From bda3eb849a4d27aa7293fb816711806a2928ba91 Mon Sep 17 00:00:00 2001 From: adam-pollard Date: Sat, 22 Aug 2026 05:24:51 +0000 Subject: [PATCH] publish: soh-field-guide --- hybrid-fault-reference.html | 2 +- hybrid-fault-reference.json | 7 +- index.html | 281 +++++++++++++++++++++++++++++------- soh.html | 178 +++++++++++++++++++++++ soh.json | 36 +++++ 5 files changed, 447 insertions(+), 57 deletions(-) create mode 100644 soh.html create mode 100644 soh.json diff --git a/hybrid-fault-reference.html b/hybrid-fault-reference.html index cf78917..bb56735 100644 --- a/hybrid-fault-reference.html +++ b/hybrid-fault-reference.html @@ -40,7 +40,7 @@ ul[data-fort]{list-style:none;margin:0;padding:0;display:flex;flex-direction:col - +

Hybrid Battery Fault Reference

Common codes and root causes on 2015–2023 Toyota Prius / Camry hybrids. Verified with factory manuals and logged packs.

diff --git a/hybrid-fault-reference.json b/hybrid-fault-reference.json index b08d4b5..5ad5bb8 100644 --- a/hybrid-fault-reference.json +++ b/hybrid-fault-reference.json @@ -5,7 +5,7 @@ "items": [ { "rel": "index.html", - "title": "Hybrid Battery Packs", + "title": "Adam Pollard", "href": "/" }, { @@ -22,6 +22,11 @@ "rel": "hybrid-diagnostic-tool.html", "title": "Hybrid Diagnostic Tool", "href": "/hybrid-diagnostic-tool.html" + }, + { + "rel": "soh.html", + "title": "Reading Battery State-of-Health", + "href": "/soh.html" } ] } diff --git a/index.html b/index.html index df5244a..2cac5d5 100644 --- a/index.html +++ b/index.html @@ -1,63 +1,234 @@ - - - Hybrid Battery Packs - - - - - - - - - + + +Adam Pollard — Hybrid & Vintage Powertrain Diagnostics + + + + + + + + -
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Hybrid Battery Packs

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Hybrid battery packs are a critical component in modern electric vehicles, combining the benefits of both electric and traditional internal combustion engines. These packs store and manage the electrical energy needed to power the vehicle, ensuring efficient and reliable performance.

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Hybrid battery packs are designed to handle the high power demands of electric vehicles while also providing the energy storage capacity needed for long-distance travel. They are typically composed of multiple lithium-ion cells, which are arranged in a specific configuration to optimize performance and safety.

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VIN: 4ORT-TECH-SPARKS-NV
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Adam Pollard

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ASE Master Technician · Hybrid & Battery Electricomotive · Vintage Small-Block Resurrection. Twenty years in the bay, now bridging distributor caps and inverter-driven motors. Sparks, Nevada.

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+ Electric traction battery inside a vehicle engine bay, harness and cooling lines visible. +
Fig. 01 — Traction battery in place. Handle it like it has a loaded gun inside; because it does — 300+ volts that don't flinch.
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Field notes from the bay, published as I do the work. The diagnostic discipline that keeps a 1973 small-block idling also keeps a 2022 hybrid inverter honest — and the saftey habits that keep you alive on high-voltage systems are the same ones that stopped you shorting a coil years ago. Everything here is grounded in what I've actually tested or torn down.

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On the Bench — Current Field Guides

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Reading Battery State-of-Health

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How I actually judge a hybrid pack without trusting the dashboard: module voltage spread, internal-resistance rise, capacity fade curves — and the equipment that does the judging.

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Open field guide →

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Reference: Li-ion pack teardown + BMS scan data
Format: interactive chart + procedure tables

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Hybrid Diagnostic Tool

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Step-by-step power/ground/signal tree for common hybrid fault codes. Built for the tech who reads codes before knowing if the part is even fed.

