100 cycles on the original WattCycle 100Ah Mini and 500 cycles on a newly added Blue Heron 100Ah Extreme Series. WattCycle's degradation rate has slowed and projections now point at 3,000–4,000 cycles to 80 % SOH — well short of the 5,000-cycle marketing claim, but more than enough for serious marine use.
Panbo published the second instalment of Ben Stein's rolling LiFePO4 cycle test on 28 April. The test setup is unchanged from the first piece — a West Mountain Radio CBA V battery analyser, 0.5 C discharge and charge (5 A on a 100 Ah cell), 30-minute rest between cycles, end-of-life pegged at 80 % state of health. What's changed is the data: the original WattCycle 12V 100Ah Mini has now passed 1,100 cycles, a Blue Heron 100Ah Extreme Series has been added at 500 cycles, and a Duracell 27DCX flooded lead-acid is being benchmarked alongside as a sanity-check.
The headline result is the WattCycle's degradation curve has bent the right way. Capacity loss has slowed since the first ~500 cycles, and the projection now points at end-of-life around 3,000–4,000 cycles — comfortably short of the manufacturer's 5,000-cycle claim, but several times longer than any flooded lead-acid would deliver in the same role. Stein measures the WattCycle's round-trip electrical efficiency at 93.7 %, which over a multi-year service life translates to meaningful energy savings on a fixed solar budget. The Blue Heron's data is harder to read: the 400–500 cycle window showed an unexpected capacity bump that complicates trend extrapolation, so its long-run projection is on hold pending more cycles.
For a marine builder weighing a $200 budget pack against a $789 feature-rich one, this is the kind of long-baseline data the consumer LiFePO4 market has historically lacked. Stein also frames the comparison against the Duracell flooded: even on rated capacity alone, ignoring efficiency, his lead-acid energy is delivered at "more than 16 times" the per-kWh cost of the WattCycle. That's a comparison the lead-acid camp will dispute on warranty/return economics, but the underlying cycle-cost math is the cleanest version of it we've seen recently.
Dragonfly Energy lands first Japanese patent allowance for solid-state electrolyte work
Battle Born's parent company received a notice of allowance from the Japan Patent Office on 23 April for 'Powderized Solid-State Electrolyte and Electroactive Materials' — the dry-electrode manufacturing platform Dragonfly has been pitching to investors as its long-term moat.
Dragonfly Energy Holdings (NASDAQ: DFLI) announced on 23 April that the Japan Patent Office has allowed its application titled "Powderized Solid-State Electrolyte and Electroactive Materials." It's Dragonfly's first allowance in Japan and the latest extension of an IP portfolio that already includes US grants on the same dry-electrode manufacturing approach. The patent covers powderised solid-state electrolyte and electroactive materials engineered to enable solvent-free electrode production — the foundation of the company's all-solid-state cell roadmap. CEO Denis Phares positions the work as "critical to the future of battery manufacturing." For Battle Born customers, the news has no near-term product implication: today's drop-in 12V LFP packs sold under the Battle Born brand are conventional wet-electrode LiFePO4, not solid-state. The patent is an investor and engineering signal — a plausible technical path that, if it scales, could differentiate Dragonfly's domestic manufacturing from Chinese cell sources several years from now.
OffGrid Benchmark launches as a no-sponsorships review platform — 92 products at opening
An independent consumer-tech publication founded by Washington State's Jordan Stambaugh went public in late April with reviews of 92 off-grid products across six categories — portable power stations, batteries, inverters, charge controllers, solar panels, and water filters — under a single transparent scoring methodology and a flat ban on paid placements.
OffGrid Benchmark — a one-person review project run out of Washington State by Eagle Scout Jordan Stambaugh — went public in late April with a programmatic comparison engine covering six off-grid categories. The opening database has 92 products: portable power stations (EcoFlow, Bluetti, Jackery, Anker SOLIX, Goal Zero, DJI), batteries (Ampere Time, Renogy, Epoch, Battle Born), inverters and charge controllers (Victron, Epever, AIMS Power), solar panels (Renogy, BougeRV) and water filters. Every product runs through the same data-first scoring methodology with published weights; affiliate links are present but flagged with the FTC-required nofollow sponsored attribute, and the site states it accepts no payments from manufacturers for editorial coverage. For a DC builder, the value of this launching is less in any one review and more in the head-to-head comparison engine — the WattCycle 100Ah-vs-Renogy Phoenix-vs-Epoch type queries that no other site indexes well.
Victron case study: 74-foot motor vessel had two of four Quattros wired wrong, hand-loose DC terminations, double grounds
Victron's 24 April blog walks through Marine Diagnostic Services' rebuild of the M/V Cowboy: thermal imaging caught hot DC terminations, two of four Quattro inverters were not connected to the system at all, and bonding produced double grounds. A useful failure-walk-through if you ever inherit someone else's install.
