--- id: DHL-001 session: fourwinns-h190 / 2026-04-28 equipment: fourwinns-h190 opened: 2026-04-28 status: open --- # Symptom User report (2026-04-28): "Battery is presently at 3 volts after check, there was some wire corrosion at the end of last year that I think was causing a discharge so salvaging the battery if possible and then trying, I do have other batterys and jump starters, I tried to charge it with a 1.5 amp charger and it wouldn't start charging." Storage state: trailer in driveway, boat cover on, last run fall 2025 (~6 months idle through Michigan winter Oct 2025 → Apr 2026). Battery in question (per photo, label data): NAPA Legend, NAPA No. 7575, BCI Group 75, 800 CA / 650 CCA, manufactured June 2018 (~7.8 years old). Boat has no battery selector switch installed (single-battery setup, all always-hot circuits permanently connected through winter). # Hypotheses ## H1 — Battery sulfated, unrecoverable (status: CONVERGED) - Predicted by: physical evidence (3V terminal voltage, charger lockout) plus battery age (~7.8 years) plus wrong group for marine duty (Group 75 is automotive side-post, not marine dual-purpose). - Evidence supporting: - 3V on a nominal 12V lead-acid is 0.5V/cell — well past the threshold where lead sulfate crystallizes into hard, non-reversing form. - 1.5A smart charger refuses to engage; smart chargers have a low-voltage detection floor (typically ~10.5V) below which they read "no battery / shorted" and won't start the charge cycle. - Battery age in marine duty service: typical service life 4–6 years, occasionally 7. At 7.8 years the unit was already at end-of-life before the discharge event. - Group 75 BCI form factor is GM-pattern automotive side-post, not marine-rated dual-purpose. Lacks marine vibration/insulation rating and USCG construction. - Evidence against: none. - Verification needed: none — three independent reasons converge. - Status reasoning: replace, do not salvage. Salvage attempt is low-yield labor against a battery that's wrong for the application even if recovered. ## H2 — Battery recoverable to limited capacity (status: ABANDONED) - Predicted by: user statement of intent to salvage. - Evidence supporting: theoretically possible if all six cells uniformly discharged with no shorts — desulfation chargers and parallel-jump protocols can recover deeply discharged lead-acid in some cases. - Evidence against: - Recovery probability to useful CCA: under 20% even with correct protocol at this discharge depth. - Wrong group for marine duty regardless of recovery success. - Status reasoning: abandoned. Even successful recovery leaves a Group 75 in a marine application. Wrong answer regardless of yield. ## H3 — Parasitic draw via corroded wiring is the root cause (status: OPEN — BLOCKING) - Predicted by: user statement (corrosion at wire terminals to battery, noted end of last year), absence of battery disconnect switch. - Evidence supporting: - Corrosion at ring terminals reported visually by user (location: at battery posts/lugs, repair status: not yet performed). - No 1/2/Both/Off battery selector — every always-hot circuit on the boat is permanently connected to battery from October through April. - Bilge pump auto-float circuit on this generation is the most common parasitic-draw culprit on stored boats. Stuck float, partially submerged float, or corroded float-switch contacts can pull 50 mA to several amps. - Battery dropping from charged state to 3V over ~6 months requires sustained drain beyond normal self-discharge (lead-acid self-discharge rate ~3–5% per month — even old batteries should retain >50% over 6 months in cold storage with no draw). - Evidence against: - User asserted "no switch drained it" — but lack of switch is not evidence of no draw, it is the opposite (every always-hot circuit is connected). User assertion is theoretical, not measurement-based. - Verification needed: - Multimeter in series on disconnected negative cable, all switches off, key out. DC amps range, fused at 10A. - Expected on clean 1989 H190: <50 mA. Up to ~80 mA with aftermarket accessories. - Hundreds of mA or any reading in amps = active fault path; pull fuses one at a time at the panel until reading drops, that's the affected circuit. - Status reasoning: BLOCKING — must verify and resolve before commissioning new battery. Otherwise the new battery dies the same way. ## H4 — Charging system fault (status: OPEN — downstream) - Predicted by: standard rule-out before declaring boat operational after multi-month storage. - Evidence supporting: none specific to this engine yet — alternator visible in engine bay photo shows surface corrosion on the case, consistent with environmental exposure but not necessarily indicative of failure. - Evidence against: none — system has not been verified either way. - Verification needed: - Voltmeter at battery posts, engine running, 1500–2000 RPM. - Spec per OMC service manual (cited via 1987 Cobra section reference, forum-confirmed): 13.0–14.7 VDC at the battery. - <13.0V running = alternator/regulator not charging adequately. - >14.7V running = regulator shorted, will overcharge new battery. - Status reasoning: open and downstream. Verify after engine is commissioned (new battery installed, parasitic draw resolved). Not blocking the immediate work but blocking declaration of "ready for the season." ## H5 — Cable corrosion progressing under insulation (status: OPEN) - Predicted by: user-reported terminal corrosion, age of boat (37 years, original or near-original wiring likely). - Evidence supporting: - Visible terminal corrosion at battery lugs (user-reported, photo not yet taken). - 1989 marine cables on a freshwater-but-trailered boat at 37 years age — copper conductor under insulation is a known degradation point even with intact-looking jacket. - Evidence against: not yet inspected. - Verification needed: - Pull rubber/heat-shrink boot back ~6 inches on each cable. - Inspect copper conductor itself for green/black wicking up the strands. - If contaminated: cut back to clean copper and re-terminate, do not just clean the lug. - Also inspect negative cable termination at engine block / starter ground stud (common hidden-corrosion site on this generation). - Status reasoning: OPEN. Not blocking battery replacement but blocking trust in cranking circuit. # Convergence summary Battery replacement is the immediate action (H1 converged). Before commissioning the new battery: parasitic draw must be quantified and resolved (H3 blocking). Charging system verification (H4) and cable condition inspection (H5) follow at first engine run.