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Use the tree →

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Format: decision-tree worksheet

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In the Other Bay — Vintage Small Blocks

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1973 Small-Block Resurrection

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Scrape, sand, listen. Reading the grain of forty years of carbon and seats before reaching for the reamer — same discipline as reading a DTC.

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Read the teardown log →

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Next: cylinder head valve job

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Shop Principles

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+ "Verify power. Verify ground. Then trace the signal path." + — The rule that scales from a dead 1964 points ignition to a hybrid inverter that won't latch. Half the time what's 'dead' was never fed in the first place. +
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⚠ High-Voltage Safety — Non-Negotiable

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  • Class-0 insulated gloves, rated and re-tested, before touching any orange connector.
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  • Disconnect and WAIT — inverter capacitors hold lethal charge for minutes after cutoff.
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  • HV isolation test with a megohmmeter, not a continuity beep.
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  • One hand in pocket near the pack. Always.
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Films

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Diagnostic Logic: Combustion to Electric

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A short on the method that crosses the whole shop: verify power, verify ground, trace signal — from points to PMSM.

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Watch on 4ort.mov →

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Reference & Data

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The numbers I work from — live facts pulled into this page on every rebuild, plus machine-readable twins of my tools.

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SOUCE: item:Q2822895 · Lithium-ion battery — rechargeable battery · Wikidata source →
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\ No newline at end of file diff --git a/soh.html b/soh.html new file mode 100644 index 0000000..538c093 --- /dev/null +++ b/soh.html @@ -0,0 +1,178 @@ + + + + + +Reading Battery State-of-Health — Field Guide + + + + + + + + +
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FIELD GUIDE · v2
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Reading Battery State-of-Health

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How I judge a hybrid pack without trusting the dashboard. Module voltage spread, internal-resistance rise, capacity fade — and the equipment that does the judging.

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← Adam Pollard · Shop

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The dashboard tells you "battery health is good" and gives you a bar chart nobody reads. That's a marketing screen, not a diagnosis. To judge a pack you need three numbers from a live BMS scan or a bench test: module voltage spread, internal-resistance rise, and capacity fade against rated. This guide is the way I actually run that read, and the thresholds where I start writing "replace module" instead of "drive another year."

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Why SOH, and Why Not the Dashboard

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State-of-health (SOH) is the catch-all term for how much usable life a pack has left versus its rated new condition. It's not one thing. Aging shows up as: lithium inventory lost to solid-electrolyte interphase growth (capacity fade), impedance climbing as conductive paths degrade (IR rise), and cells drifting apart from each other (imbalance). All three march together, but they don't mark time equally. A pack can lose 12% capacity and still read "good health" on the dash because it's balanced enough to deliver its now-shorter range. The dash graphs range, not degradation.

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HV safety — read before you sweep a pack

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  • Class-0 insulated gloves, rated and re-tested, before any orange connector.
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  • Disconnect and WAIT — capacitors hold lethal charge minutes after cutoff.
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  • Isolation test with a megohmmeter, not a continuity beep.
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  • One hand in pocket near the pack. Always.
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The Three Numbers That Matter

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MetricWhat it catchesHealthyI get suspiciousI write it up
Module voltage spreadCell imbalance / weak cells< 10 mV between modules at rest25–50 mV spread> 50 mV sustained
Internal resistance riseImpedance / degradation< +10% over rated+20–40%> +40% on any module
Capacity fadeUsable energy loss> 90% of rated80–90%< 80% (or per fleet policy)
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Those are my working bands for a typical NiMH/Li-ion hybrid traction pack. Fleet policy and the vehicle's Warranty SOH threshold override them; a taxi that's down to 82% gets pulled a lot sooner than a weekend car at 78%. The shape of the fault matters as much as the number.