Victron published a case study on 24 April covering a power-system rebuild on the 74-foot motor vessel Cowboy — written around Jake Archer of Marine Diagnostic Services, an automotive diagnostics specialist working a marine refit. The interest for Busbar readers is the diagnosis, not the rebuild: of four Victron Quattro inverters on the boat, two were not connected to the inverter network at all and the other two were misconfigured for parallel operation; AC bonding had been done in two places, producing dangerous double grounds; and several of the DC battery cable terminations were loose enough that Archer could pull cables out of their lugs by hand. Thermal imaging surfaced the hot-spot signatures of those loose terminations under load before they failed catastrophically. The fix paralleled the four Quattros correctly, added an Ekrano GX with multiple GX Tank 140 modules, integrated an ARCO Zeus alternator regulator over CAN-bus, and brought the system into Garmin via NMEA 2000. The case is worth reading even if you'll never touch a $5M motor yacht: the failure modes — wrong parallel config, bonded twice, terminations torqued by feel — are exactly what shows up when an unsupervised install scales up.
Trek Systems sets two-day Victron hands-on training in Denver for 28–29 May
Trek Systems will host a 16-credit-hour Victron training at its Denver warehouse on 28–29 May, capped at 20 attendees. Sessions cover commissioning and troubleshooting common system configurations — useful both as installer training and as an indication that the US RV-installer side of Victron is hardening up.
Trek Systems announced a two-day hands-on Victron Energy training for 28–29 May at its Denver warehouse (4800 Dahlia St., Denver CO 80216). The format is small-group bench work commissioning and troubleshooting common system configurations, with 16 credit hours toward Level 3 RVTI certification on completion and a 20-person attendance cap. Sessions run 09:00–17:00 both days. The standalone news here is small — installer training events happen regularly. The signal is that Trek Systems, a Denver-based US Victron distributor that does not run a parts-only model, is investing in installer pipeline rather than channel: that's the right move if Victron's US business expands as the 2026 product slate (MultiPlus 48V 20kVA, split-phase inverter, TR Smart 48/12) actually ships through the year.
A short Reddit thread on r/diySolar from 30 April — "12v LiFePO4 server rack batteries other than EG4 LL?" — is worth flagging because the original poster claims an email from EG4 announcing the discontinuation of their server-rack battery line. The claim has not been corroborated by EG4's website, which still lists the EG4-LL V2 and EG4 LifePower4, or by any of the major distributors. Treat as forum signal only. If genuine, the alternative pool the thread points to (SOK, Trophy, MidNite Solar PowerFlo5, EcoWorthy) is a reasonable starting list for anyone in the same shoe.
Two more threads worth a look: r/diySolar's 2 May "AC Frequency Stability in Off Grid Systems" thread is asking the right question — what 49–51 Hz drift means for a sensitive load on an islanded inverter — and gathering reasonable answers about hybrid-inverter AC-input frequency tolerances. And the 30 April r/diySolar "Bluecarbon system connectivity" thread is the latest in a slow-burn discussion of the all-in-one inverter category from a Chinese maker that's hitting the cheap end of the market — concrete reports of comms quirks rather than synthetic reviews.
Compact Group-22NF format LiFePO4 drop-in: 1,280 Wh, 100 A continuous, 100 A charge, IP65, internal Bluetooth, 100 A BMS. No heater, no Victron CAN. The reference battery in Panbo's ongoing cycle test now past 1,100 cycles.
$199 (Amazon)Shipping now via WattCycle direct and AmazonFind on Amazon →
Featured here as the test reference for this week's lead, not as a recommendation. Panbo's projection of ~3,000–4,000 cycles is roughly half of the marketing number on the box, but still credible value at $199 if you accept the trade-offs (no heater, no CAN-bus comms).
Group 27 12.8V 100Ah feature-rich drop-in: integrated heater for sub-freezing charging, Bluetooth, Victron-compatible comms, NMEA 2000, latching external power switch, four-segment SOC LED. 1.5 C continuous discharge, 500 A 3-second pulse, manufacturer's 6,000-cycle claim at 80 % DOD. UL 1973-listed.
$789Shipping now via Blue Heron direct
The other test reference battery in the Panbo bench. Blue Heron is positioning the Extreme Series above the budget tier on cycle life, BMS surge, and marine integration — the cycle data isn't yet long enough to confirm that the ~$600 price gap to a budget pack is recovered over service life.
External alternator regulator with Bluetooth, native iOS/Android app, CAN-bus and NMEA 2000 integration. Compatible with 12V–48V systems and any battery chemistry; reads two shunts simultaneously (battery + alternator) for closed-loop temperature/current management. Featured in the M/V Cowboy rebuild covered in News above.
~$1,099 (Defender, US retail)Shipping; widely stocked through Defender, Fisheries Supply, and similar marine distributorsFind on Amazon →
Listed because it shows up in the Cowboy case study as the integration backbone for high-output charging on a CAN-bus marine system. Closed-loop regulation against both battery and alternator current/temperature is the relevant differentiator for big-house-bank LFP installs.