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+ IR rise (module): ΔR% = (R_test − R_rated) / R_rated × 100
+ Capacity fade: C_fade% = C_measured / C_rated × 100
+ Voltage spread: V_max − V_min across all modules at 20% SOC rest. +
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The Procedure, In Order

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  1. Park at known SOC. I bring the pack to ~20% SOC and let it rest minimum one hour — voltages settle; a fresh-off-charge read lies.
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  2. Full module voltage sweep. Via the BMS scan tool or service port. Log every module, not just the pack average. I want the spread, not the mean.
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  3. IR test. Megohmmeter for isolation on the pack side. For per-module impedance I use the BMS's own cell-balancing current pulses — every module reports voltage under a known load, and I take the delta.
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  4. Capacity check. Controlled discharge at the nominal C-rate, logging amp-hours out. This is the slow one — it's a full discharge cycle, not a 10-minute tap.
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  5. Read the pattern, not the bar. One module 40 mV high with matching IR rise = single weak cell, replace that module. Uniform IR creep across all = whole pack age, plan for pack, not module.
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Patterns I read in the scan

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  • One high IR module — that cell's the weak link; the pack is fine, swap the module.
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  • Uniform IR rise + uniform fade — the pack is aging as a unit; schedule replacement.
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  • Spike on one cell at low SOC — classic lithium plating / dendrite risk. That module comes out NOW, not at the next service.
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  • Spread that tightens under load, widens at rest — a wiring/connector resistance, not a cell fault. Look before you condemn a battery.
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Pack Simulator — You Drive the Read

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Drag the three sliders and watch what I'd say about the hypothetical pack. This is the same arithmetic the BMS uses under the hood, rendered as a verdict instead of a bar.

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—
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Grounding: pack reads and thresholds above are from my field work on hybrid traction packs; chemistry baseline on the working anode/cathode assumptions cites lithium-ion battery (Wikidata). Slider verdicts follow the threshold bands in the table; a real diagnosis needs the full procedure, not the simulator.

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+ + + + \ No newline at end of file diff --git a/soh.json b/soh.json new file mode 100644 index 0000000..4dbae45 --- /dev/null +++ b/soh.json @@ -0,0 +1,36 @@ +{ + "title": "Reading Battery State-of-Health — Field Guide", + "author": "Adam Pollard", + "author_id": "adam-pollard", + "seo": "adam-pollard", + "url": "/soh.html", + "description": "How an ASE tech judges a hybrid pack without trusting the dashboard: module voltage spread, internal-resistance rise, capacity fade.", + "domain": "hybrid_traction_pack_diagnostics", + "method": "verify power, verify ground, then trace signal path", + "metrics": { + "module_voltage_spread": { "unit": "mV", "healthy_max": 10, "watch_min": 25, "watch_max": 50, "fail_min": 50, "note": "spread at rest, ~20% SOC" }, + "internal_resistance_rise": { "unit": "percent", "healthy_max": 10, "watch_min": 20, "watch_max": 40, "fail_min": 40, "note": "accept across full pack; per-module above band writes up" }, + "capacity_fade": { "unit": "percent_of_rated", "healthy_min": 90, "watch_min": 80, "fail_max": 80, "note": "fleet policy and warranty SOH threshold override" } + }, + "patent_fault_patterns": [ + "single_high_ir_module -> replace module", + "uniform_ir_rise_and_fade -> schedule pack replacement", + "cell_spike_at_low_soc -> lithium plating risk, remove now", + "spread_tightens_under_load -> connector/contact resistance, not cell" + ], + "schedule": { + "capacity_check": "full discharge at nominal C-rate, amp-hours out; slow test", + "rest_period": "minimum 1 hour at ~20% SOC before reading" + }, + "grounding": { + "chemistry_baseline": "https://www.wikidata.org/wiki/Q2822895", + "note": "thresholds are field-work bands, not manufacturer spec" + }, + "safety": [ + "class-0 insulated gloves before any orange connector", + "disconnect and wait for capacitor discharge", + "megohmmeter isolation test, not continuity beep", + "one hand in pocket near pack" + ], + "related": [ { "title": "Shop index", "url": "/index.html" }, { "title": "Hybrid diagnostic tree", "url": "/tool.html" } ] +} \ No newline at end